The Martin P6M Seamaster prototype, which made its first test flight on July 14, 1955. During flight testing, speeds in excess of 600 mph (966 km/h) were claimed. It embodied all the design features developed during World War II and immediately after the war. In 1952 Martin was awarded a contract, first, for a design study, and then a production contract for two prototypes known as Model 275. They would be modern in almost every way, despite their untimely destruction during tests.
They were effectively seagoing B-52s, having a small crew of four and a gross take-off weight of 160,000 lbs (72,575 kgs), the same as the Convair Tradewind. The technology involved in its design was the latest known and included four Pratt & Whitney J75-P-2 turbojet engines of 17,500 lbs (7,938 kgs) thrust mounted on top of a highly swept shoulder-mounted drooped wing which had a span of 100 ft (30.48 m).
It had a T tail configuration and a high length-to-beam ratio of its 134 ft (40.84 m) hull. The engines were mounted in such a way as to prevent ingestion of the water spray pattern into the engine air-intake ducts and the wing-tip floats were integral, enlarged parts of the drooped wing configuration. These floats served additionally as wing-tip plates and in the mooring and docking of the Seamaster they played an important role in picking up the mooring buoy which was the key to swinging the aircraft, almost automatically, into the floating beaching gear or into a dock, whichever system was being used at the time. Also incorporated in the design of the P6Ms was a watertight rotary bomb bay. This could be flipped over in flight to expose the bomb racks which could be loaded on the inside of the hull with bombs, mines, cameras or other ordinance stores.
Progress was encouraging, however during flight tests, both XP6M-1s crashed. On December 7,1955 the one thing the flying control designer feared most happened. The actuator controlling the horizontal stabilizer ran to full travel. The huge aircraft, traveling at high speed, pitched down sharply. The engines tore away from the wings, which, under the high airloads, bent down and actually touched beneath the hull, before the aircraft broke up, killing the crew of three.
Trials continued with the second prototype, but during special vibration checks, this too went out of control and executed a tight loop before breaking up. On this occasion, luckily, the crew managed to escape from the stricken aircraft. A modification was incorporated in the second ship to allow the crew to escape through a tube like hatch just aft of the flight deck. When the second XP6M-1 crashed, the crew was saved because of the escape system installation.
A major redesign program followed this mishap, during which the wing was given dihedral in place of the former anhedral. Other changes included the installation of more powerful engines, the jet pipes of which toed out sharply. Most important, a new, all-transistorized auto-pilot and flight control system was installed.
The Navy had ordered an initial fleet of 24 Sea Masters, but through the delay caused by the redesign work and the accompanying steep rise in costs, six aircraft were canceled. The first production aircraft, YP6M-1, flew in February 1959, and the Navy boasted how well their new aircraft could mine the Black Sea, and claimed it was "a major new anti-submarine warfare system . . . able to go after enemy submarines in their home ports." However, by this time the force of 18 aircraft had been reduced to eight, which were planned to operate as a single squadron from a new 'seadrome'. In the event, even these eight aircraft proved too expensive and only an additional three production P6M-2s Sea Masters were built. The Seamaster project was terminated in the autumn of 1959.
General characteristics
* Crew: 4 * Length: 134 ft 0 in (40.84 m) * Wingspan: 102 ft 11 in (31.37 m) * Height: 32 ft 5 in (9.88 m) * Wing area: 1,900 ft² (180 m²) * Empty weight: 91,300 lb (41,400 kg) * Loaded weight: 120,000 lb (54,000 kg) * Max takeoff weight: 176,400 lb (80,000 kg) * Powerplant: 4× Pratt & Whitney J75-P-2 turbojets, 17,500 lbf (77.8 kN) each
Performance
* Maximum speed: 550 kt (630 mph, 1,010 km/h) * Range: 1,700 nm (2,000 mi, 3,200 km) * Service ceiling: 40,000 ft (12,000 m) * Rate of climb: ft/min (m/s) * Wing loading: 63 lb/ft² (310 kg/m²) * Thrust/weight: 0.58
Armament
* Guns: 2× 20 mm cannon in tail turret * Bombs: 30,000 lb (14,000 kg)
And let's get one thing straight. There's a big difference between a pilot and an aviator. One is a technician; the other is an artist in love with flight. — E. B. Jeppesen
