156 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1908. 



There are still, to be sure, certain important questions to be settled, 

 among others that of proper motors, a subject in which automobile 

 manufacturers have not as yet taken special interest. More attention 

 is now, however, being paid to motors in France, for the advent of 

 the motor used by the Wrights has roused us from our apathy. Thus 

 far we have only seen at work the Antoinette and R. E. P. motors. 

 Renault has built an air-cooled motor which still needs certain im- 

 provements. The Dutheil, Chamers, and Anzani motors are also de- 

 serving of mention. 



Finally, at the exhibition this year there was opportunity to exam- 

 ine some new models, which in principle seem interesting, but of 

 which nothing can be said until we have seen them actually work in 

 the air. At present the motor question remains to be settled, and 

 surely will be in 1909. It is the weak point in French flying 

 machines. If a machine can fly for 24 kilometers, with a good motor 

 there is no reason why it should then stop, unless it be to renew the 

 supply of fuel, oil, or water. Our motors, however, so often fail 

 through a tendency to miss the spark, or through the breaking of a 

 valve, or the heating of a bearing. As soon as our motors for flying 

 machines are as perfect as those used in present-day automobiles, we 

 shall be able to fly at will. 



And this is not all ; we should likewise secure a more efficient use of 

 sustaining surfaces. We should keep constantly in mind, following 

 the advice of M. Tatin, the fact that the aeroplane is a projectile, and 

 should strive in every possible way to decrease resistance to progress 

 through the air. In the aeroplane of Santos-Dumont, built in 1906, 

 there was used a motor of 100 horsepower, Voisin had one of 50 horse- 

 power, Robert Esnault-Pelterie one of 35 horsepower, and Wright's 

 engine is about the same power. Messrs. Koechlin and Pischoff have 

 succeeded in lifting a monoplane and its aviator with a motor of 

 only 16 horsepower. These men are now building in their shops an 

 aeroplane which should fly with a 12-horsepoAver motor. We can not, 

 however, be certain that it will rise, though the principle is correct." 

 At any rate, it seems probable that the aeroplanes of the future will 

 be driven by motors of not more than 20 horsepower. 



The use of such high power is at present not advantageous, for the 

 propellers are very difficult to construct, and they undergo a very fast 

 rotation at speeds generating a centrifugal force that occasionally 



in May, 1909, at Clialous, of Latham, who, with his very successful monophme 

 Antoinette, from the Levavasseur shops, accomplished flights of over an hour's 

 duration, at an average speed of SO kilometers an hour, during rain storms and 

 heavy winds. His machine, of 50 horsepower, and carrying one or two pas- 

 sengers, is the most efficient machine we now have. Bleriot at the present time 

 is trying out a machine for four passengers (June, 1909). 

 « Since been tried at Jurisy without great success (June, 1909). 



