264 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1955 



At Langley the small but expert powerplant staff made some im- 

 portant contributions, in addition to their cooperation with the wind- 

 tunnel people in developing the remarkable NACA cowling for air- 

 cooled engines. One recalls improved finning for air-cooled engine 

 cylinders, methods to decrease the octane requirements of high-com- 

 pression engines, and work on such fundamental matters as the be- 

 havior of fuels — how they ignite, how they burn, and how this burning 

 corrodes critical parts of the engine. A principal tool in the study of 

 these latter questions was high-speed photography, and cameras 

 capable of taking pictures at the rate of 400,000 per second were 

 developed by the NACA. 



In the field of jet proi^ulsion the NACA exhibited an early aware- 

 ness of its possible advent but did little about it. In 1923, in Report 

 No. 159, "Jet Propulsion for Airplanes," Edgar Buckingham of the 

 Bureau of Standards, reported that: "The relative fuel consumption 

 and weight of machinery for the jet decrease as the flying speed in- 

 creases ; but at 250 mph. the jet would still take about four times as 

 much fuel per thrust horsepower-hour as the air screw, and the power 

 plant would be heavier and much more complicated. Propulsion by 

 the reaction of a simple jet cannot compete, in any respect, with air 

 screw propulsion at such flying speeds as are now in prospect." This 

 conclusion was entirely rational on the basis of the technology at that 

 time. 



In the early thirties, the NACA was asked by a representative of 

 the airframe industry to resurvey jet-propulsion prospects and, 

 although airplane speeds by then had passed the 250-rnph. mark which 

 Buckingham considered a goal, the story was much the same. The 

 inefficiency of the jet engine at the speeds contemplated ruled it out of 

 consideration. 



Near the end of the 1930's, some preliminary experimental work 

 on jet propulsion was undertaken at the Langley Laboratory. These 

 experiments indicated that jet engines would be so fuel-thirsty as to 

 limit their useful application to very high-speed, very short-range air- 

 craft. American thinking, perhaps because of geography, was focused 

 on long-range performance where fuel economy was paramount. This 

 idea served to discourage any real jet-development efl'ort in the United 

 States until intelligence of British and German experiments reached 

 us. 



In March 1941, Dr. Durand was recalled from retirement to head a 

 special NACA Committee on Jet Propulsion. The fact that he was 

 in his 82d year was only a matter of calendar counting. The vigor 

 with which he and his committee launched a belated development 

 effort would have done credit to a man less than half his age. Later 

 in 1941, Gen. H. H. Arnold secured from the British one of the earliest 



