Martin JRM Mars
The Martin JRM Mars was a the largest flying boat ever to enter production. The US Navy contracted the development of the Mars in 1935 as a massive transport aircraft.
The Martin Company effectively scaled up their successful PBM Mariner patrol bomber design to produce a prototype designated the XPB2M-1R Mars. After flight tests with the XPB2M between 1941 and 1943, she was passed on to the Navy which ordered 20 of the new JRM Mars based on the XPB2M. The first, named Hawaii Mars, was delivered in June 1945, but the with the end of World War II the Navy scaled back their order to just 5 more boats. Though the original Hawaii Mars was lost in an accident on Chesapeake Bay, the other 5 Mars were built with the last delivered in 1947. Named the Marianas Mars, Phillipine Mars, Marshall Mars, Caroline Mars, and a second Hawaii Mars, the Mars entered service ferrying cargo to Hawaii and the Pacific Islands. On May 5, 1950, the Marshall Mars was lost near Hawaii when an engine fire consumed the airplane after her crew had evacuated. The remaining "Big Four" flew record amounts of cargo on the San Francisco-Honolulu route efficiently until 1956, when they were parked at NAS Almeda.
In 1959, the remaing Mars were sold for scrap. A consortium of BC lumber companies' representative, Dan McIvor, recognized their potential value as water bombers and had them converted. A company called Flying Tankers Inc. was formed, and purchased the "Big Four" for aerial firefighting. The Marianas Mars crashed in 1961 and the Caroline was destroyed in a hurricane while parked onshore in 1962. The remaining Hawaii Mars and Phillipine Mars had their conversions to water bombers accelerated and entered service in 1963. The airtankers are still operated by Flying Tankers Inc., now a subsidiary of TimberWest Forest Ltd. and are based at Sproat Lake, near Port Alberni, British Columbia. When converted, the original powerplants were replaced with four Wright Cyclone R-3350-24WA engines of 2500hp (1865 kw) each. The aircraft can carry up to 7,200 US gal (27,276 Litres) of water, enough to cover an area of 4 acres (1.6 ha).
Specifications (JRM-2 Mars)
General Characteristics
- Crew: 7
- Capacity: 133 troops, 84 litters + 25 seats, or 16 tons of cargo.
- Length: 117 ft 3 in (35.70 m)
- Wingspan: 200 ft 0 in (61 m)
- Height: 38 ft 5 in (11.7 m)
- Wing area: ft² ( m²)
- Empty: 75,573 lb (34,279 kg)
- Loaded: 165,000 lb (74,843 kg)
- Maximum takeoff: lb ( kg)
- Powerplant: 4x Pratt & Whitney R-4360-4T Wasp Major 28-cylinder 4-row radials, 3,000 hp (2,238 kW) each
Performance
- Maximum speed: 221 mph (356 km/h)
- Range: 4,945 miles (7,958 km)
- Service ceiling: 14,600 ft (4,450 m)
- Rate of climb: ft/min ( m/min)
- Wing loading: lb/ft² ( kg/m²)
- Power/Mass: hp/lb ( kW/kg)
External link
Additional History Flying Tankers Inc's homepage with information on the Mars.
Related content
Related development: PBM Mariner
Comparable aircraft: PBM Mariner
Designation sequence: