Thanks Bill,
I appreciate the tips. It sounds like there really isn't a profile to go by at least in the plans.
Hi Larry,
I have read and reread the manual and plans, but can't find any reference regarding the radius of the bend. Section 5 does a good job of explaining how to make the bend, but the manual refers you to the plans for the bend profile.
I haven't started the bend yet, but I'm surprised that you would have the room for a dowel or did you just use it initially to keep the radius from getting too small?
Now is good time for some forward thinking. Check this thread and anything else you can find on the subject of elevator misalignment or twist.
http://www.vansairforce.com/community/showthread.php?t=96921
Any amount of twist in the elevators will not necessarily become apparent to you if you simply follow the plans. What you will end up with is the elevators in trail as per the balance horn positions relative to the stab, you`ll drill the steel control horns off to the control rod as per the manual, but the inboard trailing edges of the elevators will be off quite a bit and it won`t even be mentioned in the plans.
You need to devise a jigging method to ensure the left and right elevators are a matched pair.
The twist can start being built in from the bend in the trailing edge if it is slightly off.
...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.
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!
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.