burnt wing dowels on a H9 ultrastick 60 (Full Version)

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aileron101 -> burnt wing dowels on a H9 ultrastick 60 (5/16/2008 3:58:17 AM)

Hi all,

Has anyone ever run into the problem of the dowells that hold the leading edge of the wing to the fuselage actually getting charred from rubbing on the former? Obviously there must be some vibration going on and the friction is burning the dowells. my guestion is how do I fix it?

Thanks for your time!

Gentle winds and soft landings

Aileron 101



Jim Dines -> RE: burnt wing dowels on a H9 ultrastick 60 (5/16/2008 4:40:03 AM)

One fix is to epoxy a short piece of brass tubing (the size of the dowel) over the dowel and open the hole in the fuse to accept it.



Bob Paris -> RE: burnt wing dowels on a H9 ultrastick 60 (5/16/2008 7:00:22 AM)

Hay Jim,
Your correct, and I've been doing this for years. Look at the enclosed picture...and this is on a .40 size Ultra Stick...and yes, I've stuck a good .61 two stroke on it too. I used brass tubing with an O.D. of .312 . I then go to my drill collection, and pulled out a .312 drill bit, and drilled out the forward bulkhead to fit, and what was needed for this dowl size. I balance my propellers and this helps. If you nick your prop and do not re-balance it...your going to play havick with any thing that has any side play on your airframe or a less then snug fit.
Soft Landings always,
Bobby of Maui



russm -> RE: burnt wing dowels on a H9 ultrastick 60 (5/16/2008 11:33:41 AM)

excellent idea guys. it will work for stressed out dowels on older planes as well.



JimO -> RE: burnt wing dowels on a H9 ultrastick 60 (5/16/2008 5:59:31 PM)

I use aluminum rods in place of the dowels.

JimO



chuck993 -> RE: burnt wing dowels on a H9 ultrastick 60 (5/16/2008 6:29:14 PM)

I've been flying a hanger 9 Ultra Stick 60 almost every weekend...flying it hard...never had that problem



mikekosatka -> RE: burnt wing dowels on a H9 ultrastick 60 (5/16/2008 6:39:08 PM)

How about a photo? I've never seen dowels actually char. Not doubting just would like to see how severe you're talking about.
Mike



Bob Paris -> RE: burnt wing dowels on a H9 ultrastick 60 (5/16/2008 8:18:50 PM)

Hay Mike,
I've never seen charing either, but I have had my dowls ware down and create a lose fit into the forward bulkhead seat hole, for the wing hold down dowl. The only fix I could come up with was to use a brass tube over the dowls...and its been working great for me. I am wondering if some of his exhaust has leaked into the area and maybe created the dark color, or burnt area. It could also mean his wing dowl(s) are hitting his battary if it is up forward under the fuel tank...or hitting the fuel tank itself. I've had this happen before to my own models, but I must agree with you...but I wonder if this was like rubbing two sticks togeather... ? It's interesting to say the least.
Soft Landings always,
Bobby of Maui



aileron101 -> RE: burnt wing dowels on a H9 ultrastick 60 (5/17/2008 5:32:59 AM)

ok guys,

Here is the pic of what I was talking about. I didnt have this problem on the first four flights as I was just getting used to the airplane and kept it pretty mellow till I got it trimmed the way I like it.. What you see in the pic is after about 10 flights of wringing the snot out of the airplane last weekend. I have a Saito 1.25 on it for power and the engine was running kind of rough for a saito until some of my club members helped me get the valves adjusted and tweaked the mixtures last weekend. Now it purrs like a kitten.

In response to some of the earlier posts, the only thing that the dowels can be rubbing on is that bulkhead. the battery and fuel tank don't sit close enough to touch the dowels and they are both wrapped on foam. The engine exhaust exits about 4" below the other side of the fuselage (about 8" away) so it isnt a case of discoloration because of oil. (perhaps if I had some oil on it it wouldnt be developing the friction causing the burning.)

I hadn't thought of the tubing idea. I will have to give that a whirl. It cant hurt. Thanks guys for the solution.

Gentle winds and soft landings,

Aileron101



Bob Paris -> RE: burnt wing dowels on a H9 ultrastick 60 (5/17/2008 8:35:32 AM)

Aileron101,
What you showed in your picture is exactly what I saw on my model's wing dowls. A darker color, on the dowl pins. The brass tubing fix works, and make sure you keep your tolerances close when you drill out the forward bulkhead. I managed only a few flights before I needed to do this fix to my dowl pins. It surprised me that such a will built airframe would have such an issue, with less then ten flights on it, but mine did. Its a great flying model.
Soft Landings always,
Bobby of Maui



Gregor32 -> RE: burnt wing dowels on a H9 ultrastick 60 (5/17/2008 2:05:40 PM)

probabaly just some maring from the bulkhead holes that where laser cut and have a small amount of burning already on them.
greg



JimO -> RE: burnt wing dowels on a H9 ultrastick 60 (5/17/2008 3:34:45 PM)

I had the same thing and did not notice till I had to take the wing off. Was charred about a third of the way through. That is why I went to aluminum rod.

Jim



Ed_Moorman -> RE: burnt wing dowels on a H9 ultrastick 60 (5/17/2008 9:09:56 PM)

I've had 2 60 size and 1 40 size Ultra Stick and all of them had charred dowels until I put brass on the dowels.



rustypep -> RE: burnt wing dowels on a H9 ultrastick 60 (5/18/2008 1:12:22 AM)

I added a doubler behind the dowel plate to firm it up, coated the dowls in CA, and laid some weatherstripping in the wing seat for a firm fit. There was an old thread from a few years back that talked about this issue. Mine is the 40 size and haven't had the issue re-emerge in the last 50+ flights since the fix.



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