Hispano-Suiza 12Y
Encyclopedia
The Hispano-Suiza 12Y was a French
aircraft engine
in the pre-WWII
era. Developed from the earlier, and somewhat smaller, 12X, the 12Y became the primary 1,000 hp (750 kW) class engine and was used in a number of famous aircraft, including the Morane-Saulnier M.S.406
and Dewoitine D.520
. The 12Y was also produced under license in the Soviet Union as the Klimov M-100, which later spawned the highly successful Klimov VK-105
series that powered the Yakovlev and Lavochkin
fighters as well as the Petlyakov Pe-2
bomber. The 12Y design was further modified to create the more modern 12Z
, but development was never fully completed due to the German occupation of France.
with the two cast aluminium cylinder banks set at 60 degrees to each other. A unique feature was that the cylinder head
s were not removable, instead the entire block
could be quickly removed from the engine. This made it somewhat famous for being entirely leak-proof, a design that was considered by other designers and almost became a part of the Rolls-Royce Merlin
. The major design change from the earlier 12X was to use a master-articulated connecting rod
system, instead of the fork-and-blade type. A single overhead camshaft (SOHC) drove the valves
, which were filled with liquid sodium
for cooling. Only a single intake and exhaust valve were used, unlike most designs of the era which had moved to four valves per cylinder. A single-stage, single-speed supercharger
was standard, although the art of designing a useful intake
was not as well developed as in other countries, and high altitude
performance was always lacking.
The first 12Y test articles were constructed in 1932, and almost instantly the entire French aviation industry started designing around it. At the time the engine developed only 760 hp (570 kW), but it was clear it had potential to the 1,000 hp (750 kW) class. An early modification led to the Hispano-Suiza 12Ycrs which used a hollow propeller shaft
to allow a 20 mm cannon
to fire through the propeller spinner (a combination known as a moteur-canon). All later designs shared this feature. The 12Ydrs was the next major series, with a basic rating of 836 hp (623 kW) at sea level with a compression ratio
of 5.8:1.
The Armée de l'Air
changed their nomenclature, so the next version was the Hispano-Suiza 12Y-21, which increased the compression ratio to 7:1, running on 100 octane
. This boosted power to 867 hp (647 kW). In 1936 the connecting rod design was changed slightly to create the 12Y-31, but the lower 5.8:1 compression ratio was retained and the power was increased only slightly over the drs model to 850 hp (630 kW). Nevertheless this became one of the most used engine designs of the pre-war era, used in almost all French fighter designs and prototypes.
engineer Joseph Szydlowski
. The Szydlowski-Planiol device was larger, but much more efficient than the indifferent Hispano-Suiza models. This allowed the compression ratio to be raised to that of the -21's 7:1, boosting power to 900 hp (670 kW), although requiring the use of 100 octane fuel. Combined with the fully adjustable Ratier propeller, this allowed the D.520 to perform as well as contemporary designs from Germany and England. Another improvement in supercharging led to the Hispano-Suiza 12Y-49, whose performance improved from 850 hp (630 kW) at sea level to 920 hp (690 kW) at just over 10,000 ft (3,000 m). This improvement in power with altitude was a common feature of many early engines, the result of the supercharger "robbing" power at low altitudes to provide boost that then had to be dumped to avoid overboosting the engine.
The final major version was the 1,085 hp (809 kW) Hispano-Suiza 12Y-51, which had just started into production at the time of the Armistice with Germany
. The -51 was the first version that came close to the performance limits of the engine, taking advantage of the 100-octane gasoline, although the single-stage supercharging meant that it was unable to compete with designs from England and Germany above 15,000 ft (5,000 m).
n engineer Vladimir Klimov
was sent to France to obtain a license for local production of the 12Y. A series of design changes were added to cope with cold weather operation, and the engine entered production in 1935 as the Klimov M-100 with about 750 hp (560 kW). However a series of continual upgrades increased the allowable rpm from the 12Y's fairly low 2,400 to 2,700, thereby increasing power to 1,100 hp (820 kW). The resulting design, the Klimov M-105
(VK-105), became one of the major Soviet engine designs during the war, powering all Yakovlev
fighters.
In the early 1930s the Czechoslovakia
n Republic gained rights to build a license version of the HS-12Y. This was initially known locally as the Avia Vr. 36 and was produced by Avia
(Skoda
) at Prag - Čakovice
. The engine was intended to become the standard powerplant of all Czech military aircraft. Both the HS-12Ycrs and HS-12Ydrs were built in quantity and were more commonly known by these names rather than any Czech designation. Aircraft powered by these engines included the Avia B-34
, Avia B-534
, Avia B-71, Avia B-35 and Avia B-135
.
Hispano-Suiza 12Ybrs
Hispano-Suiza 12Ycrs
Hispano-Suiza 12Ydrs
Hispano-Suiza 12Yers
Hispano-Suiza 12Yfrs
Hispano-Suiza 12Ygrs
Hispano-Suiza 12Yjrs
Hispano-Suiza 12Y-21
Hispano-Suiza 12Y-25
Hispano-Suiza 12Y-26
Hispano-Suiza 12Y-28
Hispano-Suiza 12Y-29
Hispano-Suiza 12Y-30
Hispano-Suiza 12Y-31
Hispano-Suiza 12Y-32
Hispano-Suiza 12Y-33
Hispano-Suiza 12Y-34
Hispano-Suiza 12Y-36
Hispano-Suiza 12Y-37
Hispano-Suiza 12Y-43
Hispano-Suiza 12Y-45
Hispano-Suiza 12Y-49
Hispano-Suiza 12Y-50
Hispano-Suiza 12Y-51
Avia Vr. 36
Klimov M-100
Hispano-Suiza HS-77
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
aircraft engine
Aircraft engine
An aircraft engine is the component of the propulsion system for an aircraft that generates mechanical power. Aircraft engines are almost always either lightweight piston engines or gas turbines...
in the pre-WWII
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
era. Developed from the earlier, and somewhat smaller, 12X, the 12Y became the primary 1,000 hp (750 kW) class engine and was used in a number of famous aircraft, including the Morane-Saulnier M.S.406
Morane-Saulnier M.S.406
The M.S.406 was a French Armée de l'Air fighter aircraft built by Morane-Saulnier starting in 1938. Numerically it was France's most important fighter during the opening stages of World War II....
and Dewoitine D.520
Dewoitine D.520
The Dewoitine D.520 was a French fighter aircraft that entered service in early 1940, shortly after the opening of World War II. Unlike the Morane-Saulnier M.S.406, which was at that time the Armée de l'Airs most numerous fighter, the Dewoitine D.520 came close to being a match for the latest...
. The 12Y was also produced under license in the Soviet Union as the Klimov M-100, which later spawned the highly successful Klimov VK-105
Klimov M-105
-See also:-External links:*...
series that powered the Yakovlev and Lavochkin
Lavochkin-Gorbunov-Gudkov LaGG-3
|-See also:...
fighters as well as the Petlyakov Pe-2
Petlyakov Pe-2
The Petlyakov Pe-2 was a Soviet dive bomber aircraft used during World War II. It was regarded as one of the best ground attack aircraft of the war and it was extremely successful in the roles of heavy fighter, reconnaissance and night fighter...
bomber. The 12Y design was further modified to create the more modern 12Z
Hispano-Suiza 12Z
-References:...
, but development was never fully completed due to the German occupation of France.
Early development
The 12Y was a fairly traditional in construction, a 36-litre water-cooled V-12V12 engine
A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually but not always at a 60° angle to each other, with all 12 pistons driving a common crankshaft....
with the two cast aluminium cylinder banks set at 60 degrees to each other. A unique feature was that the cylinder head
Cylinder head
In an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head gasket...
s were not removable, instead the entire block
Cylinder block
A cylinder block is an integrated structure comprising the cylinder of a reciprocating engine and often some or all of their associated surrounding structures...
could be quickly removed from the engine. This made it somewhat famous for being entirely leak-proof, a design that was considered by other designers and almost became a part of the Rolls-Royce Merlin
Rolls-Royce Merlin
The Rolls-Royce Merlin is a British liquid-cooled, V-12, piston aero engine, of 27-litre capacity. Rolls-Royce Limited designed and built the engine which was initially known as the PV-12: the PV-12 became known as the Merlin following the company convention of naming its piston aero engines after...
. The major design change from the earlier 12X was to use a master-articulated connecting rod
Connecting rod
In a reciprocating piston engine, the connecting rod or conrod connects the piston to the crank or crankshaft. Together with the crank, they form a simple mechanism that converts linear motion into rotating motion....
system, instead of the fork-and-blade type. A single overhead camshaft (SOHC) drove the valves
Poppet valve
A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide...
, which were filled with liquid sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
for cooling. Only a single intake and exhaust valve were used, unlike most designs of the era which had moved to four valves per cylinder. A single-stage, single-speed supercharger
Supercharger
A supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...
was standard, although the art of designing a useful intake
Intake
An intake , or especially for aircraft inlet, is an air intake for an engine. Because the modern internal combustion engine is in essence a powerful air pump, like the exhaust system on an engine, the intake must be carefully engineered and tuned to provide the greatest efficiency and power...
was not as well developed as in other countries, and high altitude
Altitude
Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...
performance was always lacking.
The first 12Y test articles were constructed in 1932, and almost instantly the entire French aviation industry started designing around it. At the time the engine developed only 760 hp (570 kW), but it was clear it had potential to the 1,000 hp (750 kW) class. An early modification led to the Hispano-Suiza 12Ycrs which used a hollow propeller shaft
Driveshaft
A drive shaft, driveshaft, driving shaft, propeller shaft, or Cardan shaft is a mechanical component for transmitting torque and rotation, usually used to connect other components of a drive train that cannot be connected directly because of distance or the need to allow for relative movement...
to allow a 20 mm cannon
Hispano-Suiza HS.404
The Hispano-Suiza HS.404 was an autocannon widely used as both an aircraft and land weapon in the 20th century by British, American, French, and numerous other military services. The cannon is also referred to as Birkigt type 404, after its designer. Firing a 20 mm caliber projectile, it delivered...
to fire through the propeller spinner (a combination known as a moteur-canon). All later designs shared this feature. The 12Ydrs was the next major series, with a basic rating of 836 hp (623 kW) at sea level with a compression ratio
Compression ratio
The 'compression ratio' of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity...
of 5.8:1.
The Armée de l'Air
French Air Force
The French Air Force , literally Army of the Air) is the air force of the French Armed Forces. It was formed in 1909 as the Service Aéronautique, a service arm of the French Army, then was made an independent military arm in 1933...
changed their nomenclature, so the next version was the Hispano-Suiza 12Y-21, which increased the compression ratio to 7:1, running on 100 octane
Octane
Octane is a hydrocarbon and an alkane with the chemical formula C8H18, and the condensed structural formula CH36CH3. Octane has many structural isomers that differ by the amount and location of branching in the carbon chain...
. This boosted power to 867 hp (647 kW). In 1936 the connecting rod design was changed slightly to create the 12Y-31, but the lower 5.8:1 compression ratio was retained and the power was increased only slightly over the drs model to 850 hp (630 kW). Nevertheless this became one of the most used engine designs of the pre-war era, used in almost all French fighter designs and prototypes.
Late variants
A real effort to improve the performance of the engine in 1938 resulted in the Hispano-Suiza 12Y-45, which used the S-39-H3 supercharger co-designed by André Planiol and PolishPoland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
engineer Joseph Szydlowski
Joseph Szydlowski
Joseph Szydlowski , was a Jewish-Polish-French-Israeli aircraft engine designer who founded Turbomeca in France.- Biography and career :...
. The Szydlowski-Planiol device was larger, but much more efficient than the indifferent Hispano-Suiza models. This allowed the compression ratio to be raised to that of the -21's 7:1, boosting power to 900 hp (670 kW), although requiring the use of 100 octane fuel. Combined with the fully adjustable Ratier propeller, this allowed the D.520 to perform as well as contemporary designs from Germany and England. Another improvement in supercharging led to the Hispano-Suiza 12Y-49, whose performance improved from 850 hp (630 kW) at sea level to 920 hp (690 kW) at just over 10,000 ft (3,000 m). This improvement in power with altitude was a common feature of many early engines, the result of the supercharger "robbing" power at low altitudes to provide boost that then had to be dumped to avoid overboosting the engine.
The final major version was the 1,085 hp (809 kW) Hispano-Suiza 12Y-51, which had just started into production at the time of the Armistice with Germany
Armistice with France (Second Compiègne)
The Second Armistice at Compiègne was signed at 18:50 on 22 June 1940 near Compiègne, in the department of Oise, between Nazi Germany and France...
. The -51 was the first version that came close to the performance limits of the engine, taking advantage of the 100-octane gasoline, although the single-stage supercharging meant that it was unable to compete with designs from England and Germany above 15,000 ft (5,000 m).
Foreign derivatives
In the mid-1930s, RussiaRussia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
n engineer Vladimir Klimov
Vladimir Klimov
Vladimir Klimov is a Soviet sprint canoer who competed in the early 1970s. He won a bronze medal in the K-4 10000 m event at the 1971 ICF Canoe Sprint World Championships in Belgrade.-References:**...
was sent to France to obtain a license for local production of the 12Y. A series of design changes were added to cope with cold weather operation, and the engine entered production in 1935 as the Klimov M-100 with about 750 hp (560 kW). However a series of continual upgrades increased the allowable rpm from the 12Y's fairly low 2,400 to 2,700, thereby increasing power to 1,100 hp (820 kW). The resulting design, the Klimov M-105
Klimov M-105
-See also:-External links:*...
(VK-105), became one of the major Soviet engine designs during the war, powering all Yakovlev
Yakovlev
The Yak Aircraft Corporation is a Russian aircraft designer and manufacturer...
fighters.
In the early 1930s the Czechoslovakia
Czechoslovakia
Czechoslovakia or Czecho-Slovakia was a sovereign state in Central Europe which existed from October 1918, when it declared its independence from the Austro-Hungarian Empire, until 1992...
n Republic gained rights to build a license version of the HS-12Y. This was initially known locally as the Avia Vr. 36 and was produced by Avia
Avia
Avia is a Czech aircraft and automotive company notable for producing biplane fighter aircraft, especially the B-534, and trucks.- History :...
(Skoda
Škoda
Škoda is a Czech surname and brand name. It may refer to:* Škoda Auto, automobile manufacturer in the Czech Republic...
) at Prag - Čakovice
Čakovice
Čakovice is a municipal district in Prague. It is located in the north-eastern part of the city. As of 2008, there were 8,644 inhabitants living in Čakovice...
. The engine was intended to become the standard powerplant of all Czech military aircraft. Both the HS-12Ycrs and HS-12Ydrs were built in quantity and were more commonly known by these names rather than any Czech designation. Aircraft powered by these engines included the Avia B-34
Avia B-34
-References:P. Schumirast, J. Andal. Avia B-34, B-534 a Bk-534 .Jiri Vrany. Avia B-534 ....
, Avia B-534
Avia B-534
The Avia B-534 is a Czechoslovak biplane produced during the period between the Great War and World War II. The B-534 is considered one of the last aircraft built with a classic biplane design.-Design and development:...
, Avia B-71, Avia B-35 and Avia B-135
Avia B-135
|-See also:-References:NotesBibliography* Bílý, Miroslav with Dénes Bernád and Pavel Kučera. Avia B-35/B-135 . Praha, Czech Republic: MBI, 2003. ISBN 80-86524-03-5....
.
Variants
Hispano-Suiza 12YbrHispano-Suiza 12Ybrs
Hispano-Suiza 12Ycrs
- 830 hp (620 kW), hollow propeller shaft for cannon mounting
Hispano-Suiza 12Ydrs
- 760 hp (567 kW), 860 hp (641 kW)
Hispano-Suiza 12Yers
Hispano-Suiza 12Yfrs
Hispano-Suiza 12Ygrs
Hispano-Suiza 12Yjrs
Hispano-Suiza 12Y-21
Hispano-Suiza 12Y-25
- 810 hp (600 kW)
Hispano-Suiza 12Y-26
Hispano-Suiza 12Y-28
- 910 hp (679 kW)
Hispano-Suiza 12Y-29
- 910 hp (679 kW)
Hispano-Suiza 12Y-30
- 830 hp (619 kW), reduction gear 0.67 to 1, 1-speed supercharger, ratio 10 to 1, hollow propeller shaft for cannon mounting
Hispano-Suiza 12Y-31
- 830 hp (679 kW), reduction gear 0.67 to 1, 1-speed supercharger, ratio 10 to 1, hollow propeller shaft for cannon mounting, opposite rotation to -30
Hispano-Suiza 12Y-32
- 960 hp (716 kW), reduction gear 0.67 to 1, 1-speed supercharger, ratio 10 to 1
Hispano-Suiza 12Y-33
- 960 hp (716 kW), reduction gear 0.67 to 1, 1-speed supercharger, ratio 10 to 1, opposite rotation to -32
Hispano-Suiza 12Y-34
Hispano-Suiza 12Y-36
- 1,050 hp (783 kW), reduction gear 0.55 to 1, 1-speed supercharger, ratio 8.3 to 1
Hispano-Suiza 12Y-37
- 1,050 hp (783 kW), reduction gear 0.55 to 1, 1-speed supercharger, ratio 8.3 to 1, opposite rotation to -36
Hispano-Suiza 12Y-43
- 930 hp (694 kW)
Hispano-Suiza 12Y-45
- 910 hp (679 kW), fitted with a Szydlowski supercharger
Hispano-Suiza 12Y-49
Hispano-Suiza 12Y-50
- 1,085 hp (809 kW), reduction gear 0.67 to 1, 1-speed supercharger, ratio 10 to 1, hollow propeller shaft for cannon mounting
Hispano-Suiza 12Y-51
- 1,085 hp (809 kW), reduction gear 0.67 to 1, 1-speed supercharger, ratio 10 to 1, hollow propeller shaft for cannon mounting, opposite rotation to -50
Avia Vr. 36
- License production in Czechoslovakia
Klimov M-100
- License production in the USSR
Hispano-Suiza HS-77
- Licence-built 12Ycrs produced in SwitzerlandSwitzerlandSwitzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
.
Applications
- Amiot 370
- Arsenal VB 10Arsenal VB 10|-See also:-External links:*...
- Arsenal VG-33Arsenal VG-33|-See also:-References:NotesBibliography* Breffort, Dominique & Jouineau, André. French Aircraft from 1939 to 1942, Volume 1: from Amiot to Curtiss. Paris, France: Histoire & Collections, 2004. ISBN 2-915239-23-1....
- Avia 156
- Avia B-534Avia B-534The Avia B-534 is a Czechoslovak biplane produced during the period between the Great War and World War II. The B-534 is considered one of the last aircraft built with a classic biplane design.-Design and development:...
- Bloch MB.177
- Dewoitine D.510
- Dewoitine D.513
- Dewoitine D.520Dewoitine D.520The Dewoitine D.520 was a French fighter aircraft that entered service in early 1940, shortly after the opening of World War II. Unlike the Morane-Saulnier M.S.406, which was at that time the Armée de l'Airs most numerous fighter, the Dewoitine D.520 came close to being a match for the latest...
- EKW C-35EKW C-35|-References:* The Illustrated Encyclopedia of Aircraft , 1985, Orbis Publishing, Page 1593...
- Fairey Fantôme
- Farman NC.223.3
- Farman NC.223.4
- Ikarus IK-2
- Latécoère 298Latécoère 298-References:* Green, William; War planes of the Second World War - Floatplanes - Volume six; MacDonald; ISBN 0-356-01450-9-External links:* http://avia.russian.ee/air/france/latecoere_l-298.php...
- Latécoère 521Latécoère 521|-See also:- External links :* * * Popular Science, February 1935* article on Air France with page on the 521* Popular Mechanics, April 1935, cutaway drawings pp.568-569...
- Morane-Saulnier M.S.406Morane-Saulnier M.S.406The M.S.406 was a French Armée de l'Air fighter aircraft built by Morane-Saulnier starting in 1938. Numerically it was France's most important fighter during the opening stages of World War II....
- Morane-Saulnier M.S.475
- ANF Les Mureaux 110-119 series
- Renard R-36Renard R-36The Renard R-36 was a Belgian all-metal fighter aircraft designed to replace the Fairey Firefly II within the Belgian Air Force. Designed to improve on the Renard Epervier, which was never adopted by the Belgian government, the prototype R-36 first flew on 5 November 1937...
- Rogozarski IK-3Rogozarski IK-3-References:NotesBibliography* Green, William. War Planes of the Second World War, Volume Four: Fighters. London: MacDonald & Co. Ltd., 1961 . ISBN 0-356-01448-7....
12Y Derivatives
- Arkhangelsky Ar-2Arkhangelsky Ar-2|-See also:-References:* *...
- Lavochkin-Gorbunov-Goudkov LaGG-1
- Lavochkin-Gorbunov-Goudkov LaGG-3
- Mörkö-Morane
- Petlyakov Pe-2Petlyakov Pe-2The Petlyakov Pe-2 was a Soviet dive bomber aircraft used during World War II. It was regarded as one of the best ground attack aircraft of the war and it was extremely successful in the roles of heavy fighter, reconnaissance and night fighter...
- Petlyakov Pe-3Petlyakov Pe-3The Petlyakov Pe-3 was the long-range, night fighter version of the successful Petlyakov Pe-2 high-speed bomber used by the Soviet Union during World War II....
- Yakovlev Yak-1Yakovlev Yak-1The Yakovlev Yak-1 was a World War II Soviet fighter aircraft. Produced from early 1940, it was a single-seat monoplane with a composite structure and wooden wings....
- Yakovlev Yak-2Yakovlev Yak-2-See also:-Bibliography:* Gordon, Yefim. Soviet Airpower in World War 2. Hinckley, England: Midland Publishing, 2008 ISBN 978-1-85780-304-4* Gunston, Bill. The Osprey Encyclopaedia of Russian Aircraft 1875–1995. London, Osprey, 1995 ISBN 1-85532-405-9...
- Yakovlev Yak-3Yakovlev Yak-3The Yakovlev Yak-3 was a World War II Soviet fighter aircraft.Robust and easy to maintain, it was much liked by pilots and ground crew alike....
- Yakovlev Yak-4Yakovlev Yak-4-Bibliography:* Gordon, Yefim. Soviet Airpower in World War 2. Hinckley, England: Midland Publishing, 2008 ISBN 978-1-85780-304-4* Gunston, Bill. The Osprey Encyclopaedia of Russian Aircraft 1875–1995. London, Osprey, 1995 ISBN 1-85532-405-9...
- Yakovlev Yak-7Yakovlev Yak-7The Soviet Yakovlev Yak-7 was developed from the earlier Yak-1 fighter, initially as a trainer but converted into a "heavy" fighter. As both a fighter and later reverting to its original training role, the Yak-7 proved to be a capable aircraft and was well liked by air crews. The Yak-7 was simpler,...
- Yakovlev Yak-9Yakovlev Yak-9The Yakovlev Yak-9 was a single-engine fighter aircraft used by the Soviet Union in World War II and after. Fundamentally a lighter development of the Yak-7 with the same armament, it arrived at the front at the end of 1942. The Yak-9 had a lowered rear fuselage decking and all-around vision canopy...
- Yermolayev Yer-2Yermolayev Yer-2The Yermolayev Yer-2 was a long-range Soviet medium bomber used during World War II. It was developed from the Bartini Stal-7 prototype airliner before the war. It was used to bomb Berlin from airbases in Estonia after Operation Barbarossa in 1941...