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Rudder Leading Edge Dimension After Rolling

I'm working on rolling the rudder leading edge, and have a couple questions for those who've completed this task. The method I'm using is having a 1/2" black iron pipe run through two wooden blocks clamped to the table. I'm using gorilla tape between the skin and pipe. I'm bending one section at a time, i.e. bending the rudder in three sections. The actual rolling seemed to go well enough, although I am wondering if a slightly larger pipe would have been beneficial (the pipe is a hair under 1" OD).

1: There are two dimensions given in the upper right hand corner of the rudder drawing. The tip dimension is 1 5/8 from the forward side of the spar. Is anyone else able to get this dimension? I'm showing more like 1 7/16 with everything clecoed together. It just doesn't seem possible to get this dimension without creasing near the spar. The lower dimension is closer, but still a little short. This dimension for the LHS elevator I have rolled is much closer.

2: How much pull together is acceptable? The manual says there shouldn't be much preload or you risk cracking the skin at the stiffeners, but how much is normal? Right now I've rolled the edges such that the rivet holes are about 1/4" (or less) from lining up when no force is applied to the skins. It is fairly easy to pull them together to get clecos in. Is this acceptable?

This is by far the most frustrating part of the empennage build for me (granted I skipped the trim tab bending and went right to riblets). I'm admittedly a huge perfectionist, but I feel like this is unnecessarily difficult. It's taken me about 3 hours for the first elevator and about 2 hours for the rudder. The bends aren't perfect either, there is some 'faceting' of the bends in a few spots, particularly at the ends. Nothing a couple more tedious hours of tweaking won't fix.

/Rant

Thanks,

Zach
 
I'm working on rolling the rudder leading edge, and have a couple questions for those who've completed this task. The method I'm using is having a 1/2" black iron pipe run through two wooden blocks clamped to the table. I'm using gorilla tape between the skin and pipe. I'm bending one section at a time, i.e. bending the rudder in three sections. The actual rolling seemed to go well enough, although I am wondering if a slightly larger pipe would have been beneficial (the pipe is a hair under 1" OD).

1: There are two dimensions given in the upper right hand corner of the rudder drawing. The tip dimension is 1 5/8 from the forward side of the spar. Is anyone else able to get this dimension? I'm showing more like 1 7/16 with everything clecoed together. It just doesn't seem possible to get this dimension without creasing near the spar. The lower dimension is closer, but still a little short. This dimension for the LHS elevator I have rolled is much closer.

2: How much pull together is acceptable? The manual says there shouldn't be much preload or you risk cracking the skin at the stiffeners, but how much is normal? Right now I've rolled the edges such that the rivet holes are about 1/4" (or less) from lining up when no force is applied to the skins. It is fairly easy to pull them together to get clecos in. Is this acceptable?

This is by far the most frustrating part of the empennage build for me (granted I skipped the trim tab bending and went right to riblets). I'm admittedly a huge perfectionist, but I feel like this is unnecessarily difficult. It's taken me about 3 hours for the first elevator and about 2 hours for the rudder. The bends aren't perfect either, there is some 'faceting' of the bends in a few spots, particularly at the ends. Nothing a couple more tedious hours of tweaking won't fix.

/Rant

Thanks,

Zach

Honestly I thought those dimensions were rather pointless as the main goal eventually turned into "just get the two halves together and looking good". I had to use two different pipe sizes, a tighter radius towards the edge of the skin and a bigger radius towards the spar. In the end I also put a pretty good break on one of the edges as it was still a little gappy when clecoed. In the end it went together well and the results were quite good, but you are correct in assuming that it is a pain and one of the hardest parts of the empennage! As far as the preload goes I won't say there was a ton but there was a bit on mine, it seemed like nothing I could do would result in little to no preload; I had to squeeze mine together a bit. Finally, I personally found the elevators to be more difficult than the rudder but everyone's mileage may vary on this one.
 
Yes, I believe the elevator was more difficult, but it came out closer to dimension. My hands are still sore from it. Looks like I'll just smooth the bends out a bit and rivet it. I just hope there isn't an excessive gap to the vertical when installed.

Thanks,

Zach
 
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