The original engine nacelles incorporated thrust reversers taken from the 727 outboard nacelles. They retained the two inboard piston engines, the jets being housed in the outboard nacelles. Vedeneyev M-14V-26 radial engines mounted in outboard nacelles. Tiltrotor aircraft vector thrust via rotating turboprop engine nacelles. The aircraft had a bicycle undercarriage, with outriggers under the engine nacelles. The nosewheel retracted rearwards, while the mainwheels retracted forwards into the engine nacelles. The engines were carried in bulky nacelles slung directly under the wings. The 990A was developed by adding fairings to the engine nacelles, among other changes. The twin engines are housed in widely spaced nacelles. The turbocharged engines led to the flattened oval nacelles that distinguished all subsequent Liberator models. Subsequent wind tunnel testing identified a problem with the aerodynamics of the radiators and nacelles. The engines and engine nacelles are supplied by General Electric. The taller nose-gear strut keeps the same ground clearance of the engine nacelles. The bomb bays were in the engine nacelles. The 747's right, outer landing gear was torn off and two engine nacelles were damaged.