270 AJsnsruAL report Smithsonian institution, 1955 



only a few miles an hour. Now the difference may be measured in hun- 

 dreds of miles an hour. The art is being extended so rapidly that no 

 longer is there a comfortable time margin between the acquisition of 

 research data and its application. 



Hardly had the first of the NACA's transonic wind tunnels gone 

 into full operation, in 1951, when Richard T. Whitcomb, a young 

 engineer at the Langley Laboratory, began the experimental verifica- 

 tion of what has since become known as the "area rule." In essence, 

 Whitcomb worked out a rational way to balance the lengthwise distri- 

 bution of volume of fuselage and wings to produce an airplane form 

 with minimum drag at high speeds. Seemingly slight modifications 

 to the shape of the airplane fuselage greatly improved performance. 



As soon as the new design principle was verified in preliminary 

 form, it was made available in confidence to the designers of military 

 airplanes and the new information was promptly applied. 



In one instance, the prototype of a new fighter aircraft was unable 

 on test to attain supersonic speeds. With the deceptively subtle modi- 

 fications dictated by the "area rule," the airplane enjoyed a perform- 

 ance gain in speed of as much as 25 percent. 



At the velocities contemplated for our future missiles and airplanes, 

 temperatures measured in thousands of degrees Fahrenheit will be 

 encountered owing to aerodynamic heating — friction. The consequent 

 structural problems are little short of fantastic and, with presently 

 available materials of construction, the solution is not in sight. More 

 research is needed. 



The performance possible from the harnessing of nuclear energy 

 for airplane propulsion would be nonstop flight over virtually un- 

 limited range. Again, one is faced with problems of enormous com- 

 plexity and difficulty, but national security requires that research and 

 development be carried forward with imagination and vigor. 



Millions of passengers are now carried by air. Air transportation 

 also expedites the delivery of great volumes of mail and goods. Air- 

 liners regularly span oceans and continents, and smaller utility planes 

 serve remote regions in the Arctic and tropical jungles. There is 

 promise of helicopter service between nearby cities, with no need for 

 large outlying airports. 



The safety record of civil aeronautics is remarkably good, but it 

 is never good enough. We still read, from time to time, of disasters 

 from collision, fire, storm, human error, and, rarely, from structural 

 or mechanical failure of the airplane itself. The human pilot is aided 

 by wonderful instruments and by radio, radar, gyros, etc., but we 

 still depend on his judgment and skill. He must be better protected 

 against noise and fatigue — subjects for research. 



Air transportation is fast and can be faster. But greater flight 

 speed is illusory if it requires too long a climb to reach the high altitude 



