EARLY INSTRUMENT FLYING — DOOLITTLE 343 



4. Improvement and perfection of instruments allowing airplanes 

 to fly properly in fog. 



5. Penetration of fog by light rays. 



To assist in carrying out pertinent parts of this directive the di- 

 rectors of the fund decided in 1928 to establish a Full Flight Labora- 

 tory at Mitchel Field, Long Island, N.Y., with all necessary facilities 

 and equipment. In August 1928 I was borrowed from the Army Air 

 Corps to head this laboratory. Prof. William G. Brown of the Aero- 

 nautics Department of the Massachusetts Institute of Technology 

 joined us as technical assistant in Februaiy 1929. Professor Brown 

 worked with the fund's Full Flight Laboratory from then until it was 

 dissolved at the end of 1929. His technical knowledge and unbounded 

 enthusiasm provided a constant help and inspiration. 



This was a most interesting period in my life. The good book says, 

 "No man can serve two masters for ... he will hold to one and despise 

 the other." I had three: An Army boss, Lt. Col. — later Maj. Gen. — 

 Conger Pratt, commanding officer of Mitchel Field where I was sta- 

 tioned ; Capt. — ^later Vice Adm. — Land, of the Navy ; and Mr. Gug- 

 genheim, a civilian. They were all such fine, understanding, and 

 cooperative people that my existence, instead of being complex, was 

 uncomplicated and extremely pleasant. 



DEVELOPMENT OF BLIND-FLYING INSTRUMENTATION 



Our first activity in the Full Flight Laboratory was to study and 

 endeavor to analyze the work previously done on blind landing in fog. 



In England tethered balloons had been lined up with the landing 

 field and used with some success in still air and when the fog was not 

 thick. This concept was abandoned at once as not satisfactory, for 

 experience had indicated that the fog layer might be very thick and 

 that still air could not be depended upon at all times when visibility 

 was restricted — for example, in a blizzard. 



In both England and France the lead-in-cable idea was tried out. 

 In this system an electrified cable circled the field and led in to a land- 

 ing. It required very sensitive sensing equipment in the airplane, and 

 it was necessary to make a precision turn into the field at low altitude. 

 This turn presented considerable difficulty. Lt. LeRoy Wolf of the 

 Army Air Corps also experimented with the electrified cable concept 

 at Wright Field. The U.S. Navy had some success with an electro- 

 magnetic cable guide at Lakehurst Naval Air Station. 



The low-frequency radio range had been developed by the Bureau 

 of Standards and the Army, and was in limited use for aerial navi- 

 gation. An adaptation of this radio range in the form of a radio hom- 

 ing beacon seemed to offer the greatest promise for our use. It could 

 also be readily tied in with the radio receiver and other conventional 

 airborne equipment. 



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