Martin BM-2

The Martin BM was one of the U.S. Navy's first purpose-built carrier dive bombers. Originally developed as the XT5M torpedo bomber to replace the Martin T4M, the design was reworked into a rugged two-seat dive bomber and ordered into production in 1931. The initial batch was designated BM-1, followed in October 1931 by sixteen BM-2 aircraft incorporating minor refinements. The biplane could deliver a 1,000-pound bomb and was notable for introducing the bomb crutch, a tubular steel cradle beneath the fuselage that swung the bomb clear of the propeller arc during steep diving attacks.

Operating from carriers such as USS Lexington, the BM helped the Navy validate dive bombing as a primary attack technique during the early 1930s, laying groundwork for the more capable scout bombers that followed later in the decade.