188 SYMPOSIUM ON AERONAUTICS. 



2. Maximum economy of prime mover and in applying its power 

 for propulsive purposes. This will insure minimum consumption 

 of fuel and supplies per unit of time or distance, and hence will 

 serve as a factor in long life in the air or in large weight carrying 

 capacity, or in added capacity of prime mover with corresponding 

 increase of speed for shorter distances. 



3. Reliability of operation. This embodies improved methods 

 of control and navigation, and greater reliability in each of the many 

 individual elements on which overall reliability in operation de- 

 pends. These improvements are of special significance in the 

 problem of lengthening the effective life in the air and broadly in 

 the extension of the usefulness of the aeroplane especially in the 

 arts of peace. 



