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HK-1 / H-4 / Hercules / Spruce Goose

Interest in transport seaplanes ended with the abandonment of Howard Hughes' H-4 "Hercules" prototype. This project was designed to enhance strategic deployment capabilities over long distances. Hughes' most famous aircraft was an oversized wooden seaplane nicknamed the "Spruce Goose." The HK-1 designation was derived from the names Hughes and Kaiser. When Kaiser backed out of the project, Hughes redesignated the aircraft H-4, representing his aircraft company's fourth design. Completed in 1947, there was one flight by Hughes' enormous Spruce Goose flying boat.

The idea for a fleet of such planes was conceived in 1942 by shipbuilder Henry J. Kaiser, whose Liberty ships had become targets for German U-boats. In July 1942, the world was at war. America had just lost 800,000 tons of her supply ships to German U-boats. Henry Kaiser, famed industrialist and builder of "Liberty" ships, proposed a fleet of flying transports to safely move troops and materiel across the Atlantic.

Kaiser felt that a fleet of large plywood flying boats could assume the wartime role of the Liberty ships. President Franklin Roosevelt was intrigued by the idea and first proposed that Donald Douglas build the flying boats. Douglas felt the idea was impractical and technically difficult and declined.

Kaiser approached Howard Hughes with his idea. Together they formed the Hughes Kaiser Corporation and obtained an $18,000,000 government contract to construct three flying boats. Kaiser, who could build ships very quickly, thought such a plane could be built in 10 months-much faster than the usual time needed for aircraft.

Howard Hughes had an international reputation as an oil and businessman, movie producer, aeronautical engineer and world-class aviator. Henry Kaiser partnered with Hughes because of Hughes' aircraft design and construction expertise. Hughes and his team of skilled engineers designed a single hull flying boat capable of carrying 750 troops. The plans called for eight 3,000 horsepower engines, a mammoth fuel storage and ssystem, and wings 20 feet longer than a football field.

The HK-1 Hercules was designed to carry two tanks, 750 troops or 420 stretcher cases on two decks. The Spruce Goose is still the largest plane ever built. It has an overall length of 218 feet 6 inches (67 meters), a wingspan of 320 feet (98 meters), and a height of 79 feet inches (24 meters). Its propellers are 17 feet 2 inches (5 meters) in diameter, and it can hold 14,000 gallons (52,996 liters) of fuel. Adhering to the wartime mandate not to use critical materials such as steel, the plane was built of plywood, mostly birch, with only small amounts of maple, poplar, balsa [and spruce], and plastic. At a constructed weight of 400,000 lb, it is an engineering marvel for its unparalleled combination of fine structural detail, bonded construction, and immense size.

Encountering and dealing with tremendous design and engineering problems, the Hughes team developed new concepts for large-scale hulls, flying control surfaces, and complex power boost systems. Hughes engineers created the first "artificial feel system" in the control yoke, which gave the pilot the feeling he was flying a smaller aircraft, but with a force multiplied two hundred times. For example, for each pound of pressure exerted on the control yoke by the pilot, the elevator received 1,500 pounds of pressure to move it.

Adhering to the government mandate not to use materials critical to the war effort (such as steel and aluminum), the Hughes team constructed the Flying Boat out of wood. Hughes perfected a process called "Duramold" to create almost every part of the plane. Originally developed by Fairchild Aircraft Company, Howard Hughes purchased the rights to use Duramold in large aircraft. The Duramold process is a plywood-like series of thin wood laminations, with grains laid perpendicular to each other. Workers permeated the laminations with plastic glue, then they shaped and heated the pieces until cured. The result was a material that many engineers agree is both lighter and stronger than aluminum.

The world's largest-growing spruce is the Sitka spruce, sometimes exceeding 200 feet in height in the temperate rainforests of the Pacific Northwest. A tolerance for salt spray allows the spruce to grow right down to the seashore. It follows the coastline from Alaska through Canada, and southward to northern California, where it grows in the company of redwoods. Sitka Spruce wood is light and flexible, and it was found to be ideal for use in airplane construction. Sitka spruce produces high-grade lumber that is the most important wood for airplane and glider construction. In World War II, this wood was utilized in the British Mosquito bombers, built using Sitka spruce from Alaska and British Columbia. Other important uses are oars, ladders, scaffolding, and boats, particularly racing sculls.

The HK-1 was a conservative extrapolation of 1940's materials, components, and airport technologies. The Flying Boat development encountered and dealt with tremendous design and engineering problems, from the testing of new concepts for large-scale hulls and flying control surfaces, to the incorporation of complex power boost systems that gave the pilot the power of 100 men in controlling this Hercules. Engineers placed eight of the most powerful engines available on the huge wings. Hughes and his team accomplished all of this working with "non-essential" materials, building a wood aircraft that even many of his colleagues dismissed as impossible. All of this was done within the impractical schedule of wartime.

But all of the research and development that went into the new seaplane delayed the construction process. As time passed and the plane remained in the design stage, Kaiser lost interest. In mid 1944, Henry Kaiser withdrew from the project, and Hughes took personal responsibility for all facets of the flying boat's design and production. He renamed the gigantic seaplane H-4, the fourth design from the Hughes Aircraft Company.

After the war's end in 1945, criticism of the project mounted and Hughes ran afoul of the U.S. Senate. The Flying Boat prototype had exceeded the government's funding allowance and the U.S. Senate formed an investigation committee to probe alleged misappropriation of funds. By the summer of 1947, certain politicians had become concerned about Hughes' mismanagement of the Spruce Goose, built at a cost of $25 million in 1940s dollars, and the XF-11 photoreconnaissance plane project, another Hughes undertaking. They formed a special Senate committee to investigate Hughes Aircraft.

Hughes continued by himself. Hughes invested $7,000,000 of his own into the project to keep it going. While Hughes testified before the investigative committee in Washington, D.C., the Hughes team assembled the Flying Boat in the Long Beach dry dock. After his interrogation, Hughes was determined to demonstrate the capability of his Flying Boat. He returned to California and immediately ordered the seaplane readied for taxi tests.

On November 2, 1947, a crowd of expectant observers and newsmen gathered. With Hughes at the controls, the giant Flying Boat glided smoothly across a three-mile stretch of harbor. From 35 miles per hour, it cruised to 90 during the second taxi test when eager newsmen began filing their stories. During the third taxi test Hughes surprised everyone as he ordered the wing flaps lowered to 15 degrees and the seaplane lifted off the water. He flew her for a little over a mile at an altitude of 70 feet for approximately one minute at a top speed of 80 mph. The short hop proved to skeptics that the gigantic craft could fly. It was the first and only example of a large-platform WIG flight in US history. After the first flight, Hughes changed the tail number from NX37602 to N37602.

The local National Advisory Committee on Aeronautics (NACA) representative, Edwin P. Hartman, documented Hughes Aircraft Company leadership and engineers as they designed and constructed the incredible plane and was a witness to its flight in 1947. After Hughes had successfully built and tested both planes and then turned them over to the military, his Congressional critics no longer had a target to attack. Despite a highly critical committee report, Hughes and his company were cleared.

After the flight, Hughes placed the Flying Boat in its custom built hangar and ordered her maintained in flight-ready condition. She remained in "hibernation" for 33 years at a cost of approximately one million dollars per year. The events involving the large parcel just north of Los Angeles International Airport reflects larger California trends. For decades, it served as a private aviation facility for Howard Hughes. The Spruce Goose and several Hughes movies were made there while the city grew around it. Howard Hughes died on 05 April 1976.

After Hughes died in 1976, the Summa Corporation planned to fill in the Ballona wetlands with 2,000 new homes, build a regional shopping center and high rises [neighbors, environmentalists and regulatory agencies fiercely opposed the plan, which after a decade of controversy failed, and Maguire Thomas Partners later took over Playa Vista].

Soon after Hughes' death, his holding company - Summa Corporation - made plans to disassemble the historic seaplane into nine pieces for various museums unless a non-profit organization stepped forward to adopt her. At the last minute Summa made arrangements to donate the aircraft to the non-profit Aero Club of Southern California, which then leased it to the Wrather Corporation, headed by entrepreneur Jack Wrather and his wife, Bonita Granville Wrather.

Wrather Corporation moved the Flying Boat to a temporary location while they built a custom dome to place her on exhibit. On October 29, 1980, the Flying Boat immerged from seclusion and into the world's spotlight. The world's largest floating crane, Herman the German, lifted her onto the dock of the temporary storage area. After sixteen months, the new dome was ready. Floating by barge the Flying Boat moved across Long Beach Harbor, the site of its successful air tests in 1947, then gently eased into her new home, adjacent to the RMS Queen Mary. The Flying Boat exhibit opened to the public in 1983. In the late 1980s, after the deaths of Jack and Bonita Wrather, the Disney Corporation purchased the former holdings of the Wrather Corporation. In March 1990, Disney informed the Aero Club of Southern California of its intention to discontinue the dome exhibit, leaving the Flying Boat looking for yet another home.

The Aero Club requested proposals for custody and preservation of the aircraft based on two specific criteria. The winning organization would have access to land on which to house the Flying Boat and the funding necessary to move and care for her. Evergreen International Aviation's plan, as envisioned by Captain Michael King Smith, proposed to not only preserve and protect her, but also to display her as the central exhibit in a living museum. On July 9, 1990, the Aero Club voted unanimously to award custody of the Hughes Flying Boat to Evergreen Aviation, located in McMinnville, Oregon.

The Evergreen Aviation Museum in McMinnville, Ore. is best known as the home to the world's largest wooden airplane, the Spruce Goose,and also houses an SR-71 Blackbird and a Grumman F6F-3 Hellcat. In addition, there are more than 60 historic aircraft and exhibits on display, along with artwork, traveling displays, the newly remodeled Spruce Goose Café and museum store. The Spruce Goose was displayed next to the Queen Mary in Long Beach, Californiabefore being brought to Oregon in 1993. Visitors now can walk into the cargo deck of the Spruce Goose to see the interior up close.

It is so large that it fills the museum and many of the other aircraft in the museum's collection are displayed under its wings. Not only does the size of the Spruce Goose create the wow factor, but the story that goes along with this aircraft attracts visitors. This story is not only about the plane and the man that built it, but it also reminds us about America's involvement in World War II. It serves to symbolize the scale of that war and it is just one of the many ideas the Allies considered that would allow them to move massive amounts of supplies to Europe.

The four National Register Criteria represent different types of values embodied in districts, sites, buildings, structures, and objects. Associative value/Person-Criterion B are properties that are associated with the lives of persons significant in our past. Aircraft can be listed under Criterion B if they are associated with a significant aspect of an important person's life. The Hughes Flying Boat Hercules, popularly known as the "Spruce Goose," is listed under Criterion B for it association with the life of noted aviator Howard Hughes. In addition, the Hercules is significant for its engineering design and construction technique.

Lawyers know of the Spruce Goose argument, in which it is argued that there is no comparable airplane to Howard Hughes' giant, amphibious airplane, since it is one of a kind. Consequently, it is not possible to determine the value of the Spruce Goose or a methodology for valuing same by reference to comparable items. In general, property may be valued by relying on comparative sales data, or it may be valued relying on a discounted cost analysis or replacement cost new, less depreciation. An appraiser may value an item of property based on the concept of fair market value: the estimated amount expressed in terms of money that may reasonably be expected for an item of property between a willing buyer and a willing seller with equity to both, neither under compulsion to buy or sell and both fully aware of all relevant facts.

Model planes can be incredibly realistic. For example, 11 remote control planes were constructed for the movie The Aviator. The replica of the legendary Spruce Goose, the plane built and piloted by Howard Hughes, had a 25-foot wingspan, weighed 375 pounds, and flew with electric motors. Pilots operated the planes from a virtual cockpit on the ground, monitoring everything from air speed to engine temperature as the planes flew to distances between seven and 10 miles.

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Page last modified: 07-07-2011 02:33:06 ZULU