Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-05-19
REVENTION of the fiat spin,
y which constitutes one of
the greatest potential

~ REVENTION Of the fiat spin,
- which constitutes one Of
the greatest potential
L sources of danger in avla-
ton today, is the outstanding
aviation problem of 1929, it was
agreed by leading aeronautical
engineers who attended the
fourth annual aircraft engineer
ing research conference this week
at the Langley Field laboratories
of the National Advisory Com
mittee for AerinauticS.
In the fiat spin the plane is
momentarily out of control OF the
pilot. Sometimes he cannot regain
control, the plane going from one
spin into another; if close to the
ground usually with disastrous
although not necessarily fatal re-
suits.
Will Study Spin Thoroughly.
It seems probable that more at
tention will be devoted to the spin
this year than ever before, not
only in the advisory committees
laboratory, but in the research
laboratories and on the flying
fields of commercial companies.
At the Langley Field laboratory
the committee is preparing to in
stall fairly large vertical wind
tunnel in which models may be
thrown into fiat and other abnor-
NAL spins and the causes aScer-
tanned with some degree of &C
curacy. The vertical tunnel is
necessary SO that gravity may
play its proper part in the expert
ment. A small-Scale vertical
tunnel is in operation at Langley
Field, in which spins may be pro-
duced with models of about three
inch wing span. This, however,
is regarded as too small for good
results.
Preliminary investigation of the
spin has been made at Langley
Field, both in the laboratory and
in the air. Recording inStru-
ments of various types have re-
vealed the various stresses and
preSSures which occur on the
structure of plane during the
various types of spins. 1t has been
found that the distribution Of
mass of the plane has a great
bearing on the type of spin, to
which that particular plane will
be subject.
The spinning of a plane has
been compared to the spinning Of
an egg, which will spin about its
two principal axes. If the egg is
spun about any other axis than
these two it will tend to convert
the spin into rotation about one
or the other of these two major
axes.
Similarly, it has been found, an
airplane will spin around one or
two major axes. If these can be
determined the type of spin can
be forecast with some degree OF
certainty and it is hoped that
further investigation will show
what steps may be taken to shift
the spinning center SO as to pre-
vent uncontrolled spins.
Desirable in War Flying.
The investigation probably will
be devoted almost entirely to
commercial types of airplanes,
however. For military purposes
spinning, so long as it is not en-
tirely uncomfortable, is desirable,
as a means of escaping from the
attack of superior forces of enemy
planes. During the World War
many pilots escaped by this
means. Spins are part Of the
training of every military pilot to-
day.
There is a feeling on the part
of certain aviation engineers that
in curing planes of the tendency
to go into uncontrolled spins, the
designers may seriously interfere
with the efficiency of the modern
plane. Structural changes which
would make the plane so stable
as to prevent spinning, they be-
lieve, would leave it too unwieldy
for ordinary use.
Whether this is true will be one
phase of the problem to be solved
by the research workers at Lang
ley Field.
British engineers are relying
more and more upon the Handley-
Page wing slot to prevent spins or
to break them when once started.
For certain types of spins the slot
seems to be an almost certain