The Spokane press. [volume] (Spokane, Wash.) 1902-1939, 1910-07-27
ARTICLE w.
By HI FlElER.
(All Rights Reserved.)

l am going to tell you two ways
of making propellers for your min
ature monOplane. Both of then
are good ways. Maybe you can ex
pertinent for yourself until you hi
upon another way. If you can
fine!
Here is my first way.
Take, a piece of wood an inch
an da quarter wide, and plane i,
down until it Is thin enough to see
the light through it-a little less
than a sixteenth of an inch thick
Cut it off to the length of 81,
inches. Taper it to. half an inch
wide at the middle, wet it, anG
tie it to stick to dry in such a
way that both blades are twisted
in opposite directions. Twist il
about 60 degrees. When it is thor
oughly dry and properly warped
glue cork hub to the concave, OF
hollow side, at the center, balanc
ing the propeller first on the back
of your knife to make sure it is
even.
The warping or twisting process
Is rather a delicate process. Fig
l shows how it may be done II
you can curve the blades so that
the cOncave side pushes the air
you get more efficiency-or more
power for the size of the propeller
In Fig. l you see block OF
wood with raised parts at either
end. and the center part cut out
while the end pieces are slanted
off as shown. If you follow the d.
mansions shown on the end of the
block you will hit it about right
and instead of cutting the slantine
parts straight, curve them up a lit
tie as shown.
When you have this block all cut
wet the piece you have shaped for
your propeller, soaking it thorough
ly, and then tie it down to the form
as shown in the sketch labeled
Drying Out"
If you set the form in the sun
or near the stove. the propeller
ought to dry in few hours, but
1t would be just as well to let ii
dry over night, for if it dries to
quickly it will split.
The separate spetch at the TOP
of Fig. | shows how the cork hut
is to be glued on.
Remember one thing in partic
ular in making propellers; balance
them perfectly so that they will
lay on the back of your knife anC
not tip either way.
Here Is the second way to make
a propeller. and better than the
first, but it requires great care
Get a piece of Eastwood, free
from knots. Cut 1t to the size o.
seven inches long. and an inch ant
ah alf thick, and half an incl
thick. Plane it up to true dimen
sions.
Mark small three-eigths inch
circle at the center of the piece OF
bot hsides, but be careful to get
them exactly opposite.
Mark off lines from the corners
OF the board to the circle, as
shown in A, of Fig. 2. With a saw
cut down on these lines, shaping
the piece as shown by B. but take
care thta the saw cuts do not over
lap at the center. Hold the piece
tightly in a wise while you cut the
Sits (s) in G. Make these Sits or
both sides of the piece and at boti
ends, the cuts running down to al
eighth of an inch of the edges o.
the piece. Notice that you are t.
saw cross wise, taking care thai
you don't cut to the two adjacent
croenrs. You can cut these sits
every little ways by guess work
exercising care only in the depth o.
them.
When you have gone this far Il
Is an easy matter to tatke YOU
jackknife and remove the parts be
tween the Sits on both sides. II
Fig. 2. ID. shows how 1t looks al
this stage of the operation. AL
you have to do now Is to smooth
the whole piece down. thinning |,