During the design of the new SG-1 racing aircraft (SCR-21), designer Boris Ivanovich Cheranovsky applied a trapezoidal wing shape but with a broken leading edge. The center-wing was straight and the outer had a swept 25º. By the front view, the wing was a “reverse gull”, and tailless.

 

The very short fuselage had a length with a rudder of no more than 4,74 m. The drop-shape of the pilot's cabin, along with the fuselage with a hexagonal cross section in the cockpit area, was continued back to the wedge-shaped vertical tail.

The take-off weight of the SG-1 was 643 kg with empty 526 weight. The take-off and landing characteristics turned out to be outstanding. The “screen” effect reduced the landing speed to 80 km / h, and the take-off and landing respectively 110 and 100 m. It was calculated with the forced motor MB-6А (240 hp) to reach 424 km / h.

Such unusually large numbers caused a critical attitude to the project of some aerodynamics and designers. The plane was predicted of a fiasco, but some experts gave positive feedback, among them - Brig. VS. Pyshnov Mr. I rank engineer A.S. Yakovlev.

Due to the complexity of the engine supercharging system, its power, like that of the serial MB-6, was only 220l.s., and on flight tests it was possible to achieve 417 km / h. But this is only 7 less than the estimated speed. SG-1 tests were completed by the summer of 1941.