Three initial design concepts were developed for the Model 45, including one with the Bonanza's signature V-tail, but the final design that emerged in 1948 incorporated conventional tail control surfaces for the benefit of the more conservative military (featuring a relatively large unswept vertical fin that would find its way onto the Travel Air twin-engine civil aircraft almost ten years later). The Bonanza's fuselage with four-passenger cabin was replaced with a narrower fuselage incorporating a two-seater tandem cockpit and bubble canopy, which provided greater visibility for the trainee pilot and flight instructor. Structurally, the Model 45 was much stronger than the Bonanza, being designed for +10"g" and −4.5"g", while the Continental E-185 engine of 185 horsepower (hp) at takeoff (less than a third of the power of the T-6's engine) was the same as that fitted to contemporary Bonanzas.