Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-08-10

maintained their balance With
their tails and with big, finger
like feathers which they undulat-
ed gently, at the tips of their
wings.
The tail-balance principle al
ready had been applied to flying
He found that the wing tip bal
ance principle had not been ap-
piled entirely to fight by man, so
it was upon these finger-like
feathers he concentrated his
study.
From the pictures he obtained
of the birds about his circular
swing he made hundreds of meas
urementS, hundreds of calcula-
tionS on the angles at which the
birds set their wing-tip feathers
under varying conditions.
He found that in all cases an
up-tipping of these feathers by
the soaring birds maintained
them in an even keel and kept
them on the proper course-of
course with the aid of the tail
feathers. There was no action of
the feathers at the rear of the
wings, near the tip, correspond
ing to the aileronS applied by
man to his plane for maintenance
of balance in flight.
Problem Yet Remained.
He found that there was a con-
tinual undulating motion OF the
wing-tip feathers, even when the
wings were held rigidly still.
His principal problem was ap-
plying the wing-tip balance to the
fixed wings of a plane. He found
that the up-tilt at the wing-tip
must be a stationary thing, that
the undulation in bird flight was
impracticable for application to
airplane flight as 1t Is known to-
day. The undulating motion pre-
sented too big problem OF oper-
alton by the pilot.
But from his study OF the angles
at which the birds tilted these
finger-like feathers at the wing
tips he gained some valuable in
formation. He applied the up
tilt principle to model planes, and
after a few adjustments from his
first calculations, got good results.
Test flyers in Germany agreed
to take up a full sized machine
fitted with the up-tilted wings
and Immediately reported them
successful.
they took the precaution, how
ever, of seeing to it that their
planes wings had aileronS on
them just as an emergency
measure.
Hocke points out that it is not
in the interest of doing away with
aileronS that he has developed
the wing-tip up-tilt as exempli-
fed by the plane on exhibition
here. The aileron, he finds, has
made itself an indispensable place
in aviation of today, and probably
has saved as many lives in avia-
ton as any one development OF
flight.
Up-tiIted Wing Differs.
He finds, however, that the up
tilted wing tip does a great many
things the aileron does not DO,
while taking over a great deal OF
the work the aileron does. He
finds that the up-tilted wing-tip
as he has adapted it to the pres
ent-day plane not only keeps a
plane on an even keel and pre-
vents side-slipping in turning,
but that it will allow the pilot to
relinuuish the controls of his ship
and keep the plane on an even,
straight course.
Tests with the Hocke wing tips,
he says, have proved conclusively
their value in blind flying. Time
after time, he says, his pilot,
Haynes, has put the ship through
thunder heads, relinquished the
controls and come out into clear
sky to find himself flying along
the same even, straight course he
was on before entering the clouds.
The time will come, Hocke be-
lieves, when the undulating prin-
ciple applied by birds to their
wing-tip, up-tilted feathers, can
be applied to mans flight, as will,
he believes, be applied a great
many other principles OF bird
flight.
With his circular swing Hocke
plans to continue his study of the
flight of birds for application OF
other principles he expects them
to teach him.