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Lavochkin La-250A "Anakonda"

The Lavochkin La-250A "Anakonda" was a twin-engine, two-seat delta-wing interceptor designed to fly long-range missions at high altitude, armed with two large missiles. Four of these aircraft were built between 1956 and 1958 in a competition with the Tu-28, which the later won.

The LA-250 long-range supersonic all-weather fighter-missile carrier was one of the first in this class. This loitering interceptor designed to intercept aircraft or cruise missiles from the situation "on duty in the air." The two AL-7F engines, of 6500 kgf thrust, were installed on the sides of a very long fuselage with air intakes, separated from the fuselage for supersonic flight. The airplane was nicknamed "Anaconda". The "275" missiles were to become one of the first armament systems.

Destined to be the last aircraft produced by the Lavochkin design bureau, the La-250A, known unofficially as the Anaconda, was designed to meet a very demanding 1954 requirement for an ultra long-range, high-altitude single-seat super interceptor armed exclusively with missiles.

Featuring a 57 delta wing and an enormous fuselage of near-constant cross section, the La-250 was powered by two Lyulka AL-7F turbojets each rated at 6500kg which were later to be fitted with afterburners boosting thrust to 9000kg. All control surfaces were fully powered with duplex systems and without manual reversion. Intended to carry the 30km acquisition- range Uragan (Hurricane) radar, the La-250 had a planned armament of two large K-15 beam-riding missiles.

Problems with the K-15U radar and Klimov VK-9 engines forced a radical redesign of the aircraft to use the K-15M radar and, more importantly, much less powerful Lyulka AL-7F engines. This, in turn, led to the need to change "275" missiles to the lighter "275A" (interestingly, although total missile weight decreased to 800 kg (1,760 lb), the warhead actually grew to 140 kg (308 lb)).

The plane is made by the normal aerodynamic scheme and mid-delta wing and triangular horizontal tail surface. The control system of irreversible boosters have been applied to all government and each booster (for reliability) - with a two-power two hydraulic systems.

The new airframe with a smaller fuselage and a delta wing instead of the earlier swept wing was designated La-250A. The "275" missiles were now carried on underwing pylons. The lighter airframe was not enough to overcome weaker engines and projected performance suffered compared to La-250. While busy redesigning the aircraft, Lavochkin OKB also had to develop new variants of the "275" missile -- the semi-active radar homing "277," the nuclear-armed "279," and solid fuel rocket-powered "280." The first La-250A prototype was finally rolled out on June 16, 1956.

Three La-250A were built in 1957 by Lavochkin to expand the initial tests with a modified flight control system. Test flights of the five prototypes were plagued by crashes caused by failures of the hydraulic boost system and landing gear as well as poor forward visibility (the latter was corrected with fitting of a new slightly "drooped" nose).

The banana-nosed La-250A featured delta wings instead of the earlier La-250 swept wings. This plane was flown by AG Kochetkov, followed by AP Bogorodsky, who made dozens quite successful flights, because now management system has been redone (and especially with regard to the laws of damping). However, a regular flight by Kochetkova 28 November 1957 ended in a heavy accident during landing due to fog and suddenly coming out of engines. One of the main causes of the accident was poor visibility, especially during landing, marked and Air Chief Marshal KA Vershinin. To improve the view the canopy was elevated and the nose lowered by 6 degrees. On September 8, 1958 test flight of the third instance also ended an accident during landing, although not serious, caused by manufacturing defects.

The production La-250A was to carry two newly-developed K-15 medium range AAMs (which never entered production). The 'Anaconda' entered flight test but the advent of the S-75 missile system and Khruschchev's bias towards rocketry killed off the aircraft.

Due to the fact that the development of the engine-VC was delayed. Instead, the AL-7F engine, with considerably less thrust, was used, which led to the creation of virtually new aircraft, "250A" modified lightweight missiles "275A" and the radar "K-15M". Later, for a system of "K-15M" missile developed "277" with a conventional warhead and guidance and radar head "279" with a nuclear warhead.

La-250A made a single test flight in 1956, only 6 flights in 1957, and a mere 14 flights in 1958. The first prototype vehicle "250A-I" was sent to trial in April 1957. Flight testing began July 12, 1957 (the pilot AG Kochetkov). Tests revealed a design flaw - the long nose greatly impaired visibility when landing, which led to an accident in the 6th flight landing when fog suddenly appeared.

The revised second instance 250A-II was sent for trial in May 1958. Flight testing began July 30, 1958 (AP Bogorodskiy pilot). All in all it made 16 flights. At the end of 1958 two flying prototypes of the aircraft "250A" were built, and all elements of the system were ready for the start of complex tests with missile launches in the air.

Frustrated by the lack of progress, VVS stopped all work on the K-15 system in 1959. In 1959 because of a large load of OKB-301, work on the K-15 were discontinued because the task of designing a similar system was received by Tupolev.

Despite the accidents, the aircraft was considered good and promising. It was still hampered by unreliable AL-7F engines. In the end, because of the amount of difficulties and complications, the trial dragged on, and La-250 had not passed them. The flying qualities were not completely fixed. Lavochkin, after June 9, 1960, evidently, caused a cessation of tests. By 1960 the speed of 2000 km / h and a ceiling of 16 (18) miles were considered inadequate to effectively intercept supersonic aircraft carrying nuclear weapons, such as the American B-70.

Due to the lack of orders for traditional heavy bombers, Tupolev was forced to look for work in the "related" areas and the start of work on heavy interception Tu-28-80 was similar to the K-15. Lessons learned with K-15 were used to develop new interceptor system requirements which lead to Tupolev Tu-28 interceptor. Since the Lavochkin Design Bureau at this time a shortage of other priority tasks was clearly not experienced, it was decided in favor of continuing operations with Tupolev, and it was decided to cease work on the K-15 system.

In 1961 serial production began of the Tu-28P (Tu-128) loitering interceptor. In 1961 the complex Tu-28-80 went on trial in 1964 under the designation Tu-128 into service. In the future, creating a line of heavy aircraft systems intercept continued OKB AI Mikoyan, whose MiG-31 is in service at the moment. So another pioneering development, launched Lavochkin, was continued in the works of other KB. System K-15 was the last work of the SA Lavochkin in manned aircraft.

In the late 1950s, various Mikoyan designs - the I-75, Ye-150 and particularly the Ye-152, 'A and 'M - suffered the same ignominious fate. These were remarkable aircraft capable of destroying almost any target at altitudes of up to 22,000m (72,180ft) and ranges of up to 1,000km (625 miles) shortly after take-off. Like the 'Anaconda', they did not progress beyond the prototype stage. The S75's success on 1 st May 1960 was undoubtedly a major contributing factor.

The T-37 heavy interceptor developed by Sukhoi, an innovative design which made use of titanium alloys and all-welded assemblies, was even less fortunate: the prototype was scrapped without ever being flown. Still, the threat posed by USAF's large strategic bomber force led the Soviet leaders in 1965 to adopt the Tu-28-80 weapon system comprising the Tu-128 twin-engined heavy interceptor and the R-4 (alias K-80) long range AAM.




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Page last modified: 07-12-2015 10:57:42 ZULU