Blind Flight

Blind flight still remains a source of great peril to aviators. Brooks Hyde Pearson, air mail pilot, up in a blinding snowstorm, crashed into trees high up in the Alleghany Mountains. A farmer of Curwensville, Pa., saw the plane in distress, heard the crash and at daylight found the burnt remains of plane and pilot after several hours' search. Pearson had in his plane the usual flying instruments, totally insufficient in snow, fog or violent rain. Fortunately, the Army Air Service is aware of this serious problem in air navigation. Last week Eugene H. Barksdale (lieutenant) and Bradley Jones (instrument engineer of the experimental station at McCook Field) flew from Dayton (Ohio) to Mitchel Field, Mineola, L. I., far above the dangerous clouds, flying 'by dead reckoning alone and seeing no land for 450 miles. They broke the speed record for the trip, covering 575 miles in 3 hours 45 minutes in their De Haviland plane. But their real object was to test two new devices for blind flight, which--allowing pilots to keep their course without reference to land marks --will permit them to fly high above such storms as caused Pearson's death. One device is a lateral level indicator., showing whether the plane is flying on a level keel or not, even when there is no horizon or land to refer to. A pendulum or a bubble level will not correctly indicate a true vertical line, when subject to the air disturbances a plane must inevitably meet. A spinning top, once vertical, will stay with its axis vertical no matter how disturbed. So will a gyroscope. By a simple adaptation of the gyroscope, driven by an air jet, a true level indicator has been developed.

The other valuable device is a distance compass. Any ordinary compass has to be placed in the pilot's pit, where it is so disturbed by the motor and other surrounding metal, as to be partially useless. The new instrument is an earth inductor compass, with no magnetic needle, but with a revolving electric coil placed in the tail of the machine--where it is undisturbed by any metal. The contact brushes are so arranged that a galvanometer in the cockpit, connected with the revolving coil, gives no reading when the plane is on her true course. In the 450 miles of blind flight, Barksdale and Jones were only eight miles off their course.