In 1943, Sergey Ilyushin started work on a new aircraft, the Il-1 armoured fighter, in both single- and two-seat versions.
The Il-1 used the same principle of a stress-bearing armored shell to protect the engine and pilot as did the Il-2, but protection was increased by moving the oil cooler and radiator inside the shell, cooled by wing-root ducts that exhausted through an armored slot on the underside.
The landing gear retracted aft and the wheels rotated to lie flat within the wings.
A cassette of ten AG-2 aerial grenades was carried to drop in the path of pursuing fighters.
[3] Data from The Osprey Encyclopedia of Russian Aircraft 1875–1995 [4]General characteristics Performance Armament