The Spruce Goose is an aircraft designed by Howard Hughes and constructed during and after World War II. It was intended to be a military transport plane, though the prototype was not completed until well after the end of the war. It was dubbed the Spruce Goose by the media because it was made mostly of wood due to constraints placed by the government on high-demand materials such as aluminum. The Spruce Goose only made one flight, which lasted between a mile (1.6 kilometers) at an elevation of about 70 feet (21 meters).
The official designation of the Spruce Goose is the H-4 Hercules. It is currently housed at an aviation museum in Oregon in the United States. The maiden flight took place in California after a day of taxi tests performed by Hughes himself. The plane was actually a boat as well, designed to take off and land from the water. It is the largest airplane boat ever built, and it has the longest wingspan of any aircraft ever built; the wingspan measures 320 feet, 11 inches (97.54 meters). The wings featured eight propeller engines, four on each wing. After its maiden flight, the plane was put in storage in flight-ready condition. It remained in storage in its custom hangar for three decades.
No other versions of the Spruce Goose were ever built, as the prototype was the only one funded by the United States Government, though the original contract called for three aircraft. The Spruce Goose was built from birch, not from spruce as many believed. The process was called duramold, and it involved laying pieces of wood with the grain of each strip perpendicular to each other. A glue was applied between layers, and the layers were heated so they could be formed into various shapes. It was a revolutionary process at the time, and it created a product that was arguably stronger than aluminum while also saving weight over the metal.
After the war ended, Hughes came under intense scrutiny because of the project, and a senate hearing was held to determine if the project constituted a misappropriation of funds. Hughes defended the project and even invested a significant amount of his own money in it. The project had been delayed several times because of the revolutionary techniques being used to build the plane, as well as tedious design changes that took place over the course of its construction.