The Travel Air 8000 was an American general-purpose biplane of the 1920s, a member of the family of aircraft that began with the Travel Air Model A.[1] It was also known as the Travel Air 4000-CAM,[2] and later as the Curtiss-Wright CW-8 after Curtiss-Wright acquired Travel Air.[3] Only three examples were built.[4]
Design and development
Like other members of this family, the Model 8000 was an unequal-span, single-bay, staggered biplane of conventional design.[4] The passengers and pilot sat in tandem, open cockpits.[4] It had a conventional tail, and fixed, tailskid undercarriage.[4] The fuselages were built from welded steel tubes, and the wings from wood.[5] Travel Air model numbers primarily reflected changes in powerplant, and the Model 8000 was powered by a Fairchild-Caminez 447 radial engine mounted in the nose, driving a tractor propeller.[6]
The prototype Model 8000 was a re-manufactured Travel Air Model B.[2][7] Its engine was an innovative design that used a cam in place of a crankshaft.[8][9] The result was an engine that was mechanically simpler[9] and which ran at half the RPMs of a conventional radial engine for the same power,[2] promising greater efficiency.[8] The low RPMs needed a larger propeller,[2] 10 feet (3.0 m) in diameter,[10] compared to the 8-foot-4-inch (2.54 m) propeller of the Travel Air 2000.[11] In turn, the larger propeller needed more ground clearance, which meant that the whole powerplant had to be mounted higher on the Model 8000's nose.[8]
Despite much enthusiasm for the new engine among American manufacturers, it did not work well.[8] It was prone to excessive vibration, even to the point of splitting propellers,[2] it ran hot because the large propeller hubs needed to absorb its torque also blocked cooling air from the cylinders,[10] and that torque also twisted airframes.[10]
It proved very difficult for Fairchild-Caminez to get the engine operating reliably enough to pass certification.[2] By the time this was achieved, in June 1928,[2] the Model 8000 itself had already received type certificate ATC-37 in April. It would be the only aircraft type certified to use this engine.[8]
Beside the prototype, only two other examples of the Model 8000 were built, and no details about them other than one construction number have been preserved.[4]
The problems with the engine proved insurmountable,[8] and development was abandoned in fall, 1928.[9] It was withdrawn from sale,[8] and Fairchild Aircraft founder Sherman Fairchild offered customers their money back.[12]
By March 1929, the Fairchild-Caminez engine was removed from the prototype Model 8000 and the aircraft was converted into a Travel Air 2000.[4]