Avia
November 2, 2022

Why The Spruce Goose Only Flew Once?

Hughes H-4 Hercules «Spruce Goose».

Hughes H-4 Hercules, familiarly known as the Spruce Goose, was the world's largest plane. However, it was built for a war that was already over and never found a place in our modern world.

Hughes H-4 Hercules «Spruce Goose».
Hughes H-4 Hercules «Spruce Goose».

Next week will mark 75 years since the Spruce Goose flew for the first and last time. During this period, the Spruce Goose plane had the biggest wingspan in the world, at 97.82m. It was a flying boat that had eight engines and weighed 181436kgs. It would be able to carry more cargo than anything else ever conceived.

Hughes H-4 Hercules «Spruce Goose» cockpit.
Howard Hughes seen at the controls of his Hughes H-4, the Spruce Goose.

The Spruce Goose had the following specifications:
- A cruise speed of 400km/h.
- A range of 4800kms.
- Passenger capacity of 750 and three crew members.

Hughes H-4 Hercules «Spruce Goose».
Hughes H-4 Hercules «Spruce Goose».

In 1942, the US Navy was losing ships to German U-boats in the Atlantic Ocean and needed a way to transport troops and supplies to Europe by air. Shipbuilder Henry J. Kaiser came up with the idea to work with the famous plane designer Howard Hughes to create the largest aircraft ever built.

Hughes H-4 Hercules «Spruce Goose».

The dubbed HK-1 would be able to carry up to 68000kgs of materials, 750 troops or two 30-ton M4 tanks. Different concepts were considered, including a double fuselage with up to eight engines. The plane would need to be built from wood and fabric rather than aluminum, as wartime rationing prevented the use of precious metals. Mind you, this wasn't any normal wood but a particular composite of plywood and resin made from Birchwood.

Hughes H-4 Hercules «Spruce Goose».

The aircraft would take so long to design and build (thanks to Howard Hughes’ perfectionism) that Kaiser would abandon the project. Hughes would continue the project in his absence and rename it the H-4 Hercules. The military downscaled the project at the end of the war and reduced the program to a single prototype.

Construction finished at the cost of US$23 million (US$306 million today) in 1947. On November 2nd, 1947, the plane underwent water taxi tests and, on the final test, took off for a brief 26 seconds for a mile (1.6 km) at an altitude of 21 meters.

Hughes H-4 Hercules «Spruce Goose» in the Evergreen Aviation & Space Museum.

The plane sat in a hangar with its full capacity unused. Despite being fully built, it had no purpose, and further testing was unneeded.

Hughes H-4 Hercules «Spruce Goose» in the Evergreen Aviation & Space Museum.

The Spruce Goose's airframe can be seen at the Evergreen Aviation & Space Museum in Oregon today.