After the spectacular success of the Lockheed Vega and its derivatives, Mr. Northrop directed his attention to the design and fabrication of an all metal aircraft. The Alpha was the result. The design and technology made possible, among others, the legendary Douglas DC- 3, and led the way for the transition from wood/fabric construction to aluminum. This, the only surviving Northrop Alpha, is on display at the NATIONAL AIR & SPACE MUSEUM. If you have an interest in this landmark aircraft, you MUST acquire THE NORTHROP STORY, by Richard Sanders Allen. It is a definitive work.