40 YEARS OF AERONAUTICAL RESEARCH — HUNSAKER 263 



Powerplant research and structural research are expensive, and re- 

 quire extensive facilities for full-scale investigations. Small models 

 are of limited utility in powerplant research. Furthermore, power- 

 plants and structures are the immediate concern of strong and highly 

 competitive industrial firms. The Committee evidently felt that under 

 its fiscal restrictions, it would do better to concentrate on basic aero- 

 dynamic problems and might, hopefully, leave research and develop- 

 ment of powerplants and structures to the industry and the military 

 services. 



However, the Lindbergh committee in 1939 said that this past policy 

 was wrong, and the NACA agreed. It appeared that leaving funda- 

 mental research to the industry meant, in effect, that such research 

 would be indefinitely postponed. 



A competitive engine firm must concentrate on what its customers 

 want. The firm improves its engine with small changes based on 

 experience. It seeks the minimum risk of interruption of production. 

 The military services, its principal customers, conduct competitive 

 trials based on standard performance specifications. After quantity 

 orders are placed, no major changes are possible. The services, of 

 course, welcome small changes based on experience, if the risk of 

 trouble be slight. As a result, engine development tends to adhere 

 to a definite pattern and progresses slowly. 



An engine manufacturer must make a relatively heavy investment 

 in plant and tooling for production of a particular engine. The manu- 

 facturer is naturally inclined to concentrate on improvements in this 

 engine to prolong its commercial life. These improvements are essen- 

 tially proprietary in character. 



Similar remarks apply to the airplane industry. Every effort is 

 made to improve a particular airplane to prolong its vogue in produc- 

 tion. This development effort is restricted to conservative changes in 

 a basic design acceptable to the customer. 



In this country, the Navy standardized on air-cooled radial engines 

 that met Navy requirements, while the Army msisted on 12-cylinder 

 liquid-cooled engines to power the fighters in their program. 



However, there were important fundamental applications of science 

 to engme design that needed investigation in 1940. 



From the beginning, one of the principal technical committees of 

 the NACA was concerned with powerplants. During World War I, a 

 few research projects in the powerplant field were carried on under 

 its auspices, notably in the altitude facility at the Bureau of Stand- 

 ards, where engines could be operated under conditions simulating 

 those experienced by high-flying aircraft. A program of systematic 

 tests was conducted there for the NACA, including supercharging 

 with a Roots-type blower. 



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