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Lavochkin La-7 / La-120

lavla-7


The La-7 was developed from the autumn of 1943 under the bureau designation of La-120. This embodied the results of a TsAGI wind tunnel programme aimed at defining areas in which the basic La-5FN could be aerodynamically improved. Incorporating the modified wing structure (metal spars replacing the wooden box spars) intended for application to the definitive La-5FN (but not to be introduced on that fighter until the late spring of 1944), a revised inboard wing leading edge and an entirely new cowling for the Shvetsov M-82FN engine, the La-120 was first flown in November 1943. In the following spring it entered production as the La-7.

The intended armament comprised three 20mm Berezina B-20 cannon, but while this armament was installed in aircraft built at Yaroslavl, those built at Moscow reverted to the twin ShVAK cannon of the La-5FN.

The first series production La-7 were produced in March-April of 1944. That Summer they were handed over to the pilots of 63 GIAP for operational trials. Though they had inferior performance to what was expected the pilots enjoyed great success with this aircraft until engine problems and wing spar failures forced Marshal Novikov to step in an ground all La-7s until the problems could be rectified. The causes were dirt getting into the supercharger air intake at the wingroots and improper execution of lightening holes in the structure. In November 1944 all production irregularities had been worked out and production resumed of the La-7.
The last war time production model was unchanged except the armament. In February 1945 3xB-20s became the standard armament. Weight was increased to 7,325 but performance was unchanged.

115 La-7 were lost to all military causes (less than half of these to aerial combat) and at the same time accounting for more than 3,100 aerial victories.
Roll rate was considered equal to any Fw-190A.

Variants included the tandem two-seat La-7UTI trainer, the La-7TK with a pair of TK-3 turbo-superchargers,
and the rocket-boosted La-7R. The La-7TK was test flown in July- August 1944, but was destroyed when a turbo-supercharger exploded. Another example was fitted with the 2000hp ASh-71TK, trials soon being discontinued owing to the erratic behaviour of this engine's turbosuperchargers.
The La-7R, of which two prototypes were tested, was fitted in the rear fuselage with an RD-lKhZ liquid rocket motor of 300kg thrust, the first prototype being destroyed during the initial take-off run in October 1944. Flight testing of the second prototype continued until February 1945, and a further example - a conversion of one of the original prototype airframes and then referred to as the La-120R - entered test in January 1945, this having an improved rocket motor and local airframe structural changes. Testing of the La-120R continued until late 1946.

A total of 5,753 La-7s had been manufactured when production ended in 1946.

Engine: Shvetsov M-82FN, 1850hp
Max take-off weight: 3400 kg / 7496 lb
Empty weight: 2620 kg / 5776 lb
Wingspan: 9.8 m / 32 ft 2 in
Length: 8.6 m / 28 ft 3 in
Height: 2.60 m / 8 ft 6 in
Wing area: 17.59 sq.m / 189.34 sq ft
Max. speed: 680 km/h / 423 mph
Cruise speed: 450 km/h / 280 mph
Ceiling: 11800 m / 38700 ft
Range: 990 km / 615 miles
Crew: 1

La-7
Engine: ASh-82FN, 1,850hp.
Max speed: 362mph/SL
Max speed: 413mph/20,200ft.
Climb: 4,000fpm/SL.
Climb to 16,400ft: 4.6min.
Ceiling: 31,000ft.
Armament: 2xShVAK.
Test weight: 7,179 lbs.

La-7
Engine: Shvetsov M-82FN, 1850hp
Max speed: 382mph/SL.
Max speed: 421-423mph/20,200ft.
Climb SL: 4,300fpm
Climb to 16,400ft: 4.2min.
Ceiling: 34,450ft.
Test weight 7,105 lbs.
Armament: 2xShVAK (20mm).

La-7
Engine: Shvetsov M-82FN, 1850hp
Max speed: 382mph/SL.
Max speed: 421-423mph/20,200ft.
Weight: 7,325
Armament: 3 x 20mm Berezina B-20 cannon

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