Profile Fuse Warp

Greetings:

What is the best way to get a warp out of a 1/2 inch thick profile fuselage? I'm building a 13-year-old kit bought off eBay. I've completed the fuselage with the motor mounts and plywood doublers and now notice that the fuselage is bowed (slightly); I suppose due to the age. There is no "twist", just a bow so that the tail and engine ends of the fuse are closer to the flyer than is the center of the fuse.

Can I soak the inboard side with water and expect the expansion to remove the warp? Should I soak the whole thing and put it in clamps?

Thanks in advance,

Lawrence Williams
Yorba Linda, CA

I had this problem with a Ringmaster fuselage I also got from *bay. I did the following:

Soaked fuselage overnight in water in the bathtub. Weighted the fuse down with ceramic tile so it sat at the bottom of the tub.

Removed fuse from water and put flat on workbench with bow up. Put one ceramic tile under each end of fuse and stacked enough tile in the middle of the fuse to bow it back the other way. I induced a reverse bow of about 1/8" and let the fuse dry for a week.

When I removed everything the fuse sprang back straight. Good luck.

Thanks for your idea.

I'll give it a try.

Regards,

Larry

>I had this problem with a Ringmaster fuselage I also got
>from *bay. I did the following:
>
>Soaked fuselage overnight in water in the bathtub. Weighted
>the fuse down with ceramic tile so it sat at the bottom of
>the tub.
>
>Removed fuse from water and put flat on workbench with bow
>up. Put one ceramic tile under each end of fuse and stacked
>enough tile in the middle of the fuse to bow it back the
>other way. I induced a reverse bow of about 1/8" and let
>the fuse dry for a week.
>
>When I removed everything the fuse sprang back straight.
>Good luck.

Lawrence Williams
Yorba Linda, CA

Lawrence,

Your best bet would be to cut a new fuselage from a new piece of balsa. You can wet the cupped side and it will probably expand enough to take the warp out. The problem is that it will come back when the balsa dries again. If you wet the whole piece and clamp it over a form to reverse the warp it has now it may work. It might take a lot of time 'til you get it right as it takes 1/2-inch wood a lot longer to dry than the wood used in a wing panel to dry. It may work out OK but I would never trust it. It was probably a bad piece of wood from the beginning.

Other than re-warping it--which more than likely will warp back over time, here is a couple of other fixes for the existing fuse. (if you don't want to make another one)

carefully cut the fuse into to parts--along a straight line from front to back. Depending on the design, you could do this in two places as well--above and below the wing.

Rejoint the two halves adding a piece of 1/32 hard ply in between the halves.

This will add some weight but will be straight. If you want to save the weight, use a piece of carbon fiber. (flat or a rod in a groove also works)

You could also "core out" the fuse and cover it with 1/64 ply a la the mo' best articles on the PAMPA web site.

THis will be the stiffest fuse you are likely to need.

FWIW

Cut yourself out a new fuse, it's about 15 minutes worth of work.

>Cut yourself out a new fuse, it's about 15 minutes worth of
>work.

Cept he already has the motor mounts & doublers glued on. I de-warped the fuselage on a Twister using water and weights and it stayed.

You could also run a 1/4" straight router bit down the center rear of the fuselage to the wing cutout and glue in a piece of 1/4 X 1/2 spruce. This will keep it straight, add stiffness and not much weight.