Elevator Trailing Edge Bend

tsw94r · #1 04-28-2016, 05:45 AM

Hello All,

I'm ready to make the final bend on the elevators. The instructions tell you to follow the profile on the plans, but I can't find the profile to save my life.

I understand how to make the bend, just not what the trailing edge should look like when I'm done.

Tom

wjb · #2 04-28-2016, 07:35 AM

The closest thing I found was Dwg 4 zone G-10, which shows a end view of the elevator.

The skin needs to be bent down so both sides touch the spar. I followed the suggestions in the aileron section to make the surface up to the final bend as flat as I could .. use a straight edge from leading edge to trailing edge and check for a concave or convex profile and adjust to make surfaces a flat as you can.

Also, before bending, double check your stiffeners to be sure they won't interfere with each other or the opposite surface when the skin is in its final shape.

Go slow, too. IIMC, it took quite a few pressings to get it just right. Overall, its not a hard op.

tsw94r · #3 04-28-2016, 10:03 AM

Thanks Bill,

I appreciate the tips. It sounds like there really isn't a profile to go by at least in the plans.

wirejock · #4 04-28-2016, 10:12 AM

Quote:

Originally Posted by tsw94r

Thanks Bill,

I appreciate the tips. It sounds like there really isn't a profile to go by at least in the plans.

There's some info in Chapter 5. Vans is pretty specific about getting a straight, flat surface up to the bend. I believe the radius is also called out. I used a dowell inside the bend then fine tuned the final bend without it.

tsw94r · #5 04-28-2016, 10:59 AM

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?

bret · #6 04-28-2016, 01:11 PM

I used an 1/8" welding rod.

wirejock · #7 04-28-2016, 02:53 PM

Quote:

Originally Posted by tsw94r

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?

I knew you would call me out!

Sorry, I can't find it. Maybe it was a VAF tip, but according to my log, I used a 3/16" dowel.
I used a strip of Gorilla tape to keep it from slipping out. After the initial squeeze, it was removed to allow the skins to bend past the final dimension. They reflex so you actually end up bending slightly more than the final angle. 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.

N329JR · #8 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.