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LH Elevator Stiffeners

Strikefinder

Strikefinder

Member
Hey all,

I was having a very productive day and was in a really good mood...just assembling the skin and substructure on my LH elevator to do some riveting tomorrow when I noticed a note that somehow I hadn't processed earlier...sure enough, looked in the instructions and there's a very clear line that I apparently skipped over...

"Make stiffeners E-720J, E-720K and E-720L from the existing E-720D, E-720E and E-720F (See E-720 Trim Detail and Note 1, DWG 5). Set aside stiffeners for use in the left elevator assembly."

So my problem is...I didn't do that. I cut all the stiffeners from the template just like I'd done before and drilled them, dimpled them, riveted them in, and covered them with RTV before realizing that I'd missed the step of trimming them down.

Everything seemed to fit and I don't notice any issues. I'm going to take a closer look next time I get to the shop, but in the meanwhile...how much did you all trim off of these? Was it a lot? Could I have just accidentally polished them down enough that they're acceptable? Am I guaranteed to end up with a cracked elevator down the road? Any thoughts?
 
Strikefinder said:
Hey all,

I was having a very productive day and was in a really good mood...just assembling the skin and substructure on my LH elevator to do some riveting tomorrow when I noticed a note that somehow I hadn't processed earlier...sure enough, looked in the instructions and there's a very clear line that I apparently skipped over...

"Make stiffeners E-720J, E-720K and E-720L from the existing E-720D, E-720E and E-720F (See E-720 Trim Detail and Note 1, DWG 5). Set aside stiffeners for use in the left elevator assembly."

So my problem is...I didn't do that. I cut all the stiffeners from the template just like I'd done before and drilled them, dimpled them, riveted them in, and covered them with RTV before realizing that I'd missed the step of trimming them down.

Everything seemed to fit and I don't notice any issues. I'm going to take a closer look next time I get to the shop, but in the meanwhile...how much did you all trim off of these? Was it a lot? Could I have just accidentally polished them down enough that they're acceptable? Am I guaranteed to end up with a cracked elevator down the road? Any thoughts?
Click to expand...

If you cut to the template, they are probably fine. Check to see if they clear at The trailing edge and don't interfere with the spar on the forward end. The issue will be if you have enough left to make the second set for the RH Elevator.
 
wirejock said:
If you cut to the template, they are probably fine. Check to see if they clear at The trailing edge and don't interfere with the spar on the forward end. The issue will be if you have enough left to make the second set for the RH Elevator.
Click to expand...

Already riveted the RH elevator, so I'm set there.
 
I had a slightly different issue in the same procedure. You must drill out the last hole in the J K & L stiffeners (aft end) before trimming them in order to get the right length. See Note 2 on the drawing. I failed todo this and had stiffeners - now scrap - that are all 1.5 inches short. BTW $7.50 for new part.
 
If you have the scrap (empennage trim kit bundle) and need to, you can likely remake the stiffeners using an improvised bench brake.
 
tyconnell said:
If you have the scrap (empennage trim kit bundle) and need to, you can likely remake the stiffeners using an improvised bench brake.
Click to expand...

The issue is more the impact to the project to remake them. I think there's a pretty significant risk that in unbending the skin, cleaning out the RTV, and drilling out a few dozen rivets that I'll end up with something that is structurally worse off than what I started with. And to re-do the whole thing is obviously a lot of effort, since I'll need to re-do all the stiffeners, match drilling, dimpling, trim attachment plate, etc.

I didn't have a chance to look at it in detail today but I think I might try to dig out the RTV and see what the clearance is tomorrow. They really didn't look like they fit oddly when installed, so I'm wondering if I didn't compensate for any adjustments without thinking about it...or heck, maybe I made the trim adjustments and just forgot!
 
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