VAF Forums

VAF Forums (https://vansairforce.net/community/index.php)
-   RV-7/7A (https://vansairforce.net/community/forumdisplay.php?f=7)
-   -   Elevator Trailing Edge Bend (https://vansairforce.net/community/showthread.php?t=137222)

longranger 04-28-2016 11:00 PM

Quote:

Originally Posted by wirejock (Post 1074524)
...The biggest problem is the reflex on the bending jig. Even 2x6 will bend in the middle. I used at least 5 huge door hinges on mine.

I borrowed the brake a retired carpenter made to bend his RV-7's control surface trailing edges. It uses 2x4s milled flat on the narrow edge, and hinged so that narrow edge does the bending. It works MUCH better that the 2x6 brake per the manual that I used on my RV-4 empennage.


tsw94r 04-29-2016 10:17 AM

I thought about making my brake in the same way, but I made mine as indicated in the manual. So far, I've bent the right elevator about 20 degrees shy of done; going slowly and trying to for a perfect bend.

Thanks to everybody; I picked up quite a few tips.

tswanson 03-04-2018 06:55 AM

Quote:

Originally Posted by wirejock (Post 1074575)
Good point. I made a jig.
Hopefully they're straight. Guess I'll find out eventually.
Two pieces of melamine.
2 each 12"x 24"
1 each 6" x 36"
4 each studs 1/2 wood thread, 1/2 sheet metal thread
4 each wing nuts matching the sheet metal thread
Trace the end rib on one end piece aligned with the center line and more than 6" away from one end.
Clamp the two together.
Cut the "V"
Drill two holes evenly spaced along the 6" line.
Disassemble.
Place the three pieces on the bench.
Match drill the 6" brace through the ends.
Screw the four studs in the holes in the 6" brace.
Slide the uprights over the studs and install a wing nut on each.
One jig done.
Assemble the elevator in the jig.
Hang two plumb bobs from each end.
Shim the bottom of the jig till the bobs are perfect and it's square and straight.


Larry, do you have any pictures of this setup in use? I'm just getting to the step of bending the trailing edges, and I'm coming to the conclusion this is one of those things that I should do myself a favor and make sure I'm prepared to do it correctly the first time.

Thanks!

wirejock 03-04-2018 08:02 AM

Jig or brake
 
Quote:

Originally Posted by tswanson (Post 1243502)
Larry, do you have any pictures of this setup in use? I'm just getting to the step of bending the trailing edges, and I'm coming to the conclusion this is one of those things that I should do myself a favor and make sure I'm prepared to do it correctly the first time.

Thanks!

The parts in the quote are for a jig to build the elevators and ailerons. There are some photos of the jig in use on the "EMPENNAGE" page of my blog.
You mention bending the trailing edge. That would be a bending brake. There's a photo of that too but if I did it again, I would build it as posted before and use the edges of the boards. Look at Miles post #11.

tswanson 03-04-2018 08:03 PM

Quote:

Originally Posted by wirejock (Post 1243516)
The parts in the quote are for a jig to build the elevators and ailerons. There are some photos of the jig in use on the "EMPENNAGE" page of my blog.
You mention bending the trailing edge. That would be a bending brake. There's a photo of that too but if I did it again, I would build it as posted before and use the edges of the boards. Look at Miles post #11.

Ah ok, for some reason that bottom 2x4 was blending into the background for me when I looked at the picture above, so I wasn't sure what I was looking at. The clamps are just handles. All clear now, that looks pretty simple assuming your lumber is flat, smooth, and straight. Thanks.

N329JR 03-05-2018 08:20 AM

Just a quick tip regarding the bending brake construction. I used a length of heavy piano hinge over the full length of the brake instead of multiple door hinges. This provides a really strong consistent bending platform. And as others have indicated... take your time, perform multiple bend iterations and sneak up on the final bend.

az_gila 03-05-2018 09:05 AM

The more detailed :) -6 plans call for a 3/32 typ. radius for the rudder and elevator trailing edge.

BruceW 03-06-2018 12:43 AM

Ha, this brings back memories.
I still have an elevator skin sitting on a hanger shelf from when I somehow ended up with a long-axis 'bow' in the trailing edge. Did something wrong, not sure what now.

I do recall flipping the skin over and back several times while doing the squeeze. That way, if I was doing something wrong or something was slipping, it would balance out on the other side.

It all turned out fine in the end. Only took one throw away skin. :rolleyes:


All times are GMT -6. The time now is 05:54 AM.