Radio Control of Aircraft

Mr. Hammond Tells of His Experiences in Development Work.

To the Editor of The New York Times:

There has been some correspondence lately in your paper relative to radio control of aircraft and other objects at a distance, an art which I have called radiodynamics. This terminology has been accepted by the Patent Office and Congress. This art so far has been chiefly applied to the problem of the control of carriers of explosives, whether in the air, on the water or under the water, but unquestionably the future will open up many commercial applications for these devices.

In 1909, when I was at Yale, I undertook the development of a practical system of radiodynamic control. At this time I studied the patents covering this subject and found that many hundreds of inventors existed and that Gardner in England, Wirth Beck and Knauss in Germany and Gabet in France had actually built torpedoes and controlled them in a fashion by radio.

In America, Nikola Tesla built the first radio-controlled model of a boat. Admiral Fiske obtained one of the earliest United States patents and was the first to understand the military importance of the weapon. It is probably Professor Ernest Wilson of Kings College, London, who was the pioneer both from a patent standpoint and as a practical experimenter.

My study convinced me that the inventions of that date were of a laboratory nature and could not meet practical requirements. Since then I have been forced to make some 300 inventions and to expend over a million dollars in developmental research to perfect a radiodynamic system.

Certain of these patents are basic and have been granted in patent offices throughout the world. These devices led to the successful control of the U. S. S. Iowa steered as a target. They have also been employed in the submarine control of standard naval torpedoes. They were also employed in airplane control at McCook Field in 1919-20.

The Radio Corporation of America, the General Electric, Westinghouse, American Telephone and Telegraph and United Fruit companies have commercial licenses under these patents and the United States Government has licenses for governmental purposes.

JOHN HAYS HAMMOND Jr.
Washington, D. C., June 12, 1931.