Aug. 18, 1931.
1,819,497
C. F. CHISHOLM
COMBATING SLEET ON AIRPLANES
Filed May 16, 1950
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INVENTOR
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Patented Aug. 18, I931
" UNITED STATES
1,819,497
PATENT OFFICE ,
CHARLES F. GHISHOLM, OF STATEN ISLAND, NEW YORK
COMBATING SLEET 0N AIRT’LANES
‘Application ?led May 16, 1930. Serial No. 452,833.
This invention relates to combating sleet
The ?gure of the drawing is a diagram
on airplanes, the expression “combating” be matic plan view of a monoplane showing the
ing used to designate either the prevention of invention diagrammatically.
sleet formations or the removal of sleet after
The airplane is shown as comprising a
6 it has formed.
fuselage 1 and a single wing 2 which may be
The major portion of the lifting effect of considered as mounted above the fuselage.
an airplane wing is due to the sub-atmos The wing may be considered as of the all
pheric pressure produced adjacent the upper metal type with metal framework and metal
surface of the wing as the wing moves wing surfaces. Within the wing there is a ‘
10 through the air. When sleet forms on the conducting loop 3 adapted to be excited by
win , the contour of the wing and the nature any suitable source of high frequency current
of t e surface are so changed as to reduce the such as an engine driven alternator, a wind
tendency of the win to form a vacuum ad driven alternator, an oscillator, etc. Where
jacent its upper sur ace. The result is that the plane is radio equipped, a single oscillator
15 when sleet starts to form on the wings of an may be used for the radio sending set and for
airplane, the lifting effect of the wings may exciting the loop. In such case, the oscillator
fall o? so rapidly as to force the plane down should be of su?icient power; and it should '
in a very few minutes, even though the ac be capable of a wide tuning range as usually
cumulated sleet has increased the weight of lower frequencies will be- desired for sleet
20 the lane but little.
T e general object of the present invention
is to rovide a method and/or apparatus for
elfectlvely combating sleet on an airplane,
and particularly on the wings of the plane.
as Another object of the invention is to pro
vide a method and/or apparatus for combat
ing sleet which is effective to quickly remove
any sleet which has started to accumulate.
Another object is to provide sleet combat
combating than for radio sending. When
the loop is excited, the metal wing surfaces
are acted upon by an alternating magnetic
?eld and thus alternating currents are in
duced in the wing surfaces, which currents
heat the Wing and combat the sleet by either
preventing its formation or melting sleet
which has already formed. If only the
-.
framework of the wing is'metal (the wing
surfaces being nonconducting) the frame
30 ing apparatus which adds but little to the work will be heated and‘the air trapped with 80
weight of the plane.
~
in the wing will convey the heat to the wing
Other objects of the invention‘ will be ob surfaces.
vious from the following disclosure.
The amount of energy which it is necessary
The invention as herein disclosed is par to dissipate in the wing surface in order to
35
40
ticularly applicable to ‘airplanes having metal combat the sleet is comparatively small, be
wing surfaces, but is also applicable to air cause a very slight increase in the tempera
lanes having metal framework in the wings ture of the wing surface will su?ice. If the
irrespective of the material of the wing sur atmospheric temperature is slightly below
faces. In the particular form of the invention freezing, any precipitation is either in the
disclosed, a conducting loop is placed within
the wing of the lane and is so arranged that form of hail or snow, and hence sleet does
when the loop 1s suitably excited, the wing -not form on-the wing. If the atmospheric
0
temperature is slightly above freezing, any
will be traversed by an alternating magnetic precipitation is in the form of rain, and
_ surfaces on which sleet is to be combated
45
Ac
cordingly,
when
sleet
starts
to
form,
only
a
turns of insulated wire, and may be arranged
,?eld.
This loop may consist of one or more again sleet does not form on the wing.
in one or more sections so that parts of the
relatively small increase of temperature of
plane which it is not desired to subject to a the wing surface is necessary to take the
magnetic ?eld may be excluded from the mag wing 'out of the sleet forming temperature
5.° netlc action of the loop.
range. As soon as the wing has warmed 1(_
' 2
.
1,819,497
/
enough to loosen the sleet from the wing, the in said metal surface as opposed to conduct
ing heat to such surface.
The energy which is useful in combating
6. In combination, a metal surfaced air
the sleet is that which is actually dissipated plane wing, a conducting non-heating loop
in the wing surfaces and with an exciting within said wing and arranged to subject said 70
current of relatively high frequency, effi surfaces to the action of an alternating elec
cient transfer of energy to‘ the wing surfaces tromagnetic ?eld, and means to excite said
can be accomplished without utilizing mag loop with an alternating current to combat
netic core interlinkage between the loop and sleet on the wing by thereby generating heat
the
wing surfaces. This is a very practical in said metal, surface as opposed to ‘conduct 75
10
. accumulated sleet will blow off.
point because of the desirability of keeping
ing heat to such surface.
15
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I. In combination, an airplane wing hav
the weight of the airplane at a minimum.
Furthermore, with a high frequency exciting ing metal portions, a conducting non-heat
current, the wing surfaces in which the cur~ ing loop magnetically embracing metal por
rent is induced become, electrically speaking, tions of said wing, and means to excite said
a high resistance load and only a relatively loop with an alternating current to combat
small value of exciting current in ‘the loop sleet on the wing ‘by thereby generating heat
80
.
is required to transmit the necessary energy in said metal portions as opposed to conduct
20
25
to the wing surfaces. This reduces the ing heat to such portions.
8. In combination, a metal surfaced air
weight of the loop and the weight of the
plane wing, a conducting non-heating loop
equipment necessary to excite the loop.
The invention may be embodied in forms within‘said wing and arranged to subject
other than those particularly disclosed, and said surfaces to the action of an alternating
the method may be carried out by various electromagnetic ?eld, and means to excite
forms of apparatus, and hence ‘the present said loop with a high frequency current to
90
disclosure is to be considered as illustrative thereby generate heat in said metal surface
only, and not as limiting the scope of the in as opposed to conducting heat to such sur
face, the frequency being suf?ciently high
vention.
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85
to combat sleet on the wing without mag
What is claimed is :—
1. The method of combating sleet on the netic core interlinkage between the loop and
wings of an airplane which comprises induc
ing alternating currents in metal portions of 9. In combination, an airplane wing hav
the wlngs, whereby heat is generated in said ing metal portions a conducting non-heat
metal portions as opposed to being conducted ing loop magnetically embracing metal por
35 to such portions.
95
_ the wing surfaces.
tions of said wing, and means to excite said
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100
2. The method of combating sleet on air loop with a high frequency current to thereby
plane _wings having metal surfaces which generate heat in said metal portions as op
comprises inducing alternating currents in posed to conducting heat to such portions,
said surfaces, whereby heat is generated in the frequency being sufficiently high to com
40
the metal surfaces as opposed to being con
ducted to such surfaces.
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>
bat sleet on the wing without magnetic core
interlinkage between the loop and said em
3. The method of combating sleet on the
45
braced portions.
105
‘
10. In combination a metal surfaced air
wings of an airplane which comprises sub
]ecting metal portions of the wings to the plane wing, a horizontally disposed conduct
action of a high frequency electromagnetic ing loop within said wing and arranged to
?eld, whereby heat is generated in said metal subject at least a portion of the top surface
portions as opposed to being conducted to of the wing to the action of a magnetic ?eld,
110
such portions, the frequency being sufficient and means to excite said loop with an alter
ly high to render interlinkage with a mag
nating current to thereby generate heat in
said top surface as opposed to conduction to
such
surface.
4. The method of combating sleet on air
11.
airplane heating system for com
plane wings having metal surfaces which batingAn
sleet
comprising a metal wing surface
comprises subjecting said surfaces to the ac~ which is per se a heating element, and means
50 netic core unnecessary.
55
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tion of a high frequency electromagnetic comprising a non-heating'electrical loop op
?eld, whereby heat is generated in said erative to energize said heating element.
metal surfaces as opposed to being con
12. An airplane heating system for com
ducted to such surfaces, the frequency be— bating sleet comprising a metal structural
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120
ing vsu?iciently high to render interlinkage element of the airplane, which element‘ is per
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with a magnetic core unnecessary.
5. In combination, a metal surfaced air
plane wing, a conducting loop magnetically
embracing said wing, and means to excite _
65
said loop with alternating current to_ combat
sleet on the wing, by thereby generating heat
se a heating element, and means comprising 125
a non-heating electrical loop operative to
energize said heating element.
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CHARLES F. CHISHOLM.
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