JRM-2 Mars

The JRM‑2 “Mars” was the most powerful version of the United States Navy’s giant Martin seaplane, built by the Glenn L. Martin Company in the early 1940s. Derived from the earlier JRM‑1, the Mars incorporated four 3,500‑horsepower Wright R‑3350 radial engines, giving a total of roughly 14 MW and allowing a maximum take‑off weight of 140 000 lb. Its high‑mounted wing and massive hull could accommodate up to 70 troops, 20 000‑lb of cargo, or 30 000‑gal of aviation fuel, making it a versatile long‑range transport for the Pacific war effort. Only three JRM‑2s entered service, designated “Mars,” and they operated as trans‑Pacific freight carriers, ferrying supplies between the United States and forward bases such as Guam and the Philippines. After the war the type was retired from military use, but two examples were converted to fire‑fighting water bombers and remain in service in California and Alaska, proving the airframe’s durability. The JRM‑2’s sheer size—one of the largest seaplanes ever built—and its capacity to move massive loads over water secured its place as a milestone in maritime aviation and demonstrated the Martin Company’s engineering ambition during the height of World II.

Glenn L. Martin Company

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