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-   -   Rudder Trailing Edge Mistake (https://vansairforce.net/community/showthread.php?t=174706)

burrm 08-27-2019 06:21 PM

Rudder Trailing Edge Mistake
 
I'm at this step on my rudder build:

"Step 8: Put a slight bend in the trailing edge of
the R-1001 Skins so that they will lay down flat
and tight on the R-1006 Trailing Edge after
riveting (see Section 5K)."


Section 5K/5.10 talks about several methods of doing this with this final caution:

"Some tool suppliers sell tools for this purpose, usually two small rollers mounted on a variety of different tools. The edge of the
aluminum sheet is placed between the rollers and a bending pressure is held as the tool is drawn down the edge. Use these with
caution as they may tend to stretch a long edge and make it wavy. Avoid over bending the edge and causing a worse visual effect
than before. Experiment with scrap material first."


So what did I do? Not being comfortable with the hand seamer, etc., like an idiot, I ignored their warning and ordered this thing: https://aircraft-tool.com/shop/detail.aspx?id=AE1042 . Tested on some scrap sheets of same thickness as the skins about 2' long until I thought I had the hang of it, and it seemed to work well.

Well, by now you probably know where this going. After rolling it on one of my rudder skins, I was none too pleased with the results-- sure enough it made the trailing edge wavy as all get out. Looks much worse than before I started. You can see it in the pics below with the two skins laying on top of each other. The top one was rolled, and the bottom one has had nothing done to it.

Lesson learned, but not sure what I should do now. Should I be concerned about this or will it straighten itself out after riveting? Any way to fix it at this point? I thought about clecoing the two skins together or maybe to a solid piece of angle or something and let it sit for a while, but not sure if that would help or not.

Should I consider ordering a new skin? The cost of the skin itself doesn't bother me so much, but the multiple hours invested up to this point in drilling, de-burring, etc. would be frustrating. Even if I did decide to bite the bullet and order a new skin, is it possible to just replace this one skin at this point? How would I match drill it without risking enlarging the holes in the stiffeners and spar? Do I need to scrap those as well and start over?

Thanks in advance for any advice anyone cares to offer, other than the obvious "shouldn't have done that"... I got that part :mad:

-Mike










lr172 08-27-2019 06:33 PM

Never built a taper edge rudder. My emp was completed and QB wings. However, I would make a few backing plates for the prong end to grab on to and put some clecos on it. That should give you a decent idea how it will lay with rivets. I am guessing it will lay out flat. Wave are very gently sloped.

Larry

Lynnb 08-27-2019 06:51 PM

Cleco it to the R-1006 trailing edge and see what it looks like. Once it is clamped to a flat surface and Pro-Sealed in it might not be as bad as you think.

I used the same tool and it works, but isn't real intuitive on how much presure to put on it and such. I was never super happy with the job I did with it, but figured it was more my fault than the tools.

Lynn

jeffwhip 08-27-2019 09:16 PM

I recommend you order two pieces of ALUMINUM ANGLE 6061T6 from AS. You could match drill them to the TE of the rudder. After pro sealing the TE, place one on either side of the TE and either clecko it together or clamp it together. Wait about 5 days and then check it out.

Mudfly 08-28-2019 05:06 AM

I prefer using that edge rolling tool over the vise grip looking one. I too ended up with some waviness the first time I used it. Believe it was the rudder rudder trailing edge..ended up rebuilding it, but not because of the trailing edge. Some other silly reason that I can't even remember.
From my experience, I seem to get better results by starting at the center of the piece and working outboard in each direction. My theory, which could be completely wrong, is that the shorter the distance I have to roll the tool along the edge, the less chance it has to "stretch" the skin. Also, I seem to have better results using the "one and done" technique. Meaning, try and avoid going back over the skin to re-break areas that don't seem to have been broken enough. I move slowly, but consistently along the edge, trying to hold the tool at the same angle, while also maintaining inward pressure to keep the tool from riding out.
Like most things with the project, helps to practice on scrap (which I have plenty of:)) before working with the real part.
I think I would continue with your trailing edge. Maybe use some angle with proseal (or tape) and clecos like mentioned above. When clecoing to the angle, my "technique" is to start in the center of the trailing edge and work outboard skipping a few holes in between on the first pass, then filling all in on the second.
Good luck!

mulde35d 08-28-2019 05:45 AM

Tool
 
In regards to the edge rolling tool I also pondered buying the vise grip version. However, in the end I took a 3?x5? piece of 1? thick Maple (any hardwood will do) and ran my bandsaw blade 1/4? into the long edge. Sanded the sharp corners a bit and simply set the angle and run it down the trailing edge placing a slight bend as I go. Since it doesn?t squeeze the metal it has no waviness when complete. Puts In a nice pre-set IAW the instructions without any marks on the aluminum.

Total cost: $0 (it was scrap wood laying in the corner of the garage)

WingsOnWheels 08-28-2019 05:48 AM

I think you will be fine once everything is assembled. I have the same tool and had the same result, but the TE came out near perfect. As noted before, go down to home depot or a metal supplier and get some aluminum angle. Use it to clamp the TE straight while the Proseal cures.

burrm 08-28-2019 08:18 AM

Thanks everyone for the suggestions. I actually already have some angle pieces already marked with the whole pattern, as I was intending to use that technique for riveting the TE anyway. Just a bit frustrated with the results from using this tool. Seems like I would have been better off not trying to break this at all, let alone with that tool?

Which brings me to the next dilemma-- the other skin. Haven't done anything to it yet, and needless to say I am very reluctant to use this tool on it. Any potential downside to just leaving that one alone?

paul330 08-28-2019 08:14 PM

The tool works fine once you get the hang of it. First, you only need the smallest amount of pressure on the wheels. Secondly, don't let it slip off the edge. Simples .......

jwellman 09-02-2019 02:27 PM

I used the little rollers and my TE came out pretty good. Didn’t know you shouldn’t use them until now...guess I missed that part of the instructions.

When i set the wheels I always adjust the tension until the not forming portion of the wheels just grabs the sheet. This makes for a very light bend in the material. I could certainly see how this could easily be overdone though and cause stretching.

Jared


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