Northrop Delta

The Northrop Delta was an American single-engined passenger transport of the 1930s, closely related to the Gamma mail plane. Jack Northrop designed it for the new Northrop Corporation, formed in 1932 as a joint venture with Douglas. It was a low-winged all-metal stressed-skin monoplane with spatted main wheels and room for eight passengers behind an enclosed cockpit, and the first one flew in May 1933. A 1934 rule against single-engined passenger flights at night or over rough terrain ended the airliner market, so most went to executive owners, the Spanish Civil War, the US Coast Guard as the RT-1, and the Royal Canadian Air Force, which had 19 more built by Canadian Vickers. It was withdrawn from Canadian operations in late 1941.