Martin P7M SubMaster

The Martin P7M was an unbuilt aircraft designed by the Glenn L. Martin Company in the 1950s. The design was initiated to meet a requirement of the United States Navy (USN) for an anti-submarine warfare flying boat.

P7M
Role	anti-submarine warfare (ASW) flying boat
Manufacturer	Glenn L. Martin Company
Primary user	United States Navy
Number built	0 (mock-up only)
Developed from	P5M Marlin

Design and development

The design was for a flying boat that would make use of boundary layer control (BLC) to achieve slow speed flight. It was intended that this would enable the aircraft to land on the open ocean in rough seas and deploy a dipping sonar. Martin proposed a variant of the P5M Marlin, the P5M-3, to take advantage of this phenomenon.

Martin continued development of the P5M-3 under the designation P7M Submaster, introducing two General Electric J85 BLC gas generators, one in the rear of each outer engine nacelle. A mock-up was built, but the P7M, Convair XP6Y and Grumman G-132 were all cancelled when the US Navy abandoned their open-ocean seaplane requirement.^[1]

Specifications (P7M projected)

General characteristics

• Length: 136 ft (41 m)
• Wingspan: 111 ft 7 in (34.01 m)
• Height: 39 ft (12 m)
• Wing area: 2,500 sq ft (230 m²)
• Powerplant: 4 × Wright R-1820-42 radial piston engines, 1,525 hp (1,137 kW) each
• Powerplant: 2 × General Electric YJ85-GE-1 turbojet gas generators for BLC in rear of outer nacelles

Performance

• Maximum speed: 400 mph (650 km/h, 350 kn)
• Range: 1,400 mi (2,200 km, 1,200 nmi)
• Service ceiling: 25,300 ft (7,700 m) service ceiling

Armament

• Missiles, bombs, and depth charges on external hard-points

References

1. Johnson, E.R. (2009). American flying boats and amphibious aircraft : an illustrated history. Jefferson, N.C.: McFarland & Co. pp. 349–353. ISBN 978-0786439744.