Martin JRM Mars

JRM Mars
The "Caroline Mars" JRM-2 Mars in Navy service.
Role Flying boat
National origin United States
Manufacturer Glenn L. Martin Company
First flight 23 June 1942
Introduction 30 November 1943
Retired 1956 (USN)
Primary users United States Navy
Flying Tankers
Produced 1945–1948
Number built 7


The Martin JRM Mars is a large, four-engined cargo transport seaplane originally designed and built in limited numbers for the U.S. Navy during the World War II era. 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.

The surviving aircraft were later converted for civilian use to firefighting water bombers. One example of the aircraft still remains in active service.

Design and development

The Glenn L. Martin Company scaled up their PBM Mariner patrol bomber design to produce the prototype XPB2M-1 Mars.[1] The XPB2M-1 was launched on 8 November 1941. After a delay caused by an engine fire during ground runs, the aircraft first flew on 23 June 1942. After flight tests with the XPB2M between 1942 and 1943, she was passed on to the Navy. The original patrol bomber concept was considered obsolete by this time, and the Mars was converted into a transport aircraft designated the XPB2M-1R. The Navy was satisfied with the performance, and ordered 20 of the modified JRM-1 Mars.[1] The 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.[2] 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.

Operational history

U.S. Navy service

The prototype XPB2M-1 Mars

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 (2,200 kW) 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.[3] 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.[1]

Civilian use

Hawaii Mars ("Redtail")

In 1959, the remaining Mars aircraft 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 inventory. The company represented a consortium of British Columbia forest companies, and the bid was accepted and the sale completed in December 1959. The four aircraft were flown to Fairey Aviation at Victoria, British Columbia, for conversion into water bombers. The conversion involved the installation of a tank 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 crew members were lost. Just over a year later, on 12 October 1962, the Caroline Mars was damaged beyond repair by Typhoon Freda while parked onshore. The Hawaii Mars and Philippine Mars had their conversion into water bombers advanced and entered service in 1963.[1] They appeared at local airshows, demonstrating their water-dropping ability. Flying Tankers Inc. flew the water bombers to hot spots around the province when a need developed, such as in August 2003, when a large forest fire threatened the outskirts of Kelowna, British Columbia.

Hawaii Mars undergoing winter maintenance at Sproat Lake in 2008 with Philippine Mars in the background

On 10 November 2006, TimberWest Forest Ltd. announced they were looking for buyers of the Mars. A condition of sale was that the purchaser would have to donate one plane back to Port Alberni when they were retired, as an historic attraction.[4] The Maryland Aviation Museum and British Columbia Aviation Council initiated a joint effort to preserve the aircraft, one for display in Maryland and the other at the current location in Canada.[5] 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 presently 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 firefighting efforts at the California wildfires of October 2007. Meanwhile the Philippine Mars had been undergoing "extensive maintenance and renovation" and was expected to be ready to fly again by 2010.[6] As of 13 August 2009, the Hawaii Mars was in service fighting the La Brea fire east of Santa Maria in Southern California.

The aircraft can carry 7,200 U.S. gallons (27,276 litres) of water and each drop can cover an area of up to 4 acres (1.6 hectares). The aircraft can also carry up to 600 U.S. gallons (2,270 litres) of foam concentrate for gelling the load drop.[7] They are mainly used to fight fires along the coast of British Columbia and sometimes in the interior. As of July 29, 2010, the Martin Mars was being used to fight the Mason Lake/Bonaparte Lake fire north of Kamloops.[8]

On 23 August 2012, the Coulson Group of Port Alberni, British Columbia announced that the Philippine Mars, due to its lack of use for five years, would be retired and flown to the National Naval Aviation Museum at Naval Air Station Pensacola, Florida to become a static exhibit. The aircraft was repainted to its original U.S. Navy colors and was to have been delivered to the museum in November 2012.[9] As of 2014 however, the aircraft had yet to be delivered.[10]

On 10 May 2013, the B.C. provincial government announced that the Hawaii Mars would no longer be placed on contract after the 2013 season, due to not having been used to fight any B.C. fires for two years and the operation of newer and more versatile aircraft by the Coulson group including a Lockheed C-130 Hercules converted to firefighting use. Although Coulson stated that the Hawaii Mars has been under numerous recent upgrades to make it safer and more reliable,[11] no buyers have come forward to purchase the aircraft. Coulson also cautioned against any plans to open the aircraft as a tourist attraction because of the 2013 closure of the Flying Tankers Bomber Base Museum from poor attendance.[10] In May 2015, the Hawaii Mars received a contract where it will be used to train Chinese government workers in fighting forest fires over the summer of 2015.[12] Subsequently, during the early summer of 2015, numerous forest fires have caused the B.C. government to reintroduce the aircraft temporarily to fight the increasing number of fires.[13][14]

Variants

XPB2M-1
Model 170 prototype long-range patrol flying boat powered by four Wright R-3350-8 piston engines, one built, converted to XPB2M-1R.
JRM-1 BuNo 76820
Philippine Mars
XPB2M-1R
Prototype converted in December 1943 as a prototype transport version, armament removed, installation of additional cargo hatches and cargo loading equipment, existing hatches were enlarged and the decking was reinforced.
JRM-1
Model 170A, production long range transport variant, originally 20 aircraft ordered later reduced to six. Single-tail design, and having a longer hull with fewer bulkheads and a larger maximum take-off weight. It had also been fitted with equipment for overhead cargo handling and was powered by four Wright R-3350-24WA Cyclone engines with 4-bladed propellers, five built, surviving four converted to JRM-3.
JRM-2
The last JRM-1 on order was completed as the JRM-2 with the engines changed to 3,000 hp Pratt & Whitney R4360-4T engines with 4-blade, 16 ft, 8 in diameter Curtiss Electric propellers. Gross weight increased by 20,000 lb.[15]
JRM-3
Model 170B, conversion of the remaining four JRM-1s re-engined with 2,400 hp Wright R3350-24WA engines turning 16 ft, 8 in Curtiss-Electric props, of which the inboard two engines were fitted with reversible-pitch devices.

Aircraft

JRM-3 Marshall Mars burning near Honolulu, Hawaii
JRM-2 Caroline Mars in the St. Johns River at NAS Jacksonville, Florida in 1949

Specifications (JRM-3 Mars)

Bow of JRM-3 Marshall Mars

Data from 'Jane’s Fighting Aircraft of World War II[2][19]

General characteristics

Performance

See also

Related development
Aircraft of comparable role, configuration and era
Related lists

References

Notes

  1. 1 2 3 4 Goebel, Greg. "The Martin Mariner, Mars, & Marlin Flying Boats." Air Vectors, 6 May 2006. Retrieved: 13 November 2010.
  2. 1 2 Bridgeman 1946, pp. 244–245.
  3. ↑ Hills, Warring. "Caroline Mars Sets World Record 1949." cv10navalaviator.wordpress.com, 25 February 2011.
  4. ↑ "TimberWest Seeks Buyers For Martin Mars Water Bombers." TimberWest Forest Ltd., 12 November 2006.
  5. ↑ "Canadian Aviation Organization and U.S. Museum Create Alliance." Maryland Aviation Museum, 12 November 2006.
  6. ↑ Hansen, Darah. "Fires fought without super-soakers." Vancouver Sun, 6 August 2009. Retrieved: 6 August 2009.
  7. ↑ "Aircraft Fleet." Flying Tankers Inc., 6 May 2006.
  8. ↑ "Kamloops fire." bclocalnews.com. Retrieved: 13 November 2010.
  9. ↑ McCulloch, Sandra. "Water bomber retires to US." Alberni Valley Times, 23 August 2012. Retrieved: 27 August 2012.
  10. 1 2 "Mars bomber future now up in air". Alberni Valley Times. April 14, 2014. Retrieved 18 May 2014.
  11. ↑ McCulloch, Sandra. "Last summer for Port Alberni Mars water bomber as province cuts contract." Times Colonist, 10 May 2013. Retrieved: 12 May 2013.
  12. ↑ "Busy summer ahead for tankers". Alberni Valley Times. May 20, 2015. Retrieved June 12, 2015.
  13. ↑ "Martin Mars coming back - BC News". Retrieved 2015-07-08.
  14. ↑ "Martin Mars home after first action against wildfires - CHEK NEWS". Retrieved 2015-07-19.
  15. 1 2 "JRM-2 76824." Gauthier Memorial Collection. Retrieved: 13 November 2010.
  16. ↑ "Naval Aviation and Deep Water Discoveries: Pearl Harbor 2004." National Marine Sanctuaries. Retrieved: 28 December 2010.
  17. ↑ Gorell, Fred. "Mars is found in seafloor survey around Japanese mini-submarine. NOAA and Partners Survey "Flying Boat" Crash Sites." National Oceanic and Atmospheric Administration, US Department of Commerce via NOAA Magazine. Retrieved: 28 December 2010.
  18. ↑ "
  19. ↑ "Specifications" (PDF). www.martinmars.com. Coulson Flying Tankers. Retrieved 7 August 2014.

Bibliography

  • Bridgeman, Leonard. “The Martin Model 170 Mars.” Jane's Fighting Aircraft of World War II. London: Studio, 1946. ISBN 1-85170-493-0.
  • Coulson, Wayne and Steve Ginter. The Mighty Martin Mars: From 1945 US Navy Transport to 21st Century, Initial Attack Firefighting. Port Alberni, British Columbia, Canada: Half Moon Bay Publications, 2009. ISBN 978-0-9812987-0-2
  • Ginter, Steve. Martin Mars XPB2M-1R & JRM Flying Boats (Naval Fighters 29). Simi Valley, California, USA: Ginter Books, 1995. ISBN 0-942612-29-9.

External links

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