Kozlov El

Purpose: To evaluate a fighter with a variable-incidence wing.

Design Bureau: Zhukovskii WA, Soviet air force academy; design team led by Professor S G Kozlov.

Kozlov was perpetually seeking after new targets, and one that he had considered for many years was the pivoted wing, able to change its angle of incidence. Thus, for ex­ample, the aircraft could take off or land with a large angle of attack yet with the fuse­lage level. Four Russian designers had made unsuccessful variable-incidence aircraft in 1916-17. Design of the El (Eksperimentalnyi Istrebitel, experimental fighter) began in 1939. Under Kozlov’s direction the wing was designed by V S Chulkovand the landing gear by M M Shishmarev. D O Gurayev was assis­tant chief designer, and S N Kan and IA Sverdlov handled the stressing. The single El was constructed at a factory in the Moscow district, but its completion was seriously de­
layed, mainly by technical difficulties and re­peated alteration of the drawings. At last the El was almost complete in autumn 1941, but on 16th October the factory was evacuated. The El and all drawings were destroyed.

The El was said to have been a good-look­ing single-seat fighter, powered by a 1,650hp M-107 (VK-107) liquid-cooled engine. The fuselage was a Duralumin stressed-skin semi- monocoque of oval section, with heavy ar­mament around the engine. The wings had spars with steel T-booms and Duralumin webs, with glued shpon (Birch veneer) skin. The wing was fitted with flaps and differential ailerons, and was mounted on ball-bearing trunnions on the front spar and driven by an irreversible Acme-thread jack acting on the

While no illustration has been found of the El, this 1940 drawing recently came to light showing a fighter project with a more powerful engine (M-106P) and greater span.

rear spar. To avoid problems it is believed the main landing gears were attached to the fuse­lage and retracted into fuselage compart­ments. No other details survive.

There is no reason to believe that the El would not have met its designer’s objectives, but equally it had little chance of being ac­cepted for production. The only successful variable-incidence aircraft was the Vought F8U (F-8) Crusader.

Dimensions

Span 9.2m 30 ft 2K in

No other data.