The Hughes H-4 Hercules is a prototype heavy transport aircraft designed and built by the
Hughes Aircraft Company. Intended as a transatlantic transport for use during World War II, it
was not completed in time to be of use. The aircraft made only one brief flight on November
2, 1947, and the project never advanced beyond the single example produced. Built from wood
because of wartime restrictions on the use of aluminum and concerns about weight, its
critics nicknamed it the "Spruce Goose", despite it being made almost entirely of birch rather
than spruce. The Hercules is the largest flying boat ever built and has the largest wingspan
of any aircraft in history. It is on display, and remains in good condition at the Evergreen
Aviation & Space Museum in McMinnville, Oregon, USA.
Design and development
In 1942 the U.S. War Department faced 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 strategic materials.
The aircraft was the brainchild of Henry J. Kaiser, a leading Liberty ship builder. He
teamed with aircraft designer Howard Hughes to create what would become the largest aircraft
built at that time. It was designed to be capable of carrying 750 fully equipped troops
or two 30 ton M4 Sherman tanks. Its fully loaded cargo capacity was 150,000 pounds.
The original designation "HK-1" reflected the Hughes and Kaiser collaboration.
The HK-1 contract was issued in 1942 as a development contract and called for three
aircraft to be constructed under a two-year deadline to be available for the war effort.
Seven configurations were considered including twin-hull and single-hull designs with combinations
of four, six, and eight wing-mounted engines. The final design chosen was a behemoth, eclipsing
any large transport then built. It would be built mostly of wood to conserve metal; hence
the "Spruce Goose" moniker tagged on the aircraft by the media. It was also referred to as the
Flying Lumberyard by critics. Hughes himself detested the nickname "Spruce Goose".
While Kaiser had originated the "flying cargo ship" concept he did not have an aeronautical
background and deferred to Hughes and his designer, Glenn Odekirk. Development dragged
on, which frustrated Kaiser, who blamed delays partly on restrictions placed for the acquisition
of strategic materials such as aluminum, but also placed part of the blame on Hughes' insistence
on "perfection". Although construction of the first HK-1 took place 16 months after
the receipt of the development contract, Kaiser withdrew from the project.
Hughes continued the program on his own under the designation "H-4 Hercules", signing a
new government contract that now limited production to one example. Work proceeded slowly, with
the result that the H-4 was not completed until well after the war was over. It was
built by the Hughes Aircraft Company at Hughes Airport, location of present-day Playa Vista,
Los Angeles, California, employing the plywood-and-resin "Duramold" process – a form of composite
technology – for the laminated wood construction, which was considered a technological tour
de force. The specialized wood veneer was made by Roddis Manufacturing in Marshfield,
Wisconsin. Hamilton Roddis had teams of young women ironing the strong birch wood veneer
before shipping to California. The airplane was shipped on streets to Pier E in Long Beach,
California, by a company specializing in house moving. It was moved in three large sections
consisting of the fuselage and each wing, and a fourth smaller shipment containing the
tail assembly parts and other smaller assemblies. After final assembly a hangar was erected
around the flying boat with a ramp to launch the H-4 into the harbor.
Howard Hughes was called to testify before the Senate War Investigating Committee in
1947 over the use of government funds for the aircraft.
During a Senate hearing on August 6, 1947, Hughes said:
The Hercules was a monumental undertaking. It is the largest aircraft ever built. It
is over five stories tall with a wingspan longer than a football field. That's more
than a city block. Now, I put the sweat of my life into this thing. I have my reputation
all rolled up in it and I have stated several times that if it's a failure, I'll probably
leave this country and never come back. And I mean it.
Operational history During a break in the Senate hearings, Hughes
returned to California to run taxi tests on the H-4. On November 2, 1947, the taxi tests
began with Hughes at the controls. His crew included Dave Grant as copilot, two flight
engineers, Don Smith and Joe Petrali, 16 mechanics, and two other flight crew. In addition, the
H-4 carried seven invited guests from the press corps and an additional seven industry
representatives. Thirty-six were 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, the Hercules lifted off, remaining
airborne at 70 ft off the water at a speed of 135 miles per hour for around a mile. At
this altitude, the aircraft still experienced ground effect. Having proven to his detractors
that Hughes' masterpiece was flight-worthy, thus vindicating the use of government funds,
the "Spruce Goose" never flew again. Its lifting capacity and ceiling were never tested. A
full-time crew of 300 workers, all sworn to secrecy, maintained the aircraft 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.
Display
In 1980, the Hercules was acquired by the Aero Club of Southern California, which 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 Aero Club of Southern California that it no longer wished to display
the Hercules after its highly ambitious Port Disney was scrapped. After a long search for
a suitable host, the Aero Club of Southern California arranged for the Hughes flying
boat to be given to Evergreen Aviation Museum in exchange for payments and a percentage
of the Museum's profits. The aircraft was transported by barge, train, and truck to
its current home in McMinnville, Oregon southwest of Portland), where it was reassembled by
Contractors Cargo Company and is currently on display. The aircraft arrived in McMinnville
on February 27, 1993, after a 138-day, 1,055-mile trip from Long Beach. The dome is now used
by Carnival Cruise Lines as its Long Beach terminal.
By the mid-1990s, the former Hughes Aircraft hangars at Hughes Airport, including the one
that held the Hercules, were converted into sound stages. Scenes from movies such as Titanic,
What Women Want and End of Days have been filmed in the 315,000 square foot aircraft
hangar where Howard Hughes created the flying boat. The hangar will be preserved as a structure
eligible for listing in the National Register of Historic Buildings in what is today the
large light industry and housing development in the Playa Vista neighborhood of Los Angeles.
Specifications Performance specifications are projected.
General characteristics Crew: three
Length: 218 ft 8 in Wingspan: 320 ft 11 in
Height: 79 ft 4 in Fuselage height: 30 ft
Empty weight: 250,000 lb Loaded weight: 400,000 lb
Powerplant: 8 × Pratt & Whitney R-4360 Wasp Major radial engines, 3,000 hp each
Propellers: four-bladed Hamilton Standard, prop, one per engine
Propeller diameter: 17 ft 2 in
Performance Cruise speed: 250 mph
Range: 3,000 mi Service ceiling: 20,900 ft
Notable appearances in media
See also Ground effect vehicle
Aircraft of comparable role, configuration and era
Martin JRM Mars Blohm & Voss BV 238
Boeing Pelican Dornier Do X
Saunders-Roe Princess Related lists
List of large aircraft References
Notes
Citations
Bibliography
External links Evergreen Aviation Museum, McMinnville, Oregon,
home of the Spruce Goose "Tomorrow With Tom Snyder" show on the Spruce
Goose from 1979 Spruce Goose: Where Is It Now? A history of
the aircraft following Hughes' death "World's Largest Airplane Takes To The Road",
Popular Science, August 1946, "Look Inside The World's Largest Plane", Popular
Science, September 1945 200 tons and it flies! article January 1948
Popular Mechanics Howard Hughes & The Spruce Goose - slideshow
by Life magazine A film clip Cruiser Bow Ripped Off By Typhoon,
July 23, 1945 is available for free download at the Internet Archive [more]