The Martin JRM Mars is a large, four engine cargo transport seaplane originally designed and built in limited numbers for the U.S. Navy during the World War II. It was the largest Allied flying boat to enter production, although only seven were built. The United States Navy contracted the development of the XPB2M-1 Mars in 1938 as a long range ocean patrol flying boat, which later entered production as the JRM Mars long range transport. Its predecessor the Pan Am Martin M-130, still in civilian service, was supporting transportation and pre-War luxury trans-ocean travel.
After the war the surviving aircraft were converted for civilian use to firefighting water bombers. Examples of the aircraft still exist and remain in active service
The Glenn L. Martin Company scaled up their PBM Mariner patrol bomber design to produce the prototype XPB2M-1 Mars. It was launched in November 1941, after a delay caused by an engine fire during ground run-ups, the aircraft first flew in June 1942.
After flight tests the XPB2M in 1943, she was turned over to the Navy. The original patrol bomber concept was already considered obsolete by that time.
The Mars was converted into a transport aircraft. First, named Hawaii Mars, was delivered in June 1945, but with the end of World War II the Navy scaled back their order, buying only the five aircraft which were then on the production line. Though the original Hawaii Mars was lost in an accident on Chesapeake Bay a few weeks after it first flew, the other five Mars were completed, and the last delivered in 1947.
Named the Marianas Mars, Philippine Mars, Marshall Mars, Caroline Mars, and a second Hawaii Mars, the five production Mars aircraft entered service ferrying cargo to Hawaii and the Pacific Islands. The last production airplane (the Caroline Mars) was designated JRM-2, powered by 3,000 hp Pratt & Whitney R-4360 engines, and featured a higher maximum weight and other improvements. On 4 March 1949, the Caroline Mars, set a new world passenger load record by carrying 269 people from San Diego to Alameda, CA. On 5 April 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 Naval cargo on the San Francisco-Honolulu route efficiently until 1956, when they were beached at NAS Alameda.
In 1959, the remaining Mars were to be sold for scrap but a Canadian company, Forest Industries Flying Tankers (FIFT), was formed and bid for the four aircraft and a large spares holding. The company represented a consortium of British Columbia forest companies and the bid was accepted and the sale was completed in December 1959. The four aircraft were flown to Fairey Aviation at Victoria, British Columbia for conversion as water bombers. The conversion involved the installation of a tank in in the cargo bay and retractable pick-up scoops to allow uploading of water while the aircraft was taxiing. The scoops allowed 30 tons of water to be taken on board in 22 seconds. Later some of the hull fuel tanks were replaced with water tanks.
The Marianas Mars crashed near Northwest Bay, British Columbia on 23 June 1961 during firefighting operations; all four crewmembers were lost. Just over a year later, on 12 October 1962, the Caroline Mars was destroyed by Typhoon Freda while parked onshore. The Hawaii Mars and Philippine Mars had their conversions to water bombers accelerated and entered service in 1963. They appeared at local air shows, demonstrating their water-dropping ability. Flying Tankers Inc. also flew the water bombers to other hot spots around the province when a need developed, such as in August 2003, when a large forest fire threatened the city of Kelowna, British Columbia.
On 10 November 2006, TimberWest Forest Ltd. announced that they are looking for buyers of the Mars. A condition of this sale was that the purchasers would have to donate one back to Port Alberni when they are retired, as an historic attraction. The Maryland Aviation Museum and British Columbia Aviation Council have initiated a joint effort to preserve the aircraft, one in Maryland and the other at their current location in Canada. On 13 April 2007, TimberWest announced the sale of both aircraft to Coulson Forest Products, a local forestry company in Port Alberni, British Columbia. The two surviving tankers are operated by Coulson Flying Tankers and are based and maintained at Sproat Lake near Port Alberni. On 25 October 2007, the Hawaii Mars (“Redtail”) arrived at Lake Elsinore in southern California, on a private contract, to assist with the firefighting efforts containing the California wildfires of October 2007. The Philippine Mars did undergo “extensive maintenance and renovation” and was ready to fly again in 2010. The Hawaii Mars is in service fighting the La Brea fire east of Santa Maria in Southern California.
Based on historical data, each plane can make a drop every fifteen minutes. Working in tandem, this equates to 7,200 U.S. gallons every seven minutes and each drop can cover an area of up to 4 acres. The aircraft can also carry up to 600 U.S. gallons of foam concentrate for gelling the load drop. They are used to fight fires along the coast of British Columbia and sometimes in the interior. The Martin Mars are currently being used to fight fires all over British Columbia.