Installing trim tab

Hi Guys; Does anybody have a good way to install a trim tab? I seem to have a slight warp in my Viking as the inboard wing is flying low when upright. It seems about right inverted, but may need a touch more tip weight also. I have seen tabs on other planes, but have never really looked to see what was done. I thought about cutting a slot in the trailing edge, and gluing in a tab made from clear plastic, bent up slightly, or could it be glued to the bottom of the trailing edge. Thanks for any help.

This is what I did on my Humongus. The anchor is a Goldberg wingtip skid, epoxied into the capstrip & rib. As the Viking doesn't typically have capstrips, you may have to get creative for the anchor. The tab is 3 layers of 1/32", with the center lam being chordwise. I put a couple coats of Minwax PolyCrylic on it. Worked fine, but could have been bigger. Steve

Never mind the tab. What are those crankcases in the background?

Taking the warp out would be better. Use a heat gun on a film-covered wing while twisting it. Pour boiling water on a paper- or silk-and-dope-covered wing while twisting it.

LAST EDITED ON May-02-04 AT 03:46 AM (CDT)
 
As a follow up to Howards suggestion, I have had good success over the years steaming warps out of wings, hold the wing over a steaming kettle and twist it too far (it will spring back a bit), be careful of the hot steam do not sue me if you get burnt! but it does work.

Bazzer

PS best not to build them bent in the first place, as I have just done with my Flite Streak, I have got a span wise bend in the wing ie it has curved diheadral, I have got most of it out so I can progress with the build.

With silkspan and dope or silk and dope, you can also take a towel and soak it with HOT WATER. Wrap it around the wing and twist the warp out. Steam from the towel penetrates the covering and wood very well with this approach. I believe I read that GMA recommended this technique. I used this on a hand me down Sig Acromaster and it worked very well. The warps were pretty severe, but came out nicely with this method.

LAST EDITED ON May-03-04 AT 04:54 PM (CDT)
 
Right, especially if you have four hands and four arms or a very understanding wife. If you do the steam trick, DON'T do it over a stove with flame heat, use an electric stove. Don't even ask me why I know this. Wing, what wing??

An electric stove will also ignite a doped wing.

Surely you have an understanding wife, Ty. I know she's smart enough to insist on doing the pouring, too.

I actually used some aluminum cut from a beer can

Just made a hinge groove and glued it in there. Works great and is simple to adjust.

One less conspicuous way to make a trim tab is to use a piece of trailing edge stock, with the thick part to the rear. Spot glue it under the bottom trailing edge of the wing that flys lower; trim the length until the airplane flys right and then finish the trailing edge stock to blend in with the rest of the wing. Looks much better than something flapping in the breeze.

That's a divergent trailing edge. It was all the rage among aerodynamics guys about ten years ago.

I use those clear plastic index tab holders from hanging files. Cut it in half to get two tabs from each one. Cut a slit in trailing edge and plug it in. Dont glue it right away, you can take it out to trim down to full size.
Allan Perret:)

Thanks to all you guys for your replys. First I tried the boiling towel deal. Like Ty said, it would probably work if you had four arms. Then I installed a tab with two sig easy hinges but was short on room to put the adjustment thingy. Sooo, Next I put the tea kettle on the electric stove and steamed the warp out by wearing heavy gloves. Worked great. Thanks again you guys.

You don't need the towel. The tension in the covering changes as soon as it gets hot. It doesn't have to remain hot. You just hold in the twist until it cools. Extra arms help. I know a guy named Shiva who's particularly good at it.

Aluminum shims cut from beverage cans are a quick and easy route to go held on with two or three 2-56 X 1/4" bolts. Size will depend on the logo on the can as appearance points will suffer if the logo is not intact. My favorites are "Pearl" and "Lone Star" which seem to be the most pleasing to the judges.

An excellent design criterion. Too bad Night Train comes in glass bottles.

>You don't need the towel. The tension in the covering
>changes as soon as it gets hot. It doesn't have to remain
>hot. You just hold in the twist until it cools. Extra arms
>help. I know a guy named Shiva who's particularly good at
>it.

I thought Kali had more arms and Shiva had an extra eye....