Samples of Duramold process EASM 4Feb2010 (14568081446)

Duramold is a composite material process developed by Virginius E. Clark. Birch or poplar plies are impregnated with

phenolic resin Phenol formaldehyde resins (PF) or phenolic resins (also infrequently called phenoplasts) are synthetic polymers obtained by the reaction of phenol or substituted phenol with formaldehyde. Used as the basis for Bakelite, PFs were the first commerc ...

and laminated together in a mold under heat (280 °F, 138 °C) and pressure for use as a lightweight structural material. Similar to

plywood Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...

, Duramold and other lightweight composite materials like the similar

Haskelite Haskelite is the brand name of a plywood, once made by the Michigan-based Haskelite Manufacturing Corporation. It was made from waterproof glue developed by Henry L. Haskell. The moldable plywood was originally called Ser-O-Ply. It was used i ...

were considered critical during periods of material shortage in World War II, replacing scarce materials like aluminum alloys and steel.Dana T. Parker, ''Building Victory: Aircraft Manufacturing in the Los Angeles Area in World War II'', Cypress, CA, 2013, , pp. 51-52, 56. . The material has some advantages over metal in strength, construction technique, and weight. A cylinder made of Duramold is 80% stronger than a cylinder made of aluminum. Over 17 varieties of Duramold were developed, using various combinations of types of wood in thin plies. The Duramold process has also been used to make

radome A radome (a portmanteau of radar and dome) is a structural, weatherproof enclosure that protects a radar antenna. The radome is constructed of material transparent to radio waves. Radomes protect the antenna from weather and conceal antenna ...

s for aircraft as well as missile bodies. Virginius Clark developed Duramold for

Fairchild Aircraft Fairchild was an American aircraft and aerospace manufacturing company based at various times in Farmingdale, New York; Hagerstown, Maryland; and San Antonio, Texas. History Early aircraft The company was founded by Sherman Fairchild in ...

, working with George Meyercord of the Haskelite Corporation.Barton, p. 83. Fairchild patented the process, designing and constructing the F-46 as the first aircraft made using the Duramold process, and forming the Duramold Corporation. Several aircraft used Duramold in parts of their structure, the largest manufactured with the process being the

Hughes H-4 Hercules The Hughes H-4 Hercules (commonly known as the ''Spruce Goose''; registration NX37602) is a prototype strategic airlift flying boat designed and built by the Hughes Aircraft Company. Intended as a transatlantic flight transport for use duri ...

Howard Hughes Howard Robard Hughes Jr. (December 24, 1905 – April 5, 1976) was an American business magnate, record-setting pilot, engineer, film producer, and philanthropist, known during his lifetime as one of the most influential and richest people in th ...

and

Glenn Odekirk Glenn Odekirk (born Waseca, Minnesota May 9, 1905 – died Las Vegas, Nevada January 12, 1987) was an American aerospace engineer who made significant contributions to the work of Hughes Aircraft. Biography The son of Edward John and Louise (Lewis ...

, which was built almost completely with Duramold including very large sections. For this use, Hughes Aircraft bought the rights to use of Duramold on aircraft exceeding 20,000 lbs; Fairchild and Meyercord otherwise retained the rights. However, the material was found to be poorly adapted to heavy aircraft. The Duramold and Haskelite process was first developed in 1937, followed by Gene Vidal's Weldwood and later the

Timm Aircraft Company The O.W. Timm Aircraft Company was an American aircraft manufacturer founded by Otto William Timm, based in Los Angeles, California. History Between 1911 and 1922 O.W. Timm built several aircraft with varying success before he founded, in 1 ...

's Aeromold process, which differs in that it is baked at a low 100 °F (38°C) at cutting and forming, and 180 °F (82°C) for fusing together sections after the resins are added.Richard Ballard
"Plastic Airplanes"
''The Ohio State Engineer'', April 1942, pp. 24, 26. In the United Kingdom, the

De Havilland Aircraft Company The de Havilland Aircraft Company Limited () was a British aviation manufacturer established in late 1920 by Geoffrey de Havilland at Stag Lane Aerodrome Edgware on the outskirts of north London. Operations were later moved to Hatfield in He ...

(founded by

Geoffrey de Havilland Captain Sir Geoffrey de Havilland, (27 July 1882 – 21 May 1965) was an English aviation pioneer and aerospace engineer. The aircraft company he founded produced the Mosquito, which has been considered the most versatile warplane ever built, ...

, a cousin of

Olivia de Havilland Dame Olivia Mary de Havilland (; July 1, 1916July 26, 2020) was a British-American actress. The major works of her cinematic career spanned from 1935 to 1988. She appeared in 49 feature films and was one of the leading actresses of her time. ...

, the actress who dated Howard Hughes in 1938) used similar composite construction for aircraft including the DH.88 Comet, DH.91 Albatross, the

Mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "lit ...

, and

Vampire A vampire is a mythical creature that subsists by feeding on the vital essence (generally in the form of blood) of the living. In European folklore, vampires are undead creatures that often visited loved ones and caused mischief or deaths ...

References

{{Reflist Aircraft components Aerospace materials Plywood

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References