338 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1961 



BEGINNINGS OF INSTRUMENT FLYING 



Whenever pilots got together for meditation and discussion in the 

 immediate post-World War I era, the subject of "flying instinct" or 

 flying "by the seat of the pants" was likely to come up. Views were 

 divided. Some pilots believed that they could fly indefinitely without 

 reference to the visible horizon — because they had done so. Others 

 agreed that they had but claimed it was the inherent stability of their 

 aircraft which made it possible and not pilot skill. 



In the early twenties the navigational instruments most commonly 

 used were the magnetic compass, the altimeter, and the airspeed indi- 

 cator. It was customary on cross-country flights to follow railroads, 

 or less frequently, highways, and the maps generally used were the 

 standard Rand McNally maps of the individual States. These State 

 maps were each about the same size and so, unfortunately, were usually 

 not to the same scale. 



The personal experiences in the pages that follow are related to 

 illustrate conditions which affected all fliers of the era. On Sep- 

 tember 4-5, 1922, 1 flew a DH-4 airplane, in which additional gasoline 

 and oil tanks had been installed, from Pablo Beach, Fla., to Rockwell 

 Field at San Diego, Calif., with one intermediate stop for fuel at 

 Kelly Field, San Antonio, Tex. The elapsed time was 22 hours 35 

 minutes. It was the first time the North American Continent had 

 been crossed in less than 24 hours. 



It was also the first airplane in which I had used a bank-and-turn 

 indicator. To obtain the instrument it was necessary to go to the 

 Army Air Service Engineering Base at old McCook Field in Dayton, 

 Ohio, and "promote" an experimental model through the help of 

 cooperative technical friends. This instrument, invented in 1917 by 

 Elmer Sperry, Sr., built by Elmer Sperry, Jr., and first flight-tested 

 by Lawrence Sperry with Elmer, Jr., as passenger, was not yet in 

 common usage or generally available. 



I took off just after dark, having chosen a moonlight night to facili- 

 tate night flying, but about 4 hours out I ran into solid overcast and 

 then severe thunderstorms. For a while the lightning flashes were 

 almost constant and, in the otherwise black night, so intense as to 

 light up the gromid clearly for a considerable area. Some flashes 

 were so close that their familiar ozone odor could be detected, but 

 although it seemed that one could reach out and touch them, none 

 struck the plane. 



The air was extremely turbulent and the airplane was violently 

 thrown about its axes as well as up and down and, despite its excel- 

 lent stability characteristics, was held on a relatively even keel only 

 with great concentration and effort. After the lightning died away, 

 the turbulence appeared to intensify, and there was about an hour in 



