Manuscripts/Mixed Material Bulletins, from January 4, 1909 to April 12, 1909
AERODROME MOTORS: By G. H. Curtiss.
Feb. 25, 1909: — The internal combustion or gas engine is without doubt the best power for heavier-than-air flying-machines, and it remains only to choose what type or style of gas engine is best adapted to the work. Of course there are possibilities in other forms of motive power but we consider only those which are now in practical use. If, as some people predict, flying-machines are to be as common as automobiles then motors should be as simple as automobile motors, and if possible even more reliable.
It is now conceded that very light motors are unnecessary and, may be undesirable if by their lightness their endurance and reliability is sacrificed.
Suppose we want an engine of 25 H.P. This should be sufficient for a flier to carry two men an hour or one man four or five hours (assuming that the engine will consume 30 lbs. of fuel per hour). What type of motor should we adopt? There is a choice of the two or four cycle type, air or water-cooled, double cylinder opposed, three, four or six cylinder vertical, 5 or 7 cylinder star and seven or eight cylinder staggered and others besides innumerable systems of ignition, lubrication, and valve action. With such an assortment it would seem difficult to make a choice but when we consider that simplicity and reliability are the most important requirements, I believe it is safe to eliminate all the types which can be considered in the experimental state and choose an engine which has been built by the