Bending Trim Tab

bmurrish · Post by **bmurrish** » Wed Mar 30, 2005 9:10 am

Anybody have any good tips or tricks for bending the side edges of trim tab and elevator skins? Vans talks about making a wedge out of wood a using a rivet gun set on a very low pressure. I have seen a couple done like this and I wouldn't be happy to have them installed on my plane.

ptrotter · Post by **ptrotter** » Wed Mar 30, 2005 9:55 am

I had no problem bending the tabs on the trim tab using the wedge that Van's calls for. I cut it to the exact size needed and used double stick tape to secure it in the tab so it wouldn't slip. It came out fine. The tab in the elevator was another story. After a couple of tries I gave up and cut the tab off and made a small rib which I riveted in with pop rivets. A lot of people do this. If I were to do it again, I wouldn't even try the bend and would cut the tabs off immediately and use the rib.

g_e_young · Post by **g_e_young** » Wed Mar 30, 2005 11:55 am

Did you make the rib out of .o32? Any tips on making this rib? Thx, gy

ptrotter · Post by **ptrotter** » Wed Mar 30, 2005 5:35 pm

Probably .032, I don't remember. I bent it around the wooden wedge I used to bend the tabs on the trim tab. I made it a little longer than necessary and then cut it off at the end to match the desired size.

Dan A · Post by **Dan A** » Wed Mar 30, 2005 9:25 pm

I found a better idea after I had made -----and ruined --- two trim tabs. Cut off the flanges you are supposed to bend down and rivit and make a small rib to rivit in the ends of the trimtab (also the elevator it butts up agaianst). Once it is assembled it looks a great deal better than trying to get a good bend in the tab itself.
Dan

mustang · Post by **mustang** » Thu Mar 31, 2005 3:38 am

Jeez!

I have just bent my second trim tab this evening for a friends "4". Neither of the two that I have built have turned out the way I wanted, that is to say, they are nothing I can be proud of. I wished I had waited until tomorrow to do this and by then I would have read this thread! I suppose I could still simply cut off the messy bends and do the rib thing. I will look at it in the morning and make a decision.

On the "4", I think the root end should be bent, so as to get the strength into the actuator horn attachment area. The outboard end of the tab is the bugbear for me.
Cheers, Pete

captain_john · Post by **captain_john** » Thu Mar 31, 2005 6:20 am

I am "OK" with the way mine came out.

The only gripe I have is that the left side gap is wider at the trailing edge, as you can see.

Basically, the wedges moved as I was forming the bends.

The right side and the elevator bends came out pretty well, I think.

It is a matter of technique, luck and somehow bracing it securely to get a "good" result.

BTW, this was my first attempt. I guess I am lucky!

CJ

728GD · Post by **728GD** » Thu Mar 31, 2005 7:33 pm

When I built mine, I also made up to ends out of scrap. I started with some cardboard and cut and folded until I had a nice fit inside the trim tab. Then I used the cardboard pattern to cut out some .032 and just bent the flanges to 90 deg. I slid it in the trim tab, drilled the rivet holes and used pop rivets. I think I used three pop rivets on the top and bottom flanges for both the left and right side of the tab. I think they look much better than bending the "tabs" over and having a seam in the middle of the ends. Just a thought. It's easy and kind of fun to fab up a couple of pieces yourself.

Remember, if you bend the flap or tab over like Van shows, make sure the top tab is over the bottom one when you rivet. You don't want the bottom skin on the outside. It will catch all kinds of rain water.

Dale

Ron · Post by **Ron** » Wed Apr 27, 2005 1:48 pm

Here is a great way to get a good bend every time. Start with some angle stock and soften up the outside corner edge, then set up as per van's intruction's but put the angles over the wood block's where you will make your bend then clamp down tight. First time every time!! Good luck