R4D-7 Skytrain

The R4D-7 Skytrain, the United States Navy’s designation for the Douglas DC‑3, entered service in the early 1940s and became one of the most versatile transport aircraft of its era. Developed from the civilian DC‑3 and the Army Air Forces C‑47, the R4D‑7 incorporated strengthened airframe components, a larger cargo door, and a reinforced floor to accommodate heavy military loads. Powered by two Pratt & Whitney R‑1830 Twin Wasp radial engines delivering 1,200 hp each, the aircraft could cruise at 180 mph, carry up to 28 troops or 6,000 lb of cargo, and operate from short, unprepared runways—qualities that made it indispensable in World War II, the Korean War, and numerous humanitarian missions. Its robust construction allowed modifications such as glider tow capability, aerial refueling probes, and radar‑equipped night‑flight versions. The R4D‑7’s reliability and low operating cost set a benchmark for future transport designs, influencing post‑war civilian airliners and military logistics platforms. By the time it was retired in the early 1970s, the Skytrain had logged millions of flight hours, cementing its legacy as a workhorse that shaped modern air mobility and underscored Douglas’s engineering prowess.

Douglas

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