Lavochkin La-250

La-250

Picture - La-250A at the Monino air museum

Role: Interceptor
Manufacturer: Lavochkin
First flight: 1956
Status: Cancelled 1959
Primary user: Soviet Air Forces
Number built: 5

The Lavochkin La-250 "Anakonda" was a 1950s Soviet high-altitude interceptor aircraft prototype.

Development

By the mid-1950s, it became obvious that subsonic cannon-armed fighters like the Yakovlev Yak-25 would be unable to intercept fast high-altitude targets like the upcoming generation of strategic jet bombers. As a result, in 1953 Lavochkin OKB proposed addition of an air-to-air missile system to the Berkut air-defense system. Tasked with defense of Moscow, the Berkut system consisted of a large network of radars and surface-to-air missile sites as well as ground-controlled interceptor aircraft. Lavochkin's proposed missile, the G-300 utilized a guidance system based on vacuum tubes and was so heavy (about 1,000 kg (2,200 lb)) that no fighter in the Soviet arsenal could carry it. Instead, a Tupolev Tu-4 bomber (Soviet version of the Boeing B-29 Superfortress) was modified to carry four G-300s under the wings, with the whole system receiving designation G-310. For all this trouble, G-300 was expected to have a range of only 15 km (9 mi) and a ceiling of 20,000 m (65,600 ft). Although G-310 made ten flights in 1952, the system was abandoned as impractical.

In November 1952, the Soviet government ordered development of Kompleks K-15 (Complex K-15, a notion analogous to USAF's "weapon system" concept). K-15 was to consist of an interceptor "250" (later designated La-250) carrying "275" guided missiles. La-250 had to be able to intercept targets flying at 1,250 km/h (777 mph, Mach 1.18) at 20,000 m (65,600 ft) and up to 500 km (310 mi) from the airbase. Initial guidance was to be from Vozdukh-1 ground control with terminal onboard radar guidance for the last 40 km (25 mi) and automatic missile firing by the fire control system when in range. Missile "275" was projected to weigh 870 kg (1,915 lb) and, powered by a liquid fuel rocket motor, its top speed was to exceed 3,900 km/h (2,425 mph). With a 125 kg (275 lb) conventional warhead, it had a projected lethal radius of 50 m (165 ft). La-250 was to carry two "275" missiles semi-recessed into the underside of the fuselage in a tandem arrangement.

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/1,764 lb, the warhead actually grew to 140 kg/308 lb). 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 the 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. 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). La-250A made a single test flight in 1956, only 6 flights in 1957, and a mere 14 flights in 1958. Frustrated by the lack of progress, VVS stopped all work on the K-15 system in 1959. Lessons learned with K-15 were used to develop new interceptor system requirements which led to the Tupolev Tu-28 interceptor.

The abortive, trouble-filled development of La-250 was mirrored in the West by the similarly complicated creation of Convair's delta-winged F-102 Delta Dagger and F-106 Delta Dart interceptors.

Specifications (La-250A)

General characteristics

Crew: 2
Length: 26.80 m (87 ft 11 in)
Wingspan: 13.90 m (45 ft 7 in)
Height: 6.50 m (21 ft 4 in)
Wing area: 80.0 m² (860.8 ft²)
Empty weight: 18,988 kg (41,775 lb)
Loaded weight: 24,500 kg (53,900 lb)
Max takeoff weight: 27,500 kg (60,500 lb)
Powerplant: 2x— Lyulka AL-7F turbojets, 98.0 kN (22,050 lbf) afterburning thrust each

Performance

Maximum speed: 1,800 km/h (1,118 mph) without missiles; 1,600 km/h (994 mph) with missiles
Range: 2,000 km (1,240 mi)
Service ceiling: 17,000 m (55,760 ft)
Wing loading: 306 kg/m² (63 lb/ft²)
Thrust/weight: 0.41

Armament

2 x— Air-to-air missiles on underwing pylons, either "275," "277," "279," or "280." (see text for description)

Comparable aircraft

F-101 Voodoo
F-102 Delta Dagger
F-106 Delta Dart
Avro CF-105 Arrow
Tupolev Tu-28

Kopenhagen, W (ed.), Das groxŸe Flugzeug-Typenbuch, Transpress, 1987, ISBN 3-344-00162-0
http://www.airwar.ru/enc/fighter/la250.html

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Source: WikiPedia