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Trim tab hinge

Michael Burbidge

Michael Burbidge

Well Known Member
From what I can find, there are no directions on how to install the trim tab hinge. Nothing describing how to match drill the hinge, in terms of dimensions or edge distance of the holes. It looks like from the drawing you just position the hinge snug in between the two spars.

Did I miss some instructions? Or did others just make it look like the drawing?
 
[email protected] said:
From what I can find, there are no directions on how to install the trim tab hinge. Nothing describing how to match drill the hinge, in terms of dimensions or edge distance of the holes. It looks like from the drawing you just position the hinge snug in between the two spars.

Did I miss some instructions? Or did others just make it look like the drawing?
Click to expand...

I seperated the hinge and carefully attached it to the trim tab first. Reassembled the hinge, positioned the tab, clamped the hinge to the elevator, and carefully drilled. Came out good.

Good luck.
 
[email protected] said:
From what I can find, there are no directions on how to install the trim tab hinge. Nothing describing how to match drill the hinge, in terms of dimensions or edge distance of the holes. It looks like from the drawing you just position the hinge snug in between the two spars.

Did I miss some instructions? Or did others just make it look like the drawing?
Click to expand...


You didn't miss anything. The instructions, in my opinion, as the empennage progressed got progressively worse.

You simply disassemble the hinge and clamp both sides to the appropriate area and drill. I called Vans and asked this same question and the guy I spoke to made me feel like a moron for even asking the question.

When a neophyte (as most of us have never built an airplane) is building something that our lives depend on, it isn't too much to ask that a pre punched kit have detailed instructions just for safety sake.

My trim tab came out great. Just wait until you get to the part that has you bend the hinge pin and attach it to the spar. You'll love those instructions and the schematic is a joke.

Still waiting for my 9a wings for over a month now!!!
 
Yep.

First, you want the eyelets of the hinge down so they don't stick up into the slipstream. Assuming you have cut the hinge to length, pull the pin and separate the halves. Clamp the trim tab half in place, with the eyelets exposed forward of the trim tab skin. You can basically just eyeball for straightness by lining up the "cutouts" between eyelets with the edge of the trim tab skin. Clamp it down good, drill and cleco a few holes across the full length to keep it straight, then go back and drill the remaining holes. Repeat the process on the elevator and you will be good to go.

Roger
-9A slow QB
La Grande Oregon
 
Actually the fore-aft positioning of the hinges on both the elevator and trim tab are based on the trailing edges of both aligning with each other. Usually this means drilling one hinge half first and then drilling the second half of hinge wherever necessary to get a consistent trailing edge. Other than that, just follow basic rules of edge distance and rivet pitch and make it up as you go. Good luck.
 
alpinelakespilot2000 said:
Actually the fore-aft positioning of the hinges on both the elevator and trim tab are based on the trailing edges of both aligning with each other. Usually this means drilling one hinge half first and then drilling the second half of hinge wherever necessary to get a consistent trailing edge. Other than that, just follow basic rules of edge distance and rivet pitch and make it up as you go. Good luck.
Click to expand...

Pay attention to what Steve has said! If you don't reassemble the hinge prior to drilling it to the eleveator (or trim tab if you first drilled to the elevator) serious mis-alignment will result! (Not a show stopper but you'd need to order a new hinge section.) Try placing all components in position where you'd like them to be and you'll get a better indication of what you'll need to do to get it just right.
 
Ditto what Fred said!

I disassembled the hinge, riveted one half to the tab, and then reassembled the hinge and lined everything up in a hastily-created jig before drilling the hinge to the elevator.

If you drill the individual parts to the tab and elevator without having them assembled, and they actually fit, you can forget about buying lottery tickets because you've already used up all your luck.
 
Thanks!

Thanks, those last few postings helped. I'm already on my third set of parts for the trim tab. Hopefully I can finish without ordering more!
 
In positioning the assembled trim tab and hinge laterally, don't forget to allow the minimum gap between trim tab left edge and elevator. It's 3/16", if memory serves. That is more important than lining up the right hand edge with the inboard edge of the elevator.

As others have said, fore-aft position is determined by lining up the trailing edge of the trim tab with that of the elevator.

Once positioned and clamped, I just clamped the right hand end of the hinge under the trim spar with an edge clamp cleco and drilled the first hole. I put a cleco in that hole and went on drilling down the line putting clecos in each new hole after it was drilled. There was no need to support the forward half of the hinge under the trim spar, other than with those clecos.

To rivet, just draw the pin and get the trim tab out of the way
 
[email protected] said:
From what I can find, there are no directions on how to install the trim tab hinge. Nothing describing how to match drill the hinge, in terms of dimensions or edge distance of the holes. It looks like from the drawing you just position the hinge snug in between the two spars.

Did I miss some instructions? Or did others just make it look like the drawing?
Click to expand...

I made a template.

I'm building an 8 but will assume the tab goes on similarly on the 9. If that is the case you can follow what I did here and here .
 
Last edited:
docrick said:
You didn't miss anything. The instructions, in my opinion, as the empennage progressed got progressively worse.

When a neophyte (as most of us have never built an airplane) is building something that our lives depend on, it isn't too much to ask that a pre punched kit have detailed instructions just for safety sake.
Click to expand...

Not trying to scare you but the instructions get less and less detailed as you go. I'm working on my fuselage and those instructions say - "find the parts and put them together. Just kidding - but remember what you have learned and keep it fresh, the instructions do omit a lot of what they believe you should already know.
 
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