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    The Spruce Goose

    The Spruce Goose

    See also:
    Spruce Goose: Where Is It Now?
    How come Howard Hughes's "Spruce Goose" flew only once?
    Spruce Goose - large plane (YouTube)
    Hughes HK-1 (H-4) 'Spruce Goose'
    Hughes H-4 Hercules


    The Spruce Goose, formally the Hughes H-4 Hercules, was a prototype heavy transport aircraft designed and built by the Hughes Aircraft company. The aircraft made its only flight on November 2, 1947. Built from wood because of wartime raw material restrictions on the use of aluminum, it was nicknamed the "Spruce Goose" by its critics. The Hercules is the largest flying boat (see below) ever built, and has the largest wingspan and height of any aircraft in history. It survives in good condition at the Evergreen Aviation Museum in McMinnville, Oregon, USA.


    Despite its nickname, the H-4 was built almost entirely of birch, rather than spruce. The plywood-and-resin "Duramold" process, a form of composite technology, was used in the laminated wood construction, which was considered a technological tour de force. The aircraft was not finished in time for use in World War II and never advanced beyond the single prototype produced.

    In 1942, the U.S. Department of War was faced with the need to transport war materiel and personnel to Britain. Allied shipping in the Atlantic Ocean was suffering heavy losses to German U-boats, so a requirement was issued for an aircraft that could cross the Atlantic with a large payload. Due to wartime priorities, the design was further constrained in that the aircraft could not be made of metal.

    The aircraft was the brainchild of Henry J. Kaiser, who directed the Liberty ships program. He teamed with aircraft designer Howard Hughes to create what would become the largest aircraft built at that time. When completed, it was capable of carrying 750 fully-equipped troops or one M4 Sherman tank. The original designation "HK-1" reflected the Hughes and Kaiser collaboration.

    On November 2, 1947, the taxi tests were begun with Hughes at the controls. His crew included Dave Grant as co-pilot, and two flight engineers, 16 mechanics and two other flight crew. In addition, the H-4 carried seven invited guests from the press corps plus an additional seven industry representatives, for a total of 32 on board.

    After the first two taxi runs, four reporters left to file stories, but the remaining press stayed for the final test run of the day. After picking up speed on the channel facing Cabrillo Beach near Long Beach, the Hercules lifted off, remaining airborne 70 ft (21 m) off the water at a speed of 135 miles per hour (217 km/h) for around a mile (1.6 km). At this altitude, the aircraft was still experiencing ground effect (see below).

    The aircraft never flew again. Its lifting capacity and ceiling were never tested. A full-time crew of 300 workers, all sworn to secrecy, maintained the plane in flying condition in a climate-controlled hangar. The crew was reduced to 50 workers in 1962, and then disbanded after Hughes' death in 1976.

    In 1980, the Hercules was acquired by the California Aero Club, who put the aircraft on display in a large dome adjacent to the Queen Mary exhibit in Long Beach, California. In 1988, The Walt Disney Company acquired both attractions and the associated real estate. Disney informed the California Aero club that they no longer wished to display the Hercules. After a long search for a suitable host, the California Aero Club awarded custody of the Hughes flying boat to Evergreen Aviation Museum. Under the direction of museum staff, the aircraft was disassembled and moved by barge to its current home in McMinnville, Oregon (about one hour southwest of Portland) where it has been on display since. The Flying Boat arrived in McMinnville at Evergreen International Aviation on February 27, 1993 after a 138-day, 1,055-mile trip from Long Beach.

    Although the project did not move beyond the initial prototype, the H-4 Hercules was a forerunner of the massive transport aircraft of the late 20th century, such as the Lockheed C-5 Galaxy, the Antonov An-124, and the An-225.

    General characteristics:

    • Crew: 3
    • Length: 218 ft 8 in (66.65 m)
    • Wingspan: 319 ft 11 in (97.54 m)
    • Height: 79 ft 4 in (24.18 m)
    • Fuselage height: 30 ft (9.1 m)
    • Loaded weight: 400,000 lb (180,000 kg)
    • Powerplant: 8× Pratt & Whitney R-4360 Wasp Major radial engines, 3,000 hp (2,240 kW) each
    • Propellers: four-bladed Hamilton Standard, prop, 1 per engine
    • Propeller diameter: 17 ft 2 in (5.23 m)
    • Cruise speed: 220 mph (353.98 km/h)
    • Range: 3,000 mi (4,800 km)
    • Service ceiling: 20,900 ft (6,370 m)

    Topics of Interest

    Hughes Aircraft Company was a major American defense contractor founded in 1932 by Howard Hughes in Culver City, California as a division of Hughes Tool Company. The company was known for producing, among other products, the Hughes H-4 Hercules "Spruce Goose" aircraft, the Galileo spacecraft and the AIM-4 Falcon guided missile.

    Aircraft may be affected by a number of ground effects, aerodynamic effects due to a flying body's proximity to the ground.

    The Wing In Ground effect refers to the reduction in drag experienced by an aircraft as it approaches a height approximately equal to the aircraft's wingspan above ground or other level surface, such as the sea. The effect increases as the wing descends closer to the ground, with the most significant effects occurring at an altitude of one half the wingspan. It can present a hazard for inexperienced pilots who are not accustomed to correcting for it on their approach to landing, but it has also been used to effectively enhance the performance of certain kinds of aircraft whose planform has been adapted to take advantage of it, such as the Russian ekranoplans. The first to give scientific description of the ground effect and to provide theoretical methods of calculation of air cushion vehicles was Konstantin Tsiolkovsky in his 1927 paper "Air Resistance and the Express Train".

    A flying boat is a specific kind or type of seaplane configuration making up one major subclass of two specialised types of aircraft that are both designated as seaplanes — all of which are designed to take off from and land on water and so were supremely important in the founding of pioneering international commercial aviation, for there were no airports in most of the world.

    The Dornier Do X was the largest, heaviest, and most powerful flying boat in the world when it was produced by the Dornier company of Germany in 1929. First conceived by Dr. Claudius Dornier in 1924, it took seven years to design and another two years to build. During the design process, a one-to-one wooden mock-up, the first in aviation history, was built.

    The Blohm & Voss BV 238 was a German flying boat designed in World War II. It was the heaviest aircraft ever flown when it first flew in 1944, and physically was the largest aircraft produced by any of the Axis powers in World War II.

    The Boeing Pelican ULTRA (Ultra Large Transport Aircraft) is a proposed ground effect fixed-wing aircraft under study by Boeing Phantom Works.

    The Saunders-Roe Princess was a British flying boat aircraft built by Saunders-Roe, based in Cowes on the Isle of Wight. The Princess was one of the largest aircraft in existence.

    Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License and Creative Commons Attribution-ShareAlike License.)

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