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Патент USA US2411143

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Nov. 19,1946.
A. G. ALlzlER
\\\\\\\\\\\\\\\ Ill .
Patented Nov. 19, 1946
¿ai 1,143
André Georges Alizier, Chicago, Ill., assignor to
Cornet Model Airplane & Supply Company, In
corporated, a corporation of Illinois
Application November 15, 1943, Serial No. 510,329
4 Claims.
(Cl. 170-159)
plex curvature necessary for constant pitch and
approved airfoil shapes, I use thin, flat propeller
This invention relates to a propeller, and more
particularly to a propeller for model airplanes.
One feature of this invention is that it pro
blades, which may be die cut from thin sheet `ma
terial, as heavy cardboard or Very light wood or
hand cut or pre-shaped along lines printed on
the sheet material. I- form the hub carrying these
blades by spaced parallel front and back mem
vides an improved propeller for a model air
plane; another feature of this invention is that a
very eilicient and well balanced propeller may
be constructed quickly and eihciently by the
bers with a peripheral strip element, this strip
model builder; still another feature of this in
vention is that both dynamic and static balancing
element having slots at the same angle and sym
of the propeller are practically assured; and yet 10 metrically arranged around the hub. The blades
another feature of this invention is thatv two,
are slipped into the slots, properly centered, and
then fastened in place .by cementi-ng or other
three or four bladed propellers can be construct
ed with equal ease and with equally desirable re
appropriate means.
sults. Other features and advantages »of this in
Referring now more particularly to the spe
vention will be apparent from the following spec 15 ciñc embodiment of this `invention illustrated.
iíication and the drawing, in which:
herewith, it will be seen that the hub-comprises
, Figure l is aperspective View of a iinished
three-bladed propeller embodying this invention;
Figure 2 is a partially exploded view of the same
propeller; Figure 3 is a fragmentary View of the 20
propeller during assembly, before bringing one of
the hub members into place; Figure 4 is an en
larged sectional view of the propeller hub along
a diameter thereof (as the line `ll-ll of Figure 3,
with the blades removed) ;- and Figure 5 is a View 25
of the propeller strip element in initial plane p0
The construction of model airplanes is receiv
ing increasingly greater attention, both for pur
poses of instruction and relaxation.
The con
struction and assembly of the fuselage and wings
of a model airplane, by modern methods, is a
pleasant and relatively short task; but hand
shaping of a good propeller, by the methods here
tofore conventionally in use, has been dilìcult and 35
tedious. Heretofore, it has been common to start
with a rectangular block of Wood, or a very
two flat polygonal members Il) and II (he-reshown
as hexagonal) `adapted to be held in spaced par
allel relationship by a peripheral strip element
I2, shown in its initial or flat form in Figure V5.
The members Il) and II are preferablyl of the
same size and of sheet material such as light
wood or heavy cardboard.
Referring now more particularly to >Figure 5, it
will be seen that the strip vI 2 is provided with three
slots here identified as IZa, IIZb and I2C. These
are at an appropriate acute angle to the edges
of the strip (and thus at this same angle to the
front and back members Il) and -II when the hub
is assembled) as, for example, 35°; and they are
so spaced that, when the hub is assembled, they
will be symmetrically arranged or equally spaced
about the periphery of the hub. The ends of the
strip element are, of course, cemented to each
other; and both edges of the element are ce
mented to the respective front and back mem
bers I il and II, so called because they `face to
the front and to the back of the airplane when
roughly shaped piece of wood, and carve and
the propeller is in operative position thereon.
sand the propeller into final shape. Securing
good balance and proper symmetry of blade 40 The word "cemented” is used here in a broad
sense, being intended to include gluing, lacquer,
shapes was almost an impossibility by this meth
or any adhesive for binding the parts together.
od, one blade almost always carrying consider
The three blades, here identified as I3, I4 and
ably more of the torque than the other, and a
I5, are identical with each other, being die
dynamically unbalanced propeller resulted.
Moreover, this method of construction, as a prac
45 stamped or pre-shaped in accordance with a deli
tical proposition, resulted in the model airplane
constructer being limited to two blade propellers
nite pattern from light sheet material, as thin
wood or fairly heavy cardboard. The blades are
whereas models of many modern planes should
be equipped with three or four bladed propellers.
I have devised and am here disclosing and
claiming an improved method for simply making
well balanced and eilicient propellers for model
airplanes, it being quite easy to make three and
four bladed propellers in the manner here dis
closed. Rather than attempting to get the com
preferably rounded at the tip, somewhat enlarged
toward the outer end, and reduced at the end
adapted to be associated with the propeller, here
inafter termed the inner end, as shown. This
shaping results in the outer half of each pro
peller blade developing more than three-quarters
of the total possible power, so that there is no ap
preciable loss in eñiciency due to the use of a
flat blade, as contrasted with a, constant pitch
blade having a greater angle near the hub. As
may be best seen in Figures 2 and 3, the inner
ends of the blades are provided with identical
ìl-shaped notches, as the notch l3a of the blade
In assembling the propeller, the members I0
plane, including: a hub comprising spaced, paral
lel, similarly polygonal, front and back members
having an even number of sides, said sides being
at least six in number, a, peripheral element hold
ing the members in said spaced relationship, slots
symmetrically arranged in said peripheral lele
ment between the front and back members with
all slots making substantially the same angle
withsaid members, said slots being equal in num
these members), and the strip element I2 is 10 ber to one-half the number of polygonal sides
in one of said members and each slot being cen
Wrapped around the periphery of these members,
tered between corresponding sides of said polyg
-»the ends of the strip element then being cemented
onal members; and a ilat, planar propeller blade
to each other, and one edge of the strip element
for each slot having a reduced end held by said
being cemented to one of the members, as the
member Il. The reduced ends of the blades I3, 15 slot.
2. A method of constructing a propeller for
i4 and l5 are then slipped into the slots l2a-c
model airplanes, comprising shaping ñat blades
and the V-shaped slots interlocked with each
from plane sheet material, shaping front and
other around the pin to ensure proper centering
back hub members from plane sheet material,
and alignment of the blades. Two of the blades
are shown in position in Figure 2 and the third 20 forming a slotted strip of sheet material around
the periphery of one of said members, inserting
blade in Figure 3. When the parts have been
a small rod-like element through the center of
thus assembled, the inner ends of the blade are
the hub members for centering the inner ends of
cemented to each other and the parts passing
said blades, inserting the blades in the slots in
through the slots are cemented to the strip at
that point. After this is vdone the other member 25 said strip, removing the rod-like element, ias
and Il are properly related to each other (as by
passing a pin I6 through central openings in
l0 is cemented in place and the pin I6 removed,
tening the blades together and to the strip, andv
the ñnished propeller then being as shown in
bringing the other hub member into place.
3. A light Weight propeller for a model air
Figure 1.
plane, including: a plurality of flat, pre-shaped
It will be readily apparent thata light, sturdy,
symmetrical and well balanced propeller can be 30 blades having one end of each reduced in size;
readily made in this manner with any desired
number of blades. It has proved somewhat more
desirable, for proper inter-relation between the
slot‘ and the part of the blade passing through
it, to use polygonal end members with double the
number of sides that therey are blades, so that a
and a hub comprising spaced, parallel front and
back members and a slotted peripheral element
of sheet material, said slots being symmetrically
arranged around the hub and all _making the
same angle with said members, said slots re,
ceiving the reduced ends of said blade, said ends
ñat side is provided for each blade. That is, hex
of said blades interlocking with each other atl
agonal members may be used for a three blade
the center of said hub.
propeller, octagonal members for a four blade
4. A light weight propeller for a model airl
40 plane, including: a plurality of ilat, pre-shaped
blades; and a hub comprising spaced front and
While I have shown and `described certain em
back members and a slotted peripheral element,
bodiments of my invention, it is to be understood
said slots being symmetrically arranged around
that it is capable of many modifications.
Changes, therefore, in the construction and ar 45 the hub and all making the same angle with
said members, said slots receiving the inner ends'
rangement may be made without departing from
of said blades, said inner ends of said blades being
the spirit and scope of the invention as disclosed
propeller, etc.
in the appended claims.
I claim:
1. A light-Weight propeller for a model air
notched and interlocking with each other at thel
center of said hub.
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