The R3Y was designed in response to a 1945 requirement set by the US Navy for a new large flying boat. It was originally meant to be a sort of flying patrol boat armed with 8,000 lbs of munitions and ten 20 mm cannons. This version was designated XP5Y-1, and had two prototypes built. It first flew on April 18th, 1950. However, after one of the prototypes crashed, the armed version was cancelled and the design was turned into a transport aircraft.
The transport version was designated R3Y, first flew on February 22nd, 1954, and entered service in 1956. The aircraft was used for aerial refueling in addition to transportation, and set a transcontinental seaplane speed record of 403 mph that still stands today. Only 11 R3Ys were built before its production was cancelled due to unreliable engines, and all were retired and scrapped by 1958.
- Powerplant: four Allison T40-A-10 turboprop engines
- Top speed: 403 mph (624 kmph)
- Range: 2,785 miles (4,482 kilometers)
- Ceiling: 39,700 feet (12,100 meters)
- Crew: 5
- Capacity: 80 people, 47,951 lbs of cargo
- Empty weight: 71,824 lbs (32,579 kg)
- Length: 139 feet 8 inches (42.26 meters)
- Height: 51 feet 5 inches (15.68 meters)
- Wingspan: 145 feet 9 inches (44.42 meters)