The Il-28 design was conventional in layout, with high, unswept wings and a swept horizontal tail and fin. The engines were carried in bulky nacelles slung directly under the wings. The nosewheel retracted rearwards, while the mainwheels retracted forwards into the engine nacelles. The crew of three were accommodated in separate, pressurised compartments. The navigator, who also acted as bombardier, was accommodated in the glazed nose compartment and was provided with an OPB-5 bombsight based on the American Norden bombsight of the Second World War, while the pilot sat under a sideways opening bubble canopy with an armoured windscreen. The gunner sat in a separate compartment at the rear of the fuselage, operating a power driven turret armed with two Nudelman-Suranov NS-23 23 mm cannons with 250 rounds each. In service, the turret was sometimes removed as a weight saving measure. While the pilot and navigator sat on ejector seats, the gunner had to parachute out of a hatch in the floor in the event of an emergency. Two more fixed, forward-firing 23 mm cannon with 100 rounds each were mounted under the nose and fired by the pilot, while a bomb bay was located in the fuselage, capable of holding four 100 kg (220 lb) bombs in individual containers, or single large bombs of up to 3,000 kg (6,600 lb) slung from a beam in the bomb bay.