HK-1 / H-4 / Hercules / Spruce Goose
Interest in transport seaplanes ended with the abandonment of Howard Hughes' H-4 "Hercules" prototype. This project was designed to enhance strategic deployment capabilities over long distances. Hughes' most famous aircraft was an oversized wooden seaplane nicknamed the "Spruce Goose."
The idea for a fleet of such planes was conceived in 1942 by shipbuilder Henry J. Kaiser, whose Liberty ships had become targets for German U-boats. Kaiser felt that a fleet of large plywood flying boats could assume the wartime role of the Liberty ships. President Franklin Roosevelt was intrigued by the idea and first proposed that Donald Douglas build the flying boats. Douglas felt the idea was impractical and technically difficult and declined.
Kaiser persisted and persuaded Howard Hughes to partner with him. Kaiser, who could build ships very quickly, thought such a plane could be built in 10 months—much faster than the usual time needed for aircraft. The two got $18 million of Reconstruction Finance Corporation funding for a prototype plane. But when a year passed and the plane was still in the design stage, Kaiser lost interest and withdrew from the project in 1944. The HK-1 designation was derived from the names Hughes and Kaiser. When Kaiser backed out of the project, Hughes redesignated the aircraft H-4.
The H-4 Hercules, better known as the Spruce Goose, was designed to carry two tanks, 750 troops or 420 stretcher cases on two decks. The Spruce Goose is still the largest plane ever built. It has an overall length of 218 feet 6 inches (67 meters), a wingspan of 320 feet (98 meters), and a height of 79 feet inches (24 meters). Its propellers are 17 feet 2 inches (5 meters) in diameter, and it can hold 14,000 gallons (52,996 liters) of fuel.
Hughes continued by himself. Completed in 1947, there was one flight by Hughes' enormous Spruce Goose flying boat. On 02 November 1947, it flew 70 feet over the water for one mile at a top speed of 80 mph. It was the first and only example of a large-platform WIG flight in US history. After the first flight, Hughes changed the tail number from NX37602 to N37602.
