Martin JRM Mars

The Martin JRM Mars was a massive flying boat developed by the Glenn L. Martin Company in the early 1940s. Originally conceived as a commercial trans‑oceanic airliner designated the Martin Model 179, the prototype first flew on 26 July 1942. With the outbreak of World War II, the United States Navy requisitioned the design and ordered it as a long‑range transport, redesignating it JRM‑1. Six aircraft were built, three of which entered service as the “Mars” squadron at Naval Air Station Alameda. The Mars featured a hull of aluminium alloy, a wingspan of 200 ft (61 m), and four Pratt & Whitney R-4360 Wasp Major radial engines delivering 3,500 hp each, giving a maximum speed of 300 mph and a payload capacity of up to 30 000 lb of cargo or 75 troops. Its enormous internal volume allowed it to carry vehicles, ammunition, and even a small amphibious army landing craft. After the war the Mars served as a transport and later as a firefighting water‑bomber, most famously the “Phoenix” and “Sierra”. Though only a handful were built, the JRM Mars demonstrated the feasibility of very large seaplanes, influencing post‑war concepts for maritime patrol and heavy lift aviation.

Glenn L. Martin Company

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