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 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

Curtiss P-40 Warhawk in Finnish Service

Finland, WW2, , ,

Finnish flag old Republic of Finland (1943)
Fighter– 1 Operated

The Curtiss P-40 Kittyhawk/Warhawk is one of the most iconic symbols of American aviation. Having served with over a dozen nations throughout its career, the aircraft proved itself capable of handling its own in combat. Although the Republic of Finland was never a recipient or official operator of the P-40, they were still able to obtain a single example from a Soviet pilot who landed in Finnish territory with his pristine P-40M. Serving mostly as a training aid, the Finnish P-40 Warhawk would never see combat against any of Finland’s enemies.

History

The Curtiss P-40 (affectionately known as the Kittyhawk for early variants and Warhawk for later variants) is perhaps one of the most recognizable American fighters of the 1930s. Most well known for having served with the “Flying Tigers” American Volunteer Group in the Pacific Theatre, the P-40 also had a fruitful service life on the Western Front and Eastern Front. One of the lesser known parts of the P-40’s history however, is the story of the Finnish P-40M Warhawk. The Finnish Air Force (FAF) had quite an interesting history during the 1940s. Equipped with a wide variety of German, Soviet, British and American aircraft, the word “diverse” would certainly apply to them. Despite Finland never officially receiving Curtiss P-40 Kittyhawk / Warhawks, they were still able to obtain and service a single P-40M Warhawk from the Soviet Air Force during the Continuation War through a forced landing.

P-40 KH-51 after repainting for Finnish service (Kalevi Keskinen)

On December 27th of 1943, a Curtiss P-40M-10-CU known as “White 23” (ex-USAAF s/n 43-5925) belonging to the 191st IAP (Istrebitel’nyy Aviatsionnyy Polk / Fighter Regiment) piloted by 2nd Lieutenant Vitalyi Andreyevitsh Revin made a wheels-down landing on the frozen Valkjärvi lake in the Karelian Isthmus region. Finnish forces were able to quickly retrieve the plane in pristine condition.

The circumstances of Revin’s landing are quite odd, stirring up a couple of theories on why Revin decided to land his undamaged aircraft in Finnish territory. According to the 2001 January edition of the Finnish magazine “Sähkö & Tele”, Revin intentionally landed his plane in Finnish territory, suggesting he may have been working as a German spy. This magazine sourced a report by a Finnish liaison officer working in Luftflotte 1. Other contemporary sources suggest that Revin had to land due to a snowstorm which disoriented him and resulted in him getting lost, or that he simply ran out of fuel and had to make a landing. The fate of Revin is unknown. Nonetheless, White 23 was dismantled and taken to the Mechanics’ School located in Utti where it was reassembled and refurbished. Now given the identification code of “KH-51”, the aircraft was delivered to Hävittäjälentolaivue 24 (HLe.Lv.24 / No.24 Fighter Squadron) based in Mensuvaara on July 2nd of 1944.

Warhawk “White 23” in Soviet service before its capture by Finnish forces. (Kalevi Keskinen)

Although KH-51 was never deployed in combat, it served as a squadron training aid where numerous HLe.Lv.24 pilots flew the P-40 for practice without incident. On December 4th of 1944, KH-51 was handed over to Hävittäjälentolaivue 13 (HLe.Lv.13 / No.13 Fighter Squadron). No flights are believed to have happened while the aircraft was serving with this unit. On February 12th of 1945, the P-40 was taken to Tampere where a week later it would be retired and stored in the Air Depot. The total flight time recorded with KH-51 in Finnish service was 64 hours and 35 minutes. On January 2nd of 1950, KH-51 met its end once and for all when it was scrapped and sold.

Variant(s) Operated

  • P-40M-10-CU – A single example of the P-40M-10-CU known as “White 23” belonging to the Soviet 191st IAP was captured by Finnish forces after the plane’s pilot (2nd Lt. Vitalyi Andreyevitsh Revin) made a landing on Lake Valkjärvi in the Karelian Isthmus area on December 27th of 1943. The aircraft was dismantled, sent to a mechanics school, given the identification code of “KH-51”, reassembled and given to HLe.Lv.24 where it served as a training aid. KH-51 would later be reassigned to HLe.Lv.13 for a short while.

Gallery

Finnish P-40M-10-CU Warhawk “KH-51”

Sources

  • Keskinen, Kalevi, et al. Curtiss Hawk 75A, P-40M. Vol. 5, 1976.
  • Curtiss P-40 M-10 White 23 (Later Finnish KH-51) .” Soviet Warplane Pages
  • Illustrations by Haryo Panji https://www.deviantart.com/haryopanji

Sikorsky S-70C-2 Black Hawk in Communist Chinese Service

Cold War, People's Republic of China, , , ,

PRC flag People’s Republic of China (1984)
Utility Helicopter – 24 Operated

The Sikorsky Black Hawk family is one of the most well-known helicopters of recent history. In its dozens of guises, it serves over 20 militaries worldwide. One of the lesser known operators is the People’s Republic of China. Initially purchased to be operated in the mountainous terrain of Tibet and Xinjiang, the Black Hawk eventually found itself as an aid relief helicopter in the 2008 and 2013 earthquakes in Sichuan and an inspiration for the design of the Harbin Z-20 helicopter.

History

S-70C-2 in combat excercises [dser.com]
The harsh geographic characteristics of Tibet and Xinjiang undoubtedly presented many tough problems to the People’s Liberation Army (PLA). The extreme altitudes of the Tibetan and Xinjiang plateaus make the duties of border troop outposts quite difficult, with Tibet being especially problematic. The Tibetan border alone spans nearly 3,728 mi / 6,000 km, with guard posts on mountains reaching over 13,123 ft / 4,000 m. The highest guardpost is the Shenxianwan (神仙湾) post at 17,650 ft / 5,380 m altitude. At these extreme altitudes the temperature is quite low with snow covering the mountains all year around, and the air is also oxygen deficient. All these factors combined make patrols and resupplying quite difficult for the border troops. Helicopters are the only viable option for resupplying missions as there are nearly no airstrips or adequate roads. The oxygen scarcity prevents helicopter engines from working to their full capacity, as well as reducing the rotor efficiency. This means that flying a helicopter up to that altitude is risky and difficult. Even if the helicopter can safely arrive, the amount of supplies that can be transported is severely limited and it would require several trips to fully resupply a base. In order to find a solution for this problem, China began to look into the international market for a high performing utility helicopter capable of operating at high altitudes and replacing the aging Soviet Mi-8 they were using for transport duties. Adopting the principle of “comparing three products and buying the best” (货比三家，择优选购), China chose three models of helicopters from various Western companies to compete for their business. The American Bell 214ST, Sikorsky S-70 Black Hawk and French AS332 Eurocopter were chosen as potential candidates and examples of these helicopters were promptly sent to Lhasa for flight trials in December of 1983.

S-70C-2 preparing for takeoff [seesaawiki.jp]
The flight tests were conducted on an airfield at an altitude of approximately 5,600 ft / 1,600 m and had all three helicopters fly to higher mountains. Upon reaching approximately 9,840 ft / 3,000 m, it was discovered that the power of all these helicopters dropped noticeably and the engines were not able to deliver sufficient amounts of thrust and the helicopters were unable to successfully complete the test flight. After three months of research, Sikorsky’s technicians were able to successfully address most of the issues and flight tests for the Black Hawk were continued. The improved Black Hawk was able to fly over the Tanggula Mountains at an altitude of over 17,060 ft / 5,200 m and land in the nearby Ali region. After numerous thorough examinations, the Black Hawk was ultimately crowned as champion and determined to be best suited for the Tibetan and Xinjiang environment. In July of 1984, the Chinese government officially placed an order for 24 unarmed S-70C-2 Black Hawk models, which would be specially built for China. They featured high performing General Electric T700-701A engines for high altitude flights and a nose-mounted weather radar. The first batch of Blackhawks would arrive in November of the same year, designated as civilian helicopters. The transaction cost China an approximated total of 140 million USD.

S-70C-2 LH92204 participates in an aid relief operation [Sina News]
Despite officially being classified as civilian helicopters, the S-70C-2 was used in a military capacity during their service with the People’s Republic of China. Initially assigned to the People’s Liberation Army Air Force (PLAAF) in 1986, the Blackhawks were later reallocated to the PLA’s air branch. In Chinese service, the Black Hawk would mostly be assigned to the Tibetan plateaus, where they resupplied and transported border troops. During the 1987 border skirmish with India, the Blackhawks were extensively used for tactical troop transport and supply runs in the Indo-Tibetan border region. The S-70C-2 was able to carry up to 8000 lbs / 3630 kg of equipment, 12 or 14 people in normal situations , and up to 19 people in emergency situations. Unfortunately for the Chinese, support and spare parts from Sikorsky would come to an abrupt end after the 1989 Tiananmen Square massacre. The result of this massacre greatly impacted Sino-American relations and future sales of military hardware were prohibited. It seems that Sikorsky made an attempt to reestablish relations with the Chinese in 1998 by asking the government to allow the sale of replacement engines and parts to the Chinese, arguing that the parts should no longer be considered military hardware. This request, if ever made, was rejected. It would appear that only 21 of the 24 Blackhawks purchased were in service after 2000. Three Blackhawks were supposedly written off during service, probably due to piloting error or equipment malfunctions. Numerous Blackhawks were deployed during the 2008 and 2013 earthquakes in Sichuan, China to administer aid relief, alongside numerous Soviet-era helicopters such as the Mi-8. The Blackhawks are still in service with the Chinese to this day, but will most likely be replaced by the Harbin Z-20.

China’s “Indigenous” Black Hawk

Harbin Z-20 [chinese-military-aviation.blogspot.com]
When taking in account of China’s long history of reverse engineering or copying technology from other countries, it should be no surprise that the Harbin Aircraft Manufacturing Company’s (HAMC) latest Z-20 (直-20, or Zhi-20) helicopter bears a striking resemblance to the Blackhawks. Believed to have been in development since 2006, the Z-20 finally took to the skies on December 23rd of 2013. Contemporary sources seem to suggest that the Z-20 possesses superior characteristics to the Black Hawk due to the refined design, but this has yet to be confirmed. As the Z-20 has only recently entered service and is still kept in relative secrecy. One can only speculate about its capabilities.

Variants Operated

  • S-70C-2 – The People’s Republic of China operated 24 examples of the S-70C-2 which were specially built for them by Sikorsky. This variant featured a nose-mounted weather radar, improved General Electric T700-701A engines for high altitude flights and various other improvements to the fuselage.

 Gallery

Illustrations by Ed Jackson www.artbyedo.com

Sikorsky S-70C-2 – LH92207
Sikorsky S-70C-2 – LH92210
S-70C-2 Hovering (Unknown source)
Detailed closeup of cockpit exterior (afwing.info)

S-70C-2 LH92206 transports a jeep during a military exercise [Sina News]
An unidentified S-70C-2 Black Hawk evacuates civilians in the Tibetan region. [Encyclopedia of Chinese Aircraft]
An unfortunate incident involving a unidentified S-70C-2 [Army Star]

Sources

 

Gloster CXP-1001

Cold War, Republic of China, , ,

Taiwan flag UK Union Jack Republic of China / United Kingdom (1947)
Jet Fighter – 1 Mockup Built

A modern interpretation of the Gloster CXP-1001 Blueprint (theblueprints.com)

The Gloster CXP-1001 jet fighter was the result of a joint Anglo-Chinese design venture initially conducted in 1946 to provide the Republic of China with a modern and efficient jet fighter. Based on the Gloster E.1/44, the CXP-1001 would have been the first jet aircraft to enter service in China. Plagued by slow development and lack of funding, the CXP-1001 was never fully completed, although a mockup was produced. Despite the fact that the Gloster CXP-1001 was one of the most important milestones of Chinese aviation, it is relatively unknown to both the Eastern and Western world due to its obscurity.

History

With the conclusion of the Second World War, both the Communist Chinese forces under Mao Zedong and Chinese Nationalist forces under Chiang Kai-Shek were preparing themselves for the inevitable continuation of the Chinese Civil War, a conflict between the two factions that had been going on since 1927. The American Lend-Lease programme greatly assisted the modernization of the Nationalist forces during the Second World War, equipping them with contemporary weapons and vehicles. The Communist forces, on the other hand, relied on mostly obsolete weapons from the Qing-era (pre-1912). Despite this, the Nationalists expected fierce resistance from the Communists, and the fact that members from the former Imperial Japanese Army Air Service and Manchukuo Imperial Air Force were helping the Communists build up an air force alarmed the Nationalist ranks. In order to gain an upper hand on the Communists, Chiang authorized a technical mission to the United Kingdom in early 1946 to investigate the possibility of a joint Anglo-Chinese program for a fighter, a bomber and a jet fighter. After extensive negotiating, the Gloster Aircraft Company agreed to initiate a collaborative jet fighter design with China. Following an agreement on July 18th of 1946, thirty Chinese designers and engineers were to be given facilities at the Design and Drawing Offices at Hucclecote, Gloucestershire for twelve months. A team of thirty-three British designers was to reside with the Chinese in order to mentor them on improving the Chinese aircraft industry. The Chinese team arrived sometime in September of the same year and they were brought to a section of the Brockworth factory where workshops and offices were set aside for the Chinese to study the British aircraft industry. Interestingly enough, each member of the Chinese delegation was gifted an Austin 8 car for the duration of their stay. Another term of the aforementioned agreement was that, after six months, the Nationalist government could send a list of specifications to Gloster and they would design and produce three jet prototypes for them within thirty months. The prototypes would then be shipped to mainland China, where the Nationalists could decide whether or not to acquire a manufacturing licence.

During the initial days, the Chinese designers were rarely allowed to see anything of value, as the Air Ministry had, quite expectedly, declared most of the projects that were being worked on as secret. Technology such as the Gloster Meteor fighter, the Rolls-Royce Nene Mk.2 and E.1/44 fighter were all hidden from the Chinese. Despite this, the Chinese were able to negotiate a Rolls Royce Nene Mk.1 jet engine manufacturing licence, but the British Ministry of Air secretly ordered Rolls-Royce to delay the contract as much as possible.

With the worsening situation back in China, the Chinese delegate in Britain reached out to Gloster and asked them to prepare a contract for the design of a single-seat fighter aircraft powered by either the Rolls-Royce Nene or de Havilland Ghost turbojet with assistance from the Chinese engineers. As such, Gloster representatives consulted the Ministry of Air for permission to adapt the Gloster E.1/44 jet fighter to the specifications set by the Chinese, but refrain from production. This request was granted and the new aircraft proposal was assigned the designation of “CXP-102” (Chinese Experimental Pursuit) on May 14th of 1947. During development, it was noted that the situation in China worsened every day for the Nationalists and a stable aircraft industry back home would take a considerable amount of time to set up. Colonel Wu, part of the military attache and negotiator with Gloster decided to once again contact the Gloster firm with the hopes of securing a more advanced design which could be immediately exported to China for use. This time, the Ministry of Air stepped in and voiced their objections to providing a foreign air force with a jet fighter whose performance would match or even surpass the latest British fighters fielded. To make matters worse for the Chinese, more and more Gloster staff were being reassigned to work on the Gloster F.43 and F.44/46 projects, as there was a limited design capacity in the United Kingdom at the time. The Foreign Office was also hesitant on supplying a future prototype to China due to the civil war China was facing. However, they did approve of a manufacturing license as they predicted that the design was still two or three years away from completion, and that the Civil War would be over by then.

With the proposal for an already completed design rejected, Gloster and the Chinese staff began to redesign the CXP-102 to meet higher standards. This new design would be based on the E.1/44 once again, but also incorporated many parts used on the Gloster Meteor (such as the landing gear) for simplicity and quicker design. Although considered to be a clean and efficient design by the designers, the CXP-1001 was unfortunately plagued with slow development and lack of funding. By early 1949, the design was almost completed and a preliminary plan for two prototypes was made. Only a mockup and a couple of components were made before Colonel Lin (another Chinese military attache member) contacted Gloster on February 3rd to halt all work on the CXP-1001 due to the string of defeats suffered by the Nationalists. Gloster received the confirmation to halt work on February 28th but agreed to complete all unfinished blueprints and ship them to Formosa (Taiwan) along with a scale model and the mockup of the CXP-1001. The Nationalists planned to finish the work by themselves, but this would never happen as on June 12st of 1949, the British freighter Anchises was inadvertently bombed by Nationalist aircraft whilst in Shanghai. The incident soured relations between the two countries, and the British decided to freeze the blueprint and mockup shipment in October of 1950. After two years in limbo, the CXP-1001 would finally meet its fate as on November 25th of 1952, the Gloster Aircraft Company decided to dispose of all the materials on the CXP-1001 without informing the Nationalist Chinese. The Ministry of Supply (MoS) commented on this saying that disposing of the materials was justified as this was an outdated design, but also stated that they were not responsible for the actions of Gloster.

No photos of the CXP-1001 mockup or scale model are known to exist to this day but the Jet Age Museum in Staverton, Gloucestershire appears to possess official sketches of the CXP-1001 which can be seen in Tony Butler’s book British Secret Projects: Jet Fighters Since 1950. Though ultimately not making it past the mockup stage, the CXP-1001 remains one of the most important milestones of Chinese aviation history, being the first jet fighter design in which Chinese engineers were involved and would have been the first jet to enter service with the Chinese.

Misconception – Meteor or E.1/44 Variant?

One of the biggest controversies that surrounds the CXP-1001 is the debate of whether it is a Gloster Meteor variant or E.1/44 variant. Most contemporary internet sources (such as the BAE Systems Website) states that the CXP-1001 is a Meteor variant, but does not cite any sources to substantiate their claims. As mentioned earlier, most of the British technology were kept secret to the Chinese and the British refused to supply a foreign air force with an aircraft comparable or superior to the ones fielded by the Royal Air Force. This adds on to the argument that the CXP-1001 was based on the E.1/44, as stated by many credible authors with a long history of published books on aircraft (ie. Tony Butler & Derek N. James). When the CXP-1001’s blueprints are examined, it is also quite obvious that the design resembles the E.1/44 more than it does the Meteor.

Design

The CXP-1001’s design was heavily influenced by the Gloster E.1/44, essentially being a redesigned and improved variant of it. The CXP-1001 was an all-metal stressed skin jet fighter powered by a single Rolls-Royce RB.41 Nene Mk.1 engine producing 5,000 lbs / 22.2 kN of thrust and armed with four 20x110mm Hispano Mk.V cannons. The cannons would have been mounted in pairs above and below the nose intake. Each cannon would have been fed with 180 rounds, making a total of 720 rounds. The CXP-1001 would also have been able to carry two 200 gal / 757 L Drop Tanks to extend their range. Due to a lack of information, the details of the CXP-1001’s design is quite unknown and may never be found.

Variants

  • CXP-102 – Initial design concept based on the Gloster E.1/44 with estimated higher performance. The CXP-102 was redesigned into the CXP-1001.
  • CXP-1001 – Improved design based on the CXP-102 / E.1/44 which featured parts from the Gloster Meteor. Armed with four 20x110mm Hispano Mk.V cannons and powered by a single Rolls-Royce RB.41 turbojet, the CXP-1001 would have been the first jet fighter to enter service with the Chinese if it were to see production.

Operators

  • Republic of China – The CXP-1001 was designed with the assistance of the Chinese, and would have been operated solely by the Republic of China Air Force in a military capacity.
  • United Kingdom – The Gloster Aircraft Company was the main designer of the CXP-1001, and would have operated it in a testing capacity before shipping the prototype to mainland China.

Gloster CXP-1001*

* – Data taken from British Secret Projects: Jet Fighters Since 1950 by Tony Butler and Gloster Aircraft since 1917 by Derek N. James
Wingspan 38 ft 0 in / 11.6 m
Length 41 ft 9 in / 12.8 m
Height 14 ft 10 in / 4.29 m
Wing Area 360 ft² / 33.5 m²
Thickness to Chord Ratio 0.011
Wings Sweepback 20 °
Engine 1x Rolls-Royce RB.41 Nene Mk.1 turbojet (5,000 lb / 22.2 kN of thrust)
Internal Fuel Load 470 gal / 1780 L
Empty Weight 8,960 lb / 4,060 kg
Normal Weight 13,900 lb / 6,305 kg
Maximum Overload Weight 18,700 lb / 5,700 kg
Climb Rate 6,000 ft/min / 1,830 m/min at Sea Level
Service Ceiling 40,000 ft / 12,200 m
Maximum Range 410 mi / 600 km – Standard

1,000 mi / 1,600 km – With Drop Tanks
Maximum Speed 600 mph / 965 kmh at 10,000 ft / 3,050 m
Crew 1x Pilot
Armament 4x 20x110mm Hispano Mk.V cannon (180 rpg)
External Load 2x 200 gal / 760 L Drop Tanks

Gallery

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

Artist conception of the CXP-1001 in a late 1950s ROCAF livery. (Illustration by Haryo Panji)
Artist conception of the CXP-1001 in a late 1940s ROCAF livery. (Illustration by Haryo Panji)

Sources

Focke Wulf Fw 187

Weimar and Nazi Germany, WW2, , , , ,

Nazi flag Nazi Germany (1937)
Twin Engined Fighter – 9 Built

The Fw 187 Falke was a twin engine fighter that was built by Focke-Wulf in 1936, at a time when the newly-formed Luftwaffe did not consider such an airplane type necessary. Despite receiving significant negative feedback, several prototypes were built and three pre-production versions were also constructed. The three pre-production types saw limited service defending the Focke-Wulf factory in Bremen against Allied bombing in 1940. Aside from that, they saw no other combat.

History

The first Fw 187 V1 shortly after being completed.

The twin-engined fighter was a concept few countries pursued in the early days of flight. The type only started serious development in the years directly preceding the outbreak of the Second World War, with planes such as the American Lockheed P-38 Lightning entering service. Most officials across the globe agreed that two-engine fighter aircraft would be rendered unnecessary by cheaper and lighter single-engine designs. In the early 1930s, Germany had no plans to develop such an aircraft either.

However, an aeronautical engineer by the name of Kurt Tank showed an interest. Kurt Tank was the main aircraft designer of the Focke-Wulf company, who developed most of the company’s most famous aircraft. During WWII, he would go on to create the iconic Fw 190 and would later have an aircraft designation named after him, with the Ta 152 and Ta 154. He began work on the new twin-engine project, despite there being no current requirement for such an aircraft. Tank had his first chance to reveal his design at a weapons exhibition held at a Henschel plant in 1936. Tank showed off his innovative design, claiming the twin-engine layout would offer a great speed of 348 mph (560 km/h) if the aircraft mounted the newly developed Daimler Benz DB 600 engines. One of the attendants of the event was Adolf Hitler himself, who found the design particularly interesting.

The Fw 187 on jackstands. This photo was taken during testing of the double-wheeled landing gear.

But to the Technischen Amt (Technical Research Office), the design was unnecessary, as it was believed single-engine designs could perform just as well as the twin-engined concept. Another pre-war doctrine was that the current bombers would be fast enough to outrun the fighters of the enemy, and escort fighters wouldn’t be needed. Tank, not happy with this response, took his design to Oberst (Colonel) Wolfram von Richthofen, the head of the Development section of the Technischen Amt. Tank persuaded him that technological advances would eventually allow the construction of more powerful fighters that would be able to catch up with the bombers which would thus require an escort fighter. Convinced by his claim, Richthofen agreed that it would be better to have a countermeasure now rather than later. Richthofen’s term as chief was short, but in this time he authorized three prototypes of Tank’s twin-engine design. The design was officially given the name of Fw 187.

Work began on the Fw 187 soon after, but, to Tank’s dismay, the requests for the DB 600 engine were turned down. Instead, he had to work with Junkers Jumo 210 engines, as DB 600s were only allocated to projects which were viewed as being highly important. The design work was handed over to Oberingenieur (Chief Engineer) Rudi Blaser, who was the one of the most experienced members onboard Focke-Wulf. Blaser had previously headed the design of the failed Fw 159 monoplane fighter, but he was ready to continue work and move on from his failure. Blaser wanted to achieve only one thing with this design: maximum speed.

The Fw 187 V2 on a test flight.

The first prototype Fw 187 was completed in early 1937. The Fw 187 V1 (designated D-AANA) was first flown by test pilot Hans Sander. In the initial flights, the aircraft reached speeds of up to 326 mph (524 km/h). The Luftwaffe was surprised to learn that despite weighing twice as much as the Bf 109, the Fw 187 was still able to go 50 mph (80 km/h) faster. They accused the team of having faulty instruments. Blaser was determined to prove them wrong and had a Pitot tube (a device that measures air speed using the total air pressure) installed on the nose of the V1, which would accurately tell the performance. Sander once again flew and confirmed the aircraft indeed had attained such a speed. Further flight trials showed the aircraft had superb maneuverability, climbing and diving. These great characteristics led Kurt Tank to name the aircraft his “Falke” or Falcon. This name became official as well, and wasn’t just a nickname the creator gave to his creation.

In the summer of 1937, the airframe had an impressive wing loading of 30.72 Ibs/sq ft (147.7 kg/m2), something no other fighter could equal at that point. Further tests by Sander put the airframe to the extremes to try the limitations of the aircraft in diving. The rudder, during dives, was predicted to begin fluttering after 620 mph (1000 km/h), but Blaser was more cautious, and thought it would start at a lower speed. To counteract this, a balance weight was attached to the rudder. Blaser assured Sander that the aircraft would perform better in dives as long as he didn’t exceed 460 mph (740 km/h). With the new weight attached, Sander took off to begin trials. Hitting 455 mph (730 km/h), Sander noticed the tail had begun violently shaking. With the tail not responding, Sander had started to bail when he reported a loud noise came from the rear. Sander’s control over the aircraft had returned and all vibrations had ceased. Upon landing, it was found that the weight itself had been the culprit of the vibrations and the sound Sander heard was the weight breaking off the rudder.

An aft view of the V6. The surface cooling system is visible in this shot.

Several modifications were made to the V1 during testing. The frontal landing gear was switched out for a dual wheeled design at some point, but was found it offered no benefit over the single wheel and thus was reverted. The propellers were also changed from Junkers-Hamilton to VDM built ones. Weapons were eventually added as well, but these were just two 7.92mm MG 17s. The 2nd prototype arrived in the summer of 1937. Visually, the V2 was identical to the V1, but had a smaller tailwheel, modified control surfaces, and Jumo 210G engines with enhanced fixed radiators.

However, in 1936, there was a change of leadership in the Technischen Amt. The supportive Richthofen was replaced by Ernst Udet. Udet was a fighter pilot, and his experience reflected upon his decisions. He made sure no more biplane designs were being built and all designs were now of monoplane construction. He had a major focus on fighters, and believed them to be the future. The modern fighter had to be efficient, with speed and maneuverability being the utmost importance. And, from this viewpoint, he saw twin engine fighters as not being as capable as single engine fighters. With this mindset, the Luftwaffe now saw no real reason to continue developing the Fw 187 as a single seat interceptor, but it could be developed as a Zerstörer (“Destroyer” heavy fighter), the same role the Bf 110 occupied. This required a crew of more than one and much heavier armament. Tank was reluctant, and felt his design was still as capable as single engine designs were, but he knew continuing to go against the Technischen Amt would result in his aircraft being terminated, so he regretfully obliged.

The V3 was in the middle of construction and changes had to be made as a result of this. The V1 and V2 had already been produced, and any drastic changes would further affect development, so no attempt to convert the two initial planes into two-seaters ever occured. To accommodate a radioman, the cockpit had to be lengthened. This worried Blaser, who was concerned these changes would affect the size and overall performance of the aircraft. Thus, he tried making the changes that affected the aircraft’s performance as little as possible. The fuselage was increased lengthwise, the tailfin was shortened, and increased cockpit volume demanded the fuel tank be moved farther back. Engine nacelles were also shortened to allow installation of landing flaps for when the aircraft carried larger ordnance. The 7.92mms were now complemented with two 20mm MG FF cannons, although V3 never mounted any actual weapons, only mock-ups.

The Fw 187 had good luck up until this point, but this good fortune ran out shortly after the V3 was produced. A few weeks after it was finished in early 1938, the V3 was doing a test flight when one of its engines caught on fire. The aircraft was able to safely land and the fire was extinguished, but the airframe had taken some damage and needed repairs. Tragedy struck once again not too long after, on May 14th. The V1 was lost and its pilot, Bauer, was killed during a landing accident. These two events happening so close together made the already negatively viewed Falke seem not only an unnecessary weapon, but now an unreliable one as well. Two more prototypes were built late in 1938, the V4 (D-OSNP) and V5 (D-OTGN). These two were mostly identical to the V3, but had several slight modifications, such as a modified windshield. Judging by photos, one obvious trait V4 and V5 had over V3 is the lack of the radio mast mounted on the cockpit of the V3. V4 and V5 were sent to the Echlin Erprobungsstelle, a major aircraft development and testing airfield for the RLM (Reichsluftfahrtministerium, German Ministry of Aviation). The trials at this site yielded favorable evaluations of the aircraft and three pre-production examples were ordered.

One of the A-0s flying overhead.

While all of this was going on, Tank was finally able to acquire two DB 600A engines for his Falke. The plane that mounted these engines would be the V6. Before the V6 was built, Tank had shown interest in surface evaporation cooling, a drag reducing novelty which had been researched and developed by Heinkel and was soon to be worked on by Messerschmitt. With the V6 now under construction, Tank drew plans to apply the feature into the prototype to give it peak performance. V6 (CI+NY) first flew in early 1939 and showed how well the new engines and surface cooling made the aircraft perform. On takeoff, the V6 had 1,000 HP from each engine, a 43% boost over the previously used Jumo 210s. During one test flight, the V6 was flying 395 mph (635 km/h) in level flight.

The three pre-production examples previously mentioned were designated Fw 197A-0. These were were fully armed. The A-0s added armored glass to the windshield and carried two more MG 17s. The A-0 planes also returned to using the Jumo 210 engines. Due to the additional weight, the performance of the A-0s was a bit lower than the prototypes. However, the RLM continued to argue against the Falke, claiming that, because it had no defensive armament, the Fw wouldn’t be as effective as the Bf 110 in the same role (despite it being able to outperform the 110 performance-wise). The final decision related to the Falke was an idea to turn it into a night-fighter in 1943. Nothing ever came out of this proposal.

The Factory Defender

Although the Bf 110 seemingly took the Falke’s place, its story continued. As the Royal Air Force (RAF) began its attacks over mainland Germany in 1940, aircraft firms scrambled to defend their valuable factories. Several firms formed a “Industrie Schutzstaffel”, which was an aerial defence program which would have aircraft company’s factories and testing sites be defended by aircraft piloted by test pilots and to be managed by on-site personnel. Focke-Wulf was one such firm and, luckily for them, three fully operational Fw187A-0s were ready and waiting to be used in combat. These examples were sent to the Focke-Wulf factory at Bremen and were sent on numerous missions to defend the plant from Allied bombing. Allegedly, Dipl.-Ing (Engineer’s degree) Melhorn claimed several kills while flying one of these aircraft. After the stint in Bremen, the three were put back into armament and equipment testing. In the winter of 1940 to early 1941, the three were sent to a Jagdstaffel unit in Norway, where they were evaluated by pilots. One of the three was sent to Værløse, Denmark in the summer of 1942 and temporarily assigned to Luftschiess-Schule. It is likely the remaining 3 and prototypes were either scrapped or destroyed by Allied bombing, as no examples are known to have survived the war. Some sources claim the aircraft Melhorn flew was the V6 converted into a single seater and armed for combat, but no proof supports this.

The Fw 187 was no secret weapon. After the fighting in France died down, the Propaganda Ministry began producing film and photos of the Fw 187 in 1940-1941 to persuade the Allies into thinking the Falke was fully operational and replacing the Bf 110 as the Luftwaffe’s all new Zerstörer. In reality, the latter was taking over the role of the former. The campaign sort of worked, as the Fw 187 was now a part of the rogue’s gallery that the Allies expected to fight. Identification cards, models and even movies were made to train pilots in the event they should encounter the two engine terror in combat. One such film denotes that the Fw 187 is “a rare bird” and that they should comically “make it extinct”. This shows that the Allies didn’t completely fall for the propaganda that claimed it was being produced in mass quantity.

Design

The Fw 187 had a twin engine design. The airframe was of all light metal construction. To reduce drag, the airframe was actually narrower at its widest point than other fighters of the time. The wings were of metal construction and divided into three sections. The connected segments carried the fuel and the outer segments had the flaps installed. The first and second prototypes had a single seat cockpit. The cockpit was covered by a canopy that slid aft. The cockpit itself wasn’t built for comfort, as it was built for an average sized pilot. The cramped cockpit lacked the necessary space to mount certain instruments and had these mounted outside on the engine cowlings. V1 had tail sitting landing gear, with all three wheels being able to retract into the hull. V2 was similar to V1, but had modified control surfaces. Beginning after the first two, all examples of the Fw 187 had an extended greenhouse cockpit to accommodate the radioman. The cockpit now opened up in two sections, one to the front and one to the rear. The fuselage was lengthened to some degree as well. The extended cockpit required the fuel tank to be moved down the fuselage. The engine nacelles were shortened to allow landing flaps to be added. V3 also had a radio mast mounted on the rear part of the cockpit. V4 and V5 had this removed.

For engines, the majority of the Falke’s used the Jumo 210 engine. V1 mounted the 210Da, V2-V5 using the 210G, V6 using the powerful DB 600A engines and the A-0 reverting back to 210Gs. The aircraft performance stayed the same overall, with the V6 having peak performance speedwise.

For armament, V1 mounted two MG 17 machine guns. V3 had accommodations for two more MG FF cannons but only mockups were added. When the A-0s were rolled out, an additional two MG 17s were added to fill the Zerstorer role. The extra two had their ammunition mounted in front of the radioman’s seat.

Variants

  • Fw 187 V1 – First prototype. Mounted two Junkers Jumo 210Da engines. Originally mounted Junkers-Hamilton propellers but was changed to VDM airscrews. Originally had two wheeled forward landing gear which was switched to single during development. Fitted with two MG 17 machine guns.
  • Fw 187 V2 – Second prototype, had different rudders and a semi-retractable tail-wheel. Had fuel-injection Jumo 210G engines.
  • Fw 187 V3 – Third prototype. Two seat version, the cockpit was lengthened to accommodate the radioman. The engine nacelles were shortened some degree to allow new landing flaps.V-3 also mounted two MG 17 machine guns and two MG FF cannons.
  • Fw 187 V4/Fw 187 V5 – Fourth and fifth prototypes. Nearly identical to V-3, aside from several small modifications, such as having different windscreens.
  • Fw 187 V-6 – Sixth prototype. High speed version that mounted Daimler Benz DB 600A engines.
  • Fw 187A-0 – Pre-production version. Three were constructed. Armed with two MG FF cannons and four MG 17 machine guns. Frontal armored windshields were added. These three were tested and sent to various locations for trial and defensive purposes.

Operators

  • Nazi Germany – The sole operator was Nazi Germany, which reportedly used the Falke during the air defense of Bremen in 1940.

Focke Wulf Fw 187A-0 Specifications
Wingspan 50 ft 2 in / 15.3 m
Length 36 ft 6 in / 11.1 m
Height 12 ft 7 in / 3.8 m
Wing Area 327.2 ft² / 99.7 m²
Engine 2x 700 hp (522 kW) Junkers Jumo 210Ga 12-cylinder liquid cooled inline engines
Propeller 2x 3-blade VDM airscrews
Powerplant Ratings
Horsepower output Altitude
Take Off 700 hp Sea Level
Normal 730 hp 3,280 ft
Weights
Empty 8,150 lbs / 3,700 kg
Loaded 11,000 lbs / 5,000 kg
Climb Rate
Rate of Climb at Sea Level 3,450 ft / 1050 m per minute
Time to 6,560 ft / 1999.4 m 1.9 minutes
Time to 19,700 ft / 6000 m 5.8 minutes
Speed 329 mph / 530 km/h at 13,780 ft / 4,200 m

322 mph / 518 km/h at Sea Level
Range 560 mi / 900 km
Maximum Service Ceiling 32,810 ft / 10940 m
Crew 1 Pilot

1 Radio Operator
Armament
  • 2x 20mm MG FF cannons
  • 4x 7.92mm MG 17 machine guns

Gallery

llustrations by Ed Jackson www.artbyedo.com

Fw 187V2 – The second single-seat prototype with a large curved canopy
Fw 187V3 – Two seat cockpit and canopy design were established along with new engines and nacelles
Fw 187V4 – Curved windscreen was fitted, however this change would not last
Fw 187V5 – Two more MG-17 added below the canopy
Fw 187A-0 – The A series was the first and only production batch
The V5 on standby. A visual difference between the V3 and the V4/V5 is the absence of a radio mast mounted on the cockpit.
Side view of the V6.
A period 3-way illustration of the Fw 187 A-0
The Fw 187 V3 after it’s engine fire. Notice it’s greenhouse cockpit and the way it opens.
A cockpit view of one of the A-0s. Note the glass floor.
The V4 taking off. The V4 and V5 were slightly modified versions of the V3.
Three pre-production Fw 187 A-0s on standby.
An aft view of the V6. The surface cooling system is visible in this shot.

Sources

EF-18 Hornet in Spanish Service

Modern Aviation, Spain, , ,

Spanish flag Spain (1985)
Multirole Fighter Aircraft – 96 Built

The first European customer for the F/A-18 Hornet multirole fighter was the Spanish Air Force, the Ejercito del Aire Espanol (EdA). Spain did not join NATO until May of 1982, but even before that date the Spanish government had issued a requirement for a new fighter/attack aircraft that would replace its fleet of F-4C Phantoms, F-5 Freedom Fighters, and Mirages. In response to the announced requirement, the US government initially offered Spain an interim loan of 42 ex-USAF F-4E Phantoms, followed by the sale of 72 F-16s. However, the F-18 entered the competition in 1980, offering the benefit of a twin-engine safety margin.

History

In December of 1982, Spain announced that they had selected the Hornet and made plans to order 72 single-seaters (F/A-18A) and 12 two-seat (F/A-18B) versions. However, this proved more than the Spanish government could afford, and the order was reduced to only 60 A variants and 12 B variants on May 31, 1983. An option was put aside for 12 additional Hornets, but due to budgetary restrictions, they were not taken up.

As part of an offset agreement reached with Spain, Construcciones Aeronauticas SA (CASA) at Gefale is responsible for the maintenance of the EdA Hornets. CASA is also responsible for major overhauls of Canadian Hornets based in Europe, as well as the Hornets of the US 6th Fleet in the Mediterranean.

EF-18 on takeoff at exercise Anatolian Eagle, Turkey (USAF)

The Spanish Hornets are sometimes referred to as EF-18A and EF-18B, the “E” standing for “España” (Spain) rather than for “Electronic” as would normally be the case for an official Department of Defense designation. They have local EdA designations C.15 and CE.15 respectively. Serial numbers are C.15-13 through C.15-72 and CE.15-01 through CE.15-12 respectively.

The first EdA Hornet, EF-18B CE.15-01, was presented in a formal ceremony at St Louis on November 22, 1985, and made its first flight on December 4. The first few two-seaters were sent to Whiteman AFB in Missouri, where McDonnell Douglas personnel assisted in the training of the first few Spanish instructors. The first two-seater was flown to Spain on July 10, 1986. By early 1987, all 12 two-seaters had been delivered to Spain, after which the single-seaters were delivered. A total of 60 EF-18As and 12 EF-18Bs were delivered to Spain, the last planes being delivered in July of 1990.

The Hornet serves with Escuadron (Squadron) 151 and Escuadron 152 of Ala de Caza (Fighter Wing) 15 at Zaragoza-Valenzuela and with Escuadron 121 and Escuadron 122 of Ala de Caza 12 at Torrejon de Ardoz. Escuadron 151 was established first and declared combat-ready in September of 1988. In EdA service, the Hornet operates as an all-weather interceptor sixty percent of the time and as a night and day fighter-bomber for the remainder. In case of war, each of the four front-line squadrons is assigned a primary role. 121 is tasked with tactical air support for maritime operations, 151 and 122 are assigned the all-weather interception role, and 152 is assigned the suppression of enemy air defenses (SEAD) mission.

Spain has ordered 80 Texas Instruments AGM-88 HARM antiradiation missiles and 20 McDonnell Douglas AGM-84 Harpoon anti-shipping missiles. The Spanish Hornets carry the Sanders AN/ALQ-126B deception jammer and, on the last 36 aircraft, Northrop AN/ALQ-162(V) countermeasure systems. For air-to-ground work, EdA Hornets carry low-drag BR and Mk 80 series bombs, Rockeye II cluster bombs, BME-300 anti-airfield cluster bombs, BEAC fuel-air explosive bombs, GBU-10 and GBU-16 Paveway II laser bombs, AGM-65G Maverick air-to-surface missiles, and AGM-88 HARM antiradiation missiles. In the air-to-air missions, EdA Hornets carry a 20-mm M61A1 cannon, AIM-9L/M Sidewinders and AIM-7F/M Sparrows. The Sparrows were supplemented from late 1995 onward by AIM-120 AMRAAMs. Spanish Hornets can also carry AN/ALE-39 chaff/flare dispensers, ALR-167 radar homing and warning systems and ALQ-126B Jammers which have been supplanted in most of the aircraft by the more advanced ALQ-162. EdA Hornets can carry the AN/AAS-38 Nite Hawk FLIR/laser designator pod on the port fuselage stores station. Air refueling for the Spanish Hornets is provided by KC-130Hs from Grupo (Group) 31 and Boeing 707TTs from Grupo 45.

In 1993, plans were announced for the EdA’s fleet of EF-18A/B Hornets to be upgraded to F/A-18C/D standards. McDonnell Douglas reworked 46 of these planes, with the remainder being upgraded by CASA. Most of the changes involved computer improvements and new software, although some changes were required to the weapons delivery pylons. Following the rework, the planes were redesignated EF-18A+ and EF-18B+.

Worried about a “fighter gap” opening up early in the next century because of delays in the Eurofighter 2000 program, Spain searched for additional fighter aircraft, acquiring some additional Mirage F1s from Qatar and France. The USAF offered Spain 50 surplus F-16A/B Fighting Falcons and the US Navy offered about 30 F/A-18As. These F/A-18s had the advantage in the contest, since Spain already operated the Hornet, and in late 1995 the Spanish government approved the purchase of 24 US Navy surplus F/A-18A/Bs. This marked the first sale of US Navy surplus Hornets. There was a separate deal for new F404-GE-400 engines, which were being contracted directly from General Electric.

The US Navy surplus Hornets were intended to equip the 211 Escuadron of Grupo 21 based at Moron. Escuadron 211 had been operating the F/RF-5A fighter, but these planes had been phased out of front-line service and transferred to Ala 21, while the Moron-based unit was temporarily equipped with CASA C-101 Aviojets. The first six were delivered in late 1995. They bore EdA serials C.15-73 to C-15-78 (being ex-US Navy BuNos 161936, 162415, 162416, 162426, 162446, and 162471 respectively). The remainder would follow at a rate of six per year until 1998. After a period of service, they were retrofitted in Spain and later subjected to a mid-life update.

With the withdrawal of USAFE and Canadian squadrons from Europe, Spanish F-18s (and Mirage F1s) have been in demand for NATO exercises and are frequent visitors to air bases in Europe and the UK. In 1994, eight EF-18s participated in a Red Flag exercise at Nellis AFB in Nevada. Eight EF-18s participated in Deny Flight operations out of Aviano, Italy beginning in December of 1994. On May 25, they received their first taste of combat when they participated in an attack against a Serb ammunition depot near Pale (currently in Bosnia and Herzegovina).

The Hornet is extremely popular with its EdA crews and is reportedly a pure joy to fly, stable and yet highly maneuverable and with good acceleration. By 2002, only six Spanish Hornets had been lost in accidents. This is the best safety record of any EdA fighter that ever served, and as good, if not better, than that of any other F/A-18 operator.

Active Service

Spanish Hornet at a NATO Tiger Meet exercise (FloxPapa)

After the Bosnian War began in 1992, the UN Security Council passed a resolution prohibiting military flights in Bosnian Airspace. Despite this no-fly order, hundreds of violations were committed. As a result, enforcement of the UN no-fly zone over Bosnia and Herzegovina by NATO began in 1993 as Operation Deny Flight, which was successful in denying unauthorized airplane access over Bosnia, but was ineffective with regards to helicopters. However, Operation Deny Flight was extended beyond the enforcement of the no-fly-zone, with ground air strikes in support of UN forces being made in the operation. As a NATO member state, the Spanish Air Force was involved and flew missions jointly with the U.S. Air Force, with eight EF-18s, two KC-130s and one CASA 212 participating in 23,000 fighter sorties, 27,000 close air support missions, 21,000 training sorties and 29,000 SEAD and other types of sorties.

The next military operation of the Spanish Forces was Operation Deliberate Force, aimed at weakening the military power of the Bosnian Serb Army which had perpetrated the Srebrenica massacre in July 1995, in which 8300 Bosnians were murdered. The air campaign lasted for three weeks, with eight EF-18s and several other Spanish aircraft involved in operations flying over 3500 sorties.

Spanish Air Force EF-18 Hornets have also flown Ground Attack, SEAD, and combat air patrol (CAP) combat missions in Kosovo, under NATO command, in the Aviano detachment (Italy). They shared the base with Canadian and USMC F/A-18s. Over Yugoslavia, eight EF-18s, based at Aviano AB, participated in bombing raids in Operation Allied Force in 1999, a NATO military campaign directed against the Federal Republic of Yugoslavia as part of the Kosovo War. The operation was carried out without UN approval due to China and Russia vetoing it. The end of the campaign lead to the withdrawal of Yugoslav forces from Kosovo and end to the Kosovo War.

During the 2011 Libyan Civil War, a coalition of nations imposed a no-fly zone over the country in order to prevent Muammar Ghadaffi’s Lybian Armed Forces from using the air force to bomb the rebels, along with an arms embargo. Six Spanish Hornets, along with a few other Spanish planes, participated in enforcing the no-fly zone. Spain also allowed the use of its Rota, Morón and Torrejón bases by the coalition. The total costs for Spain over the 7-month operation ammounted to more than 50 million euros.

Variants

  • EF-18A – Single seat version, locally designated C.15
  • EF-18B – Two seat version, locally designated C.15E
  • EF-18A+ – Single seat version upgraded to F-18C standard
  • EF-18B+ – Two seat version upgraded to F-18D standard*Note: The “E” in “EF-18” stands for “España” rather than “Electronic [warfare]” as typically designated by the U.S. Department of Defense

EF-18A Specifications
Wingspan 40 ft 5 in / 13.5 m
Length 56 ft 0 in / 16.8 m
Height 15 ft 4 in / 4.6 m
Engine 2x General Electric F404-GE-402 turbofan engines
Maximum Takeoff Weight 51,900 lbs / 23,540 kg
Climb Rate 833 fps / 254 m/s
Maximum Speed Mach 1.7+
Range 1250 mi / 2,000 km
Maximum Service Ceiling 50,000 ft / 15,240 m
Crew 1 pilot
Armament
  • One M61A1/A2 Vulcan 20mm cannon
  • AIM 9 Sidewinder, AIM 7 Sparrow, AIM-120 AMRAAM
  • Harpoon, Harm, SLAM, SLAM-ER, Maverick missiles
  • Joint Stand-Off Weapon (JSOW)
  • Joint Direct Attack Munition (JDAM)
  • various general purpose bombs, mines and rockets

Gallery

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

Two Hornets prepare for takeoff at exercise Anatolian Eagle, Turkey (USAF)
Armed EF-18, with laser guided GBU-10 Paveway II bombs and and AIM-9 Air to Air missiles (USAF)

Sources