This armored ground attack aircraft was presented at State Trials in 1948, as a heavier 'supplement' type to the IL-10 (already in service) and IL-10M (ready for production). IL-20 differed from any other aircraft built before by its pilot's cockpit, located above the engine at extreme nose and provided unrestricted forward view. Engine and pilot's cockpit had common armour 'shell'. Landing gear (including the tail wheel) - retractable.
Four vertically movable 23mm NS-23 cannons were installed in the wing out of propeller arc. IL-20 could carry 1190kg of bombs on external hardpoints (up to 500kg each) and unguided RS family rockets.
Gunner-operator occupied separate cockpit. He operated a remotely-controlled turret with single NS-23 cannon. Defensive weapons included DAG-10 dispenser for 10 aircraft grenades AG-2.
Flight tests proved good performance of the aircraft (similar to those of lighter IL-10M, thanks to more powerful engine). But age of piston engine aircraft was fading, and IL-20 was not accepted for series production.