LL-1 Rocketplane

The LL was a transonic aerodynamic testbed authorized by LII in September 1945. Three were built: the LL-1 with a straight wing; LL-2 with a conventional swept wing; and LL-3 with a forward swept wing. The LL was towed to a 6 km release altitude by a Tu-2 aircraft. After being cast off, it would fire its Kartukov solid rocket engine and accelerate to the edge of the sound barrier, with a camera photographing air flow on the tufted wing. The LL-2 was not finished because contemporary fighter programs were already providing data on swept wing configurations. But in 1946 to 1948 the LL-1 flew 30 times and the LL-3 100 times, with test pilots M Ivanov, Amet-Khan Sultan, Anokhin, and Rybko at the controls.

Crew Size: 1. Length: 8.98 m (29.46 ft). Span: 7.22 m (23.68 ft). Mass: 2,039 kg (4,495 lb). Main Engine: PRD-1500. Main Engine Thrust: 14.700 kN (3,305 lbf). Main Engine Propellants: Solid. Main Engine Propellants: 900 kg (1,980 lb).

• 1945 September 1 - LL rocket-powered transonic aerodynamic testbed authorised. -
  In 1946 to 1948 the LL-1 flew 30 times and the LL-3 100 times, with test pilots M Ivanov, Amet-Khan Sultan, Anokhin, and Rybko at the controls.