For the engineer particularly, the fascination of the Wrights' engine story lies in its delineation of the essentially perfect engineering achievement by the classic definition of engineering--to utilize the available art and science to accomplish the desired end with a minimum expenditure of time, energy, and material. Light weight and operability were the guiding considerations; these could be obtained only through constant striving for the utmost simplicity. Always modest, the Wrights seem to have been even more so in connection with their engine accomplishments. Although the analogy is somewhat inexact, the situation is reminiscent of the truism often heard in the aircraft propulsion business--few people know the name of Paul Revere's horse. Yet, as McFarland has pointed out, "The engine was in fact far from their meanest achievement." With hardly any experience in this field and only a meagerly equipped machine shop, they designed and assembled an internal combustion engine that exceeded the specifications they had laid down as necessary for flight and had it operating in a period of about two months elapsed time. The basic form they evolved during this unequalled performance carried them through two years of such successful evolutionary flight development that their flying progressed from a hop to mastery of the art. And the overall record of their powerplants shows them to have been remarkably reliable in view of the state of the internal combustion engine at that time. Appendix Characteristics of the Wright Flight Engines ------------------------------------------------------------------------- _1903 _1904-1905 _1908-1911 _1911-1915 First flight Experimental Demonstrations service_ engine[a]_ flights_ and service_ ------------------------------------------------------------------------- Cyl./Form 4/flat 4/flat 4/vertical 6/vertical Bore and stroke (in.) 4×4 4-1/8×4 4-3/8×4 4-3/8×4-1/2 Displacement (cu. in.) 201 214 240 406 Horsepower 8.25-16 15-21 28-42 50-75 RPM 670-1200 1070-1360 1325-1500 1400-1560 MEP 49-53 52-57 70-87 70-94 Weight (lb) 140-180 160-170 160-180 265-300 -------------------------------------------------------------------------