Boeing TB

The Boeing TB (or Model 63) was an American torpedo bomber biplane designed by the US Navy and built by Boeing in 1927.

Development and design
The TB was an improved version of the Martin T3M. It was constructed of all dural, with a fabric covering. The equal-span wings were large and unstaggered, and could be folded aft, reducing the span to 21 ft for storage. The wheeled undercarriage was a conventional configuration that could be interchangeable with floats. As a landplane, the main gear units carried twin wheels. The underside of the fuselage incorporated a glazed station for the bombardier.

Even before the three XTB-1s were delivered, the Navy's Bureau of Aeronautics had changed its opinion about what was needed in a torpedo bomber, and based on experience with the NAF XTN-1 had decided that a twin-engine aircraft would better suit the role. Having thus been made redundant, no TBs past the three prototypes were built.