The Twin Bonanza was first flown on November 15, 1949 after rapid development, begun only in April of that year. The aircraft was first designed to use Franklin engines with superchargers, but engine company owner Preston Tucker diverted all of its aviation resources to support his ill-fated Tucker 48 automobile project, and the aircraft was hastily modified to accept the Lycoming GO-435. However, the engine nacelles were not redesigned to fit the smaller Lycoming, creating unusually generous internal clearances that facilitate engine maintenance. The Model 50's type certificate was awarded in 1951, and production began the same year.