RD-3 Dolphin

The Douglas RD‑3 Dolphin is the third production variant of the company’s iconic amphibious flying‑boat, developed in the early 1930s to meet both civilian and military demand for a versatile water‑capable transport. First flown in February 1931, the RD‑3 incorporated a strengthened hull, enlarged fuel tanks and a more powerful Pratt & Whitney R‑985 Wasp Junior radial engine delivering 450 hp, allowing a maximum speed of 155 mph and a range of 750 miles. Its retractable landing gear and fully enclosed cabin could accommodate up to eight passengers or a comparable cargo load, while the rear cargo door facilitated quick loading and unloading on both water and land. The United States Navy adopted the type as the RD‑3A for utility duties, employing it for liaison, personnel transfer, and search‑and‑rescue missions throughout the Pacific theater. Although only a handful were built before production shifted to the improved RD‑4, the Dolphin series demonstrated the practicality of amphibious aircraft in an era when airfields were scarce. The RD‑3’s blend of reliability, short‑takeoff capability and multi‑environment operation helped shape later designs such as the Martin PBM Mariner and cemented Douglas’s reputation as a pioneer of hybrid‑role aviation.

Douglas

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