THREE FAMOUS EARLY AERO ENGINES — METER 363 



There were two tasks which the Manly engine was to perform : it 

 had to provide sufficient power to lift and to propel the aerodrome. It 

 was calculated that 28 hp. would be enough if the weight/horsepower 

 ratio were sufficiently low. How well the engine succeeded is revealed 

 by the above specifications which show a continuous hp. of 52.4 and a 

 weight/horsepower ratio of 3.96. This was the least heavy avia- 

 tion engine for its power in the world mitil the advent of the 18-hp. 

 three-cylinder air-cooled engine created by J. C. H. EUehammer of 

 Denmark in 1906. It weighed 3 lb. per hp. 



For the next 40 years this same water-cooled radial type of engine 

 was being manufactured for various types of aircraft. Below are 

 listed some examples. 



American Albatross of 1910. 

 French Salmson of 1919. 

 French Anzani of 1920. 

 German Rumpler design of 1923. 

 German BMW 803 of 1944. 



The five-cylinder radial configuration was chosen by Balzer and 

 Manly for the following principal reasons : 



1. The greater smootliness of operation of an odd as compared with 

 an even number of cylinders. 



2. The greater uniformity of torque with increasing number of 

 cylinders. Five seemed at that time to be the greatest practical odd 

 number. 



3. The reduction of weight and complication of the radial form. 

 This class of engine, air cooled instead of water cooled, emerged as 



the principal type of aircraft powerplant for the following 40 years. 

 It is only now being replaced by jet engines. The Manly engine was 

 therefore a 100-percent airplane engine although having automobile 

 antecedents and was so well designed and built that it was a model 

 for the majority of airplane engines produced throughout the world 

 imtil the end of World War II. 



THE WRIGHT BROTHERS' ENGINE OF 1903 



The third of these engines to power an aircraft was that of the 

 Wright brothers during the winter of 1903. Orville and Wilbur 

 Wright designed the engine themselves and built it with the help of 

 their machinist, Charles E. Taylor. It was apparently based on the 

 single-cylinder natural-gas engine they had designed and built pre- 

 viously to power their 1901 wind tunnel. 



They began to build it in December 1902, and the first tests were run 

 on February 12, 1903. On the 13th dripping gasoline caused the bear- 

 ings to freeze, and this broke the engine body and frame. It was 

 necessary to order a new aluminmn casting which was received on 

 April 20, 1903. The rebuilt motor was shop tested in May. In a 



