The Hughes H-4 Hercules (registration NX37602) 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 due to
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
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.
Due to wartime restrictions on the availability of metals, the H-4 was
built almost entirely of laminated birch, not spruce as its nickname
suggests. The plywood and resin "Duramold" process,[1]
a form of composite technology, was used in the laminated wood construction.
The aircraft was considered a technological tour de force.[2]
The aircraft was not finished in time for use in World War II and
never advanced beyond the single prototype produced.
It's Design & Development
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.[3] The original
designation "HK-1" reflected the Hughes and Kaiser collaboration.[2]
The HK-1 contract in 1942, issued as a development contract,[4]
called for three aircraft to be constructed under a two-year deadline in
order to be available for the war effort.[5]
Seven configurations were considered, including twin-hull and single-hull
designs with combinations of four, six and eight wing-mounted engines.[6]
The final design chosen was a behemoth, eclipsing any large transport then
built.[4][7]
To conserve metal, it would be built mostly of wood (elevators and rudder
were fabric covered[8]);
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".[9]
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.[7]
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."[10]
Although construction of the first HK-1 had taken place 16 months after the
receipt of the development contract, Kaiser withdrew from the project.[9]
Hughes continued the program on his own under the designation "H-4
Hercules" (initially identified as the HFB-1 to signify Hughes Flying Boat,
First Design,[8])
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.
Click on Picture to enlarge
RMS Queen Mary at Long Beach, California
Hercules at Evergreen Aviation Museum
A size comparison
between four of the largest aircraft,
In 1947, Howard Hughes was called to testify before the Senate War
Investigating Committee over the usage of government funds for the aircraft.
During a Senate hearing on 6 August 1947 in the first of a series of
appearances, 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.[11]
Operational History
During a break in the Senate hearings, Hughes returned to California
to run taxi tests on the H-4.[8]
On 2 November 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.[12]
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.[13]
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 mph (217 km/h or 117 knots) for around a mile (1.6 km).[14]
At this altitude, the aircraft was still experiencing ground effect.[15]
Hughes had answered his critics and the hearings ended, but the
aircraft never flew again. 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.[16]
Display
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 an 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.
By the mid-1990s, the former Hughes Aircraft hangars, 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 (29,000 mฒ) 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 housing development Playa Vista, Los Angeles,
California.
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. The
Hercules demonstrated that the physical and aerodynamic principles of flight
are not affected by the size of the aircraft.
Propellers: four-bladed Hamilton Standard, prop, 1 per engine
Propeller diameter: 17 ft 2 in (5.23 m)
Performance
Cruise speed: 220 mph (353.98 km/h)
Range: 3,000 mi (4,800 km)
Service ceiling: 20,900 ft (6,370 m)
Although
the actual footage is of the November 2, 1947, Hughes-piloted, one
time only flight of the "Spruce
Goose," this newsreel is from 1962. It seems to me it's about
how the government hoped to recoup the $18 million it sunk into the
project.
References
Notes
Winchester 2005, p.
113. The Hughes Corporation had utilized the duramold process which
laminated plywood and resin into a lightweight but strong building
material that could be shaped.
Odekirk
1982, p. II.
McDonald 1981, p. 41.
McDonald
1981, p. 45.
Odekirk 1982, p. 1V.
McDonald 1981, pp.
4144.
McDonald
1981, p. 40. Quote: "Kaiser announces the most monumental program in
the history of aviation."
Winchester
2005, p. 113.
McDonald
1981, pp. 5859.
McDonald
1981, p. 56.
The Great Aviator:
Howard Hughes, His Life, Loves & Films - A Documentary. Los
Angeles: Delta Entertainment Corporation, 2004. Note: Hughes' Senate
Hearings testimony is now in the public domain.
McDonald 1981, pp.
7879.
McDonald 1981, pp.
8587.
Francillon 1990, pp.
100, 102.
Wing In Ground effect
aerodynamics
Dean, Paul. "The Man
Who Keeps The Spruce Goose." Los Angeles Times, April 21,
1983, p. J1.
David 1991
Bibliography
David, Peter. The Rocketeer: The Official
Movie Adaptation. Burbank, California: W D Publications Inc.,
1991. ISBN 1-5685-190-4.
Francillon, Ren้ J. McDonnell
Douglas Aircraft since 1920: Volume II. Annapolis, Maryland:
Naval Institute Press, 1990. ISBN 1-55750-550-0.
McDonald, John J. Howard Hughes and the Spruce Goose.
Blue Ridge Summit, PA: Tab Books Inc., 1981. ISBN 0-8306-2320-5.
Odekirk, Glenn E. Spruce Goose (Title inside cover:
HK-1 Hercules: A Pictorial History of the Fantastic Hughes Flying
Boat). Long Beach, California: Glenn E. Odekirk and Frank
Alcantr, Inc., 1982. No ISBN.