Pain free trailing edges

[Willja67]

One gripe i have heard from many people is about how difficult it is to get the trailing edges of wings to look good. I always have trouble with this. The only model I have built several times is my own Super Corsair. In addition to not getting the trailing edge nice and strait I always had a twist in the wing as a result of not getting the edges lined up correctly. I finally had enough and thought that there had to be a better way to design the model so this wouldn't be a problem. Well I found a way. It only works for wings without separate control surfaces but it works really good and I thought I'd share.

In a nutshell I detached the aileron and flap from the lower surface of the wing and joined the trailing edges of both. I'll let the attached PDF do the rest of the talking for me.

This is obviously mostly for designers but the ambitious soul who is doing a repaint could use this as well.

[Damraska]

This should work for wings without separate control surfaces and a lot of crazy plumbing. The builder can still skew the wings by misaligning the joint, but the error moves to the wingtip, a relatively easy area to adjust. If the wing slips over the frame, closing the joint in advance is no big deal. If the wing skins need to wrap around the frame and then close, things get a bit more interesting. Applying pressure to perfectly seal the joint could be an issue. Of course, a spar under the joint would give something to push against.

I like the idea.

-Doug

[Leif Ohlsson]

Good thinking! And you could take it one step further by dividing the wing into one forward half, and one backward. Top and bottom joints over the spar (to solve Doug's problem with something to press down on), on a panel line. Separate wingtip as an option. This could save the day for enlargements, and I'll keep it in mind next time I run into trouble enlarging a big wing from 1/33 to 1/16. - L.

[Willja67]

Thanks Leif and Doug.

Originally Posted by Damraska

The builder can still skew the wings by misaligning the joint, but the error moves to the wingtip, a relatively easy area to adjust.
-Doug

I mentioned this in the pdf but not in the text above. Since flaps and ailerons often have different depths chord wise (length from front to back) this creates a natural jog in the joint that simplifies alignment.

My biggest problem with my corsair builds was that I didn't have the trailing edge lined up perfectly and that twisted the wing (wash out or wash in, in aeronautical terms). This technique goes a long way towards eliminating that.

But in any case I'm glad that well respected modelers find it to be a worthwhile idea.

[Damraska]

Originally Posted by Willja67

I mentioned this in the pdf but not in the text above. Since flaps and ailerons often have different depths chord wise (length from front to back) this creates a natural jog in the joint that simplifies alignment.

You are right and definitely do mention this in your .pdf. I was thinking out loud and trying to imagine the technique with different kinds of wings.

Originally Posted by Willja67

My biggest problem with my corsair builds was that I didn't have the trailing edge lined up perfectly and that twisted the wing (wash out or wash in, in aeronautical terms). This technique goes a long way towards eliminating that.

Corsairs are tough. The wing geometry requires multi-piece wing skins. Any misalignment of the skins goofs up the trailing edge, especially the further you get from the root. Having the gear well right where the wing bends complicates everything. I can definitely see where your new technique would help.

Now that I think about it, for a really forgiving wing you could extend the bottom skin back and allow the bottom of the flap and aileron to overlap it.

This would also make a great technique for control surfaces. Long control surfaces, like the ailerons on an He 111, tend to warp. Move the joint to the front and boom, instant straight trailing edge.

-Doug

[Mirco]

Nice idea.
For preprinted kits with no option of rearranging the parts, I would recommend adding a stripe of cardboard with one edge sanded down into the trailing edge:

Works quite well for me:

[Leif Ohlsson]

That is another good idea! I had learned the method with an extra strip of folded paper, for curved areas cut-up with many small cuts:



Your method will accomplish the same thing, but probably better. Will also enhance rigidity greatly.

The beautiful part is that Wilja's method, and yours, are perfectly possible to combine, while the one I learned is not! Such a combination might also help out with the wingtips, right? - L.

[Don Boose]

These are momentous inventions.

Don

[3Turner]

I can see what you mean better in this PDF sample Will....thanks!

Micro's and Leif's methods are great too. I need to try those as well.

[Paperwarrior]

Much appreciated information.
Thanks guys!

Jeff