mic.pdf

MICROFILM-COVERED R.O.G.

by Leon J. Friedman and Arthur Ruthlein

Plans for two indoor endurance jobs suitable for a beginners' model program.

A larger indoor craft, the "E-X". has flown about for 12

minutes.

The "E-Z" type indoor ship is capable of better than 10

minutes.

HAVE YOU EVER sat home on the day of a

contest with your models packed and ready to go and

could not because the weather wouldn't permit

outdoor flying? In such a case, either of the models

presented here will provide a "salve" to the builder's

feelings. To steal a phase from the Post Office Dept.,

"neither rain, nor snow . " shall stop the modeler from

flying one of these ships as long as he has a fair sized

room.

The author has done 2 min. 10 sets., in his

parlor, which is very small, with the "E-Z" model.

The advanced model is slightly more critical in its

adjustments and necessitates flying in a larger circle,

and therefore is not perfectly suited for flying in a

very small room.

No one can truthfully say he is an expert

model builder unless he has tried his hand at building

indoor models. The ships presented here are for the

purpose of acquainting the builders with a very

simple indoor model which is built fundamentally the

same as any record job, yet which a builder may make

as his first indoor ship. This job we have called the

"E-Z". We also present a real contest ship built along

the same lines, which we call the "E-X". The "E-X"

should be capable of at least 12 mins. 30 secs.

Our "E-Z" ticked off a consistent 10-1/2

minutes every flight. This time in itself is not so

remarkable but one must take into consideration it

was not built for contest work and the weights were

not watched. The economy of construction is really

amazing with these models as both of them won't cost

you more than thirty cents.

Well let's get down to building it. The "E- Z" is

suggested if you have never built an indoor model and

the "E-X" if you have built one before, or if you want

to built it after finishing the "E-Z" and acquaint your-

self with indoor construction.

PROPELLER, MOTORSTICK, AND WING

FIRST AND MOST IMPORTANT item in an

indoor job is the propeller, for the basis of all high

time and consistency is a light, well balanced,

smooth, efficient prop. If desired, an 8" indoor

machine carved prop may be used but these are hard

to obtain. The best idea is to carve it from a block of

very light balsa 8" by 5/8" by 7/8”.

The block is marked out and cut down to an

"X" blank. Carve the undercamber first on both

blades and then carve the top. The prop is sand ed with

6-0 sandpaper and then finished off with 10-0

sandpaper. The shaft is then glued on. Completed it

should weigh about .004 oz.

For the "E-Z" model a solid stick 1/8" by

1/16" by 8" of very hard balsa is used. The ends are

tapered and sanded and the hook and bearing are

cemented on firmly. A hollow motorstick made of

1/64" sheet sanded, 9/16" in width and wrapped

around a piece of dowel is used on the "E-X". The

ends are capped with 1/64" sheet and the bearing and

hooks glued on.

The indoor wing construction is very

important and is quite different from outdoor types.

The "E- Z" spars are cut from 1/20" sheet and sanded

until it tapers from 1/20" at 8" from the front to 1/32"

at the end. When you take the ruler to cut the spars

you cut so that it tapers the same in the top view. This

is the method that all tapering is done on indoor

models.

Four spars are made this way for the "E-Z",

tapering from 1/20" square at the center to 1/32"

square at the tip. There are four spars to be made for

the "E-Z" but these are made a little differently A

center spar 31/2" long is made by the same method,

tapering from 3/64" by 1/32" at the center to 1/32"

square at the next rib. The wing tip spars are made by

sanding 1/32" sheet at the center to 1/64" and tapering

to 1/32" at the ends. The cut is made to have a spar

1/64" square at the center and 1/32" square at the tip.

For the "E-X" a template must be made of the

wing tip and the spar wrapped around it wet. The "E-

Z" may be laid out without bothering with templates.

The spars are laid directly on the plans and glued to-

gether. Ribs are made by cutting a template of

cardboard or aluminum and placing it on a sheet of

balsa; the size for the "E- Z" ribs is 1/32", and for the

"E-X", 1/64". By moving the template down either

1/32" or 1/64" and cutting along it again, a rib is cut

out. The leading edge of the rib is glued to the spar

and the trailing edge of the rib is cut to fit and then

glued. The wing clips are glued on firmly and you

may use wire or aluminum for the "E-Z" and

aluminum only for the "E-X" to hold the wing to the

motor stick.

wheels for the "E-Z" are made of 1/64" sheet sanded

to 1/100". A small piece of .010 wire is glued to the

struts and a piece of tissue is wrapped around a pin,

glued and cut in half and used as a tube through the

center of the wheel.

Another type of wheel is made of a thin strip

of celluloid about 1/32" wide glued in a circle with a

center brace of 3/64" by 1/32". The paper tube may

also be used here as an axle if desired. The landing

gear is glued to the body about 1-1/2" from the front

and about a 4" tread.

MAKING MICROFILM AND COVERING

IF you have never tried making microfilm don't be

frightened at the thinness of the stuff as microfilm is

really easier to cover with than tissue. If desired a sort

of makeshift microfilm can be made from either dope

or lacquer; made flexible with a few drops of castor

oil. The amount of castor oil is determined by ex-

periment; that is, add a few drops of castor oil to

some dope or lacquer and pour on water. If the stuff

spreads out nicely and after awhile starts to crinkle

around the edges, you will have to add more castor

oil. If you add too much oil you will find eithe r you

can't pick the film up with a hoop of wire or that it

becomes too tacky and sticks to everything it touches.

There are many commercial formulas for

"mike" which will save all this bother. A hoop of wire

is needed. It may be an old clothes hanger bent to

shape or 1/16" galvanized iron wire which can be

obtained anywhere, or 1/8" aluminum wire which is

the best. About 3 inches of water should be run into

either a bathtub, tank or wash basin top. For the be-

ginner, it is best to use cold water as this produces

heavy "mike" which is much easier to handle. The

solution is poured on the water, and after about three

to five minutes of drying, a hoop is placed over the

"mike", the "mike" pushed to the edges of the hoop

and lifted in a semi-circular motion away from you. A

knack of lifting will be acquired with a little

experience.

Probably the best way to cover is to lay the

uncovered parts on an enameled surface and draw a

wet finger around them, leaving them completely

encircled by water. Then wet the frames with saliva

and place back in position. If the hoop of "mike" is

then placed over the parts it will stick to the wet

enameled sur face and to the structure.

Another way is to rest the hoop on four bottles

and, place the frames wet, right on it. The mike is

trimmed with either a hot wire or a brush with

TAIL, AND LANDING GEAR

THE CONSTRUCTION of the tail is very

simple and for the "E-X" much the same as building

the wing, except the spars aren't tapered but are made

of 1/64" square which is made by cutting from 1/64"

sheet balsa. The "E- Z" is just an outline of 1/32"

square. The rudder on the "E- Z" may be made right

on the tail boom which is made like the spars of the

wing. The rudder is first covered and glued to the tail

boom and then both are glued to the side.

The landing gear struts are also made the same

way as the wing spars from tapered sheet balsa. The

acetone or thinner. Dihedral is then put in the wing

and to get the wrinkles out a hot wire is passed

beneath it.

If the ship is made to fly in a small room, it is

advisable to glue the boom on at an angle to give the

model left turn. Assemble the ship and put in about a

10” to 12” loop of 1/32” flat brown rubber. Place the

wing in position so that it glides flat. Put in about 500

turns and launch very gently. All adjustments should

be made with the tail. The “E-Z” should be able to fly

in a very tight circle but the “E-X” may be a little

more difficult to fly in a small place. Make sure the

windows are closed.

THE END

Scanned From July,1942

Flying Aces

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