POWER PLANT: One Klimov VK-105PF2 liquid-cooled piston engine, rated at 1,290 hp
PERFORMANCE: 401 mph at 13,500 ft
COMMENT: The Yakovlev Yak-3 was a single-engine single-seat World War II Soviet front line fighter aircraft. Robust and easy to maintain, it was much liked by pilots and ground crew alike. It was one of the smallest and lightest major combat fighters fielded by any combatant during the war. Its high power-to-weight ratio gave it excellent performance. It proved a formidable dogfighter.
In 1943, a group of designers headed by Alexander Sergeyevich Yakovlev designed the Yak-3, a further development of the proven Yak-1 aimed at improving survivability, flight characteristics and firepower, which required a lower weight, a higher-power engine and therefore, faster speed.
The first of two prototypes had a slatted wing to improve handling and short-field performance while the second prototype had a wooden wing without slats in order to simplify production and save aluminium. The second prototype crashed during flight tests and was written off. Although there were plans to put the Yak-3 into production, the scarcity of aviation aluminium and the pressure of the Nazi invasion led to work on the first Yak-3 being abandoned in late 1941.
In between 1942 and 1943, Yakovlev built the Yak-1M, a prototype that would ultimately lead to the Yak-3, coupled with the VK-105PF2, the latest iteration of the VK-105 engine family, where “P” indicated support for an autocannon that fires between the engine banks, through the hollow propeller shaft – mounting. It incorporated a wing of similar design but with smaller surface area (17.15 to 14.85 m2 , and had further aerodynamic refinements, like the new placement of the oil radiator, from the chin to the wing roots (one of the visual differences with the Yak-1, Yak-7, Yak-9). A second Yak-1M (originally meant as a “backup”) prototype was constructed later that year, differing from the first aircraft in that it had plywood instead of fabric covering of the rear fuselage, mastless radio antenna, reflector gunsight and improved armour and engine cooling.
The first 197 Yak-3 were lightly armed with a single 20 mm SHVAK cannon and one 12.7 mm UBS synchronized machine guin, with subsequent aircraft receiving a second UBS for a weight of fire of 2.72 kg (6.0 lb) per second using high-explosive ammunition. All armament was installed close to the axis of the aircraft with a cannon mounted in the engine “vee” firing through the propeller boss, synchronised machine guns in the fuselage, helping accuracy and leaving wings unloaded.
Lighter and smaller than Yak-9 but powered by the same engine, the Yak-3 was a forgiving, easy-to-handle aircraft loved by both novice and experienced pilots and ground crew as well. It was robust, easy to maintain, and a highly successful dog-fighter. It was used mostly as a tactical fighter, flying low over battlefields and engaging in dogfights below 13,000 ft.
Unresolved wartime problems with the Yak-3 included plywood surfaces coming unstuck when the aircraft pulled out of a high-speed dive. Other drawbacks of the aircraft were short range and poor engine reliability. The pneumatic system for actuating landing gear, flaps and brakes, typical for all Yakovlev fighters of the time, was troublesome. Though less reliable than hydraulic or electrical alternatives, the pneumatic system was preferred owing to the weight saving (Ref.: 24).
POWER PLANT: One Mikulin AM-38F liquid-cooled engine, rated at 1,720 hp
COMMENT: The Ilyushin Il-2 „Shturmovik“ was a ground attack aircraft produced by the Soviet Union in large numbers during WW II. To Il-2 pilots, the aircraft was simply the diminutive “Ilyusha”, to the soldiers on the ground, it was the “Hunchback”, the “Flying Tank” or the “Flying Infantryman”. With 36,183 units produced during the war it was the most built aircraft forever.
The idea for a Soviet armored ground-attack aircraft dates to the early 1930s. The Il-2 was designed by Sergey Ilyushin and his team at the Central Design Bureau in 1938. Designated TsKB-55 it was a two-seat aircraft with an armoured shell weighing 700 kg, protecting crew, engine, radiators, and the fuel tank. Standing loaded, the Ilyushin weighed more than 4,700 kg making the armoured shell about 15% of the aircraft’s gross weight. Uniquely for a World War II attack aircraft, and similarly to the forward fuselage design of the World War I-era Imperial German Junkers J.I armored, all-metal biplane, the Il-2’s armor was designed as a load-bearing part of the Ilyushin’s monocoque structure, thus saving considerable weight. The prototype TsKB-55, which first flew on 2 October 1939, won the government competition against the Sukhoi Su-6 and received the VVS (Soviet Air Forces) designation BSh-2 (the BSh stood for “Bronirovani Shturmovik” or armoured ground attack). The prototypes – TsKB-55 and TskB-57 – were built at Moscow plant No 39, at that time the Ilyushin design bureau’s base.
The production aircraft passed State Acceptance Trials in March 1941, and was redesignated Il-2 in April. Deliveries to operational units commenced in May 1941.
The Il-2 was a single-engine, propeller-driven, low-wing monoplane of mixed construction with a crew of two (one in early versions), specially designed for assault operations. Its most notable feature was the inclusion of armor in an airframe load-bearing scheme. Armor plates replaced the frame and paneling throughout the nacelle and middle part of the fuselage, and an armored hull made of riveted homogeneous armor steel secured the aircraft’s engine, cockpit, water and oil radiators, and fuel tanks.
In early 1941, the Il-2 was ordered into production at four factories, but by the time Nazi Germany invaded the Soviet Union on 22 June 1941, only State Aviation Factory 18 at Voronezh and Factory 381 at Leningrad had commenced production, with 249 having been built by the time of the German attack.
Production early in the war was slow because after the German invasion the aircraft factories near Moscow and other major cities in western Russia had to be moved east of the Ural Mountains. Ilyushin and his engineers had time to reconsider production methods, and two months after the move Il-2s were again being produced.
As a result, “the production of Shturmoviks rapidly gained speed. Stalin’s notion of the Il-2 being ‘like bread’ to the Red Army took hold in Ilyushin’s aircraft plants and the army soon had their Shturmoviks available in quantity.”
The first use in action of the Il-2 was with the 4th ShAP (Ground Attack Regiment) over the Berezina River days after German invasion began. The aircraft was so new that the pilots had no training in flight characteristics or tactics, and the ground crew no training in servicing or re-arming. The training received enabled the pilots only to take-off and land; none of the pilots had fired the armament, let alone learned tactics. There were 249 Il-2s available on 22 June 1941. In the first three days, 4th ShAP had lost 10 Il-2s to enemy action, a further 19 were lost to other causes, and 20 pilots were killed. By 10 July, 4th ShAP was down to 10 aircraft from a strength of 65.
Tactics improved as Soviet aircrews became used to the Il-2’s strengths. Instead of a low horizontal straight approach at 50 metres altitude, the target was usually kept to the pilot’s left and a turn and shallow dive of 30 degrees was used, using an echeloned assault by four to twelve aircraft at a time. Although the Il-2’s RS-82 and RS-132 rockets could destroy armored vehicles with a single hit, they were so inaccurate that experienced Il-2 pilots mainly used the cannon.
The main problem with the Il-2 was the inaccuracy of its attacks. Towards the end of war, the Soviets were able to concentrate large numbers of Shturmoviks to support their main offensives. The effect, however, was often more psychological than actual physical destruction of targets, particularly against dug-in and armored targets. The heavy armor of the Il-2 also meant that it would typically carry only comparatively light bomb-loads, which together with the poor accuracy of its attacks made it a far less deadly attack aircraft than contemporary Allied fighter-bombers such as the Republic P-47 „Thunderbolt“ and Hawker „Typhoon“. The rocket projectiles especially were not effective, even the larger RS-132 (of which four were carried) having a warhead with only 0.9 kg of explosives, which compared poorly with the P-47’s typical load of ten 13 cm HVAR‘s, each having a 21 kg warhead, or the 8 to 12 27 kg warheads of the Hawker „Typhoon’s“ RP-3 rockets.
Heavy losses to enemy fighters forced the reintroduction of a rear gunner; early Il-2s were field modified by cutting a hole in the fuselage behind the cockpit for a gunner sitting on a canvas sling armed with a 12.7 mm UBT machine gun in an improvised mounting. The semi-turret gun mount allowed the machine gun to be fired at angles of up to 35° upwards, 35° to starboard and 15° to port. Tests showed that maximum speed decreased by between 10 and 20 km/h and that the two-seater was more difficult to handle because the center of gravity was shifted backwards. At the beginning of March 1942, a production two-seat Il-2 with the new gunner’s cockpit began manufacturer tests. The second cockpit and armament increased all-up weight by 170 kg so the flaps were allowed to be deployed at an angle of 17° to avoid an over-long takeoff run. The new variant had a lengthened fuselage compartment with an extended canopy offering some protection from the elements. Unlike the well-armoured cockpit of the pilot compartment with steel plating up to 12 mm thick behind, beneath and on both sides as well as up to 65 mm thick glass sections, the rear gunner was provided with 6 mm thick armour, effective only against rifle-calibre rounds.
While the Il-2 was a deadly air-to-ground weapon, and even a fairly effective interceptor against slow bombers and transport aircraft, heavy losses resulted from its vulnerability to fighter attack. Losses were very high, the highest of all types of Soviet aircraft, though given the numbers in service this is only to be expected. „Shturmovik“ losses (including Il-10 type), in 1941–1945, were of 10,762 aircraft. The main defensive tactic was flying low and power down as the fighters closed in to let the fighter overshoot and fly into the Il-2’s firing range (Ref.: 24).
POWER PLANT: One Shvetsov M-82FN radial piston engine, rated at 1,960 hp
PERFORMANCE: 403 mph at 20,505 ft
COMMENT: The Lavochkin La-5 was a Soviet fighter aircraft of World War II. It was a development and refinement of the LaGG-3, replacing the earlier model’s inline engine with the much more powerful Shvetsov Ash-82 radial engine. During its time in service, it was one of the Soviet Air Force’s most capable types of warplane, able to fight German designs on an equal footing.
The La-5’s heritage began even before the outbreak of war, with the LaGG-1, a promising yet underpowered aircraft. The LaGG-3 was a modification of that design that attempted to correct this by both lightening the airframe and fitting a more powerful engine. Nevertheless, this was not enough, and the lack of power remained a significant problem.
In early 1942 the LaGG-1 and -3’s designer Vladimir Gorbunov attempted to correct this deficiency by experimentally fitting a LaGG-3 with the more powerful Shvetsov Ash-82 radial engine. Since the LaGG-3 was powered by an inline engine, they accomplished this by grafting on the nose section of a Sulhoi Su-2 (which used this engine). By now, the shortcomings of the LaGG-3 had caused Lavochkin to fall out of Joseph Stalin’s favour, and factories previously assigned to LaGG-3 construction had been turned over to building the rival Yakovlev Yak-1 and Yak-7. The design work, which required that the LaGG-3 be adapted to its new engine and still maintain the aircraft’s balance, was undertaken by Lavochkin in a small hut beside an airfield over the winter of 1941–1942, on a completely unofficial basis.
When the prototype took flight in March, the result was surprisingly pleasing – the fighter finally had a power plant that allowed it to perform as well in the air as it had been supposed to on paper. After flying, the LaG-5 (the change in name reflecting that one of the original LaGG designers, Mikhail I. Gudkov, was no longer with the program), Air Force test pilots declared it superior to the Yak-7, and intensive flight tests began in April.
The prototype was put in mass production almost immediately in factories located in Moscow and in the Yaroslav region. Design changes for main production La-5 models included slats to improve all-round performance. While still inferior to the best German fighters at higher altitudes, the La-5 proved to be every bit their match closer to the ground. With most of the air combat over the Eastern Front taking place at altitudes of under 16,404 ft, the La-5 was very much in its element.
Further refinement of the aircraft involved cutting down the rear fuselage to give the pilot better visibility, making this version the La-5F. Later, a fuel-injected engine, a different engine air intake and further lightening of the aircraft led to the designation La-5FN that would become the definitive version of the aircraft. A full circle turn took 18–19 seconds. Altogether, 9,920 Lavochkin La-5s of all variants were built, including a number of dedicated trainer versions, designated La-5UTI. Very late La-5FN production models had two 20mm Berezin B-20 cannon installed in the cowling in place of the heavier two 20mm ShVAK (both were capable of a salvo weight of 3.4 kg/s). Further improvements of the aircraft would lead to the Lavochkin La-7.
A number of La-5s continued in the service of Eastern Bloc nations after the end of WW II (Ref.: 24).
ACCOMMODATION: Crew of one or two, pilot or trainer and student
POWER PLANT: One Klimov M-105PA V-12 liquid-cooled engine, rated at 1,050 hp
PERFORMANCE: 355 mph at 16,000 ft
COMMENT: The Yakovlev Yak-7 was developed from the earlier Yakolev Yak-1 fighter, initially as a trainer but converted into a 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, tougher and generally better than the Yak-1.
In 1939, A. Yakolev designed a tandem-seat advanced trainer, originally designated “I-27” and then “UTI-26”, offered along with the original I-26 proposal that became the Yak-1. The “UTI” (Uchebno Trenirovochnyi Istrebitel, Training fighter) was intended to give pilots-in-training experience on a high-performance aircraft before transitioning to a fighter. With development work started in 1940, the UTI-26 differed from its predecessor in its larger span wing being placed farther back for balance as well as having two cockpits with dual controls and a rudimentary communication system. It was armed with a single 7.62 mm ShKAS machine gun in the cowling, mainly for use in training, but Yakovlev envisioned a multi-purpose aircraft that could also undertake courier and light transport duties at the front.
The first production aircraft known as Yak-7UTIs retained a retractable main landing gear, but beginning in the summer of 1941, a fixed landing gear variant, the Yak-7V (Vyvozoni = Familiarization) was substituted. The factory reasoned that production would be simplified and that reduced performance would not be detrimental for a trainer. Yak-7UTIs and Yak-7Vs were also equipped with skis for winter operations.
The Yak-7 proved to be an effective close support fighter although the first two-seaters were considered nose-heavy. Consequently, the factory introduced a rear cockpit fuel tank. Pilots complained about the fuel tank’s vulnerability since it was unarmored, and it was usually removed in the field. There were constant changes to the design based on combat observations including a definitive single-seat variant, the Yak-7B, which was produced in large numbers.
Generally, the Yakolev Yak-7 pleased its pilots. They reported that it was easy to fly at all altitudes, stable and easy to maintain and although it did not climb as quickly as a Messerschmitt Bf 109, it was as maneuverable and fast, except in the vertical plane. But defects were also noted: there was too much drag from the radiators, the canopy glass was of bad quality; the pilot was not protected enough, taking-off and landing distances were too long and, above all, it was underpowered.
Yakovlev suggested to Klimov, the engine builder, some modifications that resulted in the M-105PF which was 130 hp more powerful. With this modified engine, the Yak-7B top speed was of 372 mph, it climbed much faster up to 16,404 ft and it was more maneuverable both in the horizontal and the vertical planes. But because the rear tank was removed, its range was reduced and the center of gravity was moved too forward, while M-105 defects (glycol and oil overheating, oil leaks etc.) persisted.
In total 510 two-seat trainer were built, 87 were converted from Yak-7B (Ref.: 24).
POWER PLANT: One Mikulin AM-35A liquid-cooled engine, rated at 1,332 hp
PERFORMANCE: 314 mph at 25,590 ft
COMMENT: The Mikoyan-Gurevich MiG-3 was a Soviet fighter and interceptor aircraft used during World War II. It was a development of the Mikoyan-Gurevich MiG-1 by the Experimental Design Department of Factory No. 1 to remedy problems found during the MiG-1’s development and operations. It replaced the MiG-1 on the production line at Factory No. 1 on December 1940 and was built in large numbers during 1941 before Factory No. 1 was converted to build the Ilyushin Il-2.
The large number of defects noted during flight testing of the MiG-1 forced Mikoyan and Gurevich to make a number of modifications to the design. Testing was done on a full-size aircraft in the T-1 wind tunnel belonging to the Central Aero and Hydrodynamics Institute (TsAGI) to evaluate the problems and their proposed solutions. The first aircraft to see all of these changes applied was the fourth prototype of the I-200. It first flew on 29 October 1940 and was approved for production after passing its State acceptance trials. The first MiG-3, as the improved aircraft was named on December 1940, was completed same month and another 20 were delivered by the end of the year.
Changes included: the engine was moved forward, outer wing panel dihedral was increased by one degree to increase lateral stability, the back of the pilot’s seat was armored with an 8 mm plate (increased to 9 mm in later models, the supercharger intakes were streamlined, the main landing gear was strengthened and the size of the main wheels was increased and the canopy glazing was extended aft to improve the view to the rear which allowed for the installation of a shelf behind the pilot for an RSI-1 radio (later upgraded to an RSI-4)
Despite the teething problems with the MiG-3, a number of reports had been received about poor quality aircraft received by the regiments which pointed directly at the NII VVS (Naoochno-Issledovatel’skiy Institoot Voyenno-Vozdooshnykh Seel—Air Force Scientific Test Institute) as it was responsible for monitoring the quality of the aircraft delivered to the VVS (Soviet Air Force). After elimination of most problems the production started and 3,422 aircraft were built in different factories spread over the eastern parts of Soviet Union.
The MiG-3’s top speed of 398 mph at 23,622 ft was faster than the 382 mph of the German Messerschmitt Bf 109F-2 in service at the beginning of 1941 and the British Supermarine Spitfire Mk. V’s 375 mph. At lower altitudes the MiG-3’s speed advantage disappeared as its maximum speed at sea level was only 314 mph while the Bf 109F-2 could do 320 mph. Unfortunately for the MiG-3 and its pilots, aerial combat over the Eastern front generally took place at low and medium altitudes where it had no speed advantage.
MiG-3s were delivered to frontline fighter regiments beginning in the spring of 1941 and were a handful for pilots accustomed to the lower-performance and docile Polikarpov I-152 and I-153 biplanes and the Polikarpov I-16 monoplane. It remained tricky and demanding to fly even after the extensive improvements made over the MiG-1 Many fighter regiments had not kept pace in training pilots to handle the MiG and the rapid pace of deliveries resulted in many units having more MiGs than trained pilots during the German invasion. By June 1941, 1,029 MIG-3s were on strength, but there were only 494 trained pilots. However high-altitude combat of this sort was to prove to be uncommon on the Eastern Front where most air-to-air engagements were at altitudes well below 16,000 ft. At these altitudes the MiG-3 was outclassed by the Bf 109 in all respects, and even by other new Soviet fighters such as the Yakovlev Yak-1. Furthermore, the shortage of ground-attack aircraft in 1941 forced it into that role as well, for which it was totally unsuited.
Over the winter of 1941–42 the Soviets transferred all of the remaining MiG-3s to the Soviet Naval Aviation and Soviet Air Defence Forces (PVO) so that on 1 May 1942 none were left on strength with the VVS. By May 1942, Naval Aviation had 37 MiGs on strength, while the PVO had 323 on hand on May. By June 1944, the Navy had transferred all its aircraft to the PVO, which reported only 17 on its own strength, and all of those were gone by January 1945. Undoubtedly more remained in training units and the like, but none were assigned to combat units by then (Ref.: 24).
POWER PLANT: One Shvetsov Ash-82FN radial engine with a two-stage supercharger and fuel injection, rated at 1,850 hp
PERFORMANCE: 428 mph
COMMENT: The Lavochkin La-9 was a Soviet fighter aircraft produced shortly after World War II. It was a piston engined aircraft produced at the start of the turbojet age.
The Lavochkin La-9 represents a further development of the Lavochlin La-126 prototype. The first prototype, designated La-130 was finished in 1946. Similarity to the famous Lavochkin La-7 was only superficial. The new fighter had an all-metal construction and a laminar flow wing. Weight savings due to elimination of wood from the airframe allowed for greatly improved fuel capacity and four-cannon armament. Mock combat demonstrated that the La-130 was evenly matched with the La-7 but was inferior to the Yakovlev Yak-3 in horizontal flight. The new fighter, officially designated La-9, entered production in August 1946. A total of 1,559 aircraft were built by the end of production in 1948.
Like other aircraft designers at the time, Lavochkin was experimenting with using turbojet propulsion to augment performance of piston-engined fighters. One such attempt was Lavochkin La-130R with an RD-1Kh3 liquid-fuel rocket engine in addition to the Shvetsov Ash-82FN piston power plant. The project was cancelled in 1946 before the prototype could be assembled.
A more unusual approach was Lavochkin La-9RD which was tested in 1947–1948. It was a production La-9 with a reinforced airframe and armament reduced to two cannons, which carried a single RD-13 pulsejet (a German Argus As 014 engine which powered the Fieseler Fi 103, V-1 flying bomb, probably taken from surplus Luftwaffe stocks) under each wing. The 45 mph increase in top speed came at the expense of tremendous noise and vibration. The engines were unreliable and worsened the handling. The project was abandoned although between 3 and 9 La-9RD were reported to perform at airshows, no doubt pleasing the crowds with the noise.
One of the recommendations from the government testing of Lavochkin La-9 prototype was to further develop it into a long-range escort fighter, the Lavochkin La-11 (Ref.: 24).
POWER PLANT: One Klimov M-105PF2 liquid-cooled piston engine, rated at 1,290 hp
PERFORMANCE: 401 mph at 13,451 ft
COMMENT: The Yakovlev Yak-3 was a single-engine single-seat WW II Soviet front line fighter aircraft. Robust and easy to maintain, it was much liked by pilots and ground crew alike. It was one of the smallest and lightest major combat fighters fielded by any combatant during the war. Its high power-to-weight ratio gave it excellent performance. It proved a formidable dogfighter.
The origins of the Yak-3 went back to 1941 when the I-30 prototype was offered along with Yakovlev I-26 (Yak-1) as an alternative design. The I-30, powered by a Klimov M-105P engine, was of all-metal construction, using a wing with dihedral on the outer panels. Like the early Yak-1, it had a 20 mm ShVAK cannon firing through the hollow-driveshaft nose spinner and twin 7.62 mm synchronized ShKAS machine guns in cowl mounts ahead of the cockpit on the fuselage, but was also fitted with a ShVAK cannon in each wing. The first of two prototypes was fitted with a slatted wing to improve handling and short-field performance while the second prototype had a wooden wing without slats, in order to simplify production. The second prototype crashed during flight tests and was written off. Although there were plans to put the Yak-3 into production, the scarcity of aviation aluminum and the pressure of the German invasion led to work on the first Yak-3 being abandoned in late fall 1941.
In 1943, Yakovlev designed the Yak-1M which was a lighter version of the Yak-1. It incorporated a wing of similar design, but with smaller surface area and had further aerodynamic refinements, like the new placement of the oil radiator, from the chin to the wing roots (one of the visual differences with the Yak-1, -7, -9). A second Yak-1M prototype was constructed later that year, differing from the first aircraft in that it had plywood instead of fabric covering of the rear fuselage, mastless radio antenna, reflector gunsight and improved armor and engine cooling. The chief test pilot for the project P. M. Stefanovsiy was so impressed with the new aircraft that he recommended that it should completely replace the Yak-1 and Yak-7 with only the Yak-9 retained in production for further work with the Klimov VK-107 engine. The new fighter designated the Yak-3 entered service in 1944, later than the Ya-9 in spite of the lower designation number.
The first 197 Yak-3 were lightly armed with a engine-mount 20 mm ShVAK cannon and one 12.7 mm UBS- synchronized machine gun, with subsequent aircraft receiving a second UBS for a weight of fire of 2.72 kg per second using high-explosive ammunition. All armament was installed close to the axis of the aircraft (cannon mounted in the engine “vee”, and firing through the propeller boss; and synchronized machine guns in the fuselage above the engine), adding to the accuracy and leaving wings unloaded.
Production accelerated rapidly, so that by mid-1946, 4,848 had been built. Before the end of the war it was also flown by Polish Air Forces (of the Polish People’s Army formed in USSR) and after the war ended, it was flown by the Yugoslav Air Force (Ref.: 24).
POWER PLANT: One Shvetsov Ash-82FN air-cooled radial engine, rated at 1,850 hp
PERFORMANCE: 411 mph at 19,685 ft
COMMENT: The Lavochkin La-7 was a piston-engine single-seat Soviet fighter aircraft developed during WW II by the Lavochkin Design Bureau. It was a development and refinement of the Lavochkin La-5, and the last in a family of aircraft that had begun with the Lavochkin-Gorbunov-Gudkov LaGG-3 in 1938. Its first flight was in early 1944 and it entered service with the Soviet Air Forces later in the year. The La-7 was felt by its pilots to be at least the equal of any German piston-engined fighter. It was phased out in 1947 by the Soviet Air Force.
By 1943, the La-5 had become a mainstay of the Soviet Air Forces, yet both its head designer, Semyon Lavochkin, as well as the engineers at the TsAGI (Central Aerohydronamics Institute), felt that it could be improved upon. TsAGI refined earlier studies of aerodynamic improvements to the La-5 airframe in mid-1943 and modified Lavochkin La-5FN to evaluate the changes. These included complete sealing of the engine cowling, rearrangement of the wing center section to accommodate the oil cooler and the relocation of the engine air intake from the top of the cowling to the bottom to improve the pilot’s view.
The aircraft was evaluated between December 1943 and February 1944 and proved to have exceptional performance. Using the same engine as the standard La-5FN had a top speed of 425 mph at a height of 20,180 ft, some 40 mph faster than the production La-5FN. It took 5.2 minutes to climb to 16,404 ft. It was faster at low to medium altitudes than the La-5 that used the more powerful prototype Shvetsov M-71 engine.
Lavochkin had been monitoring TsAGI’s improvements and began construction in January 1944 of an improved version of the La-5 that incorporated them as well as lighter, but stronger, metal wing spars to save weight. The La-5, as well as its predecessors, had been built mostly of wood to conserve strategic materials such as aircraft alloys. With Soviet strategists now confident that supplies of these alloys were unlikely to become a problem, Lavochkin was now able to replace some wooden parts with alloy components. In addition Lavochkin made a number of other changes that differed from La-5FN. The engine air intake was moved from the bottom of the engine cowling to the wing roots, the wing/fuselage fillets were streamlined, each engine cylinder was provided with its own exhaust pipe, the engine cowling covers were reduced in number, a rollbar was added to the cockpit, longer shock struts were fitted for the main landing gear while that for the tail wheel was shortened, an improved gunsight was installed, and a new propeller was fitted. Three prototype 20 mm Berezin B-20 autocannon were mounted in the engine cowling, firing through the propeller, arming the 1944 standard-setter.
The prototype only made nine test flights in February and March 1944 before testing had to be suspended after two engine failures, but quickly proved itself to be the near-equal of the La-5FN. It was 180 kilograms lighter than the earlier aircraft, which allowed the La-7 to outclimb the other aircraft. However it was 20.5 mph slower at sea level, but only 2.5 mph slower at 19,685 ft. The flight tests validated Lavochkin’s modifications and it was ordered into production under the designation of La-7, although the B-20 cannon were not yet ready for production and the production La-7 retained the two 20-mm ShVAK cannon armament of the La-5.
Five La-7s were built in March by Factory Nr. 381 in Moscow and three of these were accepted by the Air Force that same month. The Moscow factory was the fastest to complete transition over to La-7 production and the last La-5FN was built there in May 1944. Factory Nr. 21 in Gorky was considerably slower to make the change as it did not exhaust its stock of wooden La-5 wings until October. The quality of the early production aircraft was significantly less than the prototype.
Combat trials began in mid-September 1944 and were generally very positive. However four aircraft were lost to engine failures and the engines suffered from numerous lesser problems, despite its satisfactory service in the La-5FN. One cause was the lower position of the engine air intakes in the wing roots of the La-7 which caused the engine to ingest sand and dust. One batch of flawed wings was built and caused six accidents, four of them fatal, in October which caused the fighter to be grounded until the cause was determined to be a defect in the wing spar.
Production of the first aircraft fitted with three B-20 cannon began in January 1945 when 74 were delivered. These aircraft were 65 kilograms heavier than those aircraft with the two ShVAK guns, but the level speed was slightly improved over the original aircraft. However, the time to climb to 16,404 ft increased by two-tenths of a second over the older model. More than 2000 aircraft were delivered before the war’s end, most by Zavod Nr. 21.
Production of the Lavochkin La-7 amounted to 5,753 aircraft, plus 584 La-7UTI trainers. The follow-up model, the Lavochkin La-9, despite its outward similarity, was a completely new design (Ref.: 24).
Mit der weiteren Nutzung unserer Webseite erklären Sie sich damit einverstanden, dass wir Cookies verwenden um Ihnen die Nutzerfreundlichkeit dieser Webseite zu verbessern. Weitere Informationen zum Datenschutz finden Sie in unserer Datenschutzerklärung.
