USSR (1923)
All-metal passenger aircraft – five Built
Following his successful first attempt to develop an aircraft, Andrei Nikolayevich Tupolev felt confident in his ability to attempt the design an all-metal aircraft. Although some European nations had already tested or built such aircraft during the First World War, this concept was still novel in the burgeoning Soviet Union of the early 1920s. With the advent of duralumin production in the Soviet Union, and the experimentation with various construction methods, Tupolev began work on the aircraft known as the ANT-2 in 1922. After a period of testing and evaluation, five aircraft of this type were constructed.
Tupolev ANT-2 was the Soviet first operational all-metal aircraft. Source: P. Duffy and A. Kandalov Tupolev The Man and His Aircraft
History
The success of the ANT-1 (standing for the initials of Andrei Nikolayevich Tupovlev) test aircraft prompted Tupolev to advocate for the development of fully metal-constructed aircraft. The harsh weather conditions in many parts of the Soviet Union caused wooden materials to decay quickly. Metal alloys, on the other hand, offered numerous advantages over wood: they were stronger, more durable, and allowed for overall more resilient aircraft designs. Tupolev saw the use of wood in modern aviation as an obsolete construction material.
His view was shared by others in the burgeoning Soviet aviation industry. In 1922, a commission at the Central Aero/Hydrodynamics Institute (TsAGI) was formed under the leadership of Andrei Nikolaevich. Its purpose was to spearhead the development of factories and facilities capable of producing duralumin. One such production center was already operating in Kolchuginsk, near Moscow, where the production of duralumin, nicknamed “Kolchugaluminium”, began in September 1922. This development enabled Tupolev to start working on an all-metal aircraft.
Tupolev established his design bureau with 15 supporting members. However, the initial phase was challenging, as the new technology required skilled workers who needed training in this new field. Additionally, many components used in all-metal aircraft construction had to undergo extensive testing. Tupolev, being a cautious man, did not want to risk any pilot’s life before he was certain that the new all-metal aircraft would perform as intended. Consequently, he spent considerable time refining various designs, mostly using speedboats and gliders. In 1921, Tupolev spent some time testing his ideas and designs using speedboats from his base of operations in Crimea. The experience he gained there greatly helped him in his further work.
Work On the ANT-2
As soon as Tupolev was sure that all crucial components were sufficiently tested, the work on the new all-metal aircraft, designated ANT-2, began in 1923. The design was largely driven by the requirements of the Soviet UVVS-RKKA (Directorate of the Air Fleet of the Workers and Peasants). This was the first official request for a new military aircraft, one capable of transporting two passengers, armed with two machine guns, and would most importantly, be inexpensive to build. Tupolev and his team established a small workshop in Kolchuginsk.
Initially, there were problems as the Kolchuginsk factory was only known for producing duralumin, not for shaping it into the various forms needed for aircraft construction. Time was needed to train the workers to effectively shape duralumin into the necessary parts.
During this period, while working on various proposed designs, Tupolev had the opportunity to inspect a Junkers K16 transport aircraft. The German company Junkers, wanting to avoid the sanctions on arms and aviation development imposed by the Allies, sought cooperation with the Soviets. They even managed to set up a small production plant in the Soviet Union. The Soviets, in turn, were eager to acquire new technologies. The Junkers K16 featured a high wing and an open cockpit, design characteristics that Tupolev incorporated into his ANT-2 project.
The Junkers K16 served as inspiration for the ANT-2 Source: WikiThe ANT-2, when compared to the K16, exhibits many similarities in overall shape. While Tupolev drew inspiration from the K16, he did not merely replicate it. Instead, he used it as a foundation to experiment with many of his own design elements, particularly in its wings. Source: en.topwar.ru
The prototype was completed in 1924 and underwent its first flight test in late May of that year, piloted by Nikolai Petrov. To simulate the weight of two passengers, two sandbags were used, as Tupolev did not want to risk any lives at the prototype stage. Further flight tests were conducted on May 28 by a Soviet military delegation. Starting from June 11, the ANT-2 was tested with two, and occasionally three, passengers inside its fuselage. Overall, the performance was deemed sufficient, though a significant modification was required for the rear tail assembly. The rudder and stabilizer size had to be increased, subsequently improving the aircraft’s performance. To conduct further tests, four more aircraft were built. By 1930, at least one of these aircraft was equipped with a more powerful 200 hp Wright Whirlwind engine.
Fate
A total of five ANT-2 aircraft were produced. While these were used for various tests, their specific operational roles are not well documented. The anticipated military variant, which was to feature a new cockpit positioned behind the wings and be armed with one or two machine guns, was never built. The first aircraft has been preserved and can be seen at the Aviation Museum in Monino, near Moscow. The fate of the remaining aircraft is unclear, but they were likely scrapped at some point.
The only surviving ANT-2 can be seen at the Aviation Museum Monino near Moscow. Source: WikiIn recognition of its significant role in Soviet aviation history, the ANT-2 was featured on a Soviet postage stamp. Source: stock.adobe.com
Specification
The ANT-2 was designed as a high-wing, all-metal monoplane. Tupolev chose a triangular shape for the fuselage, with the sides sloping inward from top to bottom. This triangular design provided excellent structural integrity, reducing the need for additional fuselage struts. The fuselage was divided into three sections: the front section housed the engine, the open cockpit, followed by a small passenger compartment. The compartment could accommodate two passengers seated opposite each other. Although the aircraft was intended for three occupants, this was generally avoided due to weight limitations. Passengers entered the aircraft through a door on the left side of the fuselage.
The wing was located just behind the cockpit. It was constructed with two spars connected by 13 ribs on each side and covered with duralumin. Tupolev designed the wing with a curved, concave underside. The entire wing assembly was then attached to the top of the fuselage using four bolts. To accommodate the cockpit, part of the central section of the wing was cut off. Additionally, two handles were added to the ends of the wings on both sides, allowing the ground crew to maneuver the aircraft on the ground. The rear tail assembly consisted of a metal frame covered with duralumin.
The landing gear featured two fixed road wheels mounted on vertical struts, equipped with shock absorbers to ensure smoother landings. At least one aircraft was instead fitted with skis. A pivoting tail skid was used at the rear.
It was powered by a Bristol Lucifer three-cylinder engine producing 100 horsepower. With it a maximum speed of 170 km/h could be achieved. This engine, however, had some difficulties due to its significant torque, which could occasionally damage the engine mounts. Topolev, aware of this issue, designed a strong mount to counteract this problem. To allow access for repairs, the engine cover was secured with a few bolts. The engine drove a wooden two-blade propeller with a diameter of 2.2 meters. Fuel was stored in two 36 kg tanks located in the wings.
The cockpit was open, and to enter, the pilot used a small footrest on the left side of the fuselage. The cockpit was equipped with the basic and necessary controls and indicators, such as fuel level, RPM counter, and oil pressure gauge.
The ANT-2 was powered by a Bristol Lucifer three-cylinder engine producing 100 hp with a wooden two-blade propeller with a diameter of 2.2 meters. Source: WikiAt least one aircraft was fitted with skis. Source: en.topwar.ruThe wings were constructed using two spars connected by 13 ribs on each side and covered with duralumin. Source: en.topwar.ruA good view of the real tail assembly. Source: www.valka.czThe small passenger compartment was located inside the fuselage. Source: WikiTop view of the pilot’s open cockpit. Source: en.topwar.ru
Conclusion
While the ANT-2 did not enter mass production, this was less important as it showed that the concept of using metal for the construction of a fully functional aircraft was feasible. It was the first stepping stone of the new, and slowly rising, Soviet aviation industry. It was the first such aircraft to be successfully tested by the Soviets, and paved the way for further Tupolev’s research and work, which enabled him to develop, in time, more advanced designs. In addition, it was the first aircraft that was officially ordered by the Soviets for limited production.
ANT-2 Specifications
Wingspans
10.45 m / 34 ft 3 in
Length
7.6 m / 24 ft 11 in
Height
2.12 m / 6 ft 11 in
Wing Area
17.9 m² / 193 ft²
Engine
One
Empty Weight
523 kg / 1,153 lb
Maximum Takeoff Weight
837 kg / 1,846 lb
Maximum Speed
170 km/h / 106 mph
Range
750 km/ 466 miles
Maximum Service Ceiling
3,300 m / 10,926 ft
Crew
1 pilot
Armament
None
Illustration
Credits
Article written by Marko P.
Edited by Henry H.
Illustrations by Oussama Mohamed “Godzilla”
Sources:
Duško N. (2008) Naoružanje Drugog Svetsko Rata-SSSR. Beograd.
Y. Gordon and V. Rigmant (2005) OKB Tupolev, Midland
P. Duffy and A. Kandalov (1996) Tupolev The Man and His Aircraft, SAE International
B. Gunston () Tupolev Aircraft Since 1922, Naval Institute press
USSR (1921)
Experimental Single-seat light aircraft – 1 Prototype Built
While the Russian Civil War was raging on, there were early attempts to rebuild its shattered aviation industry. Aviation engineers and enthusiasts attempted, despite the chaos around them, to build small experimental aircraft to test their ideas and concepts. One such young individual was Andrei Nikolayevich Tupolev. His ANT-1 was a specialized design to test the concept of using metal alloys in aircraft construction.
Tupolev began his career as an aircraft engineer in 1909, when he was admitted to the Moscow Higher Technical School. There he met Professor Nikolai Yagorovich who greatly influenced Tupolev’s interest in aviation. In the following years, he spent time developing and testing various glider designs. When the First World War broke out Tupolev managed to get a job at the Russian Dux Automotive factory in Moscow, which produced a variety of goods, including aircraft. There he gained valuable experience of aircraft manufacturing.
Andrei Nikolayevich Tupolev was one of the greatest Russian/Soviet aviation engineers and designers. Source: Wiki
In 1917, the October Revolution plunged the disintegrating Russian Empire into total chaos. The few aircraft manufacturing centers were either abandoned or destroyed. All work on the design and construction of new aircraft was essentially stopped. The Dux was one exception and continued to work at a limited capacity. It was renamed to Gosudarstvennyi aviatsionnyi zavod (Eng. State aircraft factory) or simply GAZ No.1. Given that he was one of few aviation engineers left, with most skilled either being killed or fled the country, Tupolev remained working for the GAZ No.1. He spent a few years working on various projects such as designs improving weapon mounts for older aircraft that were still in service.
In 1921, Tupolev was elected as the deputy of the Aviatsii i Gidrodinamiki AGO (Eng. Aviation and Hydrodynamics Department). This department was tasked with developing various aircraft designs but also including torpedo boats. In 1921 he and his team from AGO began working on a new aircraft design that was to test new concepts. Two new innovative features were that it should be a monoplane, and be built using mainly metal alloy. Its primary purpose was not to gain any production orders, but instead to serve as a test bed for new ideas and concepts. The aircraft was named ANT-1, where ANT stands for the initials of Andrei Nikolayevich Tupovlev. This designation should not be confused with a snowmobile developed by Tupolev, which shared its name.
During this period, Soviet aviation officials and the German Junkers company spent years negotiating the possibility of producing a Duralumin alloy that could be used for aviation construction. Junkers proved the validity of this concept on the J.I saw service during the First World War. The German company wanted to avoid sanctions on arms and aviation development imposed by the Allies, while the Soviets wanted the technology for themselves, not wanting to depend on the Germans entirely. The Soviet Union in 1922, managed to produce their own copy of Duralumin known as Kol’schugaluminiyem alloy. The name was related to a small village Kol’chugino where this factory was located. Limited production of this alloy began in 1923.
Due to problems with the production of the new alloy, Tupolev was forced to postpone the development of his new aircraft until 1922. At that time the alloy was not yet available, so Tupovlev decided to go on with a mix-construction design, but mostly using wood. The benefit of using wood was that it was an easily available material, with almost unlimited supply in Russia. It was cheap and there were plenty of skilled woodworkers. However, there were also numerous flaws in using wooden materials. The greatest issue was a generally short service life in harsh climates as in Russia, in addition, standardization of spare parts is almost impossible to do.
Tupolev himself preferred the new metal technology believing that it would offer many benefits to the aircraft industry, giving new aircraft a lighter and stronger overall construction. Tupolev eventually decided to go for a mixed-construction solution. His decision was based on a few factors, such as the general lack of this new material, and he wanted to be on the safe side as using metal in aircraft construction was still a new and not yet fully proven concept. In addition, he wanted to be sure about the Aluminum alloy material’s quality before proceeding to design a fully metal aircraft.
Once the choice for the construction material was solved the next step was to decide whether it was to be a single or two-seat configuration. The wing design was also greatly considered. After some time spent in calculations and small wind testing, the choice was made to proceed with a single engine and low-wing monoplane.
For the engine, three different types were proposed including 14hp and 18 hp Harley-Davidson and a 20 hp Blackburn Tomtit. Despite Tupovlev’s attempts, he failed to acquire any one of these three. It was not until early 1923 that he managed to get his hands on an old 35hp Anzani engine which was over 10 years old by that point. Despite its poor mechanical state, Tupovlev knowing that nothing else was available decided to try salvage it.
Testing and the Final Fate
The construction of this aircraft took over a year to complete. Given the general chaos at that time, this should not be surprising. It was finally completed in October 1923, and the first test flight was carried out on the 21st of October of the same year. Despite using the older engine, the flight proved successful. It was piloted by Yevgeni Pogosski.
The completed ANT-1 test aircraft. Source: www.globalsecurity.org
Following this, the ANT-1 was used mainly for various testing and evaluation. It would see service in this manner for the next two years. In 1925 the aging engine finally gave up, and this made the aircraft unflyable. Tupovlev tried to find a factory that could potentially refurbish it. He ultimately failed, as the engine was simply beyond repair by that point.
The aircraft was for some time stored at Factory No.156. The fate of this aircraft is not clear in the sources, however, there are few theories about what happened to it. After Tupovlev’s imprisonment by Josef Stalin, his plans and documentation were confiscated. The aircraft was believed to be also confiscated and scrapped in the late 1930s. Another possibility is that it was moved to another storage facility where it was eventually lost during the Axis Invasion of the Soviet Union in 1941.
Specification
The ANT-1 was designed as a cantilever low-wing monoplane aircraft of mixed construction. The fuselage consisted of four spruce longerons. The lower two were connected to the wing spars and were held in place with four bolts. The parts of the fuselage starting with the pilot cockpit to the engine were covered in the metal alloy. This alloy was also used to provide additional strength of some internal wooden components of the aircraft fuselage. The pilot Pilot cockpit was provided with a small windscreen. Inboard equipment was spartan consisting only of an rpm counter, oil pressure indicator, and ignition switch.
The cantilever wings were made of single pieces. At the end of the two tips (on each side of the wings) large wooden spars were installed. Some parts of the wing were built using metal parts such as the wing ribs, The rest of the wing was mainly covered in fabric. The tail unit was made of wood, its surfaces were covered with a metal-fabric cover.
The fixed landing gear consisted of two large wheels. These were connected to a metal frame which itself was connected to the aircraft fuselage. Small rubber bungees acted as primitive shock absorbers.
Given that nothing else was available, the ANT-1 was powered by an old, refurbished 35-hp strong Bristol Anzani engine.
A good view of the ANT-1 internal wing and fuselage construction. Source: www.globalsecurity.orgThe cantilever wings received on each side one large wooden spar. Source: WikiThe pilot cockpit received only a few basic instruments and a small windshield. Source:www.globalsecurity.org
Conclusion
The ANT-1 despite its simplicity, and being built a single, cobbled-together prototype, could be considered a great success for Tupolev. Through this experimental aircraft, Tupovlev gained valuable experience in designing an aircraft by using metal alloy. This success emboldened Tupovlev to go even further and design and build the Soviet first all-metal construction aircraft known as ANT-2. The ANT-1 was Tupovlev’s first stepping stone in a long and successful career as an aircraft designer in the following decades.
ANT-1 Specifications
Wingspans
7.2 m / 23ft 7 in
Length
5.4 m / 17 ft 8 in
Height
1.7 m / 5 ft 7 in
Wing Area
10 m² / 108 ft²
Engine
One 35 hp Bristol Anzani engine
Empty Weight
230 kg / 5,070 lb
Maximum Takeoff Weight
360 kg / 7,940 lb
Maximum Speed
125 km/h / 78 mp/h
Range
400 km / 250 miles
Maximum Service Ceiling
600 m / 1,970 ft
Maximum Theoretical Service Ceiling
4,000 m / 13,120 ft
Crew
1 pilot
Armament
None
Gallery
Credits
Article written by Marko P.
Edited by Henry H.
Illustration by Godzilla
Sources:
Duško N. (2008) Naoružanje Drugog Svetsko Rata-SSSR. Beograd.
Y. Gordon and V. Rigmant (2005) OKB Tupolev, Midland
P. Duffy and A. Kandalov (1996) Tupolev The Man and His Aircraft, SAE International
B. Gunston () Tupolev Aircraft Since 1922, Naval Institute press
Kingdom of Hungary (1938)
Reconnaissance Aircraft & Light Bomber – 128 Built
The Weiss Manfrédfrom WM 21 two-seat reconnaissance aircraft. [lasegundaguerra.com]The Hungarian Aviation industry was rather small in scope in comparison to many in Europe. Regardless, it managed to introduce a number of domestic development projects. One of these was the Weiss Manfréd from WM 21, a two-seat reconnaissance aircraft of which some 128 were produced during the Second World War.
History
In the years after the First World War, Hungary was strictly forbidden from developing combat aircraft. To overcome this limitation, the Hungarians did what the Germans did and began developing a civil aircraft industry to help gain valuable experience in aircraft design. One of these companies that would emerge during the late 1920s was Weiss Manfréd, from Csepel near Budapest. In 1928 this company began working on the design and construction of gliders and engines.
Due to an initial lack of funds, the Hungarian Air Force was forced to rely on foreign aircraft that were bought in relatively small numbers. For example, by 1937 Hungarians had only around 255 operational aircraft. To help gain more experience, Weiss Manfrédfrom began producing Fokker F.VIII and C.V aircraft under license. When sufficient funds and experience were gained, Weiss Manfrédfrom engineers in 1935 began working on a new reconnaissance biplane design. They decided on a simple design, reusing some components that were already in production, and it would be a further development of the already produced WM 16 model, which was heavily based on the D version of the Fokker C.V.
The WM 21 predecessor was the WM 16 model which in turn was based on the C.V aircraft. [Wiki]When the prototype of the new short-range reconnaissance aircraft, WM 21 “Sólyom” (Falcon) was completed, it was presented to Hungarian Air Force officials, who were generally satisfied with its performance and gave an order for some 36 WM 21 in 1938. At that time, massive funds were being allocated to the development of the aircraft industry. In addition, Hungarian Air Force officials wanted to decentralize aircraft production. For this reason, the WM 21 was to be built by various other companies, including twelve to be built by MÁVAG and MWG
It was estimated that the production would commence during April and March 1939. It took longer to do so, with the first aircraft being available at the end of 1939. While the aircraft was slowly put into production, the Hungarian Air Force asked for more aircraft to be built.
In Combat
The WM 21 was primarily designed as a reconnaissance aircraft but due to a general lack of other aircraft types, it would be adopted for other roles. Its first combat use was during the so-called Transylvanian Crisis. Namely, in June 1940 Hungarian government demanded that Romania return the Transylvania region to them. Since it looked like war was coming, Hungarian Air Force began relocating its aircraft close to the Romanian border. Thanks to the commencement of negotiations, no war broke out. But by late August the Hungarians ordered a complete mobilization as the negotiation led nowhere.
While primarily intended to be used as a reconnaissance airfare it would be also used in other roles even as a light bomber. [lasegundaguerra.com]Germany did not want to lose its vital Romanian oil supply and forced both countries to begin new negotiations under German and Italian supervision. While the negotiations were underway, some smaller air skirmishes occurred. On the 27th of August, a Romanian He 112 attacked a Hungarian Ca 135 aircraft, which was heavily damaged and one crew member was killed. The following day a WM-21 piloted by Captain János Gyenesin, dropped bombs on the Romain Szatmárnémeti airfield in retaliation for the lost airman. On its way back it crash-landed, damaging the aircraft. In the end, Hungary emerged as the victor, gaining large territorial concessions over the Romanians.
When the April War broke out on the 6th of April 1941, between the Kingdom of Yugoslavia and the Axis, the Hungarians joined the offensive. They employed their 1st Air Brigade which had some 60 aircraft. By the 17th of April, the war was over, and the Hungarian Air Force had lost 6 aircraft including one WM 21.
A colorized picture of the WM 21 rearview. [all-aero.com]On the 26th of June 1941, the Hungarian town of Kassa was bombed by three aircraft. The circumstance of this incident is not clear even to this day, but the Hungarian government asserted that it was a Soviet attack. The decision was made to declare war on the Soviet Union as a response. For the initial operation in the war against the Soviets, the Hungarian Air Force allocated 25 bombers (Ju 86 and Ca 135), 18 CR 42 fighters, and the 8th and 10th reconnaissance squadrons each equipped with 9 WM 21.
By 1942 most WM 21’s were allocated for use by training schools and as liaisons. Some would be used in later years for anti-partisan operations. By the end of the war, some WM 21 pilots managed to reach Austria where they hoped to surrender to the Western Allies.
Technical Characteristics
The WM 21 was a mixed-construction, biplane aircraft, designed to fulfill multiple roles. The fuselage and the wings were of metal construction which was covered in fabric. The lower and the upper wings were connected with each other by one “N” shaped metal strut on each side. In addition, there were two “V” shaped metal brackets that were connected with the fuselage and the upper wing. Lastly, there were two larger metal struts on each side that connected the landing gears to the top wing.
The WM 21 was a biplane two-seater aircraft. The lower and upper wings were held in place by various smaller metal bars, connecting them to each other and to the fuselage. [all-aero.com]The landing gear consisted of two fixed road wheels and a rear-positioned landing skid. Partly-covered front wheels were connected to the aircraft fuselage by three large metal bins.
Initially, the WM 21 was powered by an 870 hp Weiss WM K-14A radial piston engine. With this engine, the WM 21 could reach a maximum speed of 320 km/h. Later produced aircraft were equipped with a stronger 1,000 hp WM K-14B engine. With this engine, the maximum speed was increased to 380 km/h.
The pilot and the observer/machine gunner were placed in two separate open cockpits, the front for the pilot, and the rear for the observer. For better downward visibility the observer was provided with two fairly large glass panels, placed just under him on both fuselage sides.
Side view of the WM 21. Note the small glass panel located under the observer cockpit. [lasegundaguerra.com]The WM 21 was armed with two forward-firing 7.92 mm Gebauer machine guns. One additional defensive machine gun was placed in a flexible mount which was installed in the rear cockpit. Additionally, the offensive capabilities of the aircraft could be increased by adding bombs. The bomb bay was placed between the two crew members. To release the bomb the crews would use a release mechanism. The bomb load could consist either of 12 10kg anti-personnel bombs, or 60 1kg incendiary bombs. Later versions increased the bomb load to around 300 kg.
To the rear an additional 7.92 mm Gebauer machine gun was placed in a rotating mount for self-defense. [airwar.ru]
Production and Modifications
The WM 21 was produced in four small series. When the production ended in 1942 some 128 aircraft would be constructed. While designed by Manfred Weiss, this factory produced only 25 aircraft. The MAVAG produced 43 with the 60 being built by MWG. Due to the relatively low production numbers, only one modification of the original aircraft was ever made:
WM 21A – Powered with an 870 hp Weiss WM K-14A engine,
WM 21B – Slightly improved version powered by 1.000 hp WM K-14B engine
Some 128 WM 21 would be built by 1942 when the production ended. [all-aero.com]
Conclusion
The WM 21 was a Hungarian reconnaissance aircraft that would see service on several different fronts. While initially used in its intended role, it quickly became obsolete and was allocated to secondary missions, as a training aircraft or for liaison missions. Due to a lack of adequate aircraft, some WM 21would even see service as combat aircraft against Partisans forces, mostly in the Soviet Union.
WM-21A Specifications
Wingspan
12.9 m / 42 ft 4 in
Length
9.65 m / 31 ft 8 in
Height
3.5 m / 11 ft 5 in
Wing Area
32.75 m² / 352.53 ft²
Engine
One 870 hp (649 kW) Weiss WM K-14A radial piston engine
Empty Weight
2,450 kg / 5,400 lb
Maximum Takeoff Weight
7,606 kg / 3,450 lb
Maximum Speed
320 km/h / 200 mph
Cruising Speed
275 km/h / 170 mph
Range
750 km / 466 mi
Maximum Service Ceiling
8,000m / 26,245 ft
Climb speed
Climb to 6,000 m (19,700 ft) in 7 minutes and 30 seconds
Crew
One pilot
Armament
Three 7.92mm machine guns
Total bomb load of some 100-300kg
Gallery
Weiss Manfred WM 21 “Sólyom”
Credits
Written by: Marko P.
Edited by:
Illustrations by Carpaticus
Sources:
D. Monday (1984, 2006) The Hamlyn Concise Guide To Axis Aircraft Of World War II, Aerospace Publishing Ltd.
G. Sarhidai, G. Punka, and V. Kozlik (1996) Hungarian Eagles, Hikoki Publication
G. Punka (1994) Hungarian Air Force, Squadron Publication
S. Renner. (2016) Broken Wings The Hungarian Air Force, 1918-45, Indiana University Press
USSR (1938-1940)
Experimental Long-Range Bomber – 1 Prototype Built
The Belyayev DB-LK [airwar.ru]In the late thirties and early forties, the Soviet aviation industry had developed and tested a variety of aircraft design concepts, some quite peculiar. While generally unknown around the world, a number of these strange aircraft would represent a serious departure from anything resembling their contemporaries. Such is the case with Victor Nikolayevich Belyayev’s DB-LK experimental long-range bomber.
History
Victor Nikolayevich Belyayev, March 1896 – July 1953, began working for the Department of the Marine Experimental Aircraft Construction, OMOS, in 1925, where he gained his first experience in aircraft design. In the following years, he worked for the Central Aerohydrodynamic Institute, TsAGl, and Tupolev. During this time, he became an advocate for tailless aircraft designs. He also argued that the so-called “batwing” or “butterfly”, offered better performance, due to their reduced drag and better stability, than regular wing designs.
The “batwing” design possessed a slightly forward-swept wing with back curved tips. Belyayev managed to construct a glider, designated BP-2, which was equipped with this kind of wing design in 1933, on which he tested this concept. During its test flight, it was successfully towed in the air from Crimea to Moscow, where it proved to have good stability and control during flight.
The BP-2 glider in flight. [airwar.ru]The next year, Belyayev participated in the competition for a new Soviet military transport plane design. His design was unusual, as it consisted of a large wing and two nacelles, powered by Tumanskii M-87B 950 hp (708 kW) engines. His design was not approved nor did he build a working prototype. However, four years later, he would reuse this project and adapt it for the role of a long-range bomber. In 1938, he designed the DB-LK long-range flying wing bomber, which the TsAGl approved and ordered the construction of a fully operational prototype. The prototype was built the following year by factory No.156 and by November 1939 it was ready for testing.
Technical Characteristics
The DB-LK had an unusual overall design with no classical fuselage. Instead, the crew, armament, and other equipment were located in the two extended engine nacelles that ended in glazed tail cones (gondolas), somewhat similar to the later German Fw 189. The two extended engine nacelles were, technically speaking, the plane’s fuselage. The semi-monocoque fuselages were constructed by using a combination of metal frames and longerons covered with a duralumin sheet. The DB-LK was designed in this unusual configuration in the hope of reducing the overall drag and weight and thus increasing its speed and range.
The DB-LK’s wings had a unique design, where beside the “batwings” there was an additional center wing section between the two fuselages. Also, the wings were slightly swept to the front with back curved tips. The wings consisted of an airframe covered with light metal stressed-skin. The outer wings had a Gottingen 387 profile, while the center section had a CAHI (TsAGI) MV-6bis profile. The wing edges were curved at an angle of -5° 42′.
A side view of the DB-LK. The strange wing design can be seen. [elpoderdelasgalaxias.wordpress.com]The rear tail was located on the middle section wing between the two fuselages. The tail consists of one fin and a large 20 ft2 (1.9 m2) rudder. Above the rudder, a smaller tailplane with two, one on each side, large elevators was placed.
A rear view where the large tail and the left glazed rear cone can be seen. [airwar.ru]One Tumansky M-87B 950 hp (708 kW) 14-cylinder radial engine was installed at the front of both nacelles. For these engines, three-bladed propellers with variable pitch were used. It was planned to upgrade these two with much stronger 1,100 hp (820 kW) M-88 engines, or even the 1.700 hp M-71, but this was never implemented. The fuel was stored in the wing and fuselage tanks, with a total fuel load of 3.444 l.
The landing gear retracted rearwards, with one wheel (900 x 300 mm) in each fuselage. During later testing, the landing gear design was changed with a forward retractable one. This whole landing gear system was operated hydraulically. There was a small fixed rear wheel (450 x 150 mm) located at the bottom of the tail unit.
The DB-LK was to be operated by a crew of four: the pilot, navigator, and the two rear gunners. The pilot position was in the left cockpit and the navigator in the right. The gunners were positioned in both rear glazed cones. One of the two gunners was also the radio operator. The crews entered their positions through roof hatch doors. The two glazed cones could be mechanically rotated 360° by using a small electric engine located at the fuselage top, but the sources do not specify why this was done.
Inside the pilot cockpit [авиару.рф]The interior of one of the two fuselages. In the picture on the right, the rear machine gun mount can be seen. On the left, the radio and the mechanism that rotated the whole glazed cone can be seen. [авиару.рф]Both rear glazed tail cones had a recess where a twin 7.62 mm (.30 caliber) ShKAS machine gun mount was installed. These machine guns had a -10 to +10 field of fire in all directions. Besides these four machine guns, there were two additional ones forward mounted in the leading edge of the center section. These two machine guns were operated by the pilot. In total, around 4,500 rounds of ammunition were provided for these machine guns. The bomb bays were located behind the landing gear doors in each of the two nacelles.
Depending on the sources, the load capacity of the bomb carried is different. The authors Yefim G. and Dimitri K. note that the bomb load was 1000 kg (2,200 lb) with another 1000 kg that could be carried on external racks. According to Bill G., the capacity of each bomb bay (in each fuselage) was one 1000 kg (2.200 lb), two 500 kg (1.100 lb), or smaller bombs with a total of 1000 kg (2.200 lb) weight.
Both front and rear views of the DB-LK’s unusual design. [авиару.рф]
Flight Tests
While being completed in November 1939, the first extensive flight test would only begin the following year. This was due to the unwillingness of the test pilot to fly this plane. He did not believe that it was safe to fly due to its unorthodox design. During this time, the plane received the nickname “Kурица” (chicken).
In order to move the entire project testing through this roadblock, the Soviet Direction of the Air Force Scientific test institute, GK Nil WS, appointed M. Nyuikhtikov as the main test pilot, supported by aircraft engineer and test pilot T. T. Samarin and N. I. Shaurov. Under the new leadership, the tests were carried out in the spring of 1940. During the new leadership, the DB-LK was extensively tested in over 100 flights.
During these flights, the pilots managed to reach speeds of 245 mph (395 km/h) at sea level and 300 mph (490 km/h) at an altitude of 16,400 ft (5,000 m). The DB-LK needed a 2,030 ft (620 m) long airfield for landing and taking off. However, the DB-LK was never truly trialed with a fully loaded payload. The numbers presented above would have likely been different with a full payload of equipment.
The test pilot Nyuikhtikov, after flying on the DB-LK, pointed out some issues with the plane’s design. The main problems were the inadequate overall flight-control system, poor visibility for the pilot and the navigator, especially on the ground. He also noted the poor construction of the landing gear. These reports were examined by the Nil WS Commission led by A. I. Filin. They agreed that the control system should be improved, but Filin had a positive opinion on the landing gear construction. Ironically, during a test flight, where Filin was the pilot, there was a landing gear malfunction during the landing when one of the front wheels broke free, after a possible collision with a treetop. The aircraft was only lightly damaged and the testing continued, but this led to a change in the landing gear design.
There were also other problems mentioned during the tests, like uncomfortable cockpits, low-level of fire protection, structural problems, a limited firing arc of the rear-mounted defense machineguns, and the tendency for the crew compartments to be filled with exhaust fumes from the engines. To solve these issues, there were plans for the DB-LK improvements, with stronger engines, wings, and various other modifications, to be completed by late 1940 but they were probably never implemented.
Rearview of the accident. [авиару.рф]
Conclusion
Despite plans for more testing and improvements, unfortunately for the DB-LK design team, they never got a chance to do so. In late 1940, the Nil WS Commission gave orders for the cancellation of the DB-LK program. The main reason for this was the decision for the production of the Il-4 as the main Soviet long-range bomber.
The Yak-4. [Wiki]Following the failure of the Yak-2, Yakovlev attempted to salvage the project. One of the attempts that saw limited production was the Yak-4. While it would be powered by a somewhat stronger engine, it too would prove to be a failure and only some 100 aircraft would be built by 1941.
The Yak-2 Failure
While the Yak-2 prototype initially had excellent flying characteristics, once it was actually fully equipped with its military equipment, its performance dropped dangerously. A large number of issues, like overheating, poor flight stability, and problems with its hydraulics, were also noted during the development phase. Despite this, some 100 aircraft would be built and some were even issued for operational use.
Yak-2 side view. [Gordon & Khazanov, Soviet Combat Aircraft]One of the many weak points of the Yak-2 was its problematic Klimov M-103 engine. The Soviet designers decided to replace this with the more powerfulr M-105 engine. Two basic designs emerged, one for a dive bomber and one for a short-range bomber. During its first test flight, the dive bomber variant proved to be so disappointing that the project was canceled. The bomber version, however, showed to be somewhat promising and the green light for its development was given.
Development History
The development of the BB-22bis (also known as Izdeliye 70bis) prototype was given to Factory No.1, and the Yak-4 designation was officially adopted only in December 1940. Engineers at Factory No. 1 started to build the prototype in early 1940 and it was completed by March the same year. This was not a new aircraft, but a modified Yak-2,serial number 1002) . That same month, Factory No.1 was instructed to produce additional prototypes for testing the aircraft’s performance by the Army, which had to be completed by the start of July 1940. The Army requested a maximum speed of 590 km/h (366 mph) at 5,000 m (16.400 ft)be , an operational range of 1,200 km (745 miles), and a service ceiling of 11,000 m (36,090 ft).
The modified Yak-2 (serial number 1002) aircraft that served as the base for the BB-22bis prototype. [Y. Gordon, D, Khazanov and S. Komissarov OKB Yakovlev ]Following the completion of the first prototype, a series of test flights were carried out. During one of the test flights, carried out on the 12th May, a maximum speed of 574 km/h (356 mph) was achieved. On 23rd May, however, there was an accident and the pilot was forced to crash land at a nearby airfield, damaging two other bombers and the prototype’s wing in the process. Given the extensive damage to the aircraft’s wing, the prototype had to be written off. Due to this and delays in production, the first two trial aircraft could not be completed before the end of 1940. Interestingly enough, these were actually produced by the Moscow Aircraft Factory No.81, which started the production of the Yak-4 during October and November 1940. At that time, the type had not yet received official approval from the Soviet Army.
The damage suffered by the first prototype during its hard landing was so severe that it had to be scrapped. [Y. Gordon, D, Khazanov and S. Komissarov OKB Yakovlev]
The two trial aircraft were given to the Army for testing on 10th December 1940. These tests were held at the end of January 1941. The results were once again disappointing, as these aircraft had worse performance than the prototype. With the added weight of equipment and fuel, the maximum speed was reduced from 574 km/h (357 mph) to 535 km/h (332 mph). The cockpit was described as being too cramped, and with the full bomb load, the plane proved to be difficult to control even by experienced pilots. The commission that examined the two aircraft insisted that the Yak-4 should not be accepted for service. In late February 1941, the Director of Factory No.81 gave a report to the Soviet People’s Commissar of the Aircraft Industry, A. Shakhoorin, that the production of the Yak-4 was to be stopped and replaced with the Yak-3. Interestingly enough, while the Yak-2 was developed by Alexander Sergeyevich Yakovlev, he did not direct the design process of the Yak-4.
Technical Characteristics
The Yak-4 was an overall copy of its predecessor, the Yak-2, but there were still some differences. The most obvious change was the introduction of new engines. The older M-103 ,960 hp, was replaced with a stronger M-105 1050 hp engine. The installation of the two new engines also introduced a number of internal improvements to the ventilation and fuel systems. New 3.1 m (122 in) long VISh-22Ye type propellers were also used on this model. The landing gear retracted to the rear into the engine nacelles, but was not fully enclosed. These consisted of two pairs of 700×150 mm wheels.
The rear parts of the fuselage were lengthened and redesigned, and it was less bulkier than the Yak-2. The cockpit was improved in order to provide the crew with a slightly better overall view. The rear gunner received a completely new pivoting canopy. He operated the TSS-1 mount armed with two 7.62 mm (.30 caliber) ShKAS types machine guns.
Rear view of the Yak-4. [Wiki]The maximum bomb load was increased to 900 kg (1,980 lbs). In addition, there was an option of mounting two 90 (20 gallons) or one 250 liter (54 gallons) auxiliary fuel tanks under each wing. There were six fuel tanks placed in the wings. These had a total capacity of 1,120 litres (244 gallons) of fuel.
A front view of the Yak-4 with its new and stronger M-105 engines. [Y. Gordon, D, Khazanov and S. Komissarov OKB Yakovlev]
In Combat
The Yak-4, together with the Yak-2, was allocated to the 314th and 316th Reconnaissance Regiments in the western district. Some were given to the 10th, 44th, 48th, 53rd, 136th and 225th short to medium range Bomber Regiments. The main problem for the units that operated the Yak-2 and Yak-4 was the slow delivery of these aircraft. For example, only a few pilots from the reconnaissance units had a chance to fly on these new aircraft. By 10th June 1941, only limited numbers of Yak-4s were available for service. A shipment of some 10 new aircraft was meant to arrive but did not due to the war’s outbreak.
Pilots from the 314th Reconnaissance Regiment performed several flights over the border with Germany just prior to the Invasion of the Soviet Union while flying Yak-4s. The Germans responded by sending the Bf 109E to intercept them, but they failed to do so. However, once the war started, the German Luftwaffe destroyed many Soviet aircraft on the ground. This was also the case with the Yak-4, with the majority lost this way. Some did survive though and offered limited resistance to the Germans. By September 1941, on the Northern front, there were still fewer than 10 operational Yak-4s. To the South, there were still some 30 or so Yak-4s which were still operational by October 1941. There is no information of the use or losses of the Yak-4 after 1942. According to Y. Gordon, D, Khazanov and S. Komissarov OKB Yakovlev , at least one Yak-4 was still operational and used by the 118th Reconnaissance Regiment in 1945.
Most of the Yak-4s were destroyed on the ground by the advancing Germans. [Y. Gordon, D, Khazanov and S. Komissarov OKB Yakovlev]The advancing Hungarians, who were supporting the Germans during the Invasion of the Soviet Union, managed to capture at least one Yak-4 aircraft during 1941. The use of this aircraft by them would be limited at best, due to the scarcity of spare parts and general poor performance.
Production
The production of the Yak-4 was only carried out at Factory No.81. The production lasted from November 1940 to April 1941. Around 90 to 100 aircraft would be built, with the last 22 Yak-4s being delivered for use by late April 1941.
Operators
Soviet Union – Operated some 90 aircraft
Hungary – Managed to capture at least one Yak-4 aircraft
Conclusion
Despite attempts to resolve a number of issues noted on the previous version, the Yak-4 in general failed to do so. The problem was the overall poor design of the original Yak-2 which offered little room for improvement. The inability to improve the aircraft to the satisfaction of the Soviet Air Force led to the cancelation of the Yak-4 project after only a small number of aircraft was built.
An impressive photo of freshly produced Yak-10 sit on the Dolgoprudny airfield awaiting delivery. [Yefim Gordon]The Yakovlev Yak-10 was a four-seat multipurpose light aircraft designed in 1944 as a replacement for the Polikarpov U-2 (Po-2), a biplane which served as a liaison and passenger transport aircraft. Although the Yak-10 successfully passed state acceptance trials in January of 1945, it proved rather unsatisfactory with Soviet Air Force pilots, and thus, only 41 examples, including the prototype, were produced in 1946 before being replaced by the redesigned and superior Yak-12 light aircraft in 1947. Though unsuccessful in service, the Yak-10 provided valuable experience in light aircraft design and served as a stepping stone for the more successful Yak-12.
History
In early 1944, the Soviet High Command was beginning to realize the obsolete nature of the Polikarpov U-2 (Po-2) in its liaison role. In the wake of the quickly advancing aircraft industry, Yakovlev OKB (Experimental Design Bureau) was called upon to design a multipurpose light aircraft capable of performing liaison missions, ferrying passengers, cargo, and aerial ambulance duties for the Air Force to replace the Po-2. In response, Yakovlev OKB initiated a project with G.I. Gudimenko assigned as chief engineer and work commenced on a four-seat, high-wing monoplane using the firm’s pre-war AIR-6 design as a basis, which had similar traits. The new aircraft design was assigned the designation of Yak-14.
Due to the rather obscure nature of the project’s development, it is unknown when the first prototype was produced, but it is most likely sometime before or in early January of 1945. First flown by test pilot F.L. Abramov, the Yak-14, powered by a 5-cylinder, air cooled Shvetsov M-11FM radial engine producing 145 hp, proved to have unacceptable handling characteristics. This prompted minor redesigning and modifications to the prototype which would address the issues that emerged from the test flight. Amongst the various modifications, the aircraft was also redesignated as the Yak-10 (the Yak-14 designation would later be reused for a 1947 assault glider project). With the completion of modifications, the Yak-10 was resubmitted for state testing. The aforementioned handling characteristic issues appeared to have been addressed, and the Yak-10 passed state trials in June of 1945.
Yak-10 Blueprint Drawing
Now authorized for service, production of the Yak-10 was assigned to the No. 464 aircraft plant in Dolgoprudny (Долгопру́дный), approximately 12 mi / 20 km north of Moscow. A total of 40 models were produced in 1946, which were then delivered to air force units. An important difference between the prototype and production models was the conversion from the 145 hp M-11FM engine to the 160 hp M-11FR engine. During the Yak-10’s service life, several variants were designed. These included a dual-control trainer variant known as the Yak-10V, an aerial ambulance variant capable of carrying two stretchers and a doctor known as the Yak-10S, an experimental floatplane variant known as the Yak-10G, and an experimental ski landing gear conversion without a proper designation. Due to the scarcity of documents regarding the Yak-10, it is unknown how many Yak-10V and Yak-10S models were produced, but the Yak-10G and Yak-10 with ski gear were converted from standard Yak-10 models. Curiously, the Yak-10 also had a competitive experimental low-wing development in 1944 known as the Yak-13 (originally designated the Yak-12, which is unrelated to the 1947 development) which featured a split landing flap and various smaller modifications. Though the Yak-13 was superior to the Yak-10 in speed, the Yak-10 possessed operational advantages and thus won the favor of the Soviet high command. Though the Yak-13 was considered to be produced alongside the Yak-10, the act was deemed economically unviable and thus the Yak-13 remained a one-off prototype.
The Yak-10 prototype, still known as the Yak-14 at the time this photo was taken. [Yefim Gordon]In Soviet service the Yak-10 proved to be lacking in terms of performance, which also impacted the aircraft’s ability to be adapted to more roles. Within a year of the Yak-10’s fielding, the Yakovlev OKB was once again called upon to produce a better aircraft. In early 1947, the bureau initiated another project to fulfill the demands of the Air Force. G.I. Gudimenko was once again assigned as chief engineer, but now M.A. Shchyerbina, M.N. Beloskurskii and L.L. Selyakov joined the team as designers. The new project was designated as the Yak-12 (recycled from the Yak-13’s initial designation) and was essentially a redesigned Yak-10 that featured a redesigned rear fuselage contour and a shallower upper decking. Along with some other modifications to the wings, structure and fuselage, the Yak-12 would undergo flight testing within the same year. Though slower than the Yak-10 in speed, the Yak-12 proved to be more versatile for other roles and had greater operational characteristics. Such improvement was deemed satisfactory by the Air Force and mass production thus commenced. The success of the Yak-12 overshadowed the Yak-10 and all examples were withdrawn soon afterwards. The Yak-12 would be produced in the thousands with dozens of variants and conversions designed. It would see service with several Eastern Bloc countries, as well as the People’s Republic of China, Mongolia and possibly Cuba (it is unknown if they operated this type). The Yak-12 was saw military service well into the 1970s but were all retired prior to the 21st century. Several Yak-12 models are still flown to today for recreation, airshows and other roles.
The Yak-10, despite passing state acceptance trials, was still an operational failure and saw only limited production. However, the Yak-10 was an important stepping stone in the development of the Yak-12, which was much more successful and had a fruitful service life within the Soviet Union and several other countries.
Design
A Yak-10 flies over the Moskva River near the Moscow suburbs. [Yefim Gordon]The Yakovlev Yak-10 was a four-seat, high-wing, single-engine multipurpose light aircraft designed in 1944. The standard production Yak-10 was powered by a 5-cylinder air-cooled Shvetsov M-11FR radial engine providing 160 hp, accompanied by a two blade aluminum VISh-327 propeller. The Yak-10’s fuselage and tail was of metal construction while the wings were wooden. The wooden wings possessed a thickness to chord ratio of 11% and utilized the Clark YH airfoil. The fuselage consisted of a welded tubular steel truss while the tail possessed duralumin frames. Fabric was utilized throughout the entire aircraft for skinning. Twin bracing struts constructed of airfoil section steel tubes joined the wings and fuselage. The Yak-10 also had a non-retractable undercarriage in a taildragger configuration. It consisted of pyramid type, rubber-sprung main units and had a castoring tailwheel.
The same Yak-10 above parked at the Chkalovskaya AB during state acceptance trials at NII VVS. [Yefim Gordon]The Yak-10V dual control trainer variant would have featured a new set of controls next to the regular pilot seat. This would allow a co-pilot to fly while both pilots sat side by side. The Yak-10S ambulance variant would have a hatch on the port side of the fuselage for loading stretchers. A total of two stretchers could be accommodated in the Yak-10S along with a seat for a doctor. The Yak-10G featured the replacement of the conventional landing gear with floats previously used in the Yakovlev OKB’s previous AIR-6 multipurpose light aircraft design. Little is known about this variant, but it is known that it did not go into production due to the loss of performance caused by the floats’ drag. The experimental Yak-10 ski conversion had the landing gear replaced by Canadian manufactured wood skis of 6 ft 3 63/64 in x 1 ft 25/64 in / (1,930 x 340 mm). These skis weighed 44.7 lb (20.25 kg). The tail wheel was also replaced by a ski which measured at 1 ft 6 7/64 in x 4 47/64 in (460 x 120 mm) and weighed 4.25 lb (1.93 kg). This modification caused the aircraft’s performance to deteriorate and proved to be only capable of operating in rolled-down airfields. Consequently, the type was not adopted for use.
Variants
Yak-10 – Standard production variant powered by a 5-cylinder air-cooled Shvetsov M-11FR radial engine providing 160 hp.
Yak-10V – Dual control trainer variant of the Yak-10. An unknown amount were produced.
Yak-10S – Medical variant of the Yak-10 which featured a hatch on the port side of the fuselage for loading stretchers. The passenger compartment could accommodate two stretchers and one doctor. It is unknown how many Yak-10S models were manufactured.
Yak-10G – Experimental floatplane variant of the Yak-10. A single Yak-10 was modified to carry AIR-6 type floats in 1946. The Yak-10G underwent manufacturer’s tests but this type was not accepted for mass production, likely due to the degradation of performance generated by the floats’ drag.
Yak-10 (Skis) – Experimental conversion of a Yak-10 to replace the conventional landing gears with Canadian manufactured wooden skis. A single example was converted from a standard model in February of 1947 but was rejected for service as the skis caused the Yak-10’s performance to deteriorate. The ski variant was also deemed only capable of being operated from rolled-down airfields, thus limiting the operable areas.
Yak-13 – Development of the Yak-10 in 1944 which saw a redesigned low-wing configuration, a split landing flap and various smaller modifications. The engine was also switched to a M-11FM radial engine producing 145 hp. The Yak-13 was superior to the Yak-10 in terms of performance, but this aircraft was not accepted for mass production as the Yak-12 was deemed better in some regards and as a result, the Yak-13 remained a one-off prototype. This variant was originally designated as the Yak-12 but the name was changed to Yak-13 during trials and the designation was reused for the 1947 development project of the Yak-10.
Yak-12 – Redesigned variant which first appeared in 1947. The Yak-12 featured a redesigned rear fuselage contour and a more shallow upper decking. Though the base model was slightly inferior to the Yak-10 in speed, the redesigned variant proved more capable in other aspects and was thus mass produced and replaced the Yak-10 in service.
Operators
Soviet Union – The Yakovlev Yak-10 and it’s variants were briefly operated by the Soviet Air Force from 1946 to 1947 before being replaced by the superior Yak-12.
Yakovlev Yak-10 – Standard ModelYakovlev Yak-10 – Standard Model in Alternate LiveryYakovlev Yak-10 – Air AmbulanceYakovlev Yak-10 – Float Variant
The prototype Yak-10G floatplane variant sits in a river awaiting flight trials. [Yefim Gordon]A Yak-10 flies over the Moskva River near the Moscow suburbs. [Yefim Gordon]A white painted Yak-10S ambulance variant. The port hatch for loading stretchers is visible beside the cross. [Yefim Gordon]
The Yer-2ON was a VIP passenger transport aircraft designed in 1944 by Vladimir Grigoryevich Yermolayev and his Yermolayev OKB (design bureau). Based off of the firm’s preexisting Yer-2 bomber, the Yer-2ON was meant to fulfill the role of a government VIP transport aircraft which would carry government members to and from meetings in or out of the Soviet Union. Shortly after Vladimir Yermolayev died on December 31st of 1944 from a typhoid infection, the Yermolayev OKB firm was integrated into Pavel Sukhoi’s Sukhoi OKB firm where the project continued. Despite showing relatively promising performance, the Yer-2ON would eventually be cancelled due to the conclusion of the Second World War and the Sukhoi OKB’s need to concentrate resources on other projects. Thus, the three produced Yer-2ON would never be used for their intended purpose and were presumably scrapped some time post-war.
History
Diplomacy between the Allied countries during the Second World War was an essential step in defeating the Axis powers. With the increasing successes of the Allies during the war, meetings between representatives from the United States, Soviet Union and United Kingdom were held to discuss the future of Europe along with battle plans. In order to attend these meetings, the Soviet government became aware of the need for a long-range VIP passenger transport aircraft capable of carrying 10 to 12 people while maintaining comfort, reliability, cruising abilities at 13,000 ft to 16,400 ft (4,000 m to 5,000 m) and range of 2,500 mi to 3,100 mi (4,000 km to 5,000 km). After Joseph Stalin himself made a request for an aircraft meeting these requirements in January of 1944, a meeting was held between government and Soviet Air Force officials discussing the feasibility of converting existing bomber aircraft to meet this need. Not only would this save time, but also had the benefit of sharing the same airframe as aircraft already in production. In the end, the Yermolayev OKB’s liquid-cooled Charomskiy ACh-30B V-12 diesel engine powered Yer-2 bomber was chosen for conversion. Curiously enough, Yer-2 being used as a transport aircraft is quite ironic, as it reflects on Roberto L. Bartini’s 1937 Stal-7 transport aircraft, from which the Yer-2 bomber was originally developed from.
A frontal view of the passenger compartment. (AviaDejaVu)
Shortly after the NKAP (People’s Commissariat for Aviation Industry) approved Order 351 on May 23, 1944, the head designer of the Yermolayev OKB firm, Vladimir Grigoryevich Yermolayev, began work on converting the Yer-2 into a VIP passenger transport aircraft. In his address to the NKAP on that day, he promised that a completed example would be converted by Factory No.39 and be ready for tests by November 15th. This new variant would be designated Yer-2ON (Osoboye Naznachenie – Special Purpose). With most of the groundwork already completed, Yermolayev was able to complete the conversion blueprints by August. An inspection was conducted on the Yer-2ON’s plans on August 28th and was approved for production. The difference between the Yer-2ON and the standard bomber variant was the removal of all armament and replacement of the bomb bay with a passenger compartment. The passenger compartment would have been able to hold 9 passengers, as well as a flight attendant. All relevant technical drawings were sent to Factory No.39 in the Irkutsk Oblast. A total of four Yer-2 bombers were ordered for conversion, but standard Yer-2 production would run into difficulties as the diesel powered Charomskiy ACh-30B engines manufactured at Factory No.500 were found to have defects and needed to be addressed. As such, the project was put on hold for a considerable amount of time.
A rear view of the Yer-2ON. (Одноклассники)
On December 31st, Vladimir Grigoryevich Yermolayev passed away due to a typhoid infection. As a result, the Yermolayev OKB and its assets were integrated into Pavlov Sukhoi’s Sukhoi OKB firm. It would appear that N.V. Sinelnikov took over as head designer once the project was integrated into Sukhoi OKB. Once the issue with the engines was resolved, three Yer-2 bombers were set aside and were prepared to be converted into the Yer-2ON. Due to the relatively poor documentation of the Yer-2ON’s development, it is unknown when precisely the first Yer-2ON was completed, but most sources allege it was completed at the end of December. The manufacturer’s flight tests and maiden flight appeared to have taken place sometime in February of 1945. Through these tests it was revealed that the Yer-2ON was capable of covering a distance of 3,230 mi / 5,200 km while maintaining a flight ceiling of 19,700 ft / 6,000 m and a top speed of 270 mph / 435 kmh.
On April 16th, the first Yer-2ON made a record non-stop flight from the Irkutsk Aviation Plant’s airfield in Eastern Siberia to Moscow. This flight was accomplished by Heroes of the Soviet Union M. Alekseev and Korostylev over a flight time of 15 hours and 30 minutes and covered a distance of approximately 2,611 mi / 4,202 km. It would appear that a second flight would be conducted sometime near the end of April with the second converted aircraft once it was ready. The second flight had identical circumstances as the first flight (same pilots, destination, fuel load, etc). Interestingly enough, both flights concluded with enough fuel for four more hours of flight, attesting to the Yer-2’s long-range capabilities. A third Yer-2ON was converted at an unspecified time, but details of its tests (if it performed any at all) are unknown. Some internet sources claim that a fourth example was completed on May 10th of 1945, but this cannot be confirmed and disagrees with most publications.
One of the passenger seats of the Yer-2ON. (AviaDejaVu)
Despite the Yer-2ON performing relatively well and passing the manufacturer’s flight tests, the aircraft was never used for its intended role of government VIP passenger transportation. This was likely the result of the project being deemed as low priority within the Sukhoi OKB firm. At the time, Sukhoi was invested in other more pressing projects which led to the Yer-2ON being eventually canceled. Joseph Stalin himself was reputed to have aviophobia (a fear of flying) and the Yer-2ON not entering service did not appear to have consequences for the Sukhoi OKB. Nonetheless, the Yer-2ON project was dropped some time post-war and the three manufactured prototypes were likely scrapped as a result.
Design
A cutout drawing of the Yer-2ON’s interior. (AviaDejaVu)
The Yermolayev Yer-2ON was a two engine VIP passenger transport aircraft based on the Yermolayev Yer-2 bomber aircraft, powered by two liquid-cooled Charomskiy ACh-30B V-12 diesel engines capable of producing 1,500 hp each. The Yer-2ON was identical to the standard Yer-2 bomber in most respects, though armaments and turrets were removed and the bomb bay was converted to a passenger compartment with seats for 9 passengers and 1 flight attendant. The crew would have consisted of a commander pilot, a co-pilot, a navigator, a radio operator, and a flight attendant. In the passenger compartment, the left side (aircraft facing forward) had 5 seats while the right side had 4. The flight attendant’s seat was located behind the last seat on the right side, and was retractable. A luggage compartment was also provided. Another notable feature was the addition of a toilet compartment, as the aircraft’s long-distance travel routes required such a feature. Several windows were installed on the side of the fuselage for the passengers.
Operators
Soviet Union – The Yer-2ON was intended to be used as a passenger transport aircraft for government VIPs traveling in and out of the country to attend meetings.
Yermolayev Yer-2ON*
* – Statistics taken from “OKB Sukhoi: A History of the Design Bureau and its Aircraft” by Dmitriy Komissarov, Sergey Komissarov, and Yefim Gordon
Yermolayev Yer-2ON Side View IllustrationA side view of the Yer-2ON. (AviaDejaVu)The entrance to the passenger section. (AviaDejaVu)This photo shows what appears to be a retractable seat in the rear of the passenger compartment. This seat most certainly would be for the flight attendant. (AviaDejaVu)Toilet compartment of the Yer-2ON. (AviaDejaVu)
Nazi Germany (1945)
Rocket Interceptor Trainer – 1 Built
A rear 3/4 view of the Soviet captured “White 94” Me 163S. Colorization by Michael Jucan [Yefim Gordon]The Messerschmitt Me 163S (Schulflugzeug / Training Aircraft) Habicht (Hawk) was an unarmed two-seat training glider based off of the famous Messerschmitt Me 163 Komet. Originally designed for the purpose of training novice pilots for landing, the Habicht ultimately never saw active service with the Germans and only a single example was produced through the conversion of a serial Me 163B-1. With the sole example captured by the Russians after the war, the Habicht underwent extensive testing by the Soviet Air Force which helped them understand the flying characteristics of the Komet and prepared Soviet pilots for flying the powered Komets. The Habicht undoubtedly played a part in helping Soviet engineers understand the Komet and thus played a part in the future development of Soviet rocket aircraft.
History
A closeup view of the Me 163S showing the right wing. [Yefim Gordon]The Messerschmitt Me 163 Komet was one of Nazi Germany’s most famous aircraft produced during the Second World War. Although bearing the title of the world’s first mass-produced rocket-powered interceptor, the Komet did have its fair share of flaws, such as the volatile and sometimes dangerous Walter HWK 109-509 rocket engine, which prevented it from becoming an effective weapon against the Allies.
As the Komet was designed to have a limited amount of fuel to engage Allied bombers, pilots were expected to glide the Komet back to friendly airfields once they disengaged from combat. With gliding landings as a potential problem for the less experienced pilots, one of the ideas proposed by Messerschmitt designers in 1944 was to introduce a dedicated trainer variant of the Komet which would have a student pilot accompanied by an instructor pilot. Designated as the Messerschmitt Me 163S (Schulflugzeug / Training Aircraft) Habicht, the trainer glider differed from the production model with the addition of an instructor’s cockpit behind the forward cockpit. This addition was accompanied by the removal of the Walter HWK 109-509 rocket engine and the Habicht would have to be towed by another aircraft in order to get airborne. Another interesting addition to the Habicht was a second liquid tank behind the instructor’s cockpit for counterbalancing. All the liquid tanks would be filled with water for weight simulation and ballast. A total of twelve examples were planned for production, but only one was produced due to wartime production constraints.
The sole example of the Habicht was built by converting an earlier Me 163B-1 production model. Due to the scarcity of information regarding the Me 163S, it is unknown exactly when the Habicht was produced and what sort of testing it may have undergone during German possession. However, it is known that the Soviet Union was able to capture the only example during the final stages of the World War II’s Eastern Front. The sole Habicht was sent to the Soviet Union along with three Me 163B Komets during the Summer of 1945 for thorough inspection and testing. In historian Yefim Gordon’s book “Soviet Rocket Fighters – Red Star Volume 30”, he claims that in addition to the three Komets, seven Habicht trainer models were also captured. This, however, remains quite dubious as there is no evidence that more than one Habicht existed, and all current photographic material, research materials, and books all suggest that only a single example was produced.
The Me 163S in simulated flight configuration aided by struts. [Yefim Gordon]As the Soviets were particularly interested in rocket propulsion aircraft, the State Defence Committee issued a resolution which called for the thorough examination of the Walter 109-509 jet engine and the Me 163 Komet along with captured German documents on rocket propulsion. The three Me 163B Komets, of which only one was airworthy, and the Me 163S Habicht were sent to the Flight Research Institute (LII), the Valeriy P. Chkalov Soviet Air Force State Research Institute (GK NII VSS), and the Central Aerohydrodynamic Institute (TsAGI). The Habicht and Komets saw extensive testing in Soviet hands, undergoing several structural, static and wind tunnel tests. During the initial flight testing period, the Komet only flew as a glider as Soviet pilots and engineers were unsure of whether or not the Walter rocket engine was ready for use since bench tests were not completed. Securing the T-Stoff and C-Stoff propellants for the rocket engine was also a problem. In order to understand the handling characteristics of the Komet, the Habicht was flown numerous times at different altitudes, as was the unpowered Komet. A Tupolev Tu-2 bomber was responsible for towing the Habicht to these altitudes. Under Soviet ownership, the Habicht was given the nickname of “Карась” (Karas / Crucian Carp) due to the glider’s distinct silhouette. The test pilot responsible for flying the Habicht was Mark Lazarevich Gallaj. In general, the Habicht was considered relatively easy to handle by the Soviet test pilots. It is unknown how many test flights the Habicht underwent, but the aircraft certainly aided Soviet pilots in understanding the handling characteristics of the Komet. The Habicht’s service came to an end once the Soviet state trials of the Komet concluded. The sole example was scrapped sometime in 1946, along with seemingly all the other Komets.
If the Me 163S was able to be mass produced and flown with the Luftwaffe, the aircraft would have been a valuable tool to train German pilots. Landing the Komet was a problem for some pilots and in some cases resulted in fatalities but, with the use of the Habicht, the number of accidents would have certainly decreased.
Design
The Me 163S hung upside down in an unspecified TsAGI workshop for static testing. [Yefim Gordon]The Messerschmitt Me 163S Habicht was a semi-monocoque aluminum based two-seat training glider developed off the standard tailless Messerschmitt Me 163B-1 Komet. The sole example was converted from a production Komet, which meant dramatic modifications had to be made to the aircraft. The Walther HWK 109-509 rocket engine was removed and in its place was a cockpit for an instructor. The fuel tanks in the airframe were all filled with water to simulate fuel weight while another water tank was added behind the instructor’s cockpit for ballast purposes. There was no armament fitted to the glider. There was a small transparent section between the student pilot’s cockpit and the instructor pilot’s cockpit, presumably for the purpose of communication. As there are no known German documents on the Habicht and Russian documents are scarce, not much is known on the other differences the Habicht may have had. Detailed specifications of the Habicht are unknown, but theoretically it should have been identical to the standard Me 163B-1 Komet except for possibly weight, air drag and center of gravity.
Operators
Nazi Germany – The intended operator and producer of the Me 163S Habicht.
Soviet Union – The main operator of the Me 163S Habicht. A single Habicht was captured and tested by the Soviets after the war. The Habicht was scrapped in 1946.
*Editor’s note: As noted above, the exact specifications of the Me 163S Habicht are unknown. However they are presumed to be similar to that of the Me 163B-1 Komet.
Me 163S Habicht “White 94” in Russian Service [Haryo Panji]Me 163S Habicht in German Service [Haryo Panji]
Now known as the “White 94”, the Me 163S sits idly by. [Yefim Gordon]A closeup view of the Me 163S showing the transparent section between the two cockpits. [Yefim Gordon]The Me 163S in simulated flight configuration aided by struts. [Yefim Gordon]A top down view of the “White 94” Me 163S. [Yefim Gordon]A photo of the “White 94” Me 163S in flight being towed by a presumed Tupolev Tu-2. The pilot in the photo is likely Mark L. Gallaj. [Yefim Gordon]The Me 163S inside TsAGI’s T-101 wind tunnel for testing. The struts support the Habicht and simulate its flight configuration. [Yefim Gordon]An alternate closeup view of the Me 163S during static tests. [Yefim Gordon]
Yet another inverted static test, but this time the tail wheel strut and tire were removed from the Me 163S. [Yefim Gordon]
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
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]
USSR (1923)
Kingdom of Hungary (1938)
Nazi Germany (1945)
