eCombat, started Saturday June
4th ,2005
flier and kept asking me to cut out a
Supermarine Spitfire. I resisted for a long
time but finally relented and this is the
story of making a 32" span eSpitfire for RC
Combat.
About 11:30 on a Saturday Morning Chris
came over with two 2' X 8' sheets of
Owens Corning Foamular 150 foam that
were two inches thick. This is equivalent
to Dow High Load 15. The lower the
number the lighter the density of the
foam. The foam cuts very well.
While waiting for Chirs I made the
carboard templates shown at right to
begin cutting out the planes.
become the wing panels. The blank we used is shown at right. We used this
unusual foam blank shape to fit the elliptical wing of the Spitfire.
If I were doing it over I would have cut a conventional blank shape because the
straight line of the bow produces an airfoil that ends in straight line (duh!!) so it
would have been better to use the wood ailerons only to make the trailing edge
shape.
Shown at right are the first set of wing templates we tried. After cutting the top of
the airfoil in one panel we switched to a wider tip template which worked out well.
We cut the top airfoil wih the templates shown on the top and the bottoms of the
wing with the bottom templates. The Owens Corning Foamular 150 cut beautifully.
Chris is watching the Feather Cut from Tekoa cut a wing panel. The bow shown on
the right is suspended by string from the ceiling. The wires that connect the bow
to the power supply run through a series of weight driven pulleys. You can see
the pulleys on the blue aluminum channel in front of Chris. A weighted bar is
pulling the wires and the bow through the foam. Plans for a similar system can be
found in a link on the main Electric page of this web site. Its quite easy to build
and you will get excellent results using it.
Here we see a completed wing panel with the wing shape marked on it. If you
click on the small photo on the right and view the enlarged photo you can see the
straight line where the true airfoils stops on the rear half of the wing. Chris and I
fretted over the ailerons and the airfoil. Our final solution was to make a large
balsa aileron, that is 1-3/4" wide at its widest point, then we traced it onto the foam
cut away the matching foam. The TE of the foam is quite a bit thicker than the
balsa aileron stop but we will top hinge the ailerons. The bottom of the wing will
look funny but the to will look fine and we will possibly be the envy of all our
friends.
band wing mounting method and I am still thinking mine over. We cut out the
blank, routed a pocket in the fuselage for the receiver and the elevator servo
then used the bandsaw to square up all surfaces and taper the fuselage.
The hardest parts are done and nows its onto shaping and finishing. Stay tuned
we should have finished photos to post shortly.
