EARLY INSTRUMENT FLYING DOOLITTLE 339 



the jetblack darkness when no ground reference pomt could be seen 

 and it would have been quite impossible to maintain proper attitude 

 and course without the blessed bank and turn indicator. Although I 

 had been flying for almost 5 years "by the seat of my pants" and 

 considered that I had achieved some skill at it, this particular flight 

 made me a firm believer in proper instrumentation for bad weather 

 flying. 



In 1925 I wrote a thesis at the Massachusetts Institute of Tech- 

 nology for a doctor of science degree in aeronautics. At first I had 

 hoped to study, through carefully controlled flight tests, the pos- 

 sibility — or impossibility — of a specially trained pilot orienting him- 

 self without flight instruments and determining certain phenomena, 

 such as wind direction, without reference to a visible horizon or point 

 on the ground. But this subject was not sufficiently abstract for the 

 doctorate and was changed to an analysis of "The Effect of the Wind- 

 Velocity Gradient," employing flight tests, wind tunnel data, and 

 mathematical analyses. The thesis begins : 



There has long been an uncertainty in the minds of aviators regarding the 

 effect of the wind on the flying qualities of an airplane. Some pilots claim 

 that it is much easier to turn into the wind than with it, and that at any altitude 

 they can tell the wind direction by the feel of the ship in a turn, and this even 

 though in a dense cloud which would preclude the possibility of obtaining their 

 relative motion from any stationary object. 



Other pilots maintain that, regardless of the wind velocity or the proximity of 

 the ground, there is no difference in the feel of the plane when turning into the 

 wind and when turning with it. They claim that any apparent difference is due 

 wholly to the psychological effect on the pilot, resulting from the difference in 

 groundspeed in the two cases, and if there is any difference in the ship's perform- 

 ance, from a time-altitude standpoint, it is because the pilot handled the controls 

 differently. In other words, if the pilot were blindfolded he could not tell the 

 wind direction when turning, and a turn made into the wind would be identical 

 with a turn made with the wind. This is, of course, considering the turn in 

 relation to the medium in which it is being executed and not in relation to the 

 curves traced out on the ground. 



There is a similar difference of opinion regarding the effect of a strong wind 

 on the rate of climb. Experienced pilots are about evenly divided, half feeling 

 that a plane climbs better into the wind, and the other half feeling that the 

 wind makes absolutely no difference. 



Seven of the leading pilots of the day were questioned regarding 

 the effect of wind on flying performance. The answers given were far 

 from consistent, as might be expected from such a group of individual- 

 ists. There was, therefore, still considerable confusion — and contro- 

 versy — among the experts. 



The conclusions from the thesis, somewhat oversimplified, were that 

 in airplane flight — 



1. There is no measurable effect in level flight, at altitude, due to 

 wind direction as long as the wind is steady. 



