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Building Tips and technical articles. => ARF'S => Topic started by: Joseph Lijoi on December 02, 2011, 12:16:35 PM
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I bought a Brodak Pathfinder ARF a few years back. The wing is really warped at the trailing edge. I tried shrinking the covering, twisting the wing etc and just gave up on it. I am willing to remove the covering to get the warp out. On some thread somwhere Brett Buck talked about someone cutting the trailing edge to get the warp out of an ARF wing. He didn't really describe the technique. I can't really picture what he is describing so if anyone knows the specifics please post. Also any other ideas would be appreciated. Thanks.
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Hi Joseph,
I have had luck using ammonia, even Windex (since it contains ammonia), to remove warps on the bare balsa. Block up the wing with the correction a little on the heavy side to account for some reflex of the wood.
I soak the area pretty good then leave it overnight to dry.
Big Bear
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You may also want to call Brodak, they are pretty solid on customer service
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You may also want to call Brodak, they are pretty solid on customer service
Thanks, Mark. I should have thought of that. I bet that Joseph will receive a new wing in less than a week!
Bill
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On some thread somwhere Brett Buck talked about someone cutting the trailing edge to get the warp out of an ARF wing. He didn't really describe the technique. I can't really picture what he is describing so if anyone knows the specifics please post.
That was something Ted and I did for the Strega ARF we put together to be flown by various anonymous pilots at the first ARF-OFF. What I did was take a very long knife and make a horizontal cut right down the middle of the airfoil from about halfway out on the TE to the tip, to about halfway up to the the tip. We ended up with the TE and tip split into top and bottom, and it was pretty easy to twist. I can't recall whether or not we used the very long Exacto carving knife, or one of Shareen's bread knives (which is what I would have used if we were at my house). Then we twisted it straight and dribbled Hot Stuff on the joint to hold it that way. Took about 2 minutes.
Brett
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My second strega had a pretty bad warp in one wing. I tried to get it out by shrinking the covering, and it would not budge, I then heated up the leading edge planking, and the glue apparently let go a bit and the wing straightened out. The fix has lasted over a year, even in the hot Texas sun.
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When using heat from steam to remove a warp, be SURE to use an electric stove or turn of the flames if using a gas stove. Lonnnggg ago, when I tried to remove a warp in a free flight wing, Starduster 350, l was using a gas stove. Pooofff. Wing covering gone. Eyebrows gone, warp, still there. Concentrated on the steam, forgot where the heat to boil the water came from, big DOA. Have to admit, this was the first apartment I had with a gas stove. All the others were electric. Now I am "experienced". LL~ LL~ H^^ FWIW
I did same thing with a Goldberg Hi-Thrust Viking. pooff went the wing tip covering and some of the wood. It happens quick. Heat gun works mucho better. LL~ LL~
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Thanks everyone. Brett......that's real engineering!
I will try to fix it and then give Brodak a call if I am not successful. Thanks again.