What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Bending Trailing Edge of Elevator

CDBridgesRV7A

Active Member
Good Morning All,

I am currently working on my right elevator. Last night I clecoed the right skin to the skeleton. As I was doing that little warning bells were going off in my head but I pressed on. What the warning bells were for was that I have read in other builders logs about bending the trailing edge of the elevators so that they are straight, with no bulges nor run off from the radius. After I finished clecoing the skin on I went back into the house to verify this. Sure enough the 2 logs I went to had this step in there.

Is it OK to bend the trailing edge prior to riveting the skin on, or should it be done now prior to me final drilling the holes on the skin?

Why does Vans not put this step in the build manual? Is it a necessary step in the build process or is it more estetics? As I go through each step of the building process I put a check mark in the box next to each paragraph as I complete that step, so I know I haven't missed this step. I'm more curious than anything about why this is not in the builders plans.

As always, thanks for your advice and input.

Cheers

Chris
 
The trailing edge bend is very critical to prevent cracking at the rear-most stiffener rivets.
First get everything ready to rivet. Last thing to do before riveting to the spar is to make sure that the trailing edge is properly bent so that when the skin is on the structure, it lays naturally on the forward spar with no bulge a the trailing edge. The .016" skins have been on my -6 for over 18 years without a single crack.
 
Thanks Mel,

I'll final drill the holes tonight, then before I rivet thew skin on I'll bend the trailing edge as per some of the other build logs I have read.

That brings me back to my other question, if this is such a critical task, like you said to prevent cracking at the rear most stiffner rivet, why is this step not in the Van's build plans? I just got home from work and re-read the build steps for the right elevator and there is no mention in there about bending the trailing edge. Should it not be included in the build plans?

Cheers

Chris
 
Well, I don't know. My plans were drawn in the late 1980s and I'm pretty sure this was in the manual.
 
Van's describes building a simple bender in the instructions

In my RV-8 instructions, there was a whole paragraph divoted to the need to carefully bend the trailing edge, and how the handling qualities can be adversely affected if this step is skipped. The instructions describe making a simple bender out of a couple of 2x8's and some gate hinges. I did this and it worked pretty well.

One thing about the timing of the bending. If you have the stiffeners already riveted on, and you try to do the bends, the back edges of the stiffeners, even though they have been trimmed at a shallow angle, will limit how far you can bend the skin. If you bend too far, the edges of the stiffeners will imprint into the skin and make little ridges. Ask me how I know. So, my recommendation is to do the bend prior to back-riveting the stiffeners on. It makes the back riveting a little harder, especially getting at that last rivet. But it insures you can get just the bend you need.
 
yep

It is in the directions of my -8 as well, very important. Also if you read all the directions its is mentioned to put a dab of silicone where the stiffeners close together on the aft end. This helps dampen vibration and prevent cracking at the stiffeners. All of the above should be in the build manual, a large write up about it actually. If you don't have those in your manual Van's would be happy to send them to you. What kinda bothers me is that if you don't have that then maybe you didn't get the complete set of manuals and that could cause a lot of problems later in the build.

bird
 
Hey Gang,

I do have that write up in section 5 of my manual. It is actually fig 5-5 and 5-7. What I am saying is why is it not in the step by step process (the same as the bending of the leading edge)? As you can see, I'm not the first person to rivet the stiffners on prior to bending the trailing edge. I would have thought that the plans would have been amended to include the bending step prior to riveting the stiffners on. Just my 2 cents.

Cheers

Chris
 
DISREGARD!!

Found it :eek: It is in the "Trimming the Stiffners" section of the elevator build. Because I only trimmed the right side stiffners I didn't go all the way to the end of that section. Bending the trailing edge is the very last step in the "Trimming the Stiffner" section.

My bad

Chris
 
On mine I back riveted stiffeners, taped a 1/8 in welding rod in the radius, and bent in the 2X6 brake, came out great.
 
Why do I see references to a 1/8” rod? That’s 3mm or a radius of 1/16 much less than the 3/32 radius it should be?
 
Back
Top