Foamy: The $8 Remote Control
Airplane
Ok, so all the little pieces may cost you a bit more, but the airframe will set you
back $7.95. If you are like me, you have RC
components lying around gathering dust. I
wanted to find the fastest, cheapest way to get those items in the air. I would be working with: 05 car motor, small ESC, Cirrus CS-10 micro
servos, GWS R-4P nano-receiver, and various small battery packs. What to put them on? Guillows makes a 4.5 foot wingspan foam glider for
children. It has plug in wings halves and a
snap-on horizontal stab. It was $7.95 at a
local hobby shop. You can probably find it
for less at a big discount store. Use a
soldering iron to make all the cut-outs listed below.
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I started by cutting a small hole in the tail section to hold
two servos. I ran the leads as far forward as
they would go and cut another hole for the receiver.
The receiver was covered over with clear packing tape. |
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Now I needed to add the control surfaces. The horizontal stab
is swept back from the center, so I needed to cut off the stab for a straight trailing
edge. Using clear packing tape as hinges, top
and bottom, I taped 1/16 balsa across the back as an elevator with a 1/16
balsa control horn. Duplicating this whole
setup for the rudder, I then added small steel pushrods hanging out in the wind from the
servos to the surfaces. |
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I put the engine on a pylon with a cut-off plastic prop and
mounted the whole thing above the CG. The ESC
is strapped to the pylon, and I balanced the plane for the battery by making a large hole
just in front of the wing. The common thing
to do would be to place the engine in the nose, but you dont want to do that with
these foam planes because the first time you touch down any harder than a feather floating
to the ground, the foam nose will break off. |
The foam wings are designed to carry about zero load.
All the stuff we have added makes the strength of those wings questionable. Put one or two layers of that same clear packing
tape on the bottom surface of the wings. Tape
the wings to the fuselage, or use white glue to do the same, as the wings have a tendency
to slowly pull loose. Clean up the foam; the
main wing airfoil and tail have almost square leading and trailing edges. Use sanding paper and smooth them to good airfoil
shapes. Add some clear tape to the nose and
underside as a belly skid. Put the stickers
on that came with the plane and you are done.
Off to the field. No problem; the plane
climbs quickly out of my hand and it flies almost hands-off without any trim adjustments. I can get 10 minute flights easily with 600 mah
batteries. Remember not to do any aerobatics
unless you really beef up the wings. They
will flex and bend a lot in normal flight; a loop will snap them easily.
I fly this plane in small parks, the regular RC field, my front yard; wherever the mood
strikes. I have had comments on how quiet it
is; people who would not normally see a RC plane get exposure to the hobby. They love it when I tell them it cost me $8. I am careful to explain that was the plane price
and the startup cost for all the rest of the equipment is a bit more.
Adobe Acrobat version of this file.