The L'Anse sentinel., 1923-08-10

a flying machine glides, or volplanes,
to the vertical distance II lowers itself
In doing so; meanwhile retaining its
flying speed" or normal rate at which
1t repains under full control Of the
pilot. The ratio of six to one is a con-
servative average figure for airplaies.
That Is to say, an average airplane
with its motor shut Off at an altitude
of 1000 feet can volplane horizontal
distance of 5000 feet under control
before 1t comes to land.
An efficient glider has as good an
angle of glide as an efficient airplane
But the Important difference is that
the glider travels more slowly. AS
suming in the foregoing case, for in
stance, that the airplane would nor
mally glide to the earth, through the
5000 feet from height of 1000. In
one minute, the glider, with the same
gliding angle, but much less speed,
might take two, or even three, minutes
to glide the same distance The diff
ference is due to the varying flying
speed. The flying speed Of an
airplane or glider Is the mini
mum speed 1t must. maintain in
order to fly forward on level under
full control. 1t is. therefore, practi-
cally the same as the speed of the
craft at the moment 1t takes off, when
the speed just begins to provide "llft"
enough to overcome the weight of the
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with different types Of planes, accord
ing to design and ratio of wing area
to weight, but also varies from time to
time In an individual plane, according
to loading and to the condition of the
wings and other essential parts at the
moment. An airplane with flying
speed Of so miles an hour with pilot
only aboard will necessarily require
a slightly higher flying speed with
passenger also aboard. Mere
speed must be attained to supply
the additional lift. A plane with its
wings newly "tuned up" to afford max
imum efficiency will gradually require
higher flying speed thereafter, as the
wings sag and warp out Of best align
ment under the strain Of usage.
Flying Speed.
Flying speed in general is governed
by the ratio Of wing area to weight.
The larger the total wing surface is in
proportion to the weight Of the air.
plane or glider, the less Is the flying
speed. The less number Of pounds
that each square foot of wing surface
has to sustain the slower the wing
must pass through the air. The object
In glider construction, therefore, is to
provide as great wing area as possible
in proportion with weight. This
makes for low flying speed, which ia
cilitates the gliding and climbing. It
permits such low flying speed that glid-
ers, much more frequently than air
planes, do the trick of seeming to fly
backward, as the Dewoitine machine
did at Roosevelt field. This is due
merely to gliding or flying headed into
a wind with velocity greater than
the flying speed of the craft so that
while the craft is moving forward fast
enough to keep balance. 1t is moving
backward relatively to the earth.
The flying flivver, like Its immediate
parent the glider, seems fated to be-
come a sporting and pleasure machine,
rather than practical commercial We
hicle Of general usefulness. The gill
der has already become a popular
'play toy" In Switzerland and in the
Hartz mountains in Germany, gliding
was a familiar pastime last winter.
The snow-covered hillsides were good
places for taking off, with skids In
stead Of heavier wheels on the ma
chimes; and the snow-covered valleys
afforded equally good landing places.
with Its possible very low cost and
with its range of performance consid-
erably greater than that Of the glider,
the flying fiivver will perhaps soon be-
come successful competitor Of the
automobile runabout and the motor
boat, as q thing of sport. But its sig
nificance scarcely exceeds that, be-
cause the gliding feature Is available
only under rare aerial conditions, and
at that in few locationa--New York
Times.