Evening star., 1929-12-08

man WlnCer IN LneSe parts
with his full bag of stage
- props, featuring frigidaire
effects and northern blasts, has
been accompanied by a recrudeS-
cence of one of the pilots pet bug
abooS-ice on the wings.
Though airrnail pilots on the
coastal run passing through this
city are not affected very many
times during the average Winter
by this natural handicap, which is
caused by only a few limited COM
binationS of the elements, two of
them were forced down, one at
Baltimore and one at Greensboro,
N. c., by the formation of ice dur
ing the recent bad weather and
others had a taste of one of the
most unpleasant experiences which
come to the average pilot. Though
both men got down safely, pilots
who collect ice while flying do not
always get off unscathed.
The formation of ice on wings,
struts, wires and even the rapidly
moving propellerS of airplanes
adds great deal of weight to the
plane. This, however, is not the
most serious trouble. The ice
forms chiefly upon the leading
edge Of the wing and propeller,
changing their shapes. AS the
shape of the wing determines its
lifting power, change of its form
affects its ability to maintain the
plane in the air.
Ice Forms on Propeller.
Formation of a half inch or
more of ice on the leading edge of
a wing may so greatly change its
lift that, coupled with the added
weight of the ice, it may no longer
support the plane in the air. To
EniS may be added a loss of effi-
cheney of the propeller, caused by
the formation of ice upon its
blades.
The result is that the plane be-
gins to settle with increasing
tapidity. The pilots cue is to peer
about earnestly for a good open
place in which to set the ship
down and then get down there
The formation of ice may be
very rapid and the subsequent
forced landing a matter of mo-
ments. Pilot c. c. Taliaferro, on
his way back to Hadley Field after
flying the shuttle airmail service
here one morning last week,
picked up a quarter of an inch of
ice during the few minutes of
flight from here to Baltimore. He
had come to Boiling Field with a
quarter Of an inch of ice on the
leading edges, but elected to go
back. The plane became so loggy
that he got down at Baltimore and
stayed there until the ice forma-
tion period was over. He found
that the ice deposit had doubled
within few minutes. To have
continued for even a few minutes
more might have resulted in a
forced landing.
Preventives Not Successful.
Many expedients have been sug-
gested for outwitting the ice
demon, but so far the most logical
seems to be to keep out Of the air
when the ice plaStering is in prog
resS. It has been suggested that
the wings be oiled or chemically
treated. These methods have been
tried without much success. Heat
ing of the leading edges by cleo
tricity or piping of the exhaust
gases through the wing also has
been attempted, but without q
great deal of practical success.
To avoid areas where ice forma-
ton is likely to occur entails
the most accurate knowledge OF
weather conditions on the ground
and aloft. Thermometers at the
danger points are used by some
pilots to give them warning that
the temperature is approaching
the danger point. This is no help
after the formation of ice begins,
however, if there is no landing
field at hand.
The average pilot is not much
affected by ice formation because
he is not often in the air when
conditions are favorable for this
formation. The airmail pilot, who
must be up in all weatherS, is a
more frequent victim. Ordinarily
the only time he is able to stop
because of ice formation is after
his ship has begun to look like
refrigerator advertisement. Then
he has no choice in the matter.