Baltic
06-14-2005, 11:33 AM
Semyon Lavochkin's design for a modern Soviet jet fighter lost out to the MiG-15
DURING WORLD WAR II, the LaGG-3, La-5 and La-7 fighters designed by Semyon A. Lavochkin became mainstays of the Soviet army air force, or Voyenno-Vozdushny Sily (V-VS), and brought recognition to their designer. In contrast to his wartime successes, however, Lavochkin's postwar attempts to enter the jet age fell sadly short. The closest that Lavochkin's experimental design bureau (Opytnoye Konstruktorskoye Byuro, or 0KB) came to a production jet fighter, the La-15, is now best remembered as an ill-fated also-ran beside its rival, the Mikoyan-Gurevich MiG-15.
The Lavochkin 0KB began research into the use of liquid-propellant rocket engines, ramjet engines and pulsejet engines to boost the performance of pistonengine aircraft, usually by mounting such engines under the wings, between October 1944 and January 1948. Although they increased speed, each booster had its problems and all produced drag that affected the airplane's flight.
Also in 1944, Arkhip M. Lyulka developed a new turbojet engine with 1,250 kilograms of thrust, the S-18. On May 22, 1944, the Soviet State Committee of Defense granted Lavochkin's OKB the exclusive right to design a fighter for Lyulka's turbojet. By the end of 1944, the bureau had introduced the La-VRD, a twin-boom, twin-finned, high-wing experimental jet fighter, based on a pusher propeller design, with lateral intakes and three-wheel undercarriage. Built under the direction of S.A. Alekseyev, the La-VRD was not completed, because the S-18 engine never passed its bench-testing trials.
With the German surrender on May 8, 1945, the Soviet Union, like the Western Allies, wasted little time in adapting captured German jet engines to its industrial capabilities. Viktor Y. Klimov, for example, developed the BMW 003 into the RD-10 engine, while the Junkers Jumo 004 became the RD-20. As early as February 1945 — three months before the war ended — the design bureaus of Aleksandr S. Yakovlev, Artyom I. Mikoyan and Semyon Lavochkin had begun designing new jet planes for the German engines.
In April 1945, Lavochkin prepared two projects around the Jumo 004. One, the twin-engine La-160 heavy fighter, was judged too similar to the German Messerschmitt Me-262 and got no further than the drawing board. The La-150, a high-wing single-engine plane with a high horizontal tail plane, was more original, but its small, seminacelle-type fuselage presented many problems as to how to arrange the engine, fuel tanks and weaponry. Five prototypes were to be built in aircraft factory No. 381, which had manufactured wooden La-7 fighters during the war and was unprepared to build all-metal aircraft.
Meanwhile, V-VS interest in jet engineering increased after the Scientific Test Institute of Military Air Forces tested an Me-262 from August to November 1945. Pavel O. Sukhoi's Su-9 was directly based on the impressive German fighter, but Yakovlev managed to convince Josef Stalin to encourage the pursuit of more original and advanced designs.
At Lavochkin's factory, the La-150 was revealing shortcomings with its one-piece wing, excessively small cockpit, poor engine access and weak armament. Lavochkin therefore decided to create a new midwing monoplane using the RD-10 engine, designated the La-152, as well as the La-154 with a Lyulka-designed TR-1 engine and the La-156 with a higher-compression version of the RD-10. Production delays and the destruction of the first prototype during static tests held up the La-150's first flight test until September 11, 1946, while its competitors — the MiG-9 designed by Artyom Mikoyan and Mikhail Gurevich and Yakovlev's Yak-15 — were unveiled in August.
Both the MiG-9 and Yak-15 were transitional designs whose inferiority to Western jet fighters greatly irritated Stalin. People's Commissar of Aircraft Industry A.I. Shakhurin, Marshal A.A. Novikov, commander in chief of the V-VS, V-VS chief engineer A.K. Repin and others were dismissed and arrested. Their successors were told to have formations of improved Yak-15s, MiG-9s and the new La-150 ready for the next air display above Red Square on November 7, 1946. Working around the clock, the factories rushed out 19 Yak-15s, 10 MiG-9s and eight La-150s — which in spite of their hasty completion passed their military flight tests. After all that, however, the November 7 air display was canceled due to bad weather.
That reprieve allowed Lavochkin to continue remedying the La-150's flaws with a series of experimental jet fighters between 1946 and 1948, such as the La-150M ("Modified"), La-150F (with a boosted engine), La-152, La-154, La-156, La-174TK (Tonkoye Krylo, featuring an unswept thin wing) and La-160 Strelka (with a boosted RD-10F engine and a 35-degree leading-edge wing-sweep). During flight testing, carried out from June to September 1947, the La-160 reached Mach .92 at 5,700 meters (18,700feet), an unprecedented speed in the Soviet Union. It also yielded reliable data on improving stability and controllability with the sweptwing, including the need to install wing fences on the upper wing surfaces.
In June 1946, the Soviet trade representative in Britain was given the opportunity to purchase 10 each of the powerful Rolls-Royce Derwent and Nene turbojets, which after February 1947 were put into unlicensed Soviet production as the RD-500 and RD-45 engines, respectively. Among the Soviet aircraft bureaus that designed aircraft around those engines was Lavochkin's OKB-301, adapting the La-174TK to the Derwent V, and the La-168 for the Nene I.
Due to delays in deliveries of the Nene, Lavochkin began designing aircraft No. 174 around the Derwent V in June 1947, using as many components from the la-168 as possible. Aircraft 174 had a wing sweepback of 37 degrees 20 seconds, and both it and the La-168 had sweptback tail units. Both aircraft were high-wing monoplanes with landing gear that retracted into the fuselage and air brakes in the tail. Aircraft 174 was armed with three 23mm Nudelman cannons, with 100 shells per cannon. A novel addition to the plane was an ASP-1N automatic gunsight, a direct copy of the British Mk. IID that provided a sighting range of up to 800 meters (2,625feet) — double that of standard Soviet sights.
Completed in December 1947, Lavochkin's aircraft 174 and Mikoyan's I-310 arrived almost simultaneously at the Flight Research Institute. The I-310's first test flight occurred on December 30, while the 174's began on January 8, 1948. While testing the 174, Lavochkin OKB's Colonel Ivan Federov reported serious jolting in a longitudinal axis in some modes of flight. Several months were required to discover and eliminate the cause of that defect, resulting in a second prototype, the 174D (Duble, or double), incorporating all necessary design changes.
Although the original La-174 failed to complete its first tests, on the evening of May 11 Fedorov completed the third and final flight of the program. During acceleration to a speed of 690 kilometers per hour (428.7 mph) at 8,000 meters (26,247feet) altitude, Federov experienced buffeting that threw the plane so out of control that he had to bail out. On June 10, aircraft 174D was ready for flight testing. Fedorov first flew it on June 12 and at once noted that the buffeting had ceased and that hydraulic amplifiers considerably facilitated control. On June 22, 174D was approved for official testing.
While Lavochkin's program was being delayed, however, two Mikoyan-Gurevich I-310s were finishing their official tests and were accepted for production as the MiG-15. The official tests of 174D — now known as the La-174D — continued from August 1 to September 25, 1948. The rival fighters had equivalent maximum speeds — 1,042 kilometers per hour (647 mph) at 2,620 meters (9,843feet) altitude for the MiG-15 and 1,040 kilometers per hour (646 mph) at 3,000 meters (8,596feet) for the La-174. But the MiG-15's climb rate of 5,000 meters (16,404feet) in 2.3 minutes surpassed the La-174's by three minutes. The La-1740 had better maneuverability, acceleration and braking. Diving to a speed of Mach .93 from 8,200 meters (26,903feet) altitude, the La-174D, thanks to its modified aerodynamics, displayed good longitudinal stability and controllability, whereas the MiG-15's ailerons became less effective at Mach .86, requiring greater pilot effort on the controls.
On August 23, 1948, after official tests of the MiG-15 were finished, but long before they were completed for the La-174D, the Soviet government decided to put both planes into production. With further modifications, the La-174D would be turned out at two factories, No. 21 in Gorky and No. 292 in Saratov.
The control tests of the modified La-174, begun on December 8, 1948, showed overall improvement, though the maximum speed decreased a little — to 1,026 kilometers per hour (638 mph) at 3,000 meters (8,596feet). The first serial La-174 was built at the end of December 1948, followed by two more in January 1949. Production did not go smoothly — the next 85 to be built in the first quarter of 1949 underwent 3,000 construction alterations. Production time eventually settled at 1,200 hours per plane, and after being accepted in March 1949, the first La-174s were assigned to the 196th Fighter Aviation Regiment (IAP) at Kubinka, outside Moscow.
On February 19, 1949, static testing of the La-168 with the hopped-up Nene engine was completed, yielding data superior to both the MiG-15 and La-174, except for range. By that time, however, factories were committed to producing the La-174 and MiG-15. In September 1948, the La-176, a modified La-168 with 45-degree wing sweepback, was presented for testing, during which test pilot O. V Sokolovsky exceeded the speed of sound in level flight for the first time in Russian history. That feat would not be duplicated by Soviet aircraft until February 1950, when the MiG-17 and Yak-50 did so. Meanwhile, the La-176 was equipped with the Klimov VK-1, an improved Nene engine that raised the plane's speed to Mach 1.03. On February 3, 1949, however, Sokolovsky failed to lock the folding flap of the cockpit canopy, which opened on takeoff. As he tried to close it in flight, the plane stalled, turned over on its back, fell 50-70 meters to the ground and caught fire, killing Sokolovsky.
IN APRIL 1949, the La-174 was officially redesignated the La-15. Meanwhile the Soviet government decided, in light of the availability of the newer, more powerful VK-1 engine, to reorganize and simplify jet plane production. The MiG-15 would remain in production as the V-VS' principal frontline fighter, and the Ilyushin Il-28 would be the main tactical bomber. In consequence, Factory No. 21 was ordered to cease La-15 production in favor of the VK-1-powered MiG-15.
In May 1949, the 196th IAP, whose pilots had had previous experience on Yak-15s, began testing its 20 La-15s and soon reported a number of defects and deficiencies. At altitudes of 8,000 to 9,000 feet, the RD-500 (Derwent V) engines surged or overheated, compressor blades cracked and the hydraulic control system was unreliable, resulting in undercarriage failures. The general quality of production aircraft was markedly inferior to that of the experimental prototypes.
During preparations for Moscow's 1949 May Day parade, an La-15 fell out of control and Major A. Zotov became the first Soviet pilot to make a safe escape using an ejection seat, for which he was subsequently awarded the Order of the Red Banner. Another pilot, however, was killed in an La-15 crash on May 28. During aerobatic flying on July 21, the La-15 flown by the 196th IAP's commander, Colonel A.P. Shishkin, went into a spin from which he was unable to recover, and he was killed. A Soviet hero, Shishkin had been a close friend of Guards Lt. Gen. Vasily Stalin, the V-VS commander of the Moscow military district — and Josef Stalin's son. Consequently, General Stalin immediately ordered the V-VS to cease further test flights and hand all extant La-15s over to interceptor units. Although La-15s later participated in the traditional air display at Tushino, the planes' fate was sealed. In August 1949, the decision was made to cease production at Factory No. 292. The remainder of the 225 La-15s built continued to serve in home defense units until 1954. The La-15 received the North Atlantic Treaty Organization (NATO) code name of Fantail, but few if any NATO members ever saw one.
The only other second-generation jet project pursued by the Lavochkin OKB, No. 180, was a two-seat trainer based on the La-15. Only two were built and delivered to La-15-equipped units.
Semyon Lavochkin's efforts to build an effective jet airplane were by no means over. In 1949 he began work on the La-190, a supersonic interceptor with bicycle-type landing gear with underwing skids, a 55-degree wingsweep, nose radar and two 37mm cannons. Completed in February 1951, the La-190 showed good controllability and stability but only made eight test flights because of its poorly engineered AL-5 engine.
In September 1949, Lavochkin OKB turned out the La-200 two-seat all-weather interceptor. Powered by two VK-1 engines, staggered within the fuselage one behind another, the La-200 employed Toryi-A centimetric all-weather radar designed by A.V. Slepushkin. Factory test flying began on September 9, 1949. and official tests concluded on May 3, 1950. While the plane on the whole was satisfactory, the radar fell short of expectations. Moreover, by that time Stalin favored antiaircraft missiles over interceptors. In spite of that, the Lavochkin OKB reequipped the La-200 with new Korshun radar equipment, and after 243 test flights under all weather conditions, day and night, in April 1951 the interceptor was approved for production as the La-17. In August, however, Aleksandr Yakovlev convinced Stalin that he could produce a better twin-engine interceptor, and the initial order for 50 La-17s was canceled.
Although Lavochkin OKB was working on its V-300 and G-300 guided missiles by that time, some employees in the design bureau convinced Lavochkin to continue modernizing the La-200, with a new wing to increase range and new Sokol radar. Flight testing of the improved La-200B began on July 3, 1952, but it proved to be overloaded and ended up only serving to test the Sokol radar for Yakovlev's Yak-25M.
In July 1956, Lavochkin built his last jet fighter, the La-250. It was a single-seat, twin-engine, supersonic missile carrier with a delta wing and horizontal stabilizer. Three La-250s were constructed, and after an engine failure during the first test flight on July 16, the plane's booster control system was checked on a computer simulation stand for the first time in Soviet history. Continuing problems with the AL-7F engines, as well as the death of Semyon Lavochkin on June 9, 1960, doomed the La-250 project -and Lavochkin's prospects for carrying his aviation achievements into the jet age — to oblivion. The third La-250 prototype survives at the Central Museum of the Air Forces in Monino, near Moscow.
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Source: Semyon Lavochkin's design for a modern Soviet jet fighter lost out to the MiG-15 , By: Kulikov, Victor, Aviation History, 10768858, May2005, Vol. 15, Issue 5
La-15
Technical data
Type La-15
Function Fighter
Year 1948
Crew 1
Engines 1*1590kg RD-500
Length 9.56m
Wingspan 8.83m
Wing area 16.16m2
Empty weight 2575kg
Loaded weight 3850kg
Wing load 238kg/m2
Trust-to-Weight 0.41
Speed at 0m 900km/h
Speed at 3000m 1026km/h
Takeoff Roll 640m
Landing Roll 630m
Range 1170km
Flight Endurance 2h6min
Ceiling 13500m
Climb
5000m 3.1min
Armament
Guns 3*23mm cannons NS-23
DURING WORLD WAR II, the LaGG-3, La-5 and La-7 fighters designed by Semyon A. Lavochkin became mainstays of the Soviet army air force, or Voyenno-Vozdushny Sily (V-VS), and brought recognition to their designer. In contrast to his wartime successes, however, Lavochkin's postwar attempts to enter the jet age fell sadly short. The closest that Lavochkin's experimental design bureau (Opytnoye Konstruktorskoye Byuro, or 0KB) came to a production jet fighter, the La-15, is now best remembered as an ill-fated also-ran beside its rival, the Mikoyan-Gurevich MiG-15.
The Lavochkin 0KB began research into the use of liquid-propellant rocket engines, ramjet engines and pulsejet engines to boost the performance of pistonengine aircraft, usually by mounting such engines under the wings, between October 1944 and January 1948. Although they increased speed, each booster had its problems and all produced drag that affected the airplane's flight.
Also in 1944, Arkhip M. Lyulka developed a new turbojet engine with 1,250 kilograms of thrust, the S-18. On May 22, 1944, the Soviet State Committee of Defense granted Lavochkin's OKB the exclusive right to design a fighter for Lyulka's turbojet. By the end of 1944, the bureau had introduced the La-VRD, a twin-boom, twin-finned, high-wing experimental jet fighter, based on a pusher propeller design, with lateral intakes and three-wheel undercarriage. Built under the direction of S.A. Alekseyev, the La-VRD was not completed, because the S-18 engine never passed its bench-testing trials.
With the German surrender on May 8, 1945, the Soviet Union, like the Western Allies, wasted little time in adapting captured German jet engines to its industrial capabilities. Viktor Y. Klimov, for example, developed the BMW 003 into the RD-10 engine, while the Junkers Jumo 004 became the RD-20. As early as February 1945 — three months before the war ended — the design bureaus of Aleksandr S. Yakovlev, Artyom I. Mikoyan and Semyon Lavochkin had begun designing new jet planes for the German engines.
In April 1945, Lavochkin prepared two projects around the Jumo 004. One, the twin-engine La-160 heavy fighter, was judged too similar to the German Messerschmitt Me-262 and got no further than the drawing board. The La-150, a high-wing single-engine plane with a high horizontal tail plane, was more original, but its small, seminacelle-type fuselage presented many problems as to how to arrange the engine, fuel tanks and weaponry. Five prototypes were to be built in aircraft factory No. 381, which had manufactured wooden La-7 fighters during the war and was unprepared to build all-metal aircraft.
Meanwhile, V-VS interest in jet engineering increased after the Scientific Test Institute of Military Air Forces tested an Me-262 from August to November 1945. Pavel O. Sukhoi's Su-9 was directly based on the impressive German fighter, but Yakovlev managed to convince Josef Stalin to encourage the pursuit of more original and advanced designs.
At Lavochkin's factory, the La-150 was revealing shortcomings with its one-piece wing, excessively small cockpit, poor engine access and weak armament. Lavochkin therefore decided to create a new midwing monoplane using the RD-10 engine, designated the La-152, as well as the La-154 with a Lyulka-designed TR-1 engine and the La-156 with a higher-compression version of the RD-10. Production delays and the destruction of the first prototype during static tests held up the La-150's first flight test until September 11, 1946, while its competitors — the MiG-9 designed by Artyom Mikoyan and Mikhail Gurevich and Yakovlev's Yak-15 — were unveiled in August.
Both the MiG-9 and Yak-15 were transitional designs whose inferiority to Western jet fighters greatly irritated Stalin. People's Commissar of Aircraft Industry A.I. Shakhurin, Marshal A.A. Novikov, commander in chief of the V-VS, V-VS chief engineer A.K. Repin and others were dismissed and arrested. Their successors were told to have formations of improved Yak-15s, MiG-9s and the new La-150 ready for the next air display above Red Square on November 7, 1946. Working around the clock, the factories rushed out 19 Yak-15s, 10 MiG-9s and eight La-150s — which in spite of their hasty completion passed their military flight tests. After all that, however, the November 7 air display was canceled due to bad weather.
That reprieve allowed Lavochkin to continue remedying the La-150's flaws with a series of experimental jet fighters between 1946 and 1948, such as the La-150M ("Modified"), La-150F (with a boosted engine), La-152, La-154, La-156, La-174TK (Tonkoye Krylo, featuring an unswept thin wing) and La-160 Strelka (with a boosted RD-10F engine and a 35-degree leading-edge wing-sweep). During flight testing, carried out from June to September 1947, the La-160 reached Mach .92 at 5,700 meters (18,700feet), an unprecedented speed in the Soviet Union. It also yielded reliable data on improving stability and controllability with the sweptwing, including the need to install wing fences on the upper wing surfaces.
In June 1946, the Soviet trade representative in Britain was given the opportunity to purchase 10 each of the powerful Rolls-Royce Derwent and Nene turbojets, which after February 1947 were put into unlicensed Soviet production as the RD-500 and RD-45 engines, respectively. Among the Soviet aircraft bureaus that designed aircraft around those engines was Lavochkin's OKB-301, adapting the La-174TK to the Derwent V, and the La-168 for the Nene I.
Due to delays in deliveries of the Nene, Lavochkin began designing aircraft No. 174 around the Derwent V in June 1947, using as many components from the la-168 as possible. Aircraft 174 had a wing sweepback of 37 degrees 20 seconds, and both it and the La-168 had sweptback tail units. Both aircraft were high-wing monoplanes with landing gear that retracted into the fuselage and air brakes in the tail. Aircraft 174 was armed with three 23mm Nudelman cannons, with 100 shells per cannon. A novel addition to the plane was an ASP-1N automatic gunsight, a direct copy of the British Mk. IID that provided a sighting range of up to 800 meters (2,625feet) — double that of standard Soviet sights.
Completed in December 1947, Lavochkin's aircraft 174 and Mikoyan's I-310 arrived almost simultaneously at the Flight Research Institute. The I-310's first test flight occurred on December 30, while the 174's began on January 8, 1948. While testing the 174, Lavochkin OKB's Colonel Ivan Federov reported serious jolting in a longitudinal axis in some modes of flight. Several months were required to discover and eliminate the cause of that defect, resulting in a second prototype, the 174D (Duble, or double), incorporating all necessary design changes.
Although the original La-174 failed to complete its first tests, on the evening of May 11 Fedorov completed the third and final flight of the program. During acceleration to a speed of 690 kilometers per hour (428.7 mph) at 8,000 meters (26,247feet) altitude, Federov experienced buffeting that threw the plane so out of control that he had to bail out. On June 10, aircraft 174D was ready for flight testing. Fedorov first flew it on June 12 and at once noted that the buffeting had ceased and that hydraulic amplifiers considerably facilitated control. On June 22, 174D was approved for official testing.
While Lavochkin's program was being delayed, however, two Mikoyan-Gurevich I-310s were finishing their official tests and were accepted for production as the MiG-15. The official tests of 174D — now known as the La-174D — continued from August 1 to September 25, 1948. The rival fighters had equivalent maximum speeds — 1,042 kilometers per hour (647 mph) at 2,620 meters (9,843feet) altitude for the MiG-15 and 1,040 kilometers per hour (646 mph) at 3,000 meters (8,596feet) for the La-174. But the MiG-15's climb rate of 5,000 meters (16,404feet) in 2.3 minutes surpassed the La-174's by three minutes. The La-1740 had better maneuverability, acceleration and braking. Diving to a speed of Mach .93 from 8,200 meters (26,903feet) altitude, the La-174D, thanks to its modified aerodynamics, displayed good longitudinal stability and controllability, whereas the MiG-15's ailerons became less effective at Mach .86, requiring greater pilot effort on the controls.
On August 23, 1948, after official tests of the MiG-15 were finished, but long before they were completed for the La-174D, the Soviet government decided to put both planes into production. With further modifications, the La-174D would be turned out at two factories, No. 21 in Gorky and No. 292 in Saratov.
The control tests of the modified La-174, begun on December 8, 1948, showed overall improvement, though the maximum speed decreased a little — to 1,026 kilometers per hour (638 mph) at 3,000 meters (8,596feet). The first serial La-174 was built at the end of December 1948, followed by two more in January 1949. Production did not go smoothly — the next 85 to be built in the first quarter of 1949 underwent 3,000 construction alterations. Production time eventually settled at 1,200 hours per plane, and after being accepted in March 1949, the first La-174s were assigned to the 196th Fighter Aviation Regiment (IAP) at Kubinka, outside Moscow.
On February 19, 1949, static testing of the La-168 with the hopped-up Nene engine was completed, yielding data superior to both the MiG-15 and La-174, except for range. By that time, however, factories were committed to producing the La-174 and MiG-15. In September 1948, the La-176, a modified La-168 with 45-degree wing sweepback, was presented for testing, during which test pilot O. V Sokolovsky exceeded the speed of sound in level flight for the first time in Russian history. That feat would not be duplicated by Soviet aircraft until February 1950, when the MiG-17 and Yak-50 did so. Meanwhile, the La-176 was equipped with the Klimov VK-1, an improved Nene engine that raised the plane's speed to Mach 1.03. On February 3, 1949, however, Sokolovsky failed to lock the folding flap of the cockpit canopy, which opened on takeoff. As he tried to close it in flight, the plane stalled, turned over on its back, fell 50-70 meters to the ground and caught fire, killing Sokolovsky.
IN APRIL 1949, the La-174 was officially redesignated the La-15. Meanwhile the Soviet government decided, in light of the availability of the newer, more powerful VK-1 engine, to reorganize and simplify jet plane production. The MiG-15 would remain in production as the V-VS' principal frontline fighter, and the Ilyushin Il-28 would be the main tactical bomber. In consequence, Factory No. 21 was ordered to cease La-15 production in favor of the VK-1-powered MiG-15.
In May 1949, the 196th IAP, whose pilots had had previous experience on Yak-15s, began testing its 20 La-15s and soon reported a number of defects and deficiencies. At altitudes of 8,000 to 9,000 feet, the RD-500 (Derwent V) engines surged or overheated, compressor blades cracked and the hydraulic control system was unreliable, resulting in undercarriage failures. The general quality of production aircraft was markedly inferior to that of the experimental prototypes.
During preparations for Moscow's 1949 May Day parade, an La-15 fell out of control and Major A. Zotov became the first Soviet pilot to make a safe escape using an ejection seat, for which he was subsequently awarded the Order of the Red Banner. Another pilot, however, was killed in an La-15 crash on May 28. During aerobatic flying on July 21, the La-15 flown by the 196th IAP's commander, Colonel A.P. Shishkin, went into a spin from which he was unable to recover, and he was killed. A Soviet hero, Shishkin had been a close friend of Guards Lt. Gen. Vasily Stalin, the V-VS commander of the Moscow military district — and Josef Stalin's son. Consequently, General Stalin immediately ordered the V-VS to cease further test flights and hand all extant La-15s over to interceptor units. Although La-15s later participated in the traditional air display at Tushino, the planes' fate was sealed. In August 1949, the decision was made to cease production at Factory No. 292. The remainder of the 225 La-15s built continued to serve in home defense units until 1954. The La-15 received the North Atlantic Treaty Organization (NATO) code name of Fantail, but few if any NATO members ever saw one.
The only other second-generation jet project pursued by the Lavochkin OKB, No. 180, was a two-seat trainer based on the La-15. Only two were built and delivered to La-15-equipped units.
Semyon Lavochkin's efforts to build an effective jet airplane were by no means over. In 1949 he began work on the La-190, a supersonic interceptor with bicycle-type landing gear with underwing skids, a 55-degree wingsweep, nose radar and two 37mm cannons. Completed in February 1951, the La-190 showed good controllability and stability but only made eight test flights because of its poorly engineered AL-5 engine.
In September 1949, Lavochkin OKB turned out the La-200 two-seat all-weather interceptor. Powered by two VK-1 engines, staggered within the fuselage one behind another, the La-200 employed Toryi-A centimetric all-weather radar designed by A.V. Slepushkin. Factory test flying began on September 9, 1949. and official tests concluded on May 3, 1950. While the plane on the whole was satisfactory, the radar fell short of expectations. Moreover, by that time Stalin favored antiaircraft missiles over interceptors. In spite of that, the Lavochkin OKB reequipped the La-200 with new Korshun radar equipment, and after 243 test flights under all weather conditions, day and night, in April 1951 the interceptor was approved for production as the La-17. In August, however, Aleksandr Yakovlev convinced Stalin that he could produce a better twin-engine interceptor, and the initial order for 50 La-17s was canceled.
Although Lavochkin OKB was working on its V-300 and G-300 guided missiles by that time, some employees in the design bureau convinced Lavochkin to continue modernizing the La-200, with a new wing to increase range and new Sokol radar. Flight testing of the improved La-200B began on July 3, 1952, but it proved to be overloaded and ended up only serving to test the Sokol radar for Yakovlev's Yak-25M.
In July 1956, Lavochkin built his last jet fighter, the La-250. It was a single-seat, twin-engine, supersonic missile carrier with a delta wing and horizontal stabilizer. Three La-250s were constructed, and after an engine failure during the first test flight on July 16, the plane's booster control system was checked on a computer simulation stand for the first time in Soviet history. Continuing problems with the AL-7F engines, as well as the death of Semyon Lavochkin on June 9, 1960, doomed the La-250 project -and Lavochkin's prospects for carrying his aviation achievements into the jet age — to oblivion. The third La-250 prototype survives at the Central Museum of the Air Forces in Monino, near Moscow.
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Source: Semyon Lavochkin's design for a modern Soviet jet fighter lost out to the MiG-15 , By: Kulikov, Victor, Aviation History, 10768858, May2005, Vol. 15, Issue 5
La-15
Technical data
Type La-15
Function Fighter
Year 1948
Crew 1
Engines 1*1590kg RD-500
Length 9.56m
Wingspan 8.83m
Wing area 16.16m2
Empty weight 2575kg
Loaded weight 3850kg
Wing load 238kg/m2
Trust-to-Weight 0.41
Speed at 0m 900km/h
Speed at 3000m 1026km/h
Takeoff Roll 640m
Landing Roll 630m
Range 1170km
Flight Endurance 2h6min
Ceiling 13500m
Climb
5000m 3.1min
Armament
Guns 3*23mm cannons NS-23