The Spruce Goose Flies Once, and Only Once

An Idea Born of the U-Boat War

In the early years of the Second World War German submarines sank merchant ships faster than the Allies could build them. One proposed answer was a flying boat large enough to carry troops and equipment across the Atlantic above the reach of the submarines. Industrialist Henry Kaiser and the aircraft designer and businessman Howard Hughes took on the project, and Hughes continued it after Kaiser withdrew. Metals such as aluminum were reserved for war production, so the plane was built mostly of laminated birch wood glued in a process Hughes’s team called Duramold. Critics later gave it a nickname Hughes disliked, the Spruce Goose, although the wood was mostly birch, not spruce.

A Machine Built at the Edge of the Possible

The H-4 Hercules was enormous. Its wingspan of about 320 feet was roughly the length of a football field, and it was powered by eight large radial engines. The hull was tall enough to house a multistory interior, and the plan called for it to carry hundreds of soldiers or heavy vehicles. It was not finished until after the war ended, and by then the military no longer needed it. For decades it kept the record as the aircraft with the greatest wingspan ever built.

The Hearings

By 1947 the project had cost a great deal of public money and had produced nothing that flew. A Senate committee investigated Hughes’s wartime contracts, and in the summer he testified in a combative, widely reported hearing. He defended the aircraft and promised to leave the country if it failed to fly. The pressure to demonstrate the machine was intense, and the next test was planned for a day when taxi runs on Long Beach harbor were scheduled.

November 2, 1947

On that day Hughes was at the controls of the H-4 during a high-speed taxi test. Without a prior announcement of a flight, he advanced the throttles, and the huge boat rose out of the water. It flew for around a minute at a low altitude, covering roughly a mile, before he set it back down on the harbor. Reporters and invited guests saw it in the air. It never flew again. Hughes kept the aircraft in a climate-controlled hangar for decades, and it is now on display at the Evergreen Aviation and Space Museum in McMinnville, Oregon, as one of the strangest and largest aircraft in the history of flight.

What Happened to the Giant

After the flight Hughes kept the H-4 in a climate-controlled hangar in Long Beach, where a crew maintained it for years as if it might still be needed. In 1992 and 1993 it was taken apart and carried by barge and road to Oregon, then reassembled at the Evergreen museum. Its record for wingspan lasted until 2019, when the Stratolaunch carrier aircraft flew with a wing about 385 feet across. Although the H-4 never carried a single soldier, its size and its ambitious use of wood have made it one of the best-known aircraft of the twentieth century.