Your Opinion on My Trim Tab Gap?

[Captain Sacto]

Hi Folks!

I could use some feedback from the remarkable expertise on this forum.

I'm trying to install the trim tab on the left elevator for my 7A emp.

My bending of the little tabs that make up the ends of the trailing edges was maybe not as close to acceptable as I thought. Here's what I have between the elevator and tab, it's about 3/16 wide, although it varies. Any closer, and I have conflict between the blind rivet heads.



No worries (if you can get past the appearance), except for the inboard end of the trim tab extends beyond the inboard line of the elevator by almost 1/4 of an inch!



I figure that I might be able to trim the inboard of the trim tab down to 3/16 beyond the inboard line of the elevator, but how much is too much?

Alternatively, I'm thinking that I could use a cutoff wheel to remove the bended metal from the elevator (back to where the bend should be), then fashion a small rib to pop rivet in place. One goof with the cutoff wheel, and the elev is toast, however.

Comments and suggetions welcome.

Thanks in advance! Tom Parker in Sacramento

[BuckWynd]

Hi Tom,

Structurally speaking, there's nothing wrong with the dimensions you've achieved. The plans call for a minimum 1/8" gap on the outboard side of the tab, so you're good there. The gap looks fine, and from the first photo it looks like your trailing edges line up nicely.

On the inboard end, it all depends on how bothered you are the alignment. In your second photo (assuming the edge of the elevator skin is aligned under the edge of the ruler), I'd say it would not be worth it to trim the skin and fabricate a rib. IMHO, if you trim about 1/16" off the hinge and the nearby trim-tab skin, the resulting visual line will be so close to the elevator skin edge that no one but you will ever notice. Leave the bend. Press on.

[Captain Sacto]

Buck, excellent info, thanks!

(Love the warbird website, BTW.)

[jsharkey]

Originally Posted by BuckWynd

Hi Tom,

Structurally speaking, there's nothing wrong with the dimensions you've achieved. The plans call for a minimum 1/8" gap on the outboard side of the tab, so you're good there. The gap looks fine, and from the first photo it looks like your trailing edges line up nicely.

On the inboard end, it all depends on how bothered you are the alignment. In your second photo (assuming the edge of the elevator skin is aligned under the edge of the ruler), I'd say it would not be worth it to trim the skin and fabricate a rib. IMHO, if you trim about 1/16" off the hinge and the nearby trim-tab skin, the resulting visual line will be so close to the elevator skin edge that no one but you will ever notice. Leave the bend. Press on.

Also inspectors are looking for gaps that aren't too small - if they are things can bind and hang up when the airframe flexes and vibrates under flight loads. The last thing you need are controls that jam in flight.

It looks good - keep building

[pierre smith]

.....what they said........build on

Regards,