The direct predecessor of the Baron was the Beechcraft 95 Travel Air, which incorporated the fuselage of the Bonanza and the tail control surfaces of the T-34 Mentor military trainer. To create the new airplane, the Travel Air's tail was replaced with that of the Beechcraft Debonair, the engine nacelles were streamlined, six-cylinder engines were added, and the aircraft's name was changed. In 1960, the Piper Aztec was introduced, using two 250 hp Lycoming O-540 engines; Cessna too had improved their 310 with two Continental IO-470 D, producing 260 hp. Meanwhile, Beechcraft's Bonanza had been improved with a Continental IO-470-N, but the answer to competition was to make a true twin engined variant of the Bonanza. The first model, the 55, was powered by two, six-cylinder IO-470-L engines, producing 260 hp at 2,625rpm; it was introduced in 1961. It included the fully swept vertical stabilizer of the Debonair, while still retaining the four to four+five place seating of the Travel Air. For more details, including variants, click here'
