both direct descendants of the Model 50 Twin Bonanza. All three aircraft share the same basic wing design, as well as landing gear, flaps, instrument panels, fuel cells, and more. The Queen Air added a larger cabin to the design, while the later King Air added turbine power and pressurization. Twin Bonanza production ended in 1963 while the King Air was under development. Design The Twin Bonanza is an all-metal low-wing monoplane with a cantilever wing and retractable tricycle landing gear, initially powered by two wing-mounted geared Lycoming GO-435 piston engines, each with a wooden two-bladed propeller. The standard cabin seats six people on bench seats, three in the front and three in the rear, and several other seating configurations were offered, including club seating and a three-person sideways-facing couch. Early models had a single right-hand door above the wing, accessed by trailing edge steps, while later aircraft added a rear airstair door with retracting steps. The GO-435 was replaced by the Lycoming GO-480 in 1954; this engine was subsequently upgraded with fuel injection and then superchargers, increasing power to in 1956 and in 1957. In addition to its seating configuration, the Twin Bonanza has several other unusual design features. The main landing gear wheels retract only partially into the engine nacelles, leaving the tires exposed to assist in the event of a belly landing and allowing the pilot some directional control using differential braking. The aircraft is equipped with a tailskid to mitigate damage from a badly executed or belly landing. The exposed main wheels and tailskid potentially allow a Twin Bonanza equipped with two-bladed props to be belly-landed with minimal damage if the props are stopped horizontally. In many Twin Bonanzas, the copilot's seat and rudder pedals are not on the right as is customary, but instead are positioned in the center of the front seat; the pilots pivot the single "throwover" control yoke to the center for the copilot to fly. Instead of conventional cowl flaps for low-speed engine cooling, the engines are equipped with exhaust augmenter tubes that create a low-pressure area inside the engine nacelles, drawing in additional cooling air. The combination of the augmenter tubes and low propeller RPM and high engine RPM from the geared engines gives the Twin Bonanza a characteristic sound. The Twin Bonanza was briefly offered with "Junior JATO" rocket motors which mounted to the tops of the engine nacelles