EARLY INSTRUMENT FLYING DOOLITTLE 345 



team and did much of the experimental work. His piloting help, 

 criticism of tests carried out, sound technical counsel, and ever- 

 pleasant personality contributed greatly to the results achieved. 



As the preliminary practice flights progressed, it soon became ap- 

 parent that even with the very stable and sturdy NY-2, the available 

 instruments were not adequate. For determining heading when 

 maneuvering and when landing, the compass, owing to the northerly 

 turning error, was entirely unsatisfactory, and the bank-and-turn 

 indicator, though excellent for its purpose, was more a qualitative than 

 a quantitative measuring instrument. Also, at the moment of touch- 

 down in a blind landing, it was very desirable that the wings be 

 level with the ground. This was not easy to assure, particularly 

 when the wind was gusty. An accurate, reliable, and easy-to-read 

 instrument showing exact direction of heading and precise attitude 

 of the aircraft was required, particularly for the initial and final 

 stages of blind landings. Two German artificial-horizon instruments, 

 the Anschutz and the Gyrorector, were studied but were not deemed 

 entirely satisfactory. 



I sketched a rough picture of the dial for an instrument which I 

 thought would do the job and showed it to Elmer Sperry, Sr., a great 

 engineer and inventor who had established and headed the Sperry 

 Gyroscope Co. and who was very much interested in aviation. It was, 

 in substance, the face of a directional gyro superimposed on an arti- 

 ficial horizon. He advised that a single gyroscopic instrument could 

 be designed to meet the requirements, but recommended, for simplicity 

 of construction, two separate instruments. I agreed, and he then 

 assigned his very ingenious son, Elmer, Jr., to work with us and to 

 be responsible for the design and fabrication of the two instruments. 

 We could not have had a better colleague. Elmer, also, soon became 

 a member of the team and spent as much time at the hangar and at 

 the evening "discussion" sessions in our quarters on Mitchel Field 

 as the rest of us. These evening sessions were frequent and long. 

 The wives joined their husbands and helped in the work. Out of this, 

 as you know, came the Sperry Artificial Horizon and the Sperry 

 Directional Gyroscope which still, with their descendants, are on the 

 instrument panel of every airliner and military airplane today. 



As time passed, literally hundreds of blind and simulated blind 

 landings were made. To make a landing, the airplane was put in a 

 glide at 60 m.p.h., with some power on, and flown directly into the 

 ground. Although this was about 15 m.p.h. above stalling speed, 

 the landing gear absorbed the shock of landing and if the angle of 

 glide was just right the airplane did not even bounce. Actually, 

 after a while, it was possible to make consistently perfect landings 

 by this method. To assure just the right amount of power in the 

 glide, a mark was made at the proper place on the throttle quadrant. 



