Northrop BT-1

The Northrop BT was an American two-seat, single-engine monoplane dive bomber built by the Northrop Corporation for the United States Navy. At the time, Northrop was a subsidiary of the Douglas Aircraft Company. While unsuccessful in its own right, the BT was subsequently redesigned into the Douglas SBD Dauntless, which would form the backbone of the Navy's dive bomber force.

The design of the initial version began in 1935. It was powered by a 700 hp Pratt and Whitney XR-1535-66 double row air-cooled radial engine and had hydraulically actuated perforated split flaps (dive brakes), and main landing gear that retracted backwards into fairing "trousers" beneath the wings. The perforated flaps were invented to eliminate tail buffeting during diving maneuvers.

The U.S. Navy placed an order for 54 BT-1s in 1936 with the aircraft entering service during 1938. BT-1s served on USS Yorktown and Enterprise. The type was not a success in service due to poor handling characteristics, especially at low speeds, "a fatal flaw in a carrier based aircraft." It was also prone to unexpected rolls and a number of aircraft were lost in crashes.