The outstanding development in aviation recently, and one of the most
significant so far in aviation history was the "blind" flight of Lieut.
James H. Doolittle, daredevil of the Army Air Corps, at Mitchel Field,
L. I., which led Harry P. Guggenheim, President of the Daniel Guggenheim
Fund for the Promotion of Aeronautics, Inc. to announce that the problem
of fog-flying, one of aviation's greatest bugbears, had been solved at
last.

There has been "blind flying" done in the past but never before in the
history of aviation has any pilot taken off, circled, crossed,
re-crossed the field, then landed only a short distance away from his
starting point while flying under conditions resembling the densest fog,
as Lieut. "Jimmy" Doolittle has done, in his Wright-motored "Husky"
training-plane. It was something uncanny to contemplate.

The "dense fog" was produced artificially by the simple device of making
the cabin of the plane entirely light-proof. Once seated inside, the
flyer, with his co-pilot, Lieut. Benjamin Kelsey, also of Mitchel Field,
were completely shut off from any view of the world outside. All they
had to depend on were three new flying instruments, developed during the
past year in experiments conducted over the full-flight laboratory
established by the Fund at Mitchel Field.

The chief factors contributing to the solution of the problem of blind
flying consist of a new application of the visual radio beacon, the
development of an improved instrument for indicating the longitudinal
and lateral position of an airplane, a new directional gyroscope, and a
sensitive barometric altimeter, so delicate as to measure the altitude
of an airplane within a few feet of the ground.

Thus, instead of relying on the natural horizon for stability, Lieut.
Doolittle uses an "artificial horizon" on the small instrument which
indicates longitudinal and lateral position in relation to the ground at
all time. He was able to locate the landing field by means of the
direction-finding long-distance radio beacon. In addition, another
smaller radio beacon had been installed, casting a beam fifteen to
twenty miles in either direction, which governs the immediate approach
to the field.

To locate the landing field the pilot watches two vibrating reeds, tuned
to the radio beacon, on a virtual radio receiver on his instrument
board. If he turns to the right or left of his course the right or left
reed, respectively, begins doing a sort