Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-05-19
AVIATION
BY JOSEPH S. EDGERTON.

cure. For other types of spins. &C
cording to Navy flyers who have
tested planes so equipped, the
slots do not seem to be very eff
fective. Whether this is due to
improper designing or mounting
of the slots they have not de-
termined.
Autogiro Is Spinless.
The Cierva autogiro, now being
constructed in this country by
Pitcairn Aviation, is claimed to be
free from any tendency to spin.
There are aviation people, how
ever, who are disposed to take the
autogiro lightly. The reason it
will not spin, they point out, is be-
cause it is in a perpetual spin, the
rotor wings depending upon their
circular motion for lift. Thus the
spin, instead Of being an evil, be-
comes a necessity for autogiro
purposes.
When this point in the discus
sionS at Langley Field was reached
Lieut.. Comdr. ]. G. HunSaker, who
is dirigible man and who prob
ably regards all this talk about
spins as a confession of the in
feriority of the airplane, dryly
suggested that inaSmuch as air
planes seem to feel it incumbent
upon them to spin once in while
as a plague to suffering pilots. it
might be well to install rotating
landing gear, something like a
Swiveling Office chair, so that
planes might be landed in a spin
and keep on ground spinning until
they got tired Of this type of fool
iShneSS.
The vertical wind tunnel is to
be the latest of the family of wind
tunnels at Langley Field, to which
a giant 60 by 20 foot tunnel
capable of accommodating an en-
tire airplane soon is to be added.
During the conference this week
the delegates were taken on a tour
of the laboratory and permitted
to inspect the various tunnels in
operation.
One of the most startling of
the new tunnels is used for the
development of an airfow Of ire
mendouS speed in which the effect
of the air on propeller tips may
be studied. In this tunnel speeds
up to 900 miles per hour may be
attained. This terrific speed may
be better realized when it Is re-
called that sound travels at only
780 miles per hour in calm air.
lift decreases With Sneed.
Through the use of this tunnel
it has been found that, although
at ordinary speeds the lift Of an
airfoil or wing section increases
as the speed increases, this is not
true at the higher speeds. With
the present type of wing the lift
increases up to approximately
$40 miles per hour, but begins to
fall off again above this point.
In the high compression wind
tunnel, which today is the only
one of it's kind in the world,
precise results may be obtained
with the use of models. In pre-
vious tunnel experiments with
models serious errors were found.
This was due to the fact that al
though the size of the plane was
decreased, the volume of air flow
ing past it remained the same. In
the compression tunnel the air
may be compressed to any desired
degree and when models are used
the results are the same as those
found when full-SiZed planes are
used in the open air.
A smaller refrigerating tunnel
is used to study the formation of
ice upon airplanes. Ice formation
has been the cause of many
crashes and is one Of the worst
of the air mail pilot. In
the tunnel conditions similar to
those found in the air are repro
duced and ice is formed upon
wing sections, struts and other
fittings.
The grandfather of all the tun-
nelS at, Langley Field at present
is the 20-foot propeller research
tunnel, in which the fuselage and
part Of the wings of a full-sized
airplane may be subjected to a
wind-stream ranging up to 100
miles per hour. In this tunnel
the N. A. c. A. cowling for radial
air-cooled motors was designed.
This cowling is said by aviation
to be the outstanding
aeronautical development of 1928.