Fiat G.50 Freccia

Italy, WW2, , ,

Kingdom of Italy flag Kingdom of Italy (1935)
Fighter Plane – 774 to 791  Built

Freccia in Italian service. Colorization by Michael Jucan [monochrome-watches.com]
During the thirties, Fiat Aviazione was one of the most advanced aircraft manufacturers in Europe. With the advent of new technology at the time, it was obvious that the next stage in the development of the aircraft industry, especially in military aviation, would be centered around all-metal monoplanes. Fiat’s Chief Designer, Ing. C. Rosatelli, had been designing mixed-construction biplanes and even an all-metal bomber. As the demand for a modern, all-metal fighter plane was high, Fiat officials made a decision to hire a young aircraft engineer named Giuseppe Gabrielli, who would later design the Freccia, the first operational Italian all-metal fighter.

Giuseppe Gabrielli’s Work

The history of the Fiat G.50 began in 1931, when Fiat formed a new Aircraft Technical Bureau – Department 2 (Ufficio Tecnico Aviazione – Divisione II). The main purpose of this bureau was designing and building brand new types of modern all-metal planes. The same year, a young Italian engineer, Giuseppe Gabrielli, was hired by Fiat Chairman Senator Angelli to work for the Technical Bureau. Giuseppe Gabrielli had gained some experience in aircraft design while working for Piaggio. When he moved to Fiat, he immediately began working on several non-military aircraft projects. All of his projects were marked by the capital letter ‘G’, his initial. First was the G.2, an all-metal, three-engined plane, then the G.8 biplane trainer, and later the twin-engine passenger plane G.18.

During the thirties, the Italian Ministry of Aviation (Ministero dell Aeronautica) was interested in adopting a new, all-metal monoplane fighter and ground attack aircraft for the Italian Air Force. Some specifications for their request were: to use one radial engine, armed with at least two 0.5 in (12.7 mm) heavy machine guns with at least 300 rounds of ammunition and one 0.7 in (20 mm) gun or 1.45 in (37 mm) gun, and provisions for bombs on the ground attacker. A request was sent out to all domestic aircraft manufacturers. There were several proposals in response, but only the G.50 and the Macchi C.200 would be chosen for production. The others were either rejected (Ro.51 and A.U.T. 18) or built in limited numbers, like the Caproni F.5.

In order to solve the problem of the lack of an adequate fighter design, Fiat officials even considered the acquisition of a license to produce the American Seversky SEV-3, but nothing came of this. In April of 1935, Giuseppe Gabrielli began working on a new low-wing, all-metal plane named G.50. According to his first plans and drawings, it was to be armed with two machine guns, powered by a 550 hp radial engine (with a diameter of 39 in/1 m), weigh around 3,395 lbs (1,540 kg), and equipped with a retractable landing gear. At the same time, Fiat was testing a new FIAT A 74 RC 38 14-cylinder radial piston engine, so it was logical that Giuseppe Gabrielli decided to use it for his work. The A 74, in principle, was a direct copy of the American Pratt & Whitney R-1830 Twin Wasp which powered a large number of US planes, including the Douglas C-47, Consolidated PBY Catalina, Douglas TBD Devastator and Grumman F4F Wildcat. The expected speed of the G.50 with this new engine was around 285 mph (460 km/h) at 11,500 ft (3,500 m).

G.50 prototype (MM.334) during its first test flights. [airwar.ru]
On 28th September, 1935, Gabrielli submitted his project to the Ministry of Aviation. Military officials were impressed by the design, but ask for some modifications. These included a wingspan of 36 ft 1 in (11 m), a weight of 4,870 lbs (2,210 kg) and a maximum speed of 280 mph (452 km/h). The offensive armament was changed to two 0.5 in (12.7 mm) heavy machine guns located in the fuselage with an additional two 0.3 in (7.7 mm) machine guns placed in the wings. In addition, the G.50 was designed to carrying a bomb load of 220 lbs (100 kg) or, if needed, extra fuel tanks with 23.5 gal (90 l) capacity.

In January 1936, the Ministry of Aviation changed its original request, choosing instead to focus only on the fighter role. The Ministry of Aviation wanted to accelerate the development of the new fighter, and the proposed ground attack role was rejected. Because of this, the bomb load was deemed no longer necessary, and the main armament was reduced to only two 0.5 in (12.7 mm) machine guns with 150 rounds each. The most important requirement was that the new fighter should have the best possible flying performance.

Despite these changes, the Fiat officials decided to proceed with the G.50 project. As Fiat’s production capacities were overburdened, work on this new project was instead moved to the CMASA works at Marina di Pisa, part of Fiat since 1931. Giuseppe Gabrielli was finishing his last drawings and the list of needed materials and equipment in June 1936. In his final drawings, the armament was reduced to two heavy machine guns without the bomb load, and the plane would be powered by the new A 74 c/n engine.

The production of the first operational prototype was scheduled to begin in late summer of 1936. The prototype was finally ready at the beginning of 1937 and was transported to the city of Turin for further testing. This prototype, under registration number MM 334, made its first test flight on 26th February, 1937. The pilot was Giovanniego De Briganti, the CMASA test pilot. During initial testing, the pilot noted several faults and possible problems with the G.50. He especially pointed out the strong vibrations during flight and the aircraft’s tendency to spin.

On 22nd June, 1937, the G.50 prototype was moved to Marina di Pisa for more testing and modifications. After these modifications were completed, the prototype was sent to the Regia Aeronautica (Italian Air Force) experimental flight center near Rome. There, the G.50 prototype was tested by several army pilots. They noted that the controls were hard to work with at high speeds and a lack of climbing ability. Before the final order for mass production, Giuseppe Gabrielli was asked to solve these problems. For this reason, another prototype was made, designated MM 335.

The second prototype made its first flight on 20th October, 1937. After a series of successful flying tests, an accident occurred. On the 11th (or 8th, depending on the source) November, 1937, while flying the second prototype at high speed, the test pilot Briganti lost control of his aircraft and crashed to the ground. He did not survive the crash. His place was taken by the new chief test pilot, Enzio Guerra.

A G.50 from the 20th Group, front-side view. [wwiivehicles.com]
A combination of the accident and inferior performance that did not meet expectations, along with better overall performance of the Macchi C.200 threatened to shut down the G.50 project. But as the CMASA works were already in process of producing a series of 45 G.50’s, it was deemed a waste of resources to abandon or scrap the tooling equipment needed to produced the G.50 that had already been produced. A second reason for keeping the project running was the fact that it would take too much time for Fiat to prepare for the production of the Macchi C.200. The Air Ministry decided to go on with G.50 production, but insisted that the company correct the shortcomings of the plane by the time of production. Of the 45 ordered, the first 11 were used for many more trials. Two planes, MM 3357 and 335, the salvaged and rebuilt prototype, were sent to the experimental centre in Rome. Seven were stationed at the Pisa S.Giusto airfield and tested there. Two more ,MM 3570 and 3571, were tested by pilots Guerra, Rolandi and Cus. These trials were held in Turin and the main purpose was to investigate possible changes to the design of the G.50. The preliminary tests showed that the fully enclosed cockpit had to be changed before production, and a new design was necessary. This enclosed cockpit had several drawbacks which pilots often complained about. The closed cockpit was hard to open (especially in emergency situations), was made of poor quality plexiglass which was prone to cracking, offered poor visibility and sometimes exhaust fumes accumulated in the cockpit so the pilots were forced to fly with an open cockpit. After some testing and modifications, it was decided to used a partially enclosed cockpit. This solution was not perfect and was uncomfortable for pilots. Despite this, it was decided that all future planes would be built with an open cockpit only. More modification that were deemed necessary were the installation of a new start-up system, a better undercarriage locking system and adding a new oxygen mask for piloting at high altitude.

The G.50 was first showed to the public in October of 1937 at the International Aeronautical Show held in Milan. From 1937 to 1940, when the production was changed to the improved version, some 224 G.50 were built.

Technical Characteristics

A G.50 flying alongside a German Bf-110, possibly during the Battle of Britain [Wiki]
The G.50 Freccia, Italian for Arrow, was a single-seat, low-wing, all-metal fighter plane. The main fuselage was made from four angular shaped longerons with 17 metal frames. The wing construction consisted of a center section which was made of a steel tube connected to the lower fuselage and two metal spars connected with ribs. The four flaps were hydraulically actuated and at certain speeds they would automatically retract to their closed position. The fuselage, wing, and tail were covered with duralumin sheets. The only fabric-covered parts were the movable control surfaces in the wings and the tail.

This G.50 belonged to the 20th Group, transferred from Belgium to North Africa. [ea51.org]
The engine was placed in a tubular shaped mount made of chrome-molybdenum steel that was connected to the fuselage by four bolts. The engine and the cockpit were separated by a fireproof screen in order to protect the pilot from any possible fire outbreak, either due to engine malfunction or damage. The plane was powered by the 840 hp (626 kW) Fiat A 74 RC 38, 14 cylinder radial piston engine. With this engine, the G.50 could reach a maximum speed of 293 mph (470 km/h), with an effective range of 276 mi (445 km) and a service ceiling of 35,000 ft (10,700 m). An all-metal three-blade propeller produced by Fiat was used. One of major disadvantages of using a radial type of engine was the massive drag due to its large cross-section. In order for ground repair crews to have easy access to the engine and the fuselage interior, several access doors were added. The maximum fuel capacity was 83.5 gal (316 l.) There were two fuel tanks located in the wings 11.9 gal each (45 l) and two more in the fuselage, one larger with 26.4 gal (100 l) and a smaller one with 18 gal (68 l) with an additional auxiliary tank 13.75 gal (52 l) also located in the fuselage.

The first G.50 series had an enclosed cockpit design but as this created many issues, it was later changed to an open cockpit. Despite its disadvantages, the enclosed cockpit had an excellent rear view. Many different open cockpit designs were tested before the final design was chosen. The later version with the open cockpit had two smalls door installed to help entering or exiting the plane. The seat was adjustable, so it could be adapted to the pilot’s needs.

In front of the pilot, the dashboard was divided into three sections. On the upper section were the navigation instruments, reflector sight, fuel indicators and engine instruments. The middle section had the ammunition counter, warning lights, the position of the landing gear, compass and oxygen control panel. The lower section had the engine starter, cowling controls and compressed-air system indicator. The radio in the pilot’s cabin was the ARC 1, but the quality of the batteries was poor. A fire extinguisher system was also provided. There was also the possibility of installing one OMI FM62 camera gun.

The G.50 was equipped, like most modern aircraft of the time, with inward retracting landing gear, but the rear tail wheel was fixed. In the G.50 bis version, the rear tail wheel was changed to a retractable type. The landing gear could, if necessary, be manually operated. At first, it was of a Messier type, but it was later replaced with a Magnaghi design. The retracting landing gear was hydraulically operated, and pneumatically during lowering. In case both systems did not work for any reason, it could be manually operated. For easier and more pleasant landing, hydraulic shock absorbers were provided for both telescoping legs.

The main armament consisted of two forward-firing 0.5 in (12.7mm) Breda-SAFAT heavy machine guns, with some 150 rounds of ammunition for each machine gun. The guns were placed behind the engine top and both were synchronised in order not to damage the propeller. It is interesting to note that this gun used oil lubricant for faster firing and thus a lubricant tank was added on top of the engine. Some G.50 planes were armed with bomb racks and used in North Africa.

An Italian armourer rearming a Regia Aeronautica Fiat G.50 with ammunition gun belts at an airfield in Sardinia in June 1942. Source: reddit.com

Modifications and Prototypes

As the war progressed, the Italians realized that they were lacking planes to fulfill the different necessary roles such as fast ground attack or training. In order to save time, the most obvious solution was to try to modify existing models instead of developing new ones. The G.50 would be modified in several ways, some of which demanded major changes to the plane’s design, while others were just minor variations, like the added sand filter for the G.50 S.A.

Trainer G.50 B

The Fiat G.50 B version with the longer cockpit design for the instructor and the student. [alieuomini.it]
As the G.50 was entering production and the first operational units were formed, a trainer was needed for new pilots. As most army pilots were accustomed to flying older biplanes, retraining them for flying the monoplanes was required. For this purpose, in late 1936 the Italian Air Ministry placed an order for Fiat to developed a two seat dual control plane based on the G.50. After the mock-up was built and inspected in March 1938, it was deemed sufficient for production. By April, an order for the first prototype was placed. But due to the constant changes to the design, the production of the first prototype was frequently delayed. It was not until June 1939 when the final design with an enclosed cockpit was chosen. The plane was named G.50 B. The capital ‘B’ stands for ‘bipost,’ the Italian word for two-seater. This version was recognizable by its long glazed canopy with the rear cockpit being open from the top. The first prototype, marked 3615, would be ready in late April 1940 when it was tested by Enzio Guerra.

After only a few test flights, it was deemed adequate and was put into production. The first ten were built in 1940, with the last one built in 1943. In total, some 108 (or 100, depending on the source) G.50 B trainers were built during the war. Production by years was: 10 in 1940, 82 in 1941, 11 in 1942 and 5 in 1943.

The first series of G.50 planes produced had an enclosed cockpit design, but this was later replaced with a semi-open design. [warbirdphotographs]
The G.50 B was, in essence, a modified single-seat version with a new cockpit and dual controls. The front part of the cockpit was fully enclosed in contrast with the rear which was open. The main armament was removed on the G.50 B. This version was very successful, as it was easy to build and offered almost the same flying performance as the single-seat version.

These were used mostly by the Regia Aeronautica Fighter Schools. Smaller numbers were operated as liaison planes or even in some front based fighter units. After the Italian capitulation, small numbers, possible 20 or more, were used by the National Republican Air Force. At least one was given to the Croatian puppet state in the Balkans. The last G.50 B were used by the Flying School in Lecce for a few years after the war, up to 1948.

The Improved G.50 bis

The final decision for the mass production of the G.50 fighter was not based on its performance, but instead on the fact that CMASA had already begun producing it. The performance of the G.50 was poor compared to the Macchi C.200. In order to justify the production, the Italian Air Force requested that Fiat to improve the G.50’s overall performance. The sought modifications were adding extra fuel tanks, increasing capacity from 83.5 gal (316 l) to around 108.3 gal (410 l), redesigning the rear fuselage and the vertical tail surfaces, better glazing of the cockpit to protect the pilot from air turbulence, the addition of armor plates behind the pilot seat, and the tailwheel to be made retractable. The original ARC 1 radio, with its poor quality batteries, was only changed in October 1941 with the R.B.30.

The new improved version was designated the G.50 bis. According to Italian original plans, the first planes should have been ready by late 1938, but this was never achieved. The whole process was slow and the first aircraft was tested on 13th (or 9th) of September 1940 at Turin. As the main engine was not changed, despite the other modifications, the general flying performance was almost the same. The only improvements were easier maintenance and increased operational range. As these tests were completed, an order for production was given. From 1940 to 1943, around 439 of these versions were built by CMASA and Fiat.

G.50 S.A Ground Attacker

A G.50 somewhere in Africa, where it saw extensive combat action, in many cases as a improvised ground attack plane. [asisbiz]
A certain number of planes that were serving in North Africa were modified by adding sand filters and a bomb rack. The landing gear was also modified for easier landing.

G.50 A Ground Attacker

The G.50 A was designed to be used as a fighter-bomber on the “Aquila” aircraft-carrier which was under construction. For this modification, the G.50 B two seater version was reused. The main offensive armament was to be increased to four 0.5 in (12.7 mm) machine guns. The problem was that the wing design did not allow the installation of the new weapons directly in the wings. The solution was to increase a part of the central section of the wings in order to accommodate these guns. Additional bomb racks were also to be added. One prototype, serial number MM 8595, was built and tested in October 1942. The whole concept proved to be problematic and the project was abandoned. The prototype would be used up to 1943 in testing new wing designs. In some sources, this model is designated as G.50 A/N.

G.50 bis “Tuffo” Dive Bomber

This was a dive bomber version designed in 1941 and 42, possibly inspired by the famous German Ju-87 “Stuka.” A bomb load of up to 990 lbs (450 kg) was planned, with two 200 lbs (100 kg) bombs placed under the wings and one 550 lbs (250 kg) under the main fuselage. For this modification, the addition of dive brakes were necessary. There is no information about prototype construction, but there is a great chance that it was never made.

G.50 B Naval Observer

One plane (MM 6548) was rebuilt for a naval observation role in 1943. It had a larger tail, different wing sections, a camera and an arrestor hook for use on an aircraft carrier. It was also equipped with a B 30T transmitter, B.G.42 direction finder and a A.R.18 receiver. Only one was built, possibly because of the impending Italian capitulation.

G.50 O/R

This version was based on the G.50 bis and the only difference was the installation of a arrestor hook for aircraft carrier use. Around 16 planes were modified for this role and were in use by the 155th Group Autonomo, mostly for training, in 1943.

Other Projects

Beside these, there were some minor projects that were proposed, but the majority if not all of them were not implemented. On the base of the G.50 B some project were proposed like the: night fighter, land reconnaissance or even a floatplane fighter (G.50 Idro).

Prototypes based on the G.50

During the war, in order to improve the flying performance of the G.50, many new designs and weapon loads and engines were tested.

G.50 ter

This was a further development of the canceled G.52 project. The new project, designated the ‘G.50 ter,’ was to be equipped with the same 1000 hp (746 kW) Fiat A 76 engine as the G.52. Even before production of a prototype, the new engine was found to have a number of flaws. The first prototype powered by the new engine was ready by late July 1941. First flying tests were carried out at the Aeritalia airfield, with the plane being piloted by Agostini. During these flight tests, the engine proved to be mechanically unreliable and it could not reach expected performance. More test were held in November 1941, but in the end the project was canceled and only one plane was built.

G.50 V

The G.50 V prototype, powered by a new German engine. Even though this design solved the aerodynamic problems, it was never put into production. [Pinterest]
In late 1939, the Italian Ministry of Aviation made a decision to begin negotiations with the German Daimler-Benz company for a production license of the newest liquid cooled DB 601A engine (1035 hp). It had a much lower frontal area and had much better aerodynamics than the larger Italian radial engines. The license was eventually obtained and Alfa Romeo was put in charge of the production of this engine, but it was never built in any great numbers.

In early 1940, the Italian Ministry of Aviation asked Fiat to build a modified version of the G.50 using this new engine. Two prototypes were to be built by CMASA, and these were marked as G.50 V (the ‘V’ stand for Veloce, which means fast). The first prototype, serial number MM 479, was built and tested in late August 1941 by the test pilot Ezio Guerra. Immediately, the new design proved to have some issues, such as an inefficient engine cooling system and the controls being difficult to operate. By the end of 1941, most these problems were solved and a new series of tests was scheduled.

In December 1941, more extensive flight tests were carried out by test pilot Valentino Cus in order to determine the precise flight performance, in particular the maximum speeds at various heights and the climbing rate. Maximum speed achieved was some 360 mph (580 km/h), and a maximum altitude of 16,400 ft (5,000 m) was reached in 5 minutes and 30 seconds. Mostly due to the introduction of the new FIAT G.55 and the lack of DB 601 engines, the G.50 V project abandoned.

G.51

In 1940, it was proposed to equip one G.50 with the new A 75 R engine. Nothing came of this project.

G.52

Information about this version differs significantly depending on the source.

According to Piero Vergnano, Fiat worked on improving the performance of the A 74 engine used on the G.50 for quite some time. This lead to the development of the new 1000 hp (746 kW) Fiat A 76 engine. In 1938, Fiat suggested the installation of this engine in the G.50 to the Air Ministry. At first, the request was accepted and an order for two prototypes was placed. By late 1939, the project was canceled due to the acquisition of new German DB 601A engines, and no prototypes were ever built. According to Gianni Cattaneo, the G.52 was in fact just a further development of the G.50 V. Due to the appearance of the new G.55 fighter, this project was abandoned.

G.53

This proposal was a combination of the G.50 B powered by the DB 601A engine. It was developed in 1941. It was intended to be used as a fast reconnaissance plane, but the Air Ministry never showed any interest in this proposal and nothing came of it.

First Operational Units

As CMASA began producing the first G.50 planes in late 1938, an experimental military fighter unit was formed for further testing and training. This unit was located at the Ciampino airfield near Rome. The unit was named Gruppo Sperimentale da Caccia (Experimental Fighter Unit/Group). Command of this new unit was given to Major Mario Bonzano, at that time a famous pilot ace from the Spanish Civil War (flying the CR.32 biplane). Pilot training on this new plane lasted until January 1939, when the Italian Air Force High Command decided to send a unit of 12 planes to Spain for real combat testing.

In Spain

A group of 12 new G.50 fighters arrived in January 1939 in Spain, having been transported by sea. This unit was based at Escalona Airport, some 43.5 mi (70 km) from the capital of Madrid. Starting in March, this unit carried out flight patrols and fighter cover missions for bombers at altitudes between 24,600 to 26,240 ft (7,500 to 8,000 m). By that time, the opposing air force had been almost destroyed and air to air combat was rare. The only combat action that was recorded happened when a lone Soviet-built I-16, possibly flown by a Canadian pilot by the name of Dickinson, was intercepted by a G.50. The Italian aircraft was damaged and the pilot was forced to land. None of the 12 G.50 that were sent were lost in combat during the Spanish Civil War. At the end of this war, 11 operational G.50 fighters were given to the new Spanish fascist regime. These planes were used by the 27 Gruppo Caza (Fighter Group). After 1943, they were sent to Spanish Morocco, to be used by the 2. Regimento Mixto (mixed regiment) together with several German supplied He-112B.

A small number of G.50 fighters were used in the Spanish Civil War. Their combat operations were minimal and all were gifted to the new Spanish state. [Wiki]
After his return to Italy, Major Bonzano made his report of the effectiveness of the G.50. According to him, the G.50 had good maneuverability, effective armament and was easy to operate at altitude. On the other hand, he pointed out that the visibility was poor and the landing gear construction was weak and prone to malfunctioning. His conclusion about the effectiveness of the main armament would prove to have a great negative impact for the G.50 in the future.

In Finnish Service

Finnish G.50 on the airfield. [ww2aircraft.net]
Because of the likelihood of a Soviet attack in 1939, the Finnish government and Army wanted to equip their forces with modern equipment and weapons. As a result, a Finnish military delegation visited Turin in 1939, where the new G.50 fighters were being tested. The delegation was impressed with the aircraft’s performance, so they placed an order for 35 brand new G.50. Most of the planes sold were of the first series produced by CMASA, with serial numbers 3599 to 3614. These were supplemented by planes from the second productions series (serial numbers 4722 to 4750).

A very interesting fact is the maximum speed achieved by Finnish pilot Tapani Harmaja. As he was testing the flying performance of the G.50 at an airfield near Latina, he managed to reach a speed of 515 mph (830 km/h). He achieved this by diving from a high altitude of 11,480 ft (3,500 m) down to 1,310 ft (400 m). This was the fastest speed reached by any aircraft in Italy at that time.

Due to the outbreak of the Second World War in Europe, the transportation of the purchased aircraft was slow and complicated. The planes were disassembled and then transported by train through Italy to the north of Germany and then by ship to Sweden, and from there to Finland. As they were transported in parts, the assembly was done at Gothenburg. When they were completed, the pilots were instructed to fly them to their new stations. The first 14 G.50’s were received in February 1940 and the last in June 1940. While flying en route to their designated airfields, two planes were lost in accidents in February 1940.

The G.50 arrived too late to have any large impact on the Winter War (30 Nov. 1939 to 13 Mar. 1940) but they saw some combat during this period. The first G.50 planes were equipped with the 26th Fighter Wing (Lentolaivue 26 or just simply LeLv or HLeLv) located at Haukkajarvi. They were used to replace the older Gloster Gladiators used by this unit. By 13 March, the Finnish pilots flying the G.50 claimed to have shot down 11 Soviet planes. There is some disagreement between the sources, authors Gianni C. and David M. states that this unit did not participate in the Winter War.

Finland operated 35 G.50s during the war. Most saw extensive service during the Continuation War when, despite their obsolescence, they proved to be effective in the hands of Finnish pilots. [Wiki]
Until the German and Finnish attack on the Soviet Union in June 1941, known in Finland as The Continuation War, Finnish technicians and engineers tried to improve the performance of the G.50 fighters. Most Finnish G.50s were from the first series, equipped with the enclosed cockpit. This design was not popular with the Finnish pilots and was replaced with an open cockpit. The vertical stabilizer and rudders were replaced with improved ones. Also, the Finnish tested snow skis taken from Fokker D.XXI’s, for the G.50 allowing them to better land on on frozen airstrips.

At the start of the German invasion of the Soviet Union in 1941, Finland joined the war with a much larger air force than it had in the previous conflict. LeLv 26 was stationed at an airfield near Utti, and was charged with the protection of the area around Lake Ladoga where they saw most of the action they were involved in. The G.50 proved to be an effective fighter in the hands of Finnish pilots. On 25th June 1941, six Finnish G.50 fighters managed to shoot down 10 Soviet bombers with no losses. Later in August, pilots from LeLv 26 managed to shoot down nine Soviet fighters. The most famous Finnish pilot was Oiva Tuominen, who had a total of 23 (33 or 43 according to different sources) air victories, with around 15 while flying the G.50. For his service, he was awarded the Mannerheim Cross, the highest Finnish military medal at the time. By the war’s end, LeLv 26 had around 88 air victories with the loss of 11 G.50s. Only two were shot down by Soviet planes, one was lost to AA fire, and eight more were lost either to accidents or mechanical failures. The Finnish G.50s remained in use up to June 1944, when they were moved to the rear for second-line duties. By the end of the war, there were still some 22 (the exact numbers are not known) operational G.50 fighters and they were used up to 1947.

In Italian Service

Fiat G-50 “1-3” of the 1 Experimental Group in Escalona, in March 1939

According to the Italian military program codenamed “R” (Programme R), the Italian Air Force was to be heavily reinforced with many new units and more modern aircraft designs. With the existing G.50 fighter, it was planned to form and equip one Stormo (Stormo-regiment) and one Fighter Wing/Group (Gruppo).

The first unit to receive the new G.50s was 51° Stormo located at the Ciampino airport near Rome, in November 1939. This regiment consisted of the 20th Group, with 351st, 352nd and 353rd Squadrons, and the 21st Group, with 354th, 355th and 356th Squadrons. Almost all of the squadrons were equipped with the newer G.50 with the open cockpit, and only the 351st Squadron was equipped with the first series with the enclosed cockpits. To more effectively train both experienced and new pilots, military war game exercises were often held by the Italian Army. During one of these games the 51° Stormo would earn its military emblem, a black cat with a green mouse. During one exercises, a group of different fighter planes were tasked with intercepting a group of S.M.79 bombers, marked with the green mouse emblem. The older CR.32 biplane could not fulfill this task, but the new G.50 from the 352nd Squadron accomplished this without any problem. From that point on, the pilots from 51° Stormo began painting the emblem on their planes.

Quite soon, the order was given to form a second unit, 52° Stormo. It consisted of the 22nd Group (357th, 358th and 359th Squadrons) and the 24th Group (360th, 361st and 362nd Squadrons). The 24th Group was equipped with older FIAT CR.32 planes that were soon to be replaced with G.50’s. 52° Stormo operated from two airports, Pontendera and Sarzana. Both of these groups had around 100 brand new G.50s.

Western Front

By the time Italy entered the War in the West, there were some 118 G.50 planes on hand, with 97 operational, and some 21 were ready for delivery to designated units. In an attempt to profit from the fast Allied defeat in Western Europe, Italy declared war on France on the 10th of June 1940. Most G.50s saw some limited action, mostly covering SM.79 bombers during their attack on Corsica on 15th and 16th June. Subsequent attacks followed on 17th and 19th June. The center of operations then moved to the north, in the French Alps on 21st June. Due to a lack of proper training, the G.50 pilots had problems adapting to this type of aircraft, as most of them had flown only on the older biplanes. The G.50 proved to have good flying performance at low speeds, but was hard to control at high altitudes and higher speeds.

Battle for Britain

In order to support the German air raids on Great Britain, a special unit (Corpo Aereo Italiano C.A.I) was formed in late 1940 and was sent to Belgium. For this operation, the 20th Group, with 45-48 G.50’s, was selected under the command of Col. Bonzano. Despite the original planes being planned to reach their base of operations in Belgium by September 1940, this was delayed until October 1940. This delay occurred mostly due to bad weather. During the transfer from Italy to Belgium, two G.50’s were lost to accidents. The first combat actions were carried out in late October 1940, and were mostly bomber support missions. Similar missions were planned for 11th November against Great Yarmount, but they were canceled due to bad weather. From November 1940 to January 1941, the G.50 flew on many surveillance missions but there was no contact with enemy planes. By the end of January 1941, most Italian Air Force units returned home, with the exception of the 20th Group.

The C.A.I had great technical problems during this operation. The G.50 was designed for the Mediterranean rather than the cold climate of the North, and there were problems with freezing and defective instruments, unreliable batteries and fuel problems.

By April 1941, the remaining units were ordered to return to Italy. Missions conducted against Britain were unsuccessful and they did not go well for the Italian pilots, as they did not win any air victories. Italy had lost more than six aircraft with two dead pilots. This operation was a strategic failure for the Italian Air Force, mostly due to poor planning, adverse weather conditions and inefficiency of the planes used.

In the Balkans

Mussolini ordered an invasion of Greece in October 1940. For that purpose, fewer than 80 G.50 fighters based in Southern Italy (33) and occupied Albania (43) were used. Initially, because of the lack Greek air resistance, the G.50 were used as ground attack planes. But, after the arrival of the British forces in November, the first air battles started. Due to the fact that the Italian pilots had some experience during the Spanish Civil War, they managed to achieve some successes against the British. The G.50’s main opponent was the Gloster Gladiator, which had poorer flying performance in comparison. Later, however, more modern Hurricanes appeared, which were much more advanced than the G.50.

During the war in Greece, there were a number of engagements between the British and the Italian Air Forces. During one dogfight on 20th February 1941, some 10, possibly even 12, British planes were shot down in a single engagement by a group of 22 G.50s. The Italians only lost one plane. However, during the same day, British Hurricanes managed to shoot down four G.50s in a different engagement. On the 28th of February 1941, some 12 British planes were shot down at the loss of 27 Italian aircraft. In one unusual case, a collision took place between a G.50 and a Gladiator. Because of the heavy damage, the Gladiator crashed to the ground, while the pilot of the G.50, despite the damage received, managed to fly about 123 mi (200 km) back to his home base and safely land. Due to significant disagreements among sources, there is no accurate data on the losses of both sides. As the G.50 proved to be inferior to the Hurricane, they were gradually replaced with the more advanced Macchi C.200 planes.

During the attack on Yugoslavia, the so-called “April War” in April 1941, the G.50 were used in escort missions. There were very few air battles and, by 17th April, the war was over.

In the Mediterranean and North Africa

During the North African campaign, the first G.50s were stationed near Tripoli by the end of 1940 and early 1941. The first units to operate in Africa were the 151st, 152nd and 358th Squadrons with around 76 to 80 planes. Even before these units saw any action, there were great problems with the maintenance of these planes due to sand. Taking into account that North Africa is dominated by the Sahara desert, it is very strange that the Italian military leaders did not take into account the fact that the desert sand could affect the plane’s engine. Since a certain number of planes were taken out of action by this, the demand for special sand filters was high. There were also problems with the sand getting into the landing gear which caused issues. To solve these problems, the Air Ministry urged CMASA and Aeritalia to provide adequate sand filters and modify the landing gear. The G.50 planes modified in such a way were marked as G.50 A.S (A.S standing for Africa Sahariana).

The G.50 saw heavy fighting in North Africa. Depending on the combat situation, it was used in a standard fighter role, for ground attack, defence missions, or for bomber escort. As the war progressed, the G.50 was mostly used in a ground attack role by equipping them with a 220 lbs (100 kg) bomb load to increase its offensive armament. For this purpose, 50° Stormo was formed. 50° Stormo mostly operated around the Sidi Barrani sector, where it attained some success against the British P-40 and Hurricanes. The pilot Bovoli (from 50° Stormo) shot down six British Blenheim bombers in July 1941.

During 1941 and early 1942, despite reinforcements, G.50 losses were increasing. At the beginning of 1941 there were only 20 planes operational, but with reinforcements the number increased to 80 in October and then fell down to 35 in December 1941. Most planes were lost not in air combat but instead during enemy ground and air attacks on airfields, as well as accidents. For example, the 20th group suffered heavy losses when 18 G.50 were destroyed as British armored forces attacked the airfield at Martubi on 19th November 1941. By the end of 1941, the only unit operating the G.50 was the 12th Group stationed at Tripoli. By 1942, most G.50 fighters were either lost or replaced with more modern Macchi C.200 and C.202. The surviving G.50s were relocated to second line airfields in Sardinia (24th Group), Greece (151 Group) and in the Aegean (154th Group). By the time of the Axis defeat in Africa (1943), only the 358th Squadron was still using the G.50.

Despite having poorer flying performance than its main opponents, the P-40 and the Hurricane, the G.50 proved to be a formidable plane in the right hands. The G.50 also proved capable in its new role as a ground attack plane, in which it destroyed a large number of enemy planes on the ground.

The Last Stand

The 20th Group’s emblem, a black cat hunting green mice. [ea51.org]
After late 1942, the remaining G.50 fighters that were stationed in Italy serving as trainers and for second line operations. After the defeat in Northern Africa, the Italian army was in disarray and the rapid Allied landing in Sicily in July of 1943 worsened the situation. Many surviving G.50s were used to equip the 158th and 159th Groups. These two groups suffered heavy losses attacking strong Allied positions in Sicily. In a period of only a few days, the two groups ceased to exist.

After Sicily, the Allies landed on the Italian mainland and, on 8th September 1943, Italy capitulated. By that time, there were only around 40 to 48 G.50 airplanes still in service, of which only 17 were operational. A small number of G.50 were used by the new National Republican Air Force (Aeronautica Nazionale Repubblicana/ANR) in Northern Italy until the end of WW2 as second line and training planes. A few were even used by the Italian Co-Belligerent Air Force (Aviazione Cobelligerante Italiana, or ACI) in the southern part of Italy, which had switched over to the Allied side.

In NDH Service

In the middle of 1942, in exchange for raw resources and materials, Italy delivered 10 G.50 (9 single seat and one two-seat trainer) airplanes to the NDH, the independent state of Croatia Air Force (reg. number 3501-3510). These were not newly produced planes, but instead G.50s that returned from the front and were repaired. The planes that were supplied were used alongside French-built MS.406 fighters supplied by the Germans. In 1944, six more airplanes were obtained from Italy, now under German control (reg. number 5686, 5965 and 06186, the rest are unknown) bringing the total number used to around 16 planes, possibly more as the exact numbers are not known. According to Tihomir T. and Darko Č. NDH forces acquired three G.50, after the withdrawal of Italian forces in 1943.

Their participation in the war was negligible and they saw little if any action. On 15th September 1944, only 7 were reported, with none fully operational for service. There were several cases of desertion among Croatian pilots while flying the G.50. On 2nd September 1944, pilot Andrija Arapović escaped to the island of Vis, under the control of the Yugoslav communist Partisans. A second pilot flying a G.50 fled to the Allies stationed in Italy.

Partisan forces put the captured G.50 to use during the war and it would remain in service up to 1946. An interesting fact about Andrija Arapović’s G.50 aircraft (reg. number 3505) is that it still exists today and can be seen in the Belgrade Military Aviation museum near the airport “Nikola Tesla” in Serbia. This is the only surviving example of a G.50 in the whole world, but it is in very bad condition and has been under restoration for years. By the end of the war, the Yugoslav Partisans had captured almost all of the surviving G.50s in Croatian service, but their use was limited due to a lack of spare parts.

G.50 production attempts in China

Italians were for some time trying to negotiate with Chinese authorities about opening an aviation production factory in China. After initial negotiations in June 1934, the Chinese signed a contract with the Aeronautico Italiano per la China (Aerocina). This company was owned by the Italian Government in conjunction with Caproni, Breda, Fiat and SIAI. According to this contract, the Italians were to build the SINAW (Sino-Italian National Aircraft Works) factory in Nanchang. With this agreement, the Italians were to provide tools and machines necessary for the factory to work. The head of the soon-to-be factory was the Italian Luigi Acampora and the Director was General Chu Lin. The production of the first operational aircraft was to begin from July 1937 on and all Italian personnel were to return to Italy after five years of cooperation.

The SINAW officially started production in November 1936 with six Savoia-Marchetti SM.81B bombers. Future plans included production of 30 Breda Ba.65s and 50 Fiat G.50s. The factory was slightly damaged during the Japanese bombing of Nanchang on the 20th October 1937. By November the Italian Government made a decision to discontinue any further cooperation and stopped all future deliveries of equipment and materials. This was done mostly due to Japanese military actions and the poor cooperation of the Chinese. By early December 1937, all Italian personnel returned home, and the deal with the Chinese was abandoned without a single G.50 being built.

Production and Variants

Besides the few prototype planes, a total of 791 (source Piero V.) G.50 and its variants were built during the war. Other authors give different numbers, according to Chris B. some 774 were produced and author Gianni C. quotes the figure of 778 planes. Author Duško N. give a figure of 788 planes.

The production of the G.50 fighter began in 1937 and ended in 1940, with a total 244 planes. The production totals by years were: two prototypes in 1937, 14 planes in 1938, 75 in 1939 and 153 in 1940. The improved G.50 bis was produced from 1940 to 1943 with a total of 439 planes built (421 according to some sources). 71 planes were built in 1940, some 253 in 1941, 113 in 1942 and the last 2 were built in 1943. If we compare these production numbers with other modern fighters of the time, the G.50 was built in relatively small numbers. The G.50 and its modifications and prototypes were produced by CMASA and Fiat during the war.

Conclusion

The Fiat G.50 was the first Italian all-metal fighter plane to enter operational service in significant numbers. In the early stages of the war, it proved to be an effective fighter, but as the war progressed, it became obvious that it was outdated in comparison with other modern fighters like the Hurricane. The G.50 was easy to control at lower speeds and had good maneuverability. The negative side was the lack of engine power and the overall design of the radial engine which affected the aerodynamics of the G.50. There were problems with cockpit visibility, but the most notorious issue was the lack of effective offensive armament, which consisted of only two heavy machine guns. Despite all this, with a good pilot the G.50 proved that it could be an effective fighter and it was responsible of downing of a significant number of Allied planes during the war.

  • G.50 prototype – Two prototypes built, the second was lost in an accident.
  • G.50 – Production aircraft.
  • G.50 bis – Improved version.
  • G.50 A.S – A number of G.50 planes that were used in North Africa were modified with sand filters and improved landing gear.
  • G.50 A – One plane was modified with an increased offensive armament of four 12.7 mm machine guns in October 1942. Only one was constructed and used up to 1943 for testing different wing designs.
  • G.50 B – Two-seat trainer version, around 100 to 108 built.
  • G.50 bis “Tuffo”– Dive bomber version, none built.
  • G.50 B naval observation – One G.50 was modified to be used by the Italian Navy in 1943.
  • G.50 O/R – Based on the G.50 bis, some 16 were built and used for training in 1943.

Prototypes:

  • G.50 ter – Equipped with a stronger 1000 hp (746 kW) FIAT A.76 engine, only one built.
  • G.51– In 1940, it was proposed to equip one G.50 with the new A 75 R.C.53 engine, none built.
  • G.52 – Proposed project, none built.
  • G.50 V– Equipped with a German Daimler-Benz DB 601 engine, one built.
  • G.53 – Proposed project based on the G.50 B and powered by the DB 601, none built.

Operators

  • Kingdom of Italy – Operated around 720 G.50 aircraft, starting from the Spanish Civil War until the Italian Armistice.
  • Croatia (NDH) – Used at least 16 G.50 aircraft during the war (supplied by the Italians and Germans).
  • Finland – Operated 35 G.50’s during the Winter War and the Continuation War.
  • Fascist Spain – Used some aircraft given to them by the Italians at the end of the Spanish Civil War and after.
  • SFR Yugoslavia – Captured some G.50 fighters from NDH during the war. Their use was very limited.
  • National Republican Air Force (Aeronautica Nazionale Repubblicana/ANR) – Operated a small number of G.50s, mostly as trainers.
  • Co-Belligerent Air Force (Aviazione Cobelligerante Italiana, or ACI) – Operated limited numbers.
  • Nazi Germany – A few were captured and saw limited use with the Luftwaffe.
  • China – There were plans to produce 50 G.50 aircraft in China but nothing came of this.
G.50 Freccia Specifications
Wingspan 35 ft 11 in / 10.9 m
Length 26 ft 3 in / 8 m
Height 10 ft 7 in / 3.28 m
Wing Area 196.5 ft² / 18.25 m²
Engine One 840 hp (626 kW) Fiat A.74 RC.38, 14 cylinder radial piston
Empty Weight 4,353 lbs / 1,975 kg
Maximum Takeoff Weight 5,324 lbs / 2,415 kg
Fuel Capacity 316 l
Maximum Speed 292 mph / 470 km/h
Range 267 mi / 445 km
Maximum Service Ceiling 35,100 ft (10,700 m)
Climb speed Climb to 19,700 ft (6,000 m) in 7 minutes and 30 seconds
Crew One pilot
Armament
  • Two 12.7 mm Breda-SAFAT heavy machine guns

Gallery

Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

Fiat G.50 Prototype
Fiat G.50 “1-1” belonging to Mario Bonzano in Spain
G.50 MM4743 in Finnish Service
G.50 bis in Croatian Service circa 1941
G.50 B MM6137 in Luftwaffe Service

A G.50 from the 351st squadron in flight somewhere in Italy in January of 1941. [alieuomini.it]
Freccia in Italian service [monochrome-watches.com]
Side view of two G.50s, probably in Africa. [warbirdphotographs]

The Germans managed to capture a small numbers of surviving G.50s, but their use was limited. [warbirdphotographs]
The NDH received around 16 G.50 (with one G.50 B) planes during the war, but their use was very limited. [Asisbiz]

Credits

Messerschmitt Me 163S Habicht

Weimar and Nazi Germany, WW2, , ,

Nazi flag Nazi Germany (1945)
Rocket Interceptor Trainer – 1 Built

A rear 3/4 view of the Soviet captured “White 94” Me 163S. Colorization by Michael Jucan [Yefim Gordon]
The Messerschmitt Me 163S (Schulflugzeug / Training Aircraft) Habicht (Hawk) was an unarmed two-seat training glider based off of the famous Messerschmitt Me 163 Komet. Originally designed for the purpose of training novice pilots for landing, the Habicht ultimately never saw active service with the Germans and only a single example was produced through the conversion of a serial Me 163B-1. With the sole example captured by the Russians after the war, the Habicht underwent extensive testing by the Soviet Air Force which helped them understand the flying characteristics of the Komet and prepared Soviet pilots for flying the powered Komets. The Habicht undoubtedly played a part in helping Soviet engineers understand the Komet and thus played a part in the future development of Soviet rocket aircraft.

History

A closeup view of the Me 163S showing the right wing. [Yefim Gordon]
The Messerschmitt Me 163 Komet was one of Nazi Germany’s most famous aircraft produced during the Second World War. Although bearing the title of the world’s first mass-produced rocket-powered interceptor, the Komet did have its fair share of flaws, such as the volatile and sometimes dangerous Walter HWK 109-509 rocket engine, which prevented it from becoming an effective weapon against the Allies.

As the Komet was designed to have a limited amount of fuel to engage Allied bombers, pilots were expected to glide the Komet back to friendly airfields once they disengaged from combat. With gliding landings as a potential problem for the less experienced pilots, one of the ideas proposed by Messerschmitt designers in 1944 was to introduce a dedicated trainer variant of the Komet which would have a student pilot accompanied by an instructor pilot. Designated as the Messerschmitt Me 163S (Schulflugzeug / Training Aircraft) Habicht, the trainer glider differed from the production model with the addition of an instructor’s cockpit behind the forward cockpit. This addition was accompanied by the removal of the Walter HWK 109-509 rocket engine and the Habicht would have to be towed by another aircraft in order to get airborne. Another interesting addition to the Habicht was a second liquid tank behind the instructor’s cockpit for counterbalancing. All the liquid tanks would be filled with water for weight simulation and ballast. A total of twelve examples were planned for production, but only one was produced due to wartime production constraints.

The sole example of the Habicht was built by converting an earlier Me 163B-1 production model. Due to the scarcity of information regarding the Me 163S, it is unknown exactly when the Habicht was produced and what sort of testing it may have undergone during German possession. However, it is known that the Soviet Union was able to capture the only example during the final stages of the World War II’s Eastern Front. The sole Habicht was sent to the Soviet Union along with three Me 163B Komets during the Summer of 1945 for thorough inspection and testing. In historian Yefim Gordon’s book “Soviet Rocket Fighters – Red Star Volume 30”, he claims that in addition to the three Komets, seven Habicht trainer models were also captured. This, however, remains quite dubious as there is no evidence that more than one Habicht existed, and all current photographic material, research materials, and books all suggest that only a single example was produced.

The Me 163S in simulated flight configuration aided by struts. [Yefim Gordon]
As the Soviets were particularly interested in rocket propulsion aircraft, the State Defence Committee issued a resolution which called for the thorough examination of the Walter 109-509 jet engine and the Me 163 Komet along with captured German documents on rocket propulsion. The three Me 163B Komets, of which only one was airworthy, and the Me 163S Habicht were sent to the Flight Research Institute (LII), the Valeriy P. Chkalov Soviet Air Force State Research Institute (GK NII VSS), and the Central Aerohydrodynamic Institute (TsAGI). The Habicht and Komets saw extensive testing in Soviet hands, undergoing several structural, static and wind tunnel tests. During the initial flight testing period, the Komet only flew as a glider as Soviet pilots and engineers were unsure of whether or not the Walter rocket engine was ready for use since bench tests were not completed. Securing the T-Stoff and C-Stoff propellants for the rocket engine was also a problem. In order to understand the handling characteristics of the Komet, the Habicht was flown numerous times at different altitudes, as was the unpowered Komet. A Tupolev Tu-2 bomber was responsible for towing the Habicht to these altitudes. Under Soviet ownership, the Habicht was given the nickname of “Карась” (Karas / Crucian Carp) due to the glider’s distinct silhouette. The test pilot responsible for flying the Habicht was Mark Lazarevich Gallaj. In general, the Habicht was considered relatively easy to handle by the Soviet test pilots. It is unknown how many test flights the Habicht underwent, but the aircraft certainly aided Soviet pilots in understanding the handling characteristics of the Komet. The Habicht’s service came to an end once the Soviet state trials of the Komet concluded. The sole example was scrapped sometime in 1946, along with seemingly all the other Komets.

If the Me 163S was able to be mass produced and flown with the Luftwaffe, the aircraft would have been a valuable tool to train German pilots. Landing the Komet was a problem for some pilots and in some cases resulted in fatalities but, with the use of the Habicht, the number of accidents would have certainly decreased.

Design

The Me 163S hung upside down in an unspecified TsAGI workshop for static testing. [Yefim Gordon]
The Messerschmitt Me 163S Habicht was a semi-monocoque aluminum based two-seat training glider developed off the standard tailless Messerschmitt Me 163B-1 Komet. The sole example was converted from a production Komet, which meant dramatic modifications had to be made to the aircraft. The Walther HWK 109-509 rocket engine was removed and in its place was a cockpit for an instructor. The fuel tanks in the airframe were all filled with water to simulate fuel weight while another water tank was added behind the instructor’s cockpit for ballast purposes. There was no armament fitted to the glider. There was a small transparent section between the student pilot’s cockpit and the instructor pilot’s cockpit, presumably for the purpose of communication. As there are no known German documents on the Habicht and Russian documents are scarce, not much is known on the other differences the Habicht may have had. Detailed specifications of the Habicht are unknown, but theoretically it should have been identical to the standard Me 163B-1 Komet except for possibly weight, air drag and center of gravity.

Operators

  • Nazi Germany – The intended operator and producer of the Me 163S Habicht.
  • Soviet Union – The main operator of the Me 163S Habicht. A single Habicht was captured and tested by the Soviets after the war. The Habicht was scrapped in 1946.

*Editor’s note: As noted above, the exact specifications of the Me 163S Habicht are unknown. However they are presumed to be similar to that of the Me 163B-1 Komet.

Gallery

Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

Me 163S Habicht “White 94” in Russian Service [Haryo Panji]
Me 163S Habicht in German Service [Haryo Panji]
 

 

Now known as the “White 94”, the Me 163S sits idly by. [Yefim Gordon]
A closeup view of the Me 163S showing the transparent section between the two cockpits. [Yefim Gordon]
The Me 163S in simulated flight configuration aided by struts. [Yefim Gordon]
A top down view of the “White 94” Me 163S. [Yefim Gordon]
A photo of the “White 94” Me 163S in flight being towed by a presumed Tupolev Tu-2. The pilot in the photo is likely Mark L. Gallaj. [Yefim Gordon]
The Me 163S inside TsAGI’s T-101 wind tunnel for testing. The struts support the Habicht and simulate its flight configuration. [Yefim Gordon]
An alternate closeup view of the Me 163S during static tests. [Yefim Gordon]

Yet another inverted static test, but this time the tail wheel strut and tire were removed from the Me 163S. [Yefim Gordon]

Sources

Akaflieg Berlin B9

Weimar and Nazi Germany, WW2,

Nazi flag Nazi Germany (1942)
Experimental Aircraft – 1 Prototype Built

Three-quarters view of the B9, note the large glazed cockpit. Colorized by Michael Jucan [airwar.ru]
The Akaflieg Berlin B9 was a German experimental twin engine aircraft designed with the pilot placed in the prone position.  It was designed to withstand extremely high g-forces. One prototype was built and tested by a glider production workshop in 1943 but it would not be adopted for mass production. The author would like to especially thank Carsten Karge from the Archiv Akaflieg Berlin for providing information on this generally unknown aircraft.

Why prone position?

During sharp up and down turns while flying an aircraft, strong g-forces appear that act on the pilot, potentially leading to loss of consciousness. Under normal flying conditions, the g-forces that appear are relatively harmless. The first effect of the g-force which the pilot notices is the difficulty of moving his body normally, as normal movements feel much heavier. Another effect of strong g-forces, which is much more dangerous, is the loss of oxygen flow to the brain. In some cases, the flow of oxygen and blood to the human brain can be greatly diminished, which can lead to the pilot losing consciousness momentarily. This effect lasts a short time, but it is enough for the pilot to lose control of the plane with a potentially fatal outcome.

While today, devices such as advanced anti-g suits help the pilot withstand strong g-forces, during the World War Two, other solutions had to be found. The Germans had noticed that, especially during sharp dive bombing actions, the pilots often lost consciousness. One way to tackle this was to put the pilot into a prone position, which in essence means to fly the plane while lying on the belly. In this position, the pilot has both his heart and his brain at the same level, which means that blood is no longer stopped from travelling to the brain during high-g maneuvers. Thus, this flying position allows the pilot to endure much greater g-forces than he would normally be able to if he would be in an ordinary sitting position. Other advantages of the prone position are the reduced aircraft size, smaller fuselage, less drag due to the smaller cockpit, and it would be easier for the pilot to operate the plane when conducting bomb sighting and ground attack, among other advantages.

During the war, the Germans would test several such aircraft designs, sush as the Henschel Hs 132 or B9, mostly for the ground attack role. Beside a few prototypes built, none were ever used operationally.

History

The SF 17 prone glider was the forerunner of the B9 powered aircraft [Akaflieg Stuttgart]
In order to test the idea of an aircraft with the pilot in the prone-position, the Aero-Technical Group (Flugtechnische Fachgruppe/FFG) of Stuttgart designed and later built the FS 17 all-wood test glider. It was especially designed to withstand forces up to 14 G. It made its first test flight on 21st March, 1938. In the spring of 1939, FFG Stuttgart made the first design drawings and calculations for a prone-piloted aircraft. This aircraft was to be powered by two Hirth HM 50 engines with an estimated speed of 250 mph (400 km/h).

FFG Stuttgart never completed this project as it was forced, for unknown but likely politicaly reasons, to hand over the project to Akaflieg (Akademische Fliegergruppe/Academic Aviator Group) Berlin. It is possible the order came from the German Experimental Department for Aerospace (Deutsche Versuchanstalt für Luftfahrt e.V. Berlin-Aldershof) DVL or even from the Ministry of Aviation (RLM – Reichsluftfahrtministerium), but precise information is lacking. Akaflieg Berlin, founded in 1920, was one of the oldest gliding clubs in Germany and it still exists today.

The RLM designation for this aircraft was “8-341” but Akaflieg used the simpler B9 designation. The technical characteristics that the new plane was supposed to have were a good field-of-view for the pilot in the prone position, a high degree of safety for the pilot, a high speed during diving, good general flying characteristics and being able to withstand forces of up to 25 G, or 22 G depending on the sources.

Akaflieg Berlin had a small number of engineers and workers and an adequately equipped workshop to complete the task given. For this purpose, a design team was formed with Theodor Goedicke, Leo Schmidt and Martin G. Winter, which was responsible for the creation of this new aircraft design. The first prototype was to be ready by August 1942 but this was never achieved, and the prototype was only completed in early 1943. It made its first test flight on the 10th April, 1943 at the Schönefeld airfield, near Berlin.

The Design

Front view of the B9 [airwar]
The B9 was a single-seat, low wing, mixed construction aircraft with the pilot in prone position. It consisted of a metal airframe, made of steel ribs, covered with wood and canvas. The main fuselage’s cross-section was trapezoidal shaped. As the B9 was specifically designed to withstand forces of up to 25 G, it had to have a strong fuselage.

The wings were made of wood covered with duralumin sheets. In order for the wooden wings to withstand the strong torsional forces which occur during high acceleration maneuvers, the spaces between the spars were heavily reinforced. The middle part of the wings viewed from above have a square shape and then narrow towards the wing tips. The wings were held in place by four bolts on each side. The rear tail design was a simple one, with standard rudder and elevators.

The B9 had a standard retractable landing gear copied from the Me-108, which consisted of two larger wheels and one smaller non-retractable wheel at the back. The landing gear was lowered and raised manually. The front wheels retracted into the engine nacelles, but they were not fully enclosed.

The B9 had a large 4.9 ft (1.5 m) long glazed cockpit with good all-around view. But, as the pilot was in a prone position, the above and the rear views were limited by the human body’s inability to turn the head in these directions. The glazed cockpit was made of two parts, the front windshield and the rear larger canopy that opened to the right side. The cockpit interior had to be especially designed for a pilot lying in the prone position. The usual flight controls were almost useless in this situation and, thus, certain changes were necessary. It was important to divide the controls on both sides of the cockpit, in order to avoid the pilot crossing hands, which could lead to complications in flight. On the right side were the controls for ailerons and elevation. The pilot would use his right hand to gain access to the harness and the canopy release mechanism. For controlling the rudders and brakes, the pilot would use his feet. Using his left hand, he would operate the remaining instruments, the throttles, flaps, ignition switches, emergency pump, fire warning, undercarriage control and others. Additional engine and flight instruments were located behind the pilot. These included, among others, the distance indicator, climb indicator, compass, oil and fuel pressure gauges and airspeed indicator. For the pilot to be able to see them, a small mirror was provided. There were also inclined and horizontal line markers on the inner windshield to help the pilot with orientation. For flying at high altitude, an oxygen supply system with a mask was provided to the pilot.

The aircraft was powered by two Hirt HM 500 air-cooled engines, with 105 hp each. The maximum speed was around 140 mph (225 km/h) but, according to some sources, it was as high as 155 mph (250 km/h). The four fuel tanks, with a total capacity of 25 gallons (95 l), were located between the spars on both engine sides. The B9’s effective operational range was 250 mi (400 km). Originally, the B9 was meant to be equipped with two variable-pitch propellers, but it was instead fitted with ordinary wooden fixed pitch propellers made by the Schäfer company.

As the B9 could be used as a ground attack aircraft, a bomb rack was meant to be installed, but it is not clear if this was ever implemented.

Operational Testing

The B9 in flight [airwar]
The operational prototype was ready by the summer of 1943. The first test flights were carried out by Ing. L. Schmidt and Dipl.-lng. E. G. Friedrichs. On one flight, L. Schmidt had an accident, the details of which are not known, but the plane probably suffered only minor damage.

The B9 was meant to make a series of test flights in order to ascertain if the prone position design had any merit and to test the general flying and overall structural performance. If these proved to be successful, the B9 would serve as base for future development and be put into active service. The B9 aircraft received the ”D-ECAY” marking, which was painted on both sides of the fuselage.

The tests were carried out from July to October 1943, during which time around thirty pilots had the opportunity to fly it. The test flights were conducted without any major problems and only one accident was recorded. This accident was caused not by any mechanical problems, but by a pilot mistake during takeoff. The B9 was damaged, but it was repaired and put back into service in only a few weeks.

The pilots did not have many objections to flying in the new prone position. They described it as comfortable and that it was relatively easy to adapt to the new commands. There were some issues, like fatigue and tiredness of the neck and shoulder muscles because of the constant moving of the upper arms. There were also some complaints about the chin supporter, which was deemed as unpleasant during flight but it was essential during high g-force maneuvers. During these test flights, the control panel and the controls did receive some changes in design. The large and fully glazed cockpit provided the pilot with good front and below fields of view, while the rear and upward view was somewhat problematic due to the prone position.

These tests showed that this type of aircraft was well suited for bomber, ground attack, high speed reconnaissance and possibly even in a high-speed fighter role. But it was also noticed that, due to the somewhat restricted view, the use of low speed prone pilot aircraft without air support was not recommended. Despite being designed to withstand forces of up to 25 G, the maximum achieved was only 8.5 G. One of the reasons for this was the use of low rotational speed propellers.

For 1944 and 1945 unfortunately, there is no information about the B9’s operational use. The B9 was found abandoned at the Johannisthal airfield near Berlin after the war. In what condition it was by the time of capture is not known. What is unusual is that the B9 was captured by the Americans and not the Soviets (according to author Hans J.W.). What the Americans did with the plane is unknown to this day, but it was most likely scrapped.

Only one B9 plane prototype was ever built. By 1943 and 44, a large amount of resources were invested in the production of fighters for the defense of the Reich and there were neither the time nor the resources needed to develop and test such an aircraft.

Akaflieg Berlin B9 Specifications
Wingspan 30 ft 10 in / 9.4 m
Length 19 ft 8 in / 6 m
Height 7 ft 7 in / 2.3 m
Wing Area 128 sq ft / 11.9 m²
Engine Two Hirt HM 500 engines, with 105 hp each
Empty Weight 2,207 lbs / 940 kg
Maximum Takeoff Weight 2,458 lbs / 1,115 kg
Fuel Capacity 95 l
Maximum Speed 140 mph / 225 km/h
Range 250 mi / 400 km
Maximum Service Ceiling 13,000 ft / 4.000 m
Climb to 13,125 ft / 4,000 m 4 minutes and 12 seconds
Crew One pilot
Armament None

Gallery

Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

 

Akaflieg Berlin B9 – Prototype [Haryo Panji]
B9 drawings [airwar]

Sources

English Electric / Avro Canada Canberra T.25 “Hoverberra” [Fictional]

Fake Aircraft, ,

Canada flagUK flag Canada / United Kingdom (1960)
Fictitious Experimental VTOL Aircraft Variant – 1 Converted

The prototype Canberra T.25 during it’s first vertical flight. The Avro-Stroker B.69-420 jet engines would explode and destroy the plane just seconds after this photo was taken. (British Archives)

The English Electric Canberra T.25 (nicknamed Hoverberra by the designer team) was an experimental VTOL variant of the British Canberra jet bomber which was patented and developed by Avro Canada designer Richard Stroker. With a standard Canberra B.2 converted to mount two experimental Avro-Stroker BS.69-420 turbojet engines, the aircraft was given the experimental title of T.25 and was vertically flown for the first time on April 1st of 1960. Unfortunately, the first and only test flight resulted in catastrophic failure when the two experimental Avro-Stroker J-69-420 engines spontaneously combusted and exploded shortly after the T.25 got off the ground. Soon after, all work on the project was halted.

History

In the recent months, an experimental variant of the English Electric Canberra jet bomber was discovered in the National Archives in Greater London. Surprisingly enough, the variant was developed in the Dominion of Canada, which never officially operated or received any Canberras! This experimental variant bears the title of Canberra T.25 and was a testbed for an obscure Canadian developed turbojet engine designated as the “Avro-Stroker BS.69-420”. Much of the information regarding this variant has been lost to history, but the fundamentals appear to have been recorded by a variety of sources. Although Canada was never a recipient or official operator of the English Electric Canberra jet bomber, a single example of the Canberra B.2 found its way to Canada in February of 1959. Details of this purchase are not known, but it would appear that the aircraft was purchased by a civilian firm. As such, the aircraft was stripped of much of its military equipment.

Sometime in late 1959, a relatively unknown Avro Canada employee known by the name of Richard Stroker (referred as “Dick” by most) patented a turbojet engine which he had been working on since 1951. Stroker was part of the occupational forces in Germany after the war, and he was one of the engineers who were tasked with studying experimental Nazi hoverjet technology. Details on the precise technologies he was tasked to study are unclear. It would appear that the Avro Canada had taken an interest in this experimental engine Stroker developed, and decided to manufacture a small batch for trials. The engine received the designation of “Avro-Stroker BS.69-420” and it would appear that only four examples were manufactured. Wishing to test the engines, Avro Canada reached out to the Canadian government for permission to utilize a test frame. With the rather small size of the turbojet engines, they were envisioned to power the aircraft horizontally, allowing it to lift upwards. Previous work done on the VZ-9 Avrocar assisted with this engine’s development. As the Canberra B.2 was obtained recently, the Canadian government allocated it to the Avro Canada designers. It would appear that the British Ministry of Aviation was notified of this development, and they took a keen interest in the modification. Soon after, a team of twelve British engineers were dispatched to Canada to observe and assist in the project’s development.

By March 3rd of 1960, much of the modified Canberra’s design was completed. The Canberra received the official designation of Canberra T.25 within the United Kingdom and was nicknamed “Hoverberra” by the design team. Two BS.69-420 turbojet engines were mounted within the bomb bay and rear fuselage at a 90-degree angle. According to official engine bench tests, the BS.69-420 was capable of producing 4410 lb (2,000 kg) of thrust, which would have barely been able to power the Canberra, even with most of its military equipment stripped. As such, the Canberra T.25 was transported to the Toronto Malton Airport (today known as Pearson International Airport) on March 27th. Preparations were being made to initiate the Canberra T.25’s first vertical flight. The Canadian test pilot’s full name is unknown, but documents identified him as “Pranks.” Soon after, all preparations for the Canberra T.25’s first flight was complete. The test flight was to take place within a hangar, as the maiden flight’s purpose was to see if the aircraft could get off the ground at all, and did not instruct the pilot to fly high.

On April 1st at 0500 hours exact, the two BS.69-420 turbojet engines were ignited and the Canberra T.25 slowly lifted itself into the air. Canadian and British engineers and designers observed this process at a safe distance. Twelve seconds after the aircraft began hovering, a strange sound was reported by Pranks which he described as “a high pitched screeching.” As this was unusual and did not occur during engine bench tests, Pranks was ordered to immediately shut down the engine and descend. Just as this command was spoken, the B.69-420 turbojet engines exploded which completely destroyed the Canberra T.25 and killed Pranks. Two nearby engineers were also injured by flaming debris, one was severely burnt while the other made it off with relatively light injuries. Soon after this tragic incident, the Canadian government ordered the immediate cessation of work on this project.

As not much documentation seems to exist on this obscure project, much of the developmental history and post-cancellation history is unknown. However, the Canberra T.25 “Hoverberra” holds a special spot in aviation history as Canada’s indigenous endeavor to produce a VTOL aircraft. It is recorded that Richard Stroker soon resigned from Avro Canada following the catastrophic disaster. He soon moved from Toronto to Medicine Hat where he opened up a restaurant with his wife. He died in 1996 after suffering from colonl cancer.

Operators

  • Dominion of Canada – The Avro Canada firm developed the Canberra T.25 with assistance from British engineers. The aircraft would have likely entered service as a photo reconnaissance aircraft
  • United Kingdom – The Ministry of Aviation took great interest in the Canadian VTOL development of the Canberra and provided personnel assistance to the Avro Canada designers. It is unknown whether or not they would have adopted the type for service.

Sources

  • Fiddlesworth, R. (1962). Completely Reliable Report on Jet Aircraft: Ministry of Fictitious Aircraft & Aviation.
  • Realname, J. (1960). April 1st Report on VTOL Technology: The Canberra T.25
  • Stroker, R. (1959). Engine Patent: VTOL BS.69-420 Turbojet

PB.29E & PB.31E Supermarine Nighthawk

Great Britain, WW1, ,

UK Union Jack United Kingdom (1915 & 1917)
Anti-Airship Fighter – 1 Each Built

Supermarine PB.31E Nighthawk

In 1915, Germany began bombing Great Britain by Zeppelin. For the first time, Britain itself was under threat by enemy aircraft. Early attempts to counter the Zeppelins were ineffective. The Royal Air Corps needed an aircraft to be able to endure long, nighttime missions to chase the Zeppelins. The Pemberton-Billing aircraft company designed the PB.29E quadruplane for this task. The aircraft didn’t perform as hoped, but before a final conclusion could be made it was lost in a crash. Years later in 1917, with the company under new management and renamed Supermarine, the program would rise again as the PB.31E.  The PB.31E was dubbed the Nighthawk, and like its predecessor, proved to be ineffective in the role. The fighter is significant for its unusually large quadruplane layout and the first aircraft to be built by Supermarine.

History

The arrival of the Zeppelin in 1915 as a new type of weapon was an unwelcome one. It offered a new way of strategic bombing, as Zeppelins were faster and able to ascend higher than aircraft at the time. Zeppelins also served as a weapon of terror, as the civilians of England had never been faced with anything like it before, especially since the Zeppelins attacked mainly at night. Early attempts to counter Zeppelin raids proved ineffective, as anti-aircraft guns had a hard time spotting and aiming at the Zeppelins. Early forms of countermeasures involved aircraft dropping flares to illuminate the Zeppelins for gunners to see. None of these aircraft were used to actually intercept the airships. The Royal Air Corps needed an aircraft that would be able to reach and pursue Zeppelins on the homefront and on the battlefield. A potential solution came from a man named Noel Pemberton Billing.

Noel Pemberton Billing (1881-1948)

Noel Pemberton Billing was a man of many talents. He was an inventor, aviator, and at one point a member of Parliament. At the time, he was invested in many forms of new technology and aircraft was one of them. Having formed his own aircraft company in 1913, he built several aircraft types for the Royal Naval Air Arm (RNAA), such as the PB.25. He had taken a short break from designing planes for the RNAA and wanted to pursue aircraft to help in the war effort. The task of taking on Zeppelins got him interested in designing a plane to fill the role.

His answer was the PB.29E, a quadruplane aircraft. Information regarding the PB.29E is sparse and no specifications can be found for it. To get the aircraft to the altitudes at which Zeppelins usually lurked, Pemberton Billing applied triplane principles in making the aircraft, except taking it a step further and adding an extra wing. Having more wings, in theory, would assist with lift, a necessary factor when trying to chase the high-flying Zeppelins. Work began in late 1915, with the aircraft being finished before winter. The PB.29E was intended to fly for very long missions and needed to operate at night. To assist in spotting the behemoths, a small searchlight was to be mounted in the nose of the aircraft. The sole PB.29E crashed in early 1916. From test flights, the aircraft proved to be cumbersome and would not have been able to pursue Zeppelins. The two Austro-Daimler engines did not prove to be sufficient for the intended role, and performance suffered from it.

German Navy – R Class Zeppelin L 31

On September 20th, 1916, Noel Pemberton Billing sold his company to Hubert Scott Paine so he could become a member of Parliament. His career in Parliament was full of slander and conspiracy, and ultimately negatively affected the war effort. Soon after being acquired, Paine renamed the company as the soon to be famous Supermarine Aviation Works, in honor of the firm’s telegraph address. Work continued on a Zeppelin interceptor, which would eventually become the PB.31E. The PB.31E was technically the first aircraft built by Supermarine and it resembled a larger and more advanced version of the PB.29E. It retained many aspects from its predecessor: the quadruplane layout, the mounted searchlight, and endurance for long nighttime missions. The armament was expanded with a second Lewis gun mounted in the rear cockpit as well as a Davis gun mounted on top of the cockpit above the wings. To make the crew more comfortable, the cockpit was fully enclosed, heated, and had a bunk for crewmembers. The Austro-Daimler engines were replaced by 100hp Anzani radial engines. Expected speed was 75 mph (121 km/h) and it was to operate up to 18 hours.

The design team poses in front of the newly completed Nighthawk, fourth from the left is R.J Mitchell.

The aircraft was constructed in February of 1917, with a second in the works. On board the project was R.J Mitchell, the future designer of the Supermarine Spitfire. He began as a drafstman for the company and several designs concerning the fuselage and gun mounts of the PB.31E are labeled with his name. To the engineers, the aircraft was dubbed the Supermarine Nighthawk, however, this name was never official. Early flights were conducted at the Eastchurch airfield by test pilot Clifford B. Prodger. Tests showed that, like its predecessor, the engines weren’t capable of propelling the aircraft to its desired level of performance. To reach altitudes most Zeppelins were found at took an hour. Not to mention, newer Zeppelins could go even higher. Its expected 75 mph (121 km/h) top speed was never reached, with the aircraft only going 60 mph (96 km/h). However, it had a safe 35 mph (56 km/h) landing speed, which would have given the aircraft easy landing capability. With the performance lacking, the RAC deemed the project to be a dead end.

With the introduction of new incendiary rounds which easily ignited Zeppelins, Britain could defend itself with the improved AA guns. Along with the new rounds, the RAC started using the Royal Aircraft Factory B.E.2 to intercept Zeppelins at night. Originally intended for dogfighting, the B.E.2 proved to be ineffective and slow against fighters, but Zeppelins were easier, and much larger targets. With the Nighthawk now not needed, Supermarine ended up scrapping the first and incomplete second prototypes in 1917. Although the Nighthawk would never have been successful had it entered production, it still represents major innovations in aircraft design. It was one of the first true night-fighting aircraft to be designed, a concept later heavily utilized in the Second World War. The honor of being the first aircraft built by Supermarine under their name also goes to the Nighthawk.

Design

Overhead and side schematic views of the PB.29E

The PB.29E was a quadruplane designed to chase and intercept Zeppelins. Its fuselage was mounted between the lower two wings, with a gunner port being mounted in the upper two wings, leaving an opening in the middle between the two. Two crewmembers occupied the central fuselage with a single gunner gunner position in a seperate section above. The cockpit was open to the elements, as well as the gunner port. For armament, a single Lewis gun was mounted for attacking Zeppelins. For engines, the PB.29E had two Austro-Daimler six-cylinder engines in a pusher configuration. The tail itself was doubled.

Schematics for the Nighthawk with R.J Mitchell’s initials.

The PB.31E was a quadruplane like the PB.29E, but it was larger utilized a different fuselage design. Instead of having the fuselage between the lower two wings, the PB.31E positioned its body between the middle two wings. The body itself was of all wooden construction. To reduce splinters if the aircraft was fired upon or in the event of a crash, the fuselage was taped and covered in heavy fabric. To make the long missions more comfortable the cockpit was heated and completely enclosed by glass. A bunk was added for one crew member to rest during the flights as well, as the expected flights could last up to 18 hours. A searchlight mounted protruding from the center of the nose for use in patrols at night. The searchlight was movable to allow pointing it at different targets. It was powered by an onboard dynamo hooked up to a 5hp A.B.C petrol engine. For fuel storage, the PB.31E had 9 individual petrol tanks located around the cockpit area. The tanks were built to be interchanged if they were damaged or empty. In the front of the aircraft were several slits behind the searchlight that would assist in cooling. The wings of the PB.31E had significant cord to them. The tailplane was doubled like on the PB.29E, and the tail itself was lower to allow the rear mounted Lewis gun more range

The newly completed PB.29E, the gunner position between the two topmost wings is easily visible

of fire. For engines, the PB.31E had two Anzani radial engines in tractor configuration. These engines gave the PB.31E its slow speed of 60 mph (96 km/h), and its hour-long ascent to 10,000 ft (3000 m). The fluid lines, controls and other parts connected to the engines were placed outside the fuselage in armored casings. For armament, the PB.31E carried a frontal Lewis gun, a top mounted Davis recoilless gun and a rear Lewis gun. The Davis gun was built on a mount that allowed an easy range of motion in most directions. Lewis gun ammo was stored in six double cartridges and 10 Davis gun rounds were stored onboard as well.  Also on board were an unknown amount of incendiary flares to be dropped should a Zeppelin be directly below the craft.

Variants

  • 29E– First aircraft built for the Anti-Zeppelin role. Armed with a single Lewis gun. Crashed during testing.
  • 31E– Second aircraft. One prototype and one unfinished plane. Resembled a larger version of the PB.29E. Carried a Davis gun and two Lewis guns. Scrapped once the design was deemed unworthy.

Operators

  • Great Britain – The two prototypes were built and tested in England.

Supermarine PB.31E Nighthawk Specifications
Wingspan 70 ft / 18.29 m
Length 36 ft 11 in / 11.24 m
Height 37 ft 9 in / 5.4 m
Wing Area 962 ft² / 89 m²
Engine 2x 100 hp ( 76kW ) Anzani Radial Engines
Weights  

Empty 3677 lbs / 1667 kg
Loaded 6146 lbs / 2788 kg
Climb Rate  

Time to 10,000 ft / 3047 m 60 minutes
Maximum Speed 75 mph / 121 km/h
Cruising Speed 60 mph / 96 km/h
Landing Speed 35 mph/ 56 km/h
Flight Time Up to 18 hours of continuous flight
Crew 3-5 Crew

1 Pilot

2-4 Gunners
Armament ●      2x 7.7mm Lewis Guns

●      1x 1 ½ Pounder Davis Gun (10 rounds)

●      1x Frontally-mounted Searchlight

●      Unknown amount of incendiary flares

 

Gallery

Side profiles by Ed Jackson – www.artbyedo.com

Pemberton-Billing PB.29E
Supermarine PB.31 Nighthawk
The PB.29E under construction in Woolston
A frontal view of the PB.29E, note the searchlight
The newly constructed Nighthawk sits in a hangar at Woolston
The Nighthawk on the runway, notice the weapons and spotlight are absent

Sources

 

 

Junkers D.I

German Empire, WW1

German Empire flag German Empire (1918)
Monoplane Fighter – 40 built

The first Junkers D.I prototype J.9/I [Nhungdoicanh]
The German Air Force was responsible for several great revolutions in the development of aviation during both World Wars. While the development of jet technology in the Second World War is probably the best known, during the First World War, one of the most important such evolutions was the development of the first all-metal planes. The man responsible for this was the famous Hugo Junkers. The corrugated metalwork first seen on the D.I would become a hallmark of later Junkers aircraft.

The first all-metal projects

Aviation technology before the First World War revolved around wood as the main building material. Wood was used as it was easy to process and was easily available in great quantities and simple carpenters could be put to work on airplane construction.

One of the first persons who ever experimented with the idea of building an all-metal plane was the well-known German aviation designer and inventor Hugo Junkers (1859-1935). While working as a professor of thermodynamics at the Technische Hochschule (Technical University) in Aachen in 1907, he met a colleague, Professor Hans J. Reissner. Professor Reissner was involved in experiments with many novel ideas, such as aerodynamics in aviation. This moment would have a big impact on Hugo Junkers, as he would develop a great interest in aviation.

One of the few produced J 2 prototype which lead to the D.I [Wikimedia]
Hugo Junkers’ initial efforts were focused on solving the problem of poor aerodynamics of already existing aircraft. In 1912, his preliminary research showed that planes had better aerodynamics properties if they were designed to have an airfoil structure. In essence, this means that the whole plane, wing, body, and control surfaces had to have curved surfaces specially designed to give the best possible ratio of lift to drag. In order to perform even more experiments in aerodynamics, Junkers financed the construction of a wind tunnel at the Frankenberg laboratory. In the following years he continued his research, and by 1914 he had performed around 4,000 different tests and built 400 test models.

In 1914, Junkers had the first indications that an all-metal monoplane with thick wings was a feasible idea. While metals, like iron, were available in large quantities, lighter metals, like duralumin, an aluminum alloy, were more desirable for this purpose. The negative aspect of duralumin was the fact that it was difficult to work with. The techniques and technology of the day were inadequate, and the process of forming duralumin was slow and crude. As this could delay his work for years, Hugo Junkers decided to use the iron plates as a replacement, as they were much easier to work with.

After having constructed one all-metal wing prototype with a 9.18 ft (2.8 m) wingspan, Hugo Junkers made a request on the 2nd of February, 1915 to the German War Ministry for funds so he could build an all-metal prototype plane. This request was rejected, but it did not discourage Junkers from continuing his research. His second request was accepted in July 1915. With these funds, Hugo Junkers was able to construct a working prototype by December 1915.

The base of the prototype was made of iron ribs which were covered with iron sheets which were only 0.1 to 0.2 mm thick, held in place by electric welding. A second layer of sheet metal was added to reinforce the whole construction. The first prototype, designated the Junkers J 1, was ready by the end of 1915. It was powered by a Mercedes D.II 125 hp engine. After some ground testing, the new plane was shipped to Döberitz, the main German aviation training and test site in December 1915. Once there, the first test flight took place on 18 January, 1916. This was the first flight of a plane with an all-metal frame. The Idflieg (Inspektion der Fliegertruppen – Inspectorate of Flying Troops) was impressed with this prototype and ordered six more all-metal planes for future testing as a fighter plane. The J 1 design was not without problems, as there were some issues with the wing connection to the fuselage. During one test landing, one of the wings separated entirely.

Hugo Junkers began working on a second improved prototype named J 2. The problem with the wing-fuselage connection was solved by changing the internal design. The wings were divided into a couple of parts. The main section was connected directly to the fuselage and the others were affixed by screws. In only a few months, the first Junkers J 2 was ready to be tested. The J 2 was powered by a single Mercedes D.II 120 hp engine which was later changed to a stronger Mercedes D.III 160 hp. It made its first flight on 11 June, 1916. However, unlike the first prototype, the flying performance of the Junkers J 2 was poor. The speed was good, but the plane was simply too heavy at 2,480 lbs (1,160 kg) and thus useless as a fighter. Some six were ordered and built for future testing but the Idflieg lost any interest in it. Despite being rejected for operational service, it was still deemed important for testing construction methods and acquiring additional research.

After Hugo Junkers and his team analysed the Junkers J 2, they concluded that the plane could be vastly improved if lighter materials were used. Their solution was to undertake a study of how to make duralumin easier to work with. In time, specialized tooling and machines were developed and designed in the hope of producing adequate duralumin parts that could be used for aircraft construction. Despite the use of the duralumin in Zeppelin construction, the Junkers team made many improvements to these processes.

Thanks to these developments with aluminum processing, Junkers tried to build a fully operational all-metal monoplane. This was a private venture marked as the Junkers J 3. It was short lived, as the Idflieg refused to finance its development and only a single incomplete airframe was built. The Idflieg was more interested in all-metal ground attack biplanes.

The improved J 7 prototype

Side view of the J 7 prototype. [Wikimedia]
Hugo Junkers and his team continued to develop their own all-metal plane project. The J 4 served as a prototype for the J.I biplane and J 5 was never completed. Next in line was the Junkers J 7 as a single seat fighter and the J 8 two-seat close ground-support version. The J 8 prototype would eventually lead to the J 10 and the CL I. As the the J 7 and J 8 were developed, tests done in the wind tunnels showed that the low wing design provided good performance. One extra benefit of this design was the fact that the low wing would provide some extra protection for the pilot during a harsh landing. However, the weakest point in the design was the fuselage. Hugo and his team had significant problems designing a structure that would be strong enough to support all the necessary equipment, engine, and fuel tanks while still being light enough to maintain fighter maneuverability. They eventually reached a achieved a design that met most of the requirements.

The Junkers J 7 was constructed by using steel bars to form the structures of the plane and these were then covered in duralumin sheets. This method was copied from the J 4, with the only difference was that parts of the surface of J 4 were covered with fabric, while J 7 was all-metal. The J 7, piloted by Feldwebel Arved Schmidt, made its first test flight on 17 September, 1917. As the tests continued, Schmidt was generally pleased with how the plane behaved. In his report he said that the plane “.. made a good impression and possessed no serious fouls but the unique rotating wingtip ailerons were somewhat overbalanced…”. The J 7, despite its large front mounted radiator to accommodate the Mercedes D III 160 hp engine, managed to reach a speed of 77 mph (124 km/h). Many further trial flights were conducted, and in early October 1917 Schmidt managed to reach an altitude of 16,400 ft (5,000 m) in 17 minutes. This was a great result especially considering that the J 7 had a weight of 1,572 lbs (713 kg) and with added military equipment, the same altitude could be reached within 24 minutes.

For the next series of test flights, the J 7’s wings were equipped with conventional ailerons. These trials were held in late October 1917. The pilots were Leutnant Gotthard Sachsenberg and Theo Osterkamp. This time, the J 7 was pitted against the Albatros D.III. The J 7 proved to be a better fighter but the problems with the ailerons persisted. Both pilots gave a “green light” for the J 7 to go into production.

On 20th October, 1917 Idflieg made a decision to establish a new cooperation between Hugo Junkers and Anthony Fokker. Junkers-Fokker Werke AG was thus founded. It was hoped that the lack of production capacity of Junkers’ team would be supplemented by Fokker’s. This meant that there were two companies working on the J 7 project, Junkers (Jco) and Junkers-Fokker (Jfa). Despite the Idflieg’s hopes for good cooperation, this was never achieved as both sides sought control of the project.

Pilot and his assistant are starting the D.I. in front of the ‘Zeppelin’ hangars at Wainoden. [flyingmachines.ru]
In December, new modified ailerons were tested and the large nose radiator was also changed. While flying the J 7, the pilot, Tonny Fokker, had an accident upon landing. The plane was damaged but quickly repaired in time for the inspection made by Hauptmann Schwarzenberger from the Idflieg. He gave positive reviews of this plane and suggested that it should be used in the First Fighter Competition held in Germany. For this purpose, it was equipped with a new Mercedes engine and received new aerodynamically-balanced ailerons.

This competition was held from January to February 1918. Many front line pilots flew the J 7, including the famous Red Baron. He had positive comments for the J 7, in his report the plane being rated as having better climb rate and speed than other fighters in field use. However, he also noted the presence of some oscillation in the wings during sharp turns.

In January, Fokker once again had an accident during landing, but the damage was minimal. The plane was damaged again during its flight to Dessaou for wing modifications, but was repaired and ready for further testing by early February. These accidents also proved that its construction was much more robust than that of ordinary wooden planes. In March 1918, the last tests took place, with Leutnant Krohn as the pilot. His report read “.. On take-off the aircraft accelerates quickly and leaves the ground in a short time. It reacts instantaneously to the control. After ten degrees of control-stick movement, which suffices for an 80-degree bank, the control becomes very heavy. In a spiral, the aircraft reacts quickly to the controls. On the whole, the aircraft is at least as manoeuvrable as the new Albatros D.III or D.VI when diving at 155 mph (250 km/h) airspeed without any vibration in the wings..”

The ailerons were modified for the last time, which solved all previously mentioned problems with the controls. The J 7 prototype plane was used by a Fligertruppe in late March 1918. The J 7 was also used in the Second Fighter Competition held in July 1918. Despite proving to be an adequate fighter, the J 7 would never be accepted for service.

The J 9 and the D.I

The J 9/II rear view. [Militär Wissen]
At the same time as the J 7 was developed, Junkers began work on an improved model named J 9. Two prototypes were built, simply marked as J 9/I and J 9/II, the first of which was ready by April 1918. The J 9 was similar in construction to the J 7, but it was better suited for possible mass-production. By March 1918, Idflieg was negotiating with Junkers about the possible production of six planes for more testing. Hugo Junkers was disappointed with this, as he expected the signing of a major production contract. He thought it was a waste of precious time and that the plane did not need further testing. By early May, he managed to convince military officials to put the J 9 into production. A contract was signed for the production of 100 all-metal planes, including other Junkers models CL.I and the J.I, with around 20 copies of the J 9, now officially designated as the D.I. The first group was to be built by late July, with 6 in June and 14 by July.

This is the J 9/II prototype that was powered with the Benz Bz. IIIbo V-8 195 hp engine . Due to some mechanical problem with this engine prevent it from participating in the Second Fighter Competition. [Militär Wissen]
The D.I (J 9/I) prototype made its first flight on 12 May, 1918 (Some sources incorrectly state April), piloted by test pilot Leutnant Krohn. The D.I prototype was ready to participate in the Second Fighter Competition. For this, it was equipped with the Mercedes D. IIIaü engine. During this competition, the D.I prototype presented itself well. The second D.I prototype (J 9/II) was equipped with the Benz Bz. IIIbo V-8 195 hp engine. Due to problems with this engine, it was not used in this competition. During these tests, the J 9/I was equipped with two Spandau machine guns located above the engine compartment, with one on each side. At the end of the Second Fighter Competition, several front fighter pilots were asked to test these new models. As most pilots, such as Oberleutnant Goering, thought that biplanes were the future, they marked the D.I as a complete failure.

A second commission rejected the notion that it was a complete failure, referencing its demonstrated performance. One demerit marked by this commission was the lack of downward visibility from the cockpit. This was based on the German air fighting tactics which had been adopted due to Allied air superiority. This tactic involved attacking Allied planes using high speed dives from above, and thus downward vision was deemed critical. The D.I lacked this due the to the large low-placed wings, but it compensated with the metal construction that made it more resilient to low caliber rounds.

On the 21st August 1918, Idflieg place an order for 100 more Junkers all-metal planes, including the CL.I and the J.I, of which around 20 were D.I fighters. At the beginning of August 1918, three D.Is were ready for static machine gun testing. Three more were almost completed with five more to be constructed by early September 1918. For more firing tests, two were sent to Adlershof. Due to the installation of the offensive armament, some small modifications were needed.

Despite entering production, there were still some modification that were needed. The first D.I produced had a longer fuselage and larger wings. As it was tested, there were problems with vibrations of the fuselage and maneuverability. As this could endanger the entire production, a series of quick modifications were done to the remaining four, possibly five, produced aircraft. These were built with modified, shortened fuselages and smaller wingspans. In total, around nine operational fighters and two prototypes were ready by the war’s end.

Construction

The first four D.I planes still under construction. The plane on the right is the J.7 prototype. [Nhundoicahn]
The D.I was designed as a single seat, all-metal low-wing fighter plane. It consisted of a metal airframe of steel ribs covered with corrugated duralumin sheets. Duralumin is a trade name for one of the earliest types of aluminum alloy. The corrugated surface of the duralumin offered increased strength, rigidity, and projectile resistance without a significant weight penalty. This method of aircraft skin construction would later be used in larger Junkers bombers in World War II becoming an iconic hallmark of the company, going on to inspire the look of the Citroen H van of the late 1940s. Aluminum construction low wing monoplane designs in would later come into widespread adoption, becoming the standard by World War II. In this way, the C.I’s design was truly ahead of its time.

The airframe was designed by Hugo Junkers, but it said that even he was never completely satisfied with its design. It nevertheless did its job and was robust, durable, and easier to maintain and repair. It offered the pilot a greater chance of survival during a forced landing than a wooden airframe. The D.I’s metal airframe provide good protection from most weather conditions in comparison to standard wooden built planes. The D.I could be left out in the elements and exposed to strong rain and wind without fear of damaging the plane. Due to use of lighter metals, the D.I’s total weight was 1,835 lbs (843 kg).

The main engine chosen for this plane was the BMW III water-cooled 6-cylinder inline, supplying 185 hp (138 kW). With this engine, the maximum speed that could be achieved was 118 mph (185 km/h).

The pilot was located behind the engine and had a good visibility of the to the front, sides, above, and rear, but the downwards visibility was somewhat limited due to the plane’s large and low wings. The wing’s design was similar to previous prototypes, as it was divided into a few parts. The central part of the wings was directly connected to the fuselage and the remaining were connected by fasteners. Under the pilot there were two fuel tanks. The total fuel capacity is not precisely known.

The landing gear was fixed, like on all planes of the era. The landing wheels were mounted on an axle that was connected to the plane by triangular-shaped steel bars. The main armament consisted of two Spandau (7.92 mm) machine guns mounted above the engine compartment.

Production

Around 40 aircraft were ordered by Idflieg to be built by Junkers, 20 in May and a second group of 20 in August. Junkers completed around 27 planes before production was stopped in February of 1919.

The Junkers-Fokker joint company was also involved in the planned production of the D.I. The exact production details are not known. The Junkers-Fokker company was given an order to produce 20 more D.I, but it only produced 13. During the production run from June 1918 to February 1919, around 40 D.I fighters were built in total by both companies in addition with two prototypes..

What is interesting is the lesser known fact that Idflieg wanted to give a contract for the production of 50 D.I planes to Hansa-Brandenburg but, as the war ended in November 1918, this never took place.

In combat

This D.I was captured on the Western Front, note the two color stripe behind the pilot cockpit, suggest that it was used in combat. [Pinterest]
The war ended before more could be produced, and thus only limited numbers were sent to the front. These were given to front line units, possibly in the Flanders sector in October 1918. Later, in early 1919, during the Entente advance after the Armistice, five D.I fighters were captured. Four were found at Hombeek in Belgium. Of these four, only one was in flying condition, two were badly damaged, and the condition of the fourth is unknown. One more was found(missing half of its parts at an airfield near Brussels. There is little information about their use in combat.

However, there is evidence that gives some indication of the D.I seeing some combat. On the plane captured at Hombeek in Belgium, there were markings behind the pilot’s cockpit that may have been kill markings, but this is at best just speculation. The aircraft captured near Brussels had machine gun bullet holes, but the origin of these is unknown.

At the war’s end, the US Air Service, after analyzing the collected data and field reports, made a report “.. no one was found who had ever seen one of these airplanes in flight …. Some of the RAF pilots, however were sure that it had been used in service..”

The Junkers D.I did see combat action after the war against Soviet Bolshevik forces in the Baltic countries. The D.I was used by Kampfgeschwader Sachsenberg (under the command of Leutnant Gotthard Sachsenberg), being mostly used in the air support role, covering the German Freikorps units that remained there after the war.

Leutnant Gotthard Sachsenberg was very impressed with the D.I’s overall performance. His report reads: ”.. The Junkers aircraft have proven themselves beyond all expectations. The weather resistance of the aircraft is so great that it was possible to allow the aircraft to stand for weeks on end in the open during snow, rain, and thaw of the March season. A tarpaulin cover over the propeller and the engine sufficed to provide protection. Since neither tents nor hangars were available, no other aircraft except the Junkers would have been able to serve in Russia at that time.. the advantage of the weather resistance, the exceptional speed and the invulnerability of the aircraft outweighed the small disadvantages. In crashes and emergency landings relatively little occurred …. the Junkers aircraft, with improvement, will without doubt, take first place as a combat type…”.

Today, only a single D.I has survived the War and can been seen at the Musée de l’Air et de l’Espace near Paris.

Junkers D.I Specifications:
Wingspan 28 ft 6 in / 9 m
Length 23 ft in / 7.25 m
Height 7 ft 4 in / 2..25 m
Wing Area 159 ft² / 14.8 m²
Engine One BMW III water-cooled 6-cylinder, 138 kW (185 hp)
Empty Weight 1.440 lbs / 654 kg
Maximum Takeoff Weight 1.835 lbs / 834 kg
Climbing speed 3.280 ft / 1 km in 2 to 3 minutes
Maximum Speed 118 mph / 185 km/h
Range 185 mi / 300 km
Maximum Service Ceiling 19.700 ft / 6,000 m
Crew 1 pilot
Armament Two 7.92 mm machine guns

Gallery

Side profiles by Ed Jackson – www.artbyedo.com

Junkers D.I 5029/18
Junkers D.I in Brown
Junkers D.I 5999/18
Junkers D.I 5185/18
Junkers D.I Camouflage Livery w/ Brass Radiator & Panels

This is one of the four Junkers D.I captured by the Allies in Belgium after the war. Due to the marking on the wheels, it can be ascertained that this one was built by the Junkers company. [Nhungdoicanh]
This D.I was powered by a 185 hp engine and was used in the Third Fighter Competition held in October 1918. [Wikimedia]
Sources

 

Yakovlev Yak-23

Cold War, Soviet Union, ,

USSR flag USSR (1947)
Jet Fighter – 310 Built

Yak-23 in Czechoslovak operational service. [airwar.ru]
The Yak-23 emerged as the final step of the Yak-15 and Yak-17 development series. It made its first flight in mid-1947, powered, ironically, by a British Rolls-Royce Derwent jet-engine. By the time it entered production, the engine was changed with a Soviet-built copy. Over 300 were built, but as more advanced planes were ready for service the Yak-23s were sold to several Eastern Bloc countries. There they remained in service until replaced with the MiG-15 in the mid-1950s.

History of the Yak-23 predecessor

The Soviets began developing jet powered aircraft in the 1930s, but the process was slow with no major progress. However, by the end of World War 2, the Soviets managed to come into possession of large quantities of German war technology, engines as well as experimental and operational jet aircraft.

In April 1945, by orders of the National Defense Committee of the Soviet Union, work on a new generation of jet-powered aircraft began. In the case of jet fighters, the minimum requirement was that it had to achieve a maximum top speed of 500 mph (800 km/h). As there were a number of captured German Junkers Jumo 004B1 and BMW 003 jet engines, it was proposed to try to use them in Soviet designs. These received the new Soviet designation RD-10 Reaktinyi Dvitagatel, which is Russian for “jet engine.” The design and work on the first power plant was given to the OKB-117 Experimental Design Bureau, under the designer Vladimir Y. Klimov in late April 1945. A few months later, a second order was given to develop a new RD-20 jet engine based on the German BMW 003 jet engine. As the Soviet scientists were not familiar with this technology, the entire development ran quite slowly. The first series of these engines was ready in 1946, but the performance turned out to be limited and almost useless.

The work on the new jet fighter program was also slow and largely fruitless. Projects like the MiG-13, La-7R and Yak-3RD were built in limited numbers and proved to be unsuccessful. One of the main reasons for so many failed projects was the fact that the Soviet designers used captured and complicated German jet technology as an inspiration. There had to be a change in the way the Soviet designers and engineers approached these technologies and developments. Since time was crucial, the designers were forced to adopt simpler solutions.

The development of Yak-Jumo aircraft would later led to the Yak-23. [talkbass.com]
Several new projects resulted from these decisions, one of which was the A.S.Yakovlev Yak-Jumo project. It was based on Yakovlev’s own analysis of German technology, especially the light weight, stepped fuselage and the forward position engine design. His first idea was to try to take advantage of the already existing piston engine-powered fighters and, if possible, install one or more jet engines on them. He reused one Yak-3 fighter and modified it to mount one rocket engine instead of the piston engine. Most parts of the Yak-3 were reused, wings, including the whole fuselage, tail surfaces, undercarriage and most in-built systems and equipment. The new engine was fitted in the forward part of the fuselage, but tilted at a 430’ angle with respect to the plane’s axis. Besides this, it was necessary to redesign the whole fuel system. A new redesigned cockpit was installed and the armament would consist of two 23 mm NS-23K autocannons each with 60 rounds of ammunition located above the engine. The German Jumo 004 engine was used and thus the project name was Yak-Jumo or Yak-3 Jumo (depending on the source).

The first prototype was completed and ready by late 1945. During its first several ground tests, many problems were reported. One of them was the excessive heating of the rear lower fuselage caused by the engine exhaust gases. A second complete and improved prototype was built in December 1945. It was equipped with the Soviet-built RD-10 which was a direct copy of the Jumo 004. Tests on the second prototype plane began during the second half of 1946. During these tests, several complaints were noted and the aircraft was returned to the factory in order to resolve these issues. By that time, this plane received a new military designation, the Yak-15.

On 12th September, 1946, an order for a limited production run was given by the Ministry of Aircraft Production. The Yak-15 and MiG-9s were first presented to the public during a military parade held in Moscow’s Red Square of that year.

Yak-23 Rear View [Avions Legendaires]
Due to the rapid development of Western jet aircraft, Soviet military authorities demanded improved and more advanced jet planes. The new fighters had to be able to reach a maximum speed of 620 mph (1,000 km/h), but mostly due to lack of adequate jet engines this was only successfully implemented in later, much more improved models like the MiG-17. This was the reason why some jet fighters were put into production despite much lower top speeds.

Due to obsolescence and new problems discovered during the Yak-15’s service, most were modified to be used as advanced trainers, but some were operated as standard fighters. Yakovlev was again tasked with the development of an improved jet fighter. It was required to have a significantly better aerodynamic layout and was to be powered by an RD-10 engine. Estimated maximum speed was to be around 527 mph (850 km/h) at an altitude of 16.400 ft (5,000 m). Besides this, a novelty was the installation of an ejection seat and armored glass plate for the windscreen. By September 1946, the first Yak-17 was ready for testing. These tests were considered successful, especially by the pilots who considered it to have good flying performance. Serial production was to start in the autumn of 1947. The Yak-17 would be built in relatively small numbers as more advanced designs would replace it in the following years, designs like the Yak-23.

History of the Yak-23

Drawing of the Yak-23’s internal components. [Airwar.ru]
Later development of new Yakovlev aircraft was characterized by several different methods of approaching development. One of the many Yakovlev design teams, lead by Leonid L. Selyakov, worked on a completely new design that would later lead to the Yak-25. The main goal of this project was to build a completely new aircraft. In addition to this team, a second team advocated for the improvement of the already existing Yak-15 and Yak-17 designs.

The second team’s design was a lightweight and with highly maneuverable jet fighter. This new fighter was to be powered by an RD-500 jet engine, which itself was based on a British Rolls-Royce Derwent 5 turbojet engine. The whole aerodynamic concept was taken from the older Yak-17, but improved with an all-metal construction. The new plane was a lightweight mid-wing monoplane, but with unswept wings and rear tail. The cockpit was placed at the middle of the fuselage and equipped with an ejection seat. To save weight, some modifications were done such as the omission of air brakes, the armor plate being removed, fuel tank capacity lowered, no pressurization fitted to the cockpit and decrease of the wing thickness. The calculated weight with these modifications was about 4,725 lbs (1,902 kg). By the time it entered production, there was a slight increase of weight. The main armament was also relatively light, as it consisted of only two 0.9 in (23 mm) cannons, with some 90 rounds for each cannon.

The work on this project began in the early 1947. Plant No.115 was tasked with the construction of the first operational prototype. On 17th June, 1947 the prototype, designated Yak-23-1 was completed. The first factory test flight was made on 8th July, 1947 by the test pilot M.I. Ivanov. The results of these first flights showed that the Yak-23-1 had a high rate of climb and excellent maneuverability. The maximum speed achieved was 578 mph (932 km/h) at low level. Some issues that were noted during these first flights were solved in time.

In September the same year, on the insistence of the Minister of Aircraft Production, Mikhail V. Khruniche, the Yak-23 was accepted for additional test trials. For this purpose, a second prototype was built, named Yak-23-2. For the series of new test flights, besides G.A.Sedov, the main test pilot, many more pilots were also chosen to test the Yak-23, such as A.G. Proshakov, Valentin, I. Khomvakov among others. By March 1948, these test flights were successfully completed. The Yak-23 displayed great maneuverability during flights. In contrast to other models, like Su-9 and MiG-9, the Yak-23 proved to have much better climb rate. But it was not without its problems: during acceleration, the forward fuselage tended to suddenly rise and the lack of air brakes made potential dog-fighting very difficult. At higher speeds it took a lot of time to slow down and the lack of a pressurized cockpit made the Yak-23 incapable of operating at high altitudes. The second prototype was lost on 14th July, 1948, during one of the many flight exercises for the planned military parade to be held at Tushino. During these exercises, an unknown object struck the wing of Yak-23-2 flown by M.I. Ivanov, which caused the wing to break and fall off. The pilot lost control and crashed to the ground. Ivanov died immediately and the aircraft was totally destroyed. A subsequent investigation found that the main culprit was a balance tab that was torn from the tail of one of the Tu-14 bombers that was flying above the Yak-23.

Despite these problems, the Yak-23 was considered a successful aircraft worthy of production. Plant No.31 was chosen for manufacturing. By mid-1949, the production began, however, at first, the process was slow due the lack of RD-500 engines. The first batch was not ready until October 1949. In the period of January to March 1950, some 20 aircraft were used to conduct more tests. These trials revealed that the Yak-23 had a few more problems to be worked out, such as smoke in the cockpit, among other small issues.. As these problems were considered minor and did not endanger the production of the Yak-23 at the time.

Design

Yak-23UTI Front View [Aero Concept]
The Yak-23 was designed as a lightweight, all-metal, mid-wing monoplane with unswept wings and tail surfaces. The long front fuselage was designed and constructed so that it could be easily changed or removed for ease of maintenance.

The external fuselage was made of 0.039 in (1 mm) thick duralumin sheets (D16AWTL) and the inner part was made of 0.031 in (0.8 mm) sheets. To protect the main landing wheels, a special cover was installed close to the exhaust nozzle. The lower part of the Yak-23 fuselage was covered with a specially designed heat resistant plate in order to protect the plane’s inner structure from any potential thermal damage. The two unswept wings were made of 17 ribs that were covered in 0.05-0.07 in (1.3-1.8 mm) duralumin panels. At the wing’s trailing edges, ailerons and flaps were fitted. The wings were made mostly of duralumin sheet metal. The wing ends were flat and it was possible to mount two external fuel tanks that were ejectable. The rear tail had a tapered design and was made of metal covered with duralumin sheets. There were no air brakes installed and this caused the Yak-23 to have some problems with maneuvering. This would be a major problem in any potential dogfight with other fighters.

The main engine was the RD-500 turbojet engine with 3,500 lbs (1590 kg) of thrust that was fitted with a single centrifugal compressor and nine cylindrical shaped combustion chambers. The engine had a diameter of 3.58 ft (1.09 m) and 6.76 ft (2.06 m) long. It was angled downwards by 4°30’ with respect to the plane’s centerline. This was not a perfect design choice as when the pilot accelerated the plane, it tended to suddenly pitch up. The main jet fuel was kerosene, stored in five large tanks mounted in the fuselage with a capacity of 240 gallons (910 liters) and two smaller 50 gallon (190 liters) tanks located in the wings. With this fuel capacity, the maximum operational range was around 640 mi (1,030 km). The Yak-23’s flight endurance was very low, with only one hour of operational flight. With this engine, the maximum speed achieved was 606 mph (975 km/h) with a climb rate of 6,693 ft (2,041 m) per minute. The air intake was located at the front, which split into two symmetrical ducts that passed under the cockpit. There was a headlight located in the air intake to help during landings.

The landing gear was a tricycle design typical of jet planes of the era. The front nose wheel retracted forward, while the larger rear wheels retracted into the fuselage sides. A built in shock absorber mechanism with double rebound system was used for the landing gear.

The Yak-23’s operational service life in the Soviet Union was very limited due to the rapid development of better jet planes. [Wikipedia]
The cockpit was located at the center of the upper fuselage. The cockpit was designed with a fixed windscreen with an armored glass panel and a rear sliding hood with non-armored glass. For the pilot to enter his seat, he had to climb on top of the wings. The Yak-23 was equipped with an ejection seat that could be used by the pilot in case of emergency. The ejection seat with parachute was activated with a command handle located next to the armrest of the seat’s right side. A small explosive charge was used to catapult the seat from the plane. The main command instruments were in the standard configuration. All instruments were placed ahead of the pilot and the rudder pedals were mounted at the floor. The pilot’s instrument panel was divided into three sections. In the central section were the main and most important flying instruments: M-46 Mach meter, PDK-45 compass, AGK-47A artificial horizon, and engine control indicators. Secondary controls were located at sides of the main control panel. An oxygen supply system with a capacity of 2.11 gal (8 l) with a KM-16 model mask was fitted in the cockpit. Electric power was provided by 1.5 kW GSK-1500 generator and 12A-10 type battery. For communication, a RSI-6K radio set and a RPKO-10M radio-direction finder/semicompass were used. Also, the SCh-ZM IFF (Identification Friend or Foe) system was used.

The offensive weapon load consisted of only two 0.9 in (23 mm) NR-23 cannons placed in the lower forward part of the fuselage. Available ammunition for these two cannons was limited with only 90 rounds per gun. The main weapons were aimed by the semi-automatic gyro gun sight placed above the pilot’s instrument panels. Additional offensive armament could consist of two 123 lb (60 kg) bombs attached in the place of the external fuel tanks.

Beside the Yak-23 fighter aircraft, a trainer version, the Yak-23 UTI, was developed. One Yak-23 (serial number 115001) was converted for this purpose. A second instructor cockpit was installed at the rear of the pilot’s seat. The prototype was tested from March to September of 1949, but this modification was ultimately deemed unsuccessful. A new attempt was made with the redesigned Yak-23 UTI-II. The fuselage was stretched by some 7.8 inches (200 mm) to the front, and this time the instructor was moved to the front. A special periscope was installed to allow the instructor to see what the pilot was doing in the rear seat. The armament was reduced to only one 0.5 in (12.7 mm) machine gun. Many more changes were made, which resulted in the third version, Yak-23 UTI-III. By this time, the more impressive MiG-15 UTI was entering production and so the Yak-23 UTI project was canceled.

Operational use

Despite its good flying characteristics the Yak-23, also known by its NATO designation “Flora,” was built in small numbers, 310 planes in total. Its operational service life in the Soviet Union was very limited, as it was operated by only a few fighter regiments located in the Caucasus and Volga military districts. As more modern planes were becoming available, the Yak-23 would be sold off to Eastern bloc countries such as Czechoslovakia, Bulgaria, Romania and Poland.

In Czechoslovak Service

Czechoslovakia had extensively negotiated with Soviet military officials in the 1950s about the purchase of new jet-powered fighters. These negotiations had been preceded by earlier ones, from which Czechoslovakia received one older Yak-17 under designation S-100. This sole aircraft was to be used as a basis for future local production. However, since this plan went nowhere, the Yak-17 was sent to a military museum and it was never used operationally. An agreement was made in November 1950 for a possible license production of the Yak-23 under a new name, S-101, and also for the engine under the M-02 name. The first group of 12 Yak-23s arrived in Czechoslovakia in late 1950. Their first public appearance of nine planes were used in a military parade on 6th May, 1951, the anniversary of the liberation of Czechoslovakia by the Soviet Red Army in WW2. A second group of 9 Yak-23s was allegedly received, possibly in 1951 or 1952, but precise information is lacking.

The Yak’s were first used by the 3rd Fighter Division, but as the more advanced MiG-15 arrived, the Yak-23s were given to the 11th Fighter Regiment, part of the 5th Fighter Division, from June to August 1951. By early 1952, this unit had 11 operational Yak-23s in total. One Yak-23 was lost in an accident on 16 October, 1952. In 1953, all available Yaks were given to the 51st Air Regiment, which was renamed as the 7th Air Regiment in October. By early 1954, there were 12 Yak-23s reported in service, of which 11 were operational.

Due to the purchase of newer types of aircraft, the Czechoslovakian military authorities thought that the Yak-23 plane was inadequate and outdated and so the original plans for a license production were dropped. By 1956, a decision was made to withdraw all Yak-23s from operational service. Only a small number of Yak-23s where ever used by the Czech Air Force, thought to be around 21, but the exact number is unknown. Most of these were sold, 10 to Poland in 1953, possibly 7 to Bulgaria, with one given to a military museum and at least one was lost in an accident.

In Bulgarian Service

Yak-23 put on display at the Bulgarian Air Force Museum [Deano’s Travels]
Bulgarian military officials purchased several Yak-17 UTI training variants and 12 Yak-23s from the Soviet Union in early 1951. These were used to form the 19th Fighter Regiment in March 1951. The first pilot to fly on one of the Yak-23s was Major Vasil Velichkov. On his first take-off, the engine suddenly stopped working and he was forced to land in a field near the airfield. Because it was necessary to train new pilots to fly the Yaks, some planes were supplied to the 2nd Training Combat Air Regiment, located at the Georgi Benkovski Flying School. In order to increase the number of units equipped with the Yak-23s, some 72 new planes were purchased from the Soviet Union in 1952. Around 7 Yak-23s were sold to Bulgaria by Czechoslovakia in early 1956. As in Czechoslovakia, the Yak-23 would not stay long in service, and by 1959 all were retired.

In Romanian Service

After the Second World War, the Romanian Military leadership had great plans for the revival of their shattered air force and acquiring modern jet planes. Some 60 Yak-23s were bought from the Soviet Union during the fifties, with the first 12 planes reaching Romania in early 1951. The total number of planes used is not known. As the more modern MiG-15 was received during 1953, the Yak-23 was considered obsolete and only small numbers were ever used. One Yak-23 was modified by the Romanian air engineers of the AEMV-2 (Atelierele de Reparații / Material Volant) to be used as a dual-command trainer aircraft. A new instructor cockpit was installed. This new modified plane was designated as Yak-23 DC (Dublă Comandă / double command), but only a single prototype was built.

On the 24th June, 1953, Romanian pilot Mihail Diaconu escaped to Yugoslavia in Yak-23, where he sought asylum. Not long afterwards, another pilot flying a MiG-15 flew over and later landed onto Yugoslav territory, most likely due to a navigation error. Both planes were thoroughly researched and tested. Pilots Todorović and Prebeg both flew the Yak-23 with more than 4 flight hours. Beside the flying performance, the weapon systems were also tested during 1954. According to the agreement between US and Yugoslav military officials (code name ‘Zeta’), the Yak-23 was disassembled and sent to the Wright-Patterson Air Force Base in order to test the progress of Soviet aviation technology. Test flights were conducted on 4th November and, by 25 November, it was ready to be sent back to Yugoslavia. The Yak-23 was disassembled, and loaded onto a C-124 and later flown to Pančevo airfield. The whole operation was a complete success as it remained a secret for nearly 40 years. After several months, this Yak-23 was returned to Romania, without the Soviets ever realizing where it was the whole time.

In Polish Service

A few of the Polish Yak-23s would be put in Museums. [Wikipedia]
After the Second World War, Poland was economically and militarily devastated. It took several years before the beginning of the renewal of Polish military power. The new Polish military leadership wanted to built up the shattered air force and, despite their plans to acquire a new jet fighter by 1948, this was not possible. The process of acquiring new jet fighters began only in the spring of 1950. The first negotiations with the Soviet Union focused on the acquisition of Yak-15s, but this was later changed to the Yak-17. Due to outbreak of the Korean war, Soviet authorities decided to supply their allies with larger numbers of newer jet fighters. On 6th January, 1951, Poland received its first Yak-23 planes. The planned production of the older Yak-17s was suspended in favor of the Yak-23 under the Polish designation G-3.

Besides the 1st Fighter Aviation Regiment (PLM for short in Polish) which had some 16 Yak-23, a second unit, the 2nd PLM was also supplied with this plane. To train the new pilots, Yak-17 UTI training planes were used. In mid-1952, all operational Yaks were used by five Fighter Regiments: 2nd PLM with 26, the 39th PLM with 19, the 40th PLM with 19, the 26th PLM with around 11 and the 29th PLM with 14 Yak-23. From 1953 onwards, according to the new Polish military strategy, the first line fighter units would be equipped with the new MiG-15, while second-line units received all available Yak-23s.

In the early fifties, the Western Allies were eager to examine and spy on the military power of the East. A simple way to do this was by using various types of balloons. They were used for propaganda, meteorological, and reconnaissance duties. The Polish Air Force was heavily engaged with shooting down these balloons.

The final fate of Polish Yak-23s was sealed by the start of licenced production of the MiG-15 (under the name Lim-1). The remaining Yak-23s were gradually phased out of service. All operational Yak planes were allocated to training units at Radom, where they were used for training new officers and pilots. Some Yak-23s were temporarily used as reconnaissance aircraft in the 21st PLZ (21st Scout Aviation Regiment). By late August 1954, all Yak-23s were moved to Radom. The ones that were not operational were cannibalized for spare parts. On 1st September, 1959, the remaining 39 Yak-23s were removed from the Polish Air Force and a few would be used as memorials. During its operational service in the Polish Air Force, several planes were lost in crashes but, in most cases, the pilots escaped without any injuries.

Albanian Yak-23

Albanian Air Force allegedly operated a unknown number of Yak-23. Possibly bought from Poland sometime after 1951, according to author Yefim G.

Hungary and the Yak-23

Hungary allegedly also used the Yak-17 and 23, but there is no documentation or any information to confirm this (Source Marian M.). But according to author Yefim G. an unknown number of Yak 23 were operated by the Hungarian Air Force during the 1955 to 1956. But this author does not specify the number of planes used nor describes in more detail operational service life.

Production and modifications

A relatively small number of planes of this type were ever produced. As more advanced planes were becoming rapidly available, there was no need to continue the production of the old Yak-23. Most of the Yak-23s produced would be later sold to Eastern bloc countries.

In total, 310 aircraft plus three prototypes were built by Plant No.31. The plant produced these in twelve series, with 25 to 26 aircraft in each batch. Production was stopped by the end of 1950.

Variants

  • Yak-23 – Main production aircraft
  • Yak-23 UTI – One Yak-23 was modified to be used as a fighter trainer. It did not enter production.
  • Yak-23 DC (Dublă Comandă) – Romanian experimental dual control trainer, only one tested.

Operators

  • Bulgaria – Used over 70 Yak-23s
  • Soviet Union – Operated only two fighter regiments equipped with the Yak-23
  • Romania – Some 60 Yak-23 were bought from the Soviet Union during the fifties
  • Poland – Used around 101 planes, under the designation G-3
  • Czechoslovakia – Operated around 21 aircraft (possibly more) under the designation S-101
  • Yugoslavia – Used one Romanian interned plane for experimenting with flying performance and weaponry
  • USA – Briefly tested one aircraft that was supplied by Yugoslavia
  • Hungary – Allegedly used this type of aircraft, but proof is lacking
  • Albania – Possibly operated a small numbers of Yak-23

Conclusion

The Yak-23, despite proving that it had good flying performance and good handling, had a rudimentary design and was produced too late to have any great impact or role in the Soviet fighter force. Due to the rapid development of jet technology, more advanced planes were soon ready for service like the La-15 or MiG-15. The Yak-23 finished its career in service with many Eastern Block air forces.

Although its operational service life was short and its significance was negligible, the Yak-23 was an example of how, with only a short time and using limited resources, a solid jet fighter could be designed and built by the Soviets.

Yakovlev Yak-23 Specifications
Wingspan 28 ft 7 in / 8.73 m
Length 26 ft 7.8 in / 8.12 m
Height 10 ft 10.3 in / 3,31 m
Wing Area 145.32 ft² / 13.5 m²
Engine One Klimov 3,505 lbs/1,590 kg thrust RD-500 turbojet engine
Empty Weight 4,409 lbs / 2,000 kg
Maximum Takeoff Weight 6,693 lbs / 3,306 kg
Fuel Capacity 1,290 l
Climb Rate 154 ft / 47 m per second
Maximum Speed
  • Near the ground
  • At altitude of 16.404 ft/5.000 m
  • At altitude of 32.800 ft/10.000 m
  • 575 mph / 925 km/h
  • 565 mph / 910 km/h
  • 539 mph / 868 km/h
Take-off run

Landing run
  • 600 yd /550 m
  • 710 yd /650 m
Range 640 mi / 1,030 km
Maximum Service Ceiling 32,800 ft / 10,000 m
Crew 1 pilot
Armament
  • Two nose-mounted 0.9 in (23 mm) cannons
  • Bomb load of 132 lb (60 kg)

Gallery

Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

Soviet Yak-23
Soviet Yak-23 UTI
Polish Yak-23
Czech Yak-23
Bulgarian Yak-23

 One dual control Yak-23 was tested but the development was stopped, mostly due to production of more advanced MiG-based trainers. [Krasnayazvezda]
Yak-23 under construction in Plant No. 35 [Krasnayazvezda]
Yak-23 Side View [Aviastar]

Sources

Ikarus MM-2

WW2, Yugoslavia, ,

Yugoslavia flag Yugoslavia (1939)
Prototype Advanced Trainer – 1 Built

The MM-2 prototype had an unusual color scheme with a combination of red and polished aluminum.

With the emergence of new fighter planes in the years leading up to the Second World War, it became necessary to replace the older biplane trainer aircraft, which were too slow, in order to efficiently train new pilots to fly the newest fighters. Thus, it was logical that more modern advanced trainer aircraft would be needed. The MM-2 was an experimental Yugoslavian solution to this problem.

First Steps

At the end of the thirties, the Yugoslav Air Force was equipped with modern planes, such as the German Me-109, the indigenous IK-3, and the British Hurricane, highlighting the need for an updated trainer. There were several older aircraft in use for the role, like the FP-2 and the Rogožarski PVT, with a maximum speed of around 140 mph (230 km/h) but there was a need for a much faster and modern aircraft trainer.

The designer of the MM-2 trainer, Captain Dragutin Milošević.

To fill this gap, Air Force engineer and pilot Captain 1st Class Dragutin Milošević, on his own initiative, began to work on a new advanced trainer in 1936. The first aerodynamic calculations, choice of engine, structure, and the design were done by 1937. This new plane was conceived as a two-seater with seats one behind the other, with an enclosed cockpit and dual controls. It had a low wing, mixed construction, with a single engine and retractable landing gear. The engine would have been the Renault 6Q-02, giving 162 kW (220 hp). Milošević never gave a designation for this plane, but was later simply named the M-1.

Captain Dragutin Milošević submitted this project to the Yugoslav Department of Aviation in 1937. The Department analyzed this proposal and, while on paper it would have had great flying performance, a decision was made to reject it because the parts necessary for its construction had to be imported from abroad.

This decision did not discourage Captain Milošević, and he made attempts to improve his design. He proposed replacing the Renault with the license-built Gnome-Rhone K-7 309 kW (420 hp) air-cooled 7-cylinder engine. By adding this engine, the length of the plane would be reduced from 23 ft 7 in to 20 ft 4 in (7.2 m to 6.7 m) but the total weight increased to 2,160 lbs (980 kg). To improve the landing characteristics of the aircraft, it would have been necessary to increase the distance between two front landing wheels from 6 ft 2 in to 7 ft 10 in (1.9 m to 2.39 m). All aerodynamic and statistical calculations were finished by 1939. The second version was named M-2 and it was, in essence, the basis of the future MM-2 aircraft.

One wooden model (1:10 scale) was built by the Albatros factory in Sremska Mitrovica. This model would be used to test the aerodynamic properties and accuracy of earlier calculations. Aerodynamic properties were tested in the Paris wind tunnels on the 17th and 18th of July 1939. After these trials, the fuselage length reverted to the original 23 ft 7 in (7.2 m).

Later, Captain Milošević did new calculations that showed that certain changes to the design of the aircraft were necessary. Adding weapons and increasing fuel capacity would lead to an increase of the mass of the M-2 by 242 lbs (110 kg), some 60 lbs (30 kg) in fuel and 176 lbs (80 kg) in armament. After all the other modifications, the total mass reached 2,782 lbs (1,262 kg) compared to the initial 2,160 lb (980 kg). The wing area had to be increased from 129 to 146 sq ft (12 to 13.6 m²) and the wingspan from 27 ft 10 in to 30 ft 3 in (8.5 to 9,23 m).

Adoption of a Prototype

Captain Milošević submitted a letter, together with documents, plans and calculations, to the supreme headquarters of the Yugoslavian Air Force, notifying them of the test results of the proposed M-2 aircraft. Since he did not receive any kind of response, he asked Major Đorđe Manojlović, also an aviation engineer, for help. Although Đorđe Manojlović did not have a direct impact on the design of the M-2, his great influence and connections in the Supreme Air Force Command lead to the continuation of the project. The cooperation of these two men lead to the final approval for construction of the M-2 aircraft project.

The only MM-2 prototype during its construction by Ikarus.

When the Air Force Headquarters of the Army of the Kingdom of Yugoslavia accepted the M-2, construction of this project was given to the Ikarus factory. The contract was signed on the 25th March 1940. It was planned to build one prototype aircraft for testing in order to ascertain if the M-2 was fit to be accepted for serial production. The project was monitored by a team composed of engineer Sava Petrović, Air Force Major Vojislav Popović and the technician Stefan Lazić. The prototype was ready by the first half of November 1940.

Origin of the Name

In the Kingdom of Yugoslavia, there was a custom of using the initials of the names of the designers as the official designation for most of new types of aircraft in service (like the IK-2/3), and MM-2 was no exception. MM comes from the initials of the surnames of Captain Dragutin Milošević and the constructor and engineer Major Đorđe Manojlović. There is sometimes confusion about the exact name of this aircraft. It is sometimes also called MiMa-2. In some documents found after the war, it is also called M.M. 2. In this article, the MM-2 name will be used, as it is the most common.

Technical Characteristics

Captain Dragutin Milošević’s first drawing of the MM-2. Note that the engine nose design appears to be for an inline engine, different from the actual prototype.

The MM-2 was designed as an advanced two-seater trainer, with seats one behind the other, with dual controls and a fully enclosed cockpit. It was a low wing, mixed construction, a combination of wood and metal, single engine aircraft with retractable landing gear.

The wings had a trapezoidal shape with a rounded top. They were constructed by using two racks which were made of steel tubes welded together. The racks were welded to the plane’s hull and the wooden ribs were connected to them by rivets. The wings were covered with canvas, except for the central parts, which were made of aluminum sheet. This was done so that the technicians and repair crews could have easy access to the inside of the wing. The ends of the wings were made of wood that were held in place by steel fittings. The flaps were covered in canvas and operated either manually or hydraulically.

The MM-2 hull was of mixed construction. The main body was made by using welded pipes. The front part was covered with aluminum sheet and the rear with canvas. The tail was made mostly of wood and covered with canvas.

The main engine was the Gnome-Rhone K-7, which supplied 310 kW (420 hp). It was domestically built under license from Franch aircraft manufacturer Rakovica. It was hoped to use a two-bladed metal propeller but, due to the lack of resources, wood was used. The maximum estimated speed (never achieved) was around 250 mph (400 km/h), with an effective range of 475 mi (764 km) with some 40 gallons (150 l) of fuel capacity. Climbing to 6,500 ft (2,000 m) could be achieved in 3 minutes and 9 seconds, but the maximum service ceiling was never adequately tested.

The landing gear was supposed to be of the ‘Nardi’ type imported from Italy, but it was planned to domestically build the landing gears for the production version, to avoid being dependent on foreign countries. On the prototype, no radio was installed but it was hoped to equip all future production aircraft with the FuG VII radios.

The main armament consisted of two wing-mounted 7.7 mm Darn-type machine guns with 175 rounds of ammunition for each gun. The total bomb load consisted of four 10 kg bombs carried under the wings. It must be noted that the armament was never installed on the prototype, as testing was interrupted by the beginning of the war.

First Test Flights

MM-2 Side View

The first test flights were made by the beginning of the 1941 at the Zemun airport. The pilot for these flights was Vasilije Stojanović, the test pilot of the Ikarus factory. By the end of March 1941, some 45 flights had been made with a total of 20 flying hours. The pilot assessed the flying performance of this plane as excellent. The results of these tests indicated that this aircraft had good flight performance. The controls were adequate, both instructor and the students cockpits had enough room with a good field of view and, during flights, the aircraft did not present any tendencies for sudden unpredictable movements. Due to its good air brakes and flaps, take-offs and landings were quite easy. There were no major objections from the test pilot about the MM-2.

The MM-2 could very easily reach speeds of up to 217 mph (350 km/h). The design maximum speed was never tested, but calculations suggested that it could be as high as 250 mph (400 km/h). This was never confirmed due to the outbreak of the war. The MM-2 prototype had an unusual color scheme with a combination of red on most of the rear fuselage and wings, and polished aluminum on the majority of the fuselage and the engine section, with a small Yugoslav flag painted on both sides of the tail.

On the 25th of March 1941, a contract was signed between Ikarus and the Air Force. According to this contract, Ikarus was to prepare for production of MM-2 trainer planes in the near future. Before the production would begin, a last series of tests was to be conducted by a test group at an airfield near city of Kraljevo. An order was given to Stojanović to fly the MM-2 from Zemun to the Kraljevo airfield. Once there, it was planned to do some more flight performance trials in order to examine the limit of the flying characteristics of the MM-2 aircraft. Stojanović completed the flight on the 4th April. Final production was never achieved due to the German invasion of Yugoslavia that started only a few days later.

Operational Service

The MM-2 did not see any active service in the Royal Yugoslav Army because of the beginning of the April war, the German attack on Yugoslavia in April 1941. After the defeat of the Yugoslav army, the Independent State of Croatia, or NDH, was created. In order to form the new NDH military air force, it was necessary to find and obtain planes to equip these new units. Like many other former Yugoslav planes, the MM-2 was also pressed into NDH service in a very limited role.

It seems that the MM-2 had some engine problems (possibly sabotaged) when it was captured by the Germans at airfield near Kraljevo. It is possible that it was in a bad condition since the Germans did not even bother to repair it and put it into operational use.

The MM-2, together with other Yugoslav captured aircraft, was collected and handed over to the NDH. After a while, the MM-2 was repaired under code name No. 6301, and returned to active service. Additional flight tests were conducted by Georgije Jankovski, a test pilot for Dornier-Werke. In September 1941, the plane was transferred to the Zemun airport and handed over to Croatian Major Ivan Pupis for future use. Major Pupis was the leader of the group responsible for the repair, reception and later transfer of all Yugoslavian aircraft captured during the April war. When the MM-2 was repaired and ready for active service, Pupis to keep it for his personal use rather than handing it over to the military.

On the May 13 1942 pilot Vid Saić, he lost control of the aircraft and crashed due to inexperience. The MM-2 was deemed too complicated and expensive to repair.

The MM-2 was ‘owned’ by Pupis until March 23rd, 1942, when he received a direct order from the Croatian Aviation Command to transfer the MM-2 to the ‘Rajlovac’ airfield near the city of Sarajevo in Bosnia. The aircraft arrived at the beginning of April 1942. The MM-2 was given to the 17th Squadron (Jato) which was part of the 6th group (Skupina) under the Command of the Major Romeo Adum. The MM-2 was used mostly for limited test flights. On May 13, 1942 while piloted by Vid Saić (from the 18th Squadron), the plane crashed. The pilot survived the crash with no injuries. A commission was formed to investigate the causes of the crash and found several irregularities: The pilot did not ask for permission and had no orders to fly on the MM-2 that day, and he also did not know anything about the flying characteristics or the condition of the plane. The conclusion was that the pilot was guilty for the accident and, as punishment, Vid Saić lost his Pilot rank. The damage to the MM-2 was estimated to be around 90%. There was no point to try to rebuild it from scratch and the remaining parts were destroyed. There is no information whether it was equipped with any armament in Croatian military service.

Production

Due to the outbreak of war on April 6th, 1941, except for the prototype, no other specimen of this aircraft was ever built. In some documents and letters found after the Second World War, it was discovered that the Ministry of Aviation planned to order around 50 copies of the MM-2 aircraft. Along with this, the Yugoslav military negotiated with Germany for the purchase of Arado Ar 96 training planes, but nothing came of this.

After the war, the new communist Ministry of Aviation and the Ikarus factory representatives were also interested in restarting the production of this aircraft but, as the chief designer had died in one of the many German prison camps and the necessary machines and tools were lost during the war, this was too difficult and was abandoned.

Operators

  • Kingdom of Yugoslavia – Built and tested the single prototype.
  • Independent State of Croatia NDH – Used the MM-2 captured during the April war, but it was lost in an accident.

MM-2 Specifications
Wingspan 30 ft 6 in / 9.23 m
Length 23 ft 7 in / 7.20 m
Height 9 ft 6 in / 2.89 m
Wing Area 14.6 ft² / 13.60 m²
Engine One Gnome-Rhone K-7, 309 kW (420 hp) air-cooled 7-cylinder engine
Empty Weight 1,071 lbs / 894 kg
Maximum Takeoff Weight 2,290 lbs / 1,330 kg
Fuel Capacity 150-160 l
Maximum Speed 250 mph / 400 km/h
Cruising Speed 390 mph / 630 km/h
Range 475 mi / 764 km
Maximum (estimated) Service Ceiling 6,600 ft / 2,000 m
Climb speed Climb to 2,000 m in 3 minutes and 9 seconds
Crew Two, instructor and student pilot
Armament
  • Two Darn M30 7.7 mm machine guns in wings
  • Total bomb load around 40 kg.

Gallery

Illustration by Haryo Panji https://www.deviantart.com/haryopanji

Ikarus MM-2 Side View [Haryo Panji]
MM-2 Front View
MM-2 Rear View

Sources

Hütter Hü 136 Stubo

Weimar and Nazi Germany, WW2,

Nazi flag Nazi Germany (1938)
Armored Ground Attack Aircraft – 1 Replica Built

Stubo I Replica [aviationmuseum.eu]
The Hütter 136 was an interesting concept for a ground attack aircraft that employed numerous experimentations in its design. The cockpit was fully armored, the landing gear was replaced by a skid, and the entire propeller would be jettisoned off during landings. The aircraft came in two forms: the Stubo I, a short design with the ability to carry an external 500 kg bomb, and the Stubo II, a lengthened version that could carry two internal 500 kg bombs. The program never progressed as far as production and work stopped on the project shortly after the Henschel Hs 129 was ordered for production.

History

Artist’s Impression of the Stubo I [Heinz Rodes]
During the years leading up to the Second World War, Nazi Germany found itself needing a competent air force to rival those it would soon face. Restrictions set by the Treaty of Versailles severely hindered the German military both in size and equipment in order to ensure that German power would not threaten the continent again, as it did during the First World War. History notes that the Germans broke this treaty, at first covertly and then overtly, with the Allies showing no response or protestation to the blatant violations. Germany began amassing a massive military force in preparation for war. New programs and requirements were laid down in preparation for the inevitable war. These projects included many newly tested concepts, such as dive-bombing. The Junkers Ju-87 Stuka proved the effectiveness of dive bombing in the Spanish-Civil War, with a famous example being the Bombing of Guernica, but a newer attacker was eventually needed to complement it. An order in 1938 was put out by the Reichsluftfahrtministerium (Aviation Ministry, “RLM”) to develop a new armored ground-attacker. One of the companies that would participate in this requirement would be Hütter.

2-way and cutaway of the Stubo II

The designs of Ulrich and Wolfgang Hütter are relatively unheard of when it comes to aircraft. They began their aviation career designing glider aircraft in the 1930s, such as the popular Hü 17, some of which were used post-war. The Hütter brothers built a career in designing aircraft for the Luftwaffe (German Air Force) between 1938 and 1944 under the codename of Ostmark. The two began working on the project mentioned before for an RLM request for a new ground-attacker in 1938. The requirement laid down very specific guidelines to be followed. The new aircraft needed to have good flight performance and an armored airframe for extra protection, as well as enough speed to evade fighters. In preparation for the new designs, the RLM notified designated factories that would begin to produce these airframes upon adoption into service. The Hütter brother’s response would be the Hü 136. Other competitors included the Henschel Hs 129 and the Focke-Wulf Fw 189V-1b, an armored ground attack version of their reconnaissance plane. Not all projects for a new attacker were armored at this time. Other new designs included the Junkers Ju 187 and Henschel Hs P 87.

The Hütter Hü 136 was nicknamed the Stubo, a shortened version of the name Sturzbomber (Dive Bomber). The aircraft itself would be a single-engine design. Two versions of this aircraft existed. The first, Stubo I, was meant to fill the need for a heavily armored attacker and would be used in ground-attack and dive-bombing tactics. The second was the Stubo II, a two-seater which was essentially a longer version of the Stubo I and carried twice the bomb load internally. The flight performance of the Stubo II was estimated to be the same as that of the Stubo I although, given the design characteristics, that estimation is highly doubtful. The two designs did not meet the requirements for bomb load and range. To make the aircraft more efficient, the brothers took an interesting design change. Taking a note from their glider designs, they removed the conventional landing gear and replaced it with an extendable landing skid, which made the aircraft lighter and freed more space for fuel. This, however, posed serious designs problems. The Hü 136 now had to take off using a detachable landing gear dolly, similar to how the Messerschmitt Me 163B rocket plane would take off a couple years later. Due to this, the propeller would not have enough clearing and would hit the ground during landings. To fix this, the two brothers made the propeller detachable. During landings, the aircraft would eject the propeller, which would gently parachute to the ground above an airfield for recovery and reuse. To assist in landings, a new surface brake was also added to the aircraft.

2-way and cutaway of the Stubo I

The far more conventional Henschel Hs 129 would be designated the winner of the competition. Subsequently, no construction was ever started on either the Stubo I or II. The Stubo proved to be an interesting but flawed concept. The limited visibility from the armored cockpit would negatively affect the aircraft in all operations. Dogfighting, bombing and even flying in general would be affected by the cockpit’s design. The change in landing gear design may have extended the range and lowered weight, but pilots now had to learn how to land using a skid. The fact the entire propellor evacuated the aircraft was a huge issue in itself. Once ejected, the landing could not be aborted, and if the landing attempt failed, there was no chance to loop around and try again.

This, however, would not be the last project designed by the Hütter brothers for the Luftwaffe. Wolfgang would begin working on a long-range reconnaissance version of the Heinkel He 219 called the Hütter Hü 211. Another project is the rather unknown Hütter Fernzerstörer (Far Destroyer), a long-range turboprop attacker meant to be used on the Eastern Front. With the war ending, no further Hütter aircraft were designed. One would think the story of the Stubo ends with its cancellation, but the story continued rather surprisingly recently. The Military Aviation Museum in Virginia Beach, VA, acquired a full-scale replica of the Stubo I in 2017 and it is currently on display in their German Experimentals section, along with full-scale replicas of other “Luft 46” designs.

Design

The Stubo I was a single-engine armored ground attacker. In the front, it mounted a detachable propeller and a Daimler-Benz DB 601 inline engine. In the fuselage, a large gap was present between the engine and cockpit. This was most likely the fuel tank where the fuel tank was placed. Beneath the aircraft, a single 1010 Ibs bomb (500 kg) was mounted on an external hardpoint. This hardpoint most likely would be in the way of the landing skid, implying the payload had to be dropped before making an attempt at landing. For takeoff, a dolly would have to be mounted beneath the aircraft. This would be jettisoned shortly after the Stubo would be airborne. For landing, the aircraft would use an extendable skid. The wings of the aircraft had slight dihedral, which meant the wings were angled upward from the body. The Stubo I had an armored steel cockpit that was completely enclosed. For visibility, a small sight in the front and two side portholes were given. Had the aircraft been produced, peripheral vision would have been nonexistent and dogfighting would have been near impossible if it needed to defend itself. Normal operations, such as navigation and landing would have also been hindered, while combat operations such as target acquisition and attack run planning would have been exceedingly difficult. A tailfin was mounted directly behind the cockpit and not in a conventional tail design. Sources also mention the Stubo I would have mounted machine-guns, but the plans do not show exactly where or of what type these would have been.

Artist’s Impression of the Stubo II [Heinz Rodes]
The Stubo II was virtually identical to the Stubo I, aside from its extended fuselage. This lengthened design would allow the Stubo II to carry two 1010 Ibs (500 kg) bombs in a bomb bay, compared to the single bomb carried on a hardpoint by the Stubo I. Among smaller differences, the Stubo II’s wings had no dihedral compared to the angled dihedral of the Stubo I. With the lengthened fuselage, the landing skid was also extended to accommodate the longer airframe. It most likely also carried over the machine guns used on the Stubo I. The Stubo II uses nearly identical sized wings to the Stubo I, which gives the Stubo II a rather odd design, having the body lengthened but the wing size remaining the same. This would have definitely affected performance and possibly would have made the aircraft more unstable in maneuvering with the extra weight.

Variants

 

  • Stubo I – Armored ground-attacker that would carry a single external 500 kg bomb. Sources also mention machine guns, but documents don’t show where exactly they would have been located.
  • Stubo II – A lengthened version of the Stubo I, the Stubo II had an internal bomb load of two 500 kg bombs.

 

Operators

 

  • Nazi Germany – If the Hütter 136 would have entered production, Nazi Germany would have been the main operator of the craft.

Hütter 136 “Stubo I” Specifications
Wingspan 21 ft 4 in / 6.5 m
Length 23 ft 7 in / 7.2 m
Height (estimate) 5 ft 3 in / 1.6 m
Engine 1x 1,200 hp (894 kW) DB 601 Inline Engine
Loaded Weight 8,160 lbs / 3,700 kg
Maximum Speed 348 mph / 560 km/h
Range 1,240 mi / 2,000 km
Maximum Service Ceiling 31,170 ft / 9,500 m
Crew 1 pilot
Armament
  • 1x 1010 lbs (500 kg) bomb
  • At least 2 machine guns of unknown type (Most likely MG 15 or MG 17)

Gallery

Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

Stubo I Side View [Haryo Panji]
Stubo II Side View [Haryo Panji]

Sources

Martin-Baker Tankbuster

UK, WW2, ,

UK Union Jack United Kingdom (1942)
Anti-Tank Aircraft Design – None Built

3D artist impression of the Tankbuster in flight [candymountain.jp]
The Martin-Baker Tankbuster was a concept British anti-tank aircraft that was designed according to an order in 1942 for a specialized ground attacker. The aircraft had a twin-boom, pusher design and was only armed with a 6-pounder (57mm) cannon, most likely a Molins M-Class Gun. Compared to its competitors, the Tankbuster was strictly limited to exactly what it was named for; busting tanks, and would find itself having trouble against other ground targets or even defending itself. With the program being canceled in early 1943 and Martin-Baker working on more important projects, all work stopped on developing the Tankbuster any further.

History

Drawing of the Martin-Baker Tankbuster [British Secret Projects]
In early 1942, the Royal Air Force began seeking a new ground-attack aircraft that would replace the 40mm-armed Hawker Hurricane Mk.IID. An order was officially placed on March 7th for a specialized ground attacker that would be used against a multitude of targets including ground units, enemy aircraft, transports/shipping, and a main focus on destroying tanks. To accomplish the destruction of the aforementioned targets, the aircraft was meant to use more heavier guns than the Hurricane Mk.IID. Alternative weapon arrangements included: three 40mm Vickers S cannons, four 20mm Hispano Mk.V cannons, a combination of two 20mm with two 40mm cannons, six unguided rocket (RP) racks with two 20mm cannons or one 47mm Vickers gun with two 20mm cannons. Two 500Ibs bombs could also be added. The expected speed for the design had to reach at least 280mph (450 km/h) at 3,000ft (900 m). Visibility was also a necessity and forward view had to be unobstructed and clear. Full production was to be expected by 1944. The programs would be overseen by the Air Staff.

Over 10 different designs by several aircraft companies were subsequently created for this program. A majority of them were of unorthodox design. Armstrong-Whitworth (AW.49) and Boulton-Paul (P.99) both created twin boom designs. Boulton-Paul also submitted a canard design labelled P.100 and a biplane design labelled P.101, the latter being seen as a safe alternative to the radical canard and twin boom designs prevalent through the program. Perhaps the most interesting of the designs was the submission by Martin-Baker.

3D artist impression of the Tankbuster [candymountain.jp]
At the time of its submission, Martin Baker had been working steadily on their MB.5 project, which would eventually become one of the best performing piston aircraft built by Britain, but this wouldn’t be completed until 1944. Their design for the ground attacker was submitted several months after the order was given by the Air Staff and was only named the “Tankbuster”. Martin Baker’s concept was for a twin boom design that deviated extensively from the given requirements. The aircraft was armed with a single 6-pounder (57mm) cannon, and the aircraft would be completely encased in 1/2-inch armor. The armor itself weighed 4,900Ibs (2,200kg).

The project wasn’t very impressive nor reasonable in the eyes of the Air Staff, especially compared to the other designs in the program. Its single large-caliber gun extremely limited its target range and it would only have been able to attack one of six predicted target types the program requested. The aircraft lacked any other offensive or defensive armament and would rely on its armor alone to protect itself, a gambit that other designs in the program resolved by following the armaments listed by the Air Staff. Attempts to add more ordnance such as additional guns, rockets or bombs to the wings would have added too much stress on the airframe. The main feature of the aircraft was the root of its problems, its gun. The gun itself couldn’t be removed from the airframe and an aircraft going into battle with a single weapon would be inefficient for resources. The Tankbuster didn’t meet the armament expectations and fell under the expected speed by 10mph (16 km a h). On April 15th, 1943, Air Marshall F J Linnell (who was a good friend of James Martin, a founder of the company) advised Martin-Baker to drop development of the Tankbuster in favor of continuing work on the more successful MB.5 project going on at the same time.

Near the later days of April 1943, the Air Staff brought the program the Tankbuster was designed for to an end. They concluded that, at the time, developing and producing an entirely new ground attack aircraft would impede the current war programs and that the submissions were too specialized in design compared to modifying aircraft already being produced for ground attack duties. One such aircraft they pointed to was the Hawker Hurricane Mk IV, a ground attacker version of the famous fighter which was performing successfully in the role and had started production in March of 1943. Later additions to the ground attack role would be the Hawker Typhoon, which became a scourge to German ground troops. Even if the program had continued towards production, it was significantly unlikely the Tankbuster would have been chosen for the role. The aircraft was way too specialized and disliked by the Air Staff, and Martin Baker was working on an aircraft that would yield much better results. Although the Tankbuster may have been the runt of a doomed program, it still proves to be an interesting, albeit flawed solution in the name of destroying enemy armor.

Design

The Martin-Baker Tankbuster was a twin-boom single-engine design. The aircraft would have been constructed entirely of metal. The airframe itself would be covered in an additional 1/2-inch (12.7mm) armor. This armor would weigh 4,900Ibs (2,223kg) on its own. The armor covered the entire body and also the engine cowling. What’s interesting to note is that the aircraft had two engine intakes, one facing forward and one facing the rear. The radiator and oil tank were mounted in the frontal fuselage. The radiator itself was armored by offset plates that would prevent bullets from ricocheting inside. The cockpit area had clear forward visibility, and would seat a single pilot. The canopy would most likely have had bulletproof glass to complement the rest of the armored body. For it’s engine, the Tankbuster would have mounted a Griffon II engine in pusher configuration. This is relevant to Martin-Baker’s other project, the MB.5, as this aircraft also used the Griffon. The reason the aircraft utilized a pusher configuration was it gave the pilot clear visibility in the front and the gun could be placed directly forward. The pusher configuration isn’t common because of the fact that it leaves the engine open to enemies that are chasing the aircraft. This would have been especially deadly for the Tankbuster, given it has no defensive armament. The tail section and wings would also be constructed of metal. The wings were wide to improve low level flight. There was an attempt to diversify the targets by adding additional weapons to the wings, but this would only overload them. The Tankbuster had a fixed tricycle landing gear. This decision was made to conserve interior space but would have slowed the aircraft considerably. The only armament the aircraft would have been armed with would be a 6-pounder cannon (57mm) that would be frontally mounted, supplied with 30 rounds of ammunition. The aircraft would only be allowed to target heavily armored targets. To assist in aiming, the gun was placed towards on horizontal axis. This would prevent the aircraft from pitching when the gun was fired.

Role

The Tankbuster’s design might seem odd by conventional aircraft standards, but every single feature the aircraft had was to assist in it’s role of attacking enemy armor. Long, flat wings would give the aircraft an edge in low-level flight. The pusher engine would give the aircraft a clear view and nothing to obstruct the cannon. The entire airframe being heavily armored would protect against AA fire and enemy aircraft. Going into battle, the Tankbuster would need escort fighters to protect against opposing interceptors. Once in the combat zone, the Tankbuster would begin its assault on enemy tanks. The De Havilland Mosquito also mounted the 6-pounder Molins gun and was also used in the ground-attack role, but only for a short time before switching to an anti-shipping role. It is likely the Tankbuster would have also undergone this change had it entered production.

Variants

  • Martin-Baker “Tankbuster” – The only version of the Tankbuster drawn was the original design with a single cannon.

Operators

  • United Kingdom – This aircraft would have been operated by the Royal Air Force had it been produced.

Martin-Baker Tankbuster Specifications
Wingspan 47 ft 10.8 in / 14.6 m
Length 41 ft / 12.5 m
Wing Area 471.5 ft² / 43.8 m²
Engine 1x 1,730 hp ( 1,290 kW ) Griffon II Inline-Engine
Weights 12,000 Ibs / 5,440 kg
Climb Rate 2,250 feet/min / 686 meters/min
Maximum Speed 270 mph / 434 km/h
Minimum Speed 75 mph / 122 km/h
Crew 1 pilot
Armament
  • 1x 6-pounder (57mm) Molins M-Class cannon

Gallery

Illustration by Haryo Panji https://www.deviantart.com/haryopanji

Scale model of the Tankbuster [modelingmadness.com]

Sources