Martin XLB-4

Last revised July 10, 1999

The Martin XLB-4 was a 1926 proposal for an all-metal biplane bomber powered by a pair of Pratt & Whitney R-1690 Hornet radials. The USAAC ordered one prototype and assigned it the serial number of 27-332, but the Army was reluctant at that stage to experiment with all-metal aircraft, and the project never got off the drawing board.


  1. United States Military Aircraft Since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian, 1989.

  2. American Combat Planes, Ray Wagner, Third Edition, Doubleday, 1982.