Howard Hughespersonal (3) birch wood shear test samples from the development of the H-4 Hercules Flying Boat (Spruce Goose). (ca. 1942) Three samples of laminated birch: one trapezoidal 5 x 3 x 2 in. with "O.K. To Close HFB / 5" stamp, and two rectangular: 4.5 x 2.4 x .75 in. with "Glue No. #238 Test Shear" stamp and 3.75 x 2.75 x .4 in. with line in pencil drawn across. The H-4 Hercules Flying Boat would become the plane with which Howard Hughes was most closely associated in the public mind. Intended as a troop transport for use in World War II, the Hercules wasn't completed until 1947 and flew only once. Because of wartime restrictions on aluminum, the plane was constructed entirely of wood-mostly birch-leading the media to dub it the "Spruce Goose" (a moniker Hughes despised). The H-4 remains the largest flying boat ever built and has the second longest wingspan (320 ft. 11 in.) of any plane ever flown. From the personal collection of Howard Hughes. $200 - $300