The Martin Model 156 was intended to be a successor aircraft to the M130 for Pan American Airways.
Lateral buoyancy was provided by seawings rather than conventional sponsons or outboard floats. Interior furnishings provided for either a maximum of 46 passengers or a more luxurious arrangement allowing for night sleeping for a reduced number of passengers. Four 1,000-hp nine-cylinder radial engines were mounted in nacelles on the leading edge of the center section.
Only one was built and it was sold to the Russians in 1937. The sale included a complete set of production drawings as the Russians intended to mass produce the aircraft. WWII and invading Germans ruined their plans. The single type was used by the Russians for troop movements during the war. It is distinguishable from the M130 by the twin tails structure.
Engines four 1,000-hp Wright Cyclones
Gross wt. 63,000 lb
Empty wt. 30,414 lb
Top speed 190 mph
Cruise 156 mph
Takeoff 70 mph
Range 2,410 miles
Ceiling 15,500 ft