Got the wing joined today, glad I had a lot of room in the
garage!!! Used a 1/2 inch plywood center rib between the balsa ribs
to create a "probe" to lock the leading edge to the fuze. I'll put
1/4-20 nylon bolts at the rear edge. Not mentioned in the plans, but
I think I'll beef up the center section a little, seems like it might
be a tad weak, can't see any wood covering in that area. But I'll
have another look at the plans anyway.
Planned separate aileron servos, and two flap servo bays. I'm
hoping to tie the two flaps together and run with one servo in the
wing driving one flap. Really don't want to see any split flaps in
flight. Made the ailerons 26 inches long, and increased the chord 1/2
inch to give the same total area as original plans
Functional wing struts: Looking at that wing, I think I will be
installing functional struts. Looks like I will have to fabricate the
hardware, prob from 1/8" alum, 1/2" wide. Something simple, paperclip
to join and lock for flight. But what wood to make the struts??? I
have poplar, cedar, fir, and oak available, maybe some cherry. I'm
thinking 1/4" thick by 1" wide.
One last comment, I just found out that I can fly from the local
airport, just have to yield to the full scale planes. Guys use the
taxi way parallel to the runway. Mighty long, and very wide. Paved,
with not a tree in sight!
Really appreciate some thoughts on the wood, and any other comments
"Robert Reynolds" wrote>>
Yes, that would work well, but be VERY careful of the grain runout, as many
dowel rods do not have the grain running very parallel with the rod. If
that is the case, it could split and separate, very easily, with the wing
and then the fuselage being returned to a "kit-like" form, very quickly.
Well, I was thinking of Fir with aluminum ends made from Alum
tubing and sheet, but the wire control rods with the metal thingies
would give the strength needed, and the balsa fairing for looks.
Should be easy connect/disconnect too. Think I'll dummy up some
samples and see what they look like. With the epoxy set overnight, I
can get an engine hoist and lift up that wing now that it's joined and
see about attachment points..
That's good advice, especially when you consider how you intend to
attach the end fittings. I cut slots in my dowels and inserted brass
sheet fittings. The brass was epoxied in place, then the end of the
dowel was wrapped with thread and epoxied. I had to make sure the grain
was straight or one of the sides would have flaked off. Now that I'm
thinking about it, I recall making a smaller set of struts using a piece
of threaded rod and a clevis for the end hardware.
You can buy airfoil shaped spruce sticks to use for struts. I had a ton
of them from a buyout deal I made a few years ago, but I sold them all
to a scale builder in Kansas City. I'd rather just make my own struts
out of dowels, not that I do it very often anyway.
I just thought of another way to make functional struts. Make a strut
out of a piece of 1/16" music wire with clevises soldered to the ends
for attachment to the airplane. Sandwich the wire between two pieces of
hard 1/8" x 1" balsa with a little groove carved along the length to
accommodate the wire. Sand the balsa to an airfoil shape. You should
be able to turn out a set in a couple of hours. You could paint them or
cover them with Monokote. I think I like that idea even better than the
My favorite strut attachment point is a piece of phenolic board
protruding from the wing with a little hole drilled in it for the clevis
to attach to. Make it long enough on the inside of the wing to reach
all the way to the top spar. Glue it to the back of the spars like a
shear web. The protruding part can be about a quarter to 3/8" in
diameter with the hole drilled right in the middle. Then put a little
bit of balsa around it for the Monokote to stick to. You could easily
use a quarter inch stick glued to the back of the spar with a little
notch for the phenolic board.
Don't make your fitting from plywood because it will splinter sooner or
later. I can't recommend a source for phenolic board right off the top
of my head. Phenolic is what circuit boards are made of, but what you
want is the raw board without traces, holes or the green solder mask
that gets applied in the electronics factory. I have several pieces
that have been with me for over 15 years. I think I got them from the
tool crib at the aircraft overhaul facility where I used to work. We
used to sharpen one side, wrap the other end with tape, and use them to
scrape paint and gunk from the airplanes.
K&S used to make airfoil shaped aluminum tubing. It was specially for
struts. Use wood in the ends where you put your mounting bolts through.
Great stuff. Check your local hobby shop for it. My LHS has it.
When using these for load bearing structures, be sure to FILL them with some
sort of hardwood sticks. Then make sure your attachment mechanism goes
through the wood.
The aluminum tubes DO fatigue crack. You can ask how I know but I did not
like the answer. It got real exciting and not fun once.
Hobby Lobby used to sell airfoiled hardwood sticks in sets of 2 that worked
very well. I have started going to the local hardwood dealer and buying
spruce sticks (1x1/2) and used a belt sander to airfoil them when the LHS
tried to charge me $8 PER STICK on a build that needed 4 sticks. Now I do
it that way for fun and cheap. The LHS finally figured out their mistake, 2
years too late.
DUH! Missed the stuff in Tower when I looked for end fittings. That
alum streamline tube is just the thing! Next order will include it.
I'm wondering how an aluminum tube is better than a wire through balsa
wood. Aluminum tubing would be very fragile when it comes to ordinary
handling and hangar rash. Also, you have to attach something to the end
of the aluminum, then attach the clevis or other fitting to the end of
the something that you attached to the aluminum. Also, aluminum cracks
easily under flight conditions. I wouldn't bother with it.
I'm not trying to plead my case or anything. I'm just thinking of
practical applications of different materials.
one of these on each end of a long 6-32 threaded rod which runs through the
center of a hollow fiberglass shaft.
Tighten up the ends to put the rod under some tension, and the arrow shaft under
8-32 screw attached to hard points on the bottom of the fuselage and the bottom
of the wing
Brutally strong but UGLY !!
But that's what I did