Located at the Museum of Flight and in the 'Red Barn' is a static aircraft fuselage on display. A nearby placard highlights this fuselage and it reads:
1927 Boeing Model 40A Fuselage (Reproduction)
The Boeing Model 40 was designed to replace weary de Havilland DH-4 mail planes. The prototype version, with a Liberty engine and fuselage made from an odd combination of steel tubing, wood formers and wood veneer, first flew on July 7, 1925.
In 1927, when the Boeing Airplane Company bid on the San Fancisco to Chicago airmail run, the 40 was redesigned to give the company's pilots suitable equipment for the difficult route. The new 40s had Pratt & Whitney air-cooled engines and a cabin between the cockpit and the mail compartment to carry passengers. Model 40As had a 420-h.p. 'Wasp' engine and could carry two passengers, while later 40B-4s had a 525-h.p. 'Hornet' engine and could take four paying customers into the air.
One of the major differences between the prototype and later versions was that the earlier mixed wood and steel fuselage was replaced with a structure made entirely from welded steel tubing --
like the one seen here. First used in the PW-9 fighter in 1922,
Boeing's employees perfected an efficient process for pre-welding light steel tubing for use in aircraft.