page_title: Martin JRM Mars
section_title: Design and development
hierarchical_section_title: Martin JRM Mars / Design and development
caption_attribution_description: The U.S. Navy Martin XPB2M-1 Mars (BuNo 1520) in flight. It first flew as a patrol bomber prototype (XPB2M-1) on 3 July 1942 and was converted to a transport (XPB2M-1R) in December 1943. It was named Old Lady and finally beached at Alameda, California (USA), in mid-1945, before being subsequently scrapped.
context_page_description: The Martin JRM Mars is a large, four-engined cargo transport flying boat designed and built by the Martin Company for the United States Navy during 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.
  Four of the surviving aircraft were later converted for civilian use to firefighting water bombers. One example of the aircraft still remains based at Sproat Lake just outside of Port Alberni, British Columbia, although it is not operational.
context_section_description: The Glenn L. Martin Company scaled up their PBM Mariner patrol bomber design to produce the prototype XPB2M-1 Mars. 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. 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. 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.
caption: The prototype XPB2M-1 Mars, 1942
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