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"Pillowing" on leading edge of practice kit.

jonbo

Member
After rolling the leading edge, and using the edge forming tool, I couldn't quite find the right way to match drill the front and back rolled edges.

It seemed ok when clecoed, but of course, it got this pillowy look after pull-riveting.

I'm looking for some tips on the best way to get these smooth. I saw an RV 7 at the airport that had a very nice rudder and it looked like the bend had a lip on the inside, so it was curved and then kinda clamped at 90degrees perpendicular to the bend. Is anyone familiar with that technique?

Thanks!
 

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Leading edge

Its under shaped. First break the edge with an edge break tool. The top layer will have a slight bend along the edge so it sits flat after riveting. I usually make the first roll with a smaller diameter pipe. 1/2". Second roll is larger diameter. 3/4. The goal is to get the two seams lay together with very little tension.
 
A few things.
#2 - I introduce a slight bend along the edge of the overlap piece. This helps to stabilize the edge & minimize the pillowing.
#3 - edge was allowed to lift away from the form pipe a bit resulting on the last 1/2" of the surface to not be bent. This is most likely cause of the pillowing.
#4 - the edge kept tight to the pipe during bending so the radius continues right to the edge where it's taped to the pipe. I usually over bent (roll) these edges, than manually spring them back to align the rivet holes, usually results in a more consistent overall shape.
These are the tools I use to bend the overlapping edge.
Hope this helps
 

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Last edited:
Wonderful Leading Edge Bending Demonstration

Ralph,

This is a wonderful example, I've shamelessly copied it to my notes!

Thanks!
Mike
 
There's a good description the edge rolling technique in section 5 of the construction manual (for RV-14, Section 5.9). The key trick is the firmly duct tape the leading edge to the pipe so it takes on the curvature as you bend it.
 

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Using the pipe

I put a couple 'U' bolts over the pipe and through the table. Of course you need to keep some pipe hanging off the side of the table to grab it with a wrench or something.

That really helps getting a consistent bend.
 
I had the hardest time with this on my elevators. I was using 1" OD PVC, but it seems even that might have been to large an OD?

I ended up having some minor pillowing after working on the elevators all day, and just said screw it and added additional blind rivets just to the middle section which ended up looking just fine.
 
Rolling the leading edge

Here's how I did mine.
Two pieces of pipe. 1/2 & 3/4 drill a cross set of holes in both ends for phillips screwdrivers.
Roll of black gorilla tape
Ild shower curtain
Two large J-hooks, nuts, washers. Grind the hook so the control surface can't catch the edge. Mount with double nuts so the height of the hook won't hit the edge.
Run an edge break along the outer edge.
Probably best to roll the inner skin first.
Lay down the shower curtain.
Lay the control surface on top.
Lay down a strip of tape.
Lay the leading edge on top and press firmly.
Clamp the 1/2 pipe down loose so it can rise up as it gets close.
Slide the surface with tape under the pipe and press firmly wrapping the tape around.
Crank both screwdrivers evenly. The surface should slide toward the pipe. Roll till the edge is just past the 90 degree position.
Disasemble and repeat with the 3/4. This time roll as far as the hooks will allow.
 
I had the hardest time with this on my elevators. I was using 1" OD PVC, but it seems even that might have been to large an OD?

I ended up having some minor pillowing after working on the elevators all day, and just said screw it and added additional blind rivets just to the middle section which ended up looking just fine.

Extra rivets, did this also.
 
Rolling the edge

I riveted an old socket inside one end of the pipe and had a friend work the ratchet while I guided the bend. Gave better control and a better result
 
Is a little bit of pillowing a problem?
No one will never see it when installed.
Is there a structural problem? Probably not.
Riven on.
 
As long as the elevator or rudder clears the stabilizer spars, should be OK. If it is an issue, go back & add a rivet to squash it down.
More important would be to get a nice rounded shape there so you don’t have skin rubbing issues with the stabilizer skins on the plane.

On a practice piece… noting your errors, & figuring out the solutions is the point of the exercise.
 
Get more aggressive with the edge forming tool also. As mentioned, it is hidden in the final installation, so having a pretty good edge bend is not a cosmetic issue, but does get the edge to lay down tight.
 
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