What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Stupid Trim Tab!

330Jock

Well Known Member
OK guys. Need your opinions! Tried to do everything right: hardwood, carpet tape, big clamps. But it moved a little anyway. The small bends turned out fine, but the trailing edge of inboard side of trim tab moved a little. Is this trash or am I being too critical. Honest opinions of what you would do if this was yours. By the way I've already ordered new parts so you won't hurt my feelings either way.
DSCN0146_zps8f246f6d.jpg

DSCN0147_zps1ccc061a.jpg

DSCN0148_zpsd425c9bd.jpg

DSCN0149_zps4594a569.jpg
 
Last edited by a moderator:
trim tab

Guess it depends on your acceptance level...When building an RV-6 and RV-7, I ended up building two on each project to get the one I liked. Guess I forgot what I had learned on the first project...:eek:
 
Oak Jig

It took me four! - The key was to make the proper jig.

The most important part in this wood jig is where the tip of the trinagle piece stands proud, about 1/8", past the end of the larger piece and is blunt at the end to fit the inside corner. THis allows you to clamp down very very tight without ruining anything else. Once the tab is clamped in i made the bend with a mallet and flush rivet set.

Yours maybe okay, I trashed a couple about like that. I was able to get it perfect once I figured out this jig.


sbpz88.jpg

2v3ft6p.jpg

2qno905.jpg
 
Last edited:
Once you've forced the trailing edge into shape, you can easily file off that little bit of overhang shown in the last two photos.

Dave
 
With so much trouble with these

you would think someone with really good tooling would bend these for folks for 10 or 20 bucks. Allan, here's your new product.

Being finished with the aluminum work on my QB -8, I've found little use for the knowledged gleaned from making that part, other than learning to deal with frustration. I'm thinking that isn't a critical skill. (except of course it makes you an around more skilled and experienced building, but I'd trade that away for this one)
 
Put the Trim Tab in a box, and the replacement parts. Move on.

Come back to the Trim Tab in X years time when you've built the rest. Decide if the rest of the aircraft is so perfectly built that this minor imperfection is the most significant problem - if so, rebuild Trim Tab ;)
 
Put the Trim Tab in a box, and the replacement parts. Move on.

Come back to the Trim Tab in X years time when you've built the rest. Decide if the rest of the aircraft is so perfectly built that this minor imperfection is the most significant problem - if so, rebuild Trim Tab ;)
This is good, practical advice. It may very well be that you'll want to rebuild it. However, there's no need to do it right now. You'll have much better perspective from which to decide after a couple more years of build experience. I wasted too much money on replacement parts (and shipping!) when I could have easily repaired them per AC43.13. Only realized that later as I gained experience. Good luck.
 
Riblet is the way

I just got a couple of extra elevator ribs, cut off the forward portion, cut off the flanges of the trim tab, and constructed the tab similarly to the rest of the elevator. No hitches, and it looks like the rest of the elevator.

Just my choice, never attempted the bending routine.
 
When I finished my tab (for the second time) the EAA tech counselor said it was fine -- and I know it's airworthy, but not perfect. I figure I can build another one later if I don't feel it's up to snuff AFTER building the rest of the plane. Trim tabs are cheap.
 
Trim tab follies

I built two trim tabs. The first, I used blind rivets where I could. Then, after I pro-sealed the ribs in and squeezed them into place using the clamping fixture, I noticed an imperfection. If I angled the finished tab just right, I could see two slight indentations in the skin where the ribs are prosealed. I was apoplectic. I lost sleep. I had trim tab nightmares. I decided I would do another.

So I did. I built another trim tab but this time I used solid rivets and I clamped the ribs more loosely to avoid these unsightly indentations. When I was done, I noticed, INDENTATIONS!!

Now I have two perfectly good trim tabs for my RV-9 and worked another 4-9 hours on a trim tab I will probably never need I somehow damage the first.
 
Back
Top