n HISTORICAL PERSPECTIVE When the

The H-4 Hercules, the world’s largest airplane, skims across the water at Long Beach Harbor in California. Sixty years ago Hercules this month the airplane made its first and only flight. took to the air B oeing ar ch i v es ph oto

chase of a Boeing Stratoliner, the first air- across the Atlantic Ocean to England was World’s biggest-ever liner with a pressurized passenger cabin. critical to the Allied effort in World War II, The Hercules originally was envi- and perhaps the mission could be accom- airplane conducted its sioned as a transport aircraft to support plished by air. military activity. In 1942, when German Kaiser approached aircraft designer only flight 60 years ago U-boats were taking a tremendous toll on Hughes, and together they formed the U.S. shipping, industrialist and shipbuilder Hughes Kaiser Corporation. That year, By Erik Simonsen Henry Kaiser conceived the idea of a large they secured a U.S. government de- ixty years ago this month at Long fleet of cargo-carrying flying boats. The velopment contract for $18 million to Beach Harbor, Calif, after an ar- movement of troops and war supplies develop three large flying boats, each ca- Sduous journey of development and political controversy, the H-4 Hercules— an airplane that’s the world’s largest and What big wings you have is still one of its most legendary—made its first and only flight. A comparison of wingspans of several large aircraft, including the Hughes H-4 Hercules. The airplane—or perhaps more to the point, the flying boat—reflected the am- Hughes H-4 Hercules 320 feet (97.5 meters) bition of Howard Hughes, the renowned Antonov An-225 Mriya 290 feet (88.4 meters) entrepreneur and the subject of the 2004 Convair B-36 Peacemaker 230 feet (70.1 meters) movie “The Aviator.” Hughes is connect- ed to Boeing through the products created Boeing 747-400 211.5 feet (64.5 meters) by Hughes-owned companies that are now Boeing B-52H Stratofortress 185 feet (56.4 meters) part of Boeing, as well as his personal pur-

 November 2007 BOEING FRONTIERS n HISTORICAL PERSPECTIVE pable of carrying up to 750 troops or two airplane was canceled, and the U.S. mil- 80 mph for about a mile (129 kilometers M4 Sherman tanks. However, because of itary’s post-war strategy didn’t call for per hour for about 1.6 kilometers). Some wartime restrictions on strategic materials, procuring large airborne troop carriers. detractors later proclaimed that the huge the aircraft, designated the HK-1, would Yet, the determined Hughes continued in- aircraft actually remained in “ground have to be made primarily of wood. jecting his own funding to keep the proj- effect,” which is the interaction of the down Not only was Hughes a perfectionist, ect alive. draft of an aircraft and the surface below it. but an aircraft of such a size presented de- Eventually the world’s largest flying Delta-winged aircraft commonly encoun- sign and assembly challenges that caused boat was completed, and in June 1946 ter this phenomenon during landing and extensive delays. As a result, throughout a team of 2,000 workers moved the air- their sink rate is reduced or cancelled out. the past 60 years a lot of misinformation craft overland in large sections, from the Nevertheless, the H-4 had flown, and has emerged about the flying boat. Known Hughes factory in Culver City, Calif., to Howard Hughes had proven his point. by many as the “Spruce Goose,” the air- a Long Beach Terminal Island dry dock. This would be the Hercules’ one and only plane was actually made of birch. Hughes When finally assembled, the Hercules had flight—a flight of determination.n disliked the “Spruce Goose” tag and con- an empty weight of more than 300,000 [email protected] sidered it disrespectful to the workers on pounds, a wingspan of 320 feet, a length the HK-1 team. of 218 feet 6 inches, and a height of 79 feet Despite delays, the assembly process (136,000 kilograms, and 97.5 meters, was quite sophisticated and broke new 66.6 meters and 24 meters, respectively). ground. After purchasing the rights to Other H-4 innovations included the first produce the “Duramold” laminating pro- “artificial feel system,” which provided cess (first developed by Fairchild Aircraft more control authority on the control sur- Company), Hughes perfected it for aero- faces: The pilot’s yoke would respond as After the flight dynamic shaping. The HK-1 team creat- would that of a small aircraft yet multiply After the Hercules’ first flight, Howard ed cross-layered laminations of thin wood the control forces by 200 times to move the Hughes ordered that the H-4 be stored in strips, injecting glue and then shaping and extremely large aerilons and rudder. flying condition. Shortly after Hughes’ death heating the segments until they solidified. On the morning of Nov. 2, 1947, the in 1976, Hughes’ Summa Corporation donat- Many aeronautical engineers considered mood was festive at Long Beach Harbor, ed the aircraft to the Aero Club of California. the resulting wood aircraft sections to be as invited celebrities and members of the The airplane was preserved and displayed stronger and lighter than aluminum. Fab- press were gathered to view the H-4 taxi under a huge dome in Long Beach, Calif., ric was used on the elevators and rudder to tests. Everyone had expected the first flight next to the former ocean liner Queen Mary. save additional weight. the following spring. In 1988, The Walt Disney Co. acquired both Ultimately, the assembly schedule After several test runs across the har- attractions. Disney sold the giant plane to proved too slow for Kaiser. When he pulled bor, Hughes called for 15-degree flaps the Evergreen Aviation Museum in 1993— out of the contract, Hughes renamed the and increased power in the eight engines. which disassembled the aircraft and moved airplane the H-4 Hercules. Once World Shortly, the behemoth was airborne at an it to its current home in McMinnville, Ore. War II ended, government funding for the altitude of 70 feet (21 meters) and flew at

To complete assembly of the Hercules, massive sections of the airplane were moved overland in June 1946 from the Hughes factory in Culver City, Calif., to a Long Beach Terminal Island dry dock. B oeing ar ch i v es ph oto

BOEING FRONTIERS November 2007