wrung out my ultra stick 40 last nite-got pretty wild with it (plane only has maybe 10 flights on it, tame ones until the 2 tonite)-after removing wing, I noticed the dowels looked burned on top with about 1/32 inch deep groove in them-also, the holes in the bulkhead the dowels fit in to looked a little wallowed out-my hold down screws were tight-any idea what is causing this and what to do to fix it before the wing leaves me? Running an mds 58 on it (please, no mds flames!! Thanks, Mike.

Precisely the reason I don't like the dowel method. Put a piece of aluminum arrow shaft or a piece of brass tubing over the dowels and epoxy in place. I countersink the arrow shaft into the leading edge to add more strength as well. Wood to wood will burn when rubbed together fast (vibration and twisting of the fuselage)......

Very interesting, I saw the same thing but didn't realize it was the wood to wood vibration. I thought it was just the stress of the type of flying I was doing :surprised

On mine the bulk head that has the holes also started coming loose.

To fix both problems I used fiberglass cloth and epoxy over the top of the fuse down over the bulk head and over the dowel holes. I then cut an "X" in the cloth where the holes are and folded the tabs into the hole and soaked with epoxy to reinforce the hole and help fill in where it had been widened. I also used wood shavings to help fill in the hole.

I think it's starting to wear again now. Guess I need to try the metal around the dowels!

Thanks for the tip furloughed ual.

Keith

mine did the same, burnt half way thru dowels b4 i removed wing and realized it.
chris

I had the same problem, I glued a piece of spruce to the other side of the former with the dowel holes to quadruple the thickness and drilled the holes through, gave the dowels a coat of thin CA to harden them and put foam wing saddle tape on the saddle to stop movement. 40 flights since then,no more problem. I think that former is too thin.


JJ

Same problem. I too just added a piece of ply to the back side of the former and drilled the holes thru. No more problems

Mine were half-way through when I noticed the problem...replaced the former with a real thick piece of hardwood, and replaced the dowels with some 3/8 ceramic dowels.

You know that "howl" the plane makes at speed ? I think that has something to do with it.

Dave

My US60 makes that sound on the GROUND! WOW... so that's what it is.

I've friggin looked all over the place for a certain sound my plane makes on the ground, only at a high idle.... at just a certain rpm, the vibration's just right to induce this vibration.

Ugh. Guess I'm going to be working on a metal fitting myself.

I love that Ultra Stik Whooooosh. I'm pretty sure it helps me fly her.

JJ

Making the bulkhead that the dowels go through thicker and hardening with CA will help, and I also do this on my planes, but to stop the burning, you need to get wood off wood under the vibration and twisting of flight loads. This is especially evident on planes that have a relatively flexible nose....

On my planes that have exhibited frictional burning of the wing dowels (and that IS what caused it!), I always just found some brass tubing that was a slip fit over the dowels, and like the one post said, counter sunk them into the leading edge of the wing a good .25 to .5 inch before glueing them over the dowel. Obviously, I then had to open up the holes ever so slightly in the bulkhead that receives the dowels, but that has always stopped the problem for me. Don't know if it is a case of the brass being harder/smoother that stops the friction, or that it can conduct any heat generated away fron the pressure point. What ever it is, it does the trick! Oh, and as to how to counter sink the tubing over the original dowel into the wing? I just took a length of the brass tube and using a triangle file, worked on the end or the tube to make a toothed "core barrel" type drill bit out of it. With this piece chucked into a drill (low speed please!) I can carefully slide it down over the wing dowel and cut a very clean and neat hole AROUND the dowl that will then accept the brass sleve perfectly!

Lee

When I run into the dowel burning problem, I slightly enlarge the dowel holes in the fuse and install heat-shrink tubing on each dowel.

If any wear is noticed on the heat-shrink after a while, it is simple to slice it off and shrink on another piece.

Great idea Crash and burn.......simple and easy.....thats what I like!

I took some advice from a couple of your posts-reinforced bulkhead with lite ply-epoxied in, filled in grooves in dowels and used heat shrink over them. Maybe try it this weekend-thanks for the help! By the way, I emailed Horizon support-this is what they said (I cut and pasted this post to their support form):::

quote:
Dear Mike,

You can take some CA to the dowels and then smooth them out, make sure there
is a nice tight fit w/the bulkhead after that. I hope we have answered all
of your questions. If you have any further problems, feel free to call us
here at Horizon at 1-877-504-0233.

Thank you,
Horizon Product Support


Great help, huh!?
Thanks again, Mike.

I think you might be onto something with the "flexible nose" theory....

Iv'e busted two stock engine mounts in about 20 flights. K&B .61 engine....

Are the busted mounts, and the wing dowel problems related ?

I had two muffler header pipes break due to vibration on my US40 (OS 70 FS). I finally braced the muffler to help prevent the third one from breaking.

I've also noticed that when the wing is off the plane if you simply talk loud close to it, it resonates from your voice. Also, if you slightly bump the wing it makes a loud drum sound. Maybe this has something to do with the vibration that is "burning" the dowels.

Keith