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Rudder trailing edge suggestions?

F

Flying Scotsman

Well Known Member
Sometime shortly after returning from the Reno Air Races :) I'll be doing the rudder trailing edge. I want a razor-sharp, perfectly straight trailing edge here...any suggestions?

I see in the instructions to use a piece of angle aluminum as a sort of backing material, and match-drill everything including the AA, cleco it together and use fuel tank sealant. So far, so good, that makes sense. What about perhaps using a second piece of angle on the *other side*, to make a sort of "sandwich" to hold the sucker squoze up tight and straight?

And any suggestions to avoid getting a nice straight edge that is twisted with respect to the rest of the airfoil?

Or other tips?
 
IMHO,
Just follow the instructions and it should come out great (mine did). The second Alu angle might help some but you will need some long clecos to get through the both of them and you won't be able to see the prepunched holes. I did a 9A and all trailing edges are done with this technique and it worked just fine.
 
Worked fine for me as well. I don't think there is any need for a second piece of angle. Also, believe it or not, you can actually effect the straightness of the edge as you set the rivets. If you work slowly and evenly, you can tune the final edge by how much you set particular rivets as you go.
 
Use an Aluminum level from Home Depot or Lowes!!

I had no angle so I used what I had. Worked absolutly great. It was an aluminum level from Lowes. Not expensive but perfectly straight. When finished with the gluing of the rudder trailing edge I cleaned all the glue off of my level and it is good as new all be it has a few holes in it now. The trailing edge of the rudder came out perfect. :)
 
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MHO

Contrary to what you may expect the rudder is really a non issue. I personally found it much easier than I?d expected. When finished with mine it was straight arrow but while working it I had developed a technique for working small waves out. I will share it here. Follow the manual closely that step alone should give great if not perfect results. Waves are removed if need be at all by tapping the inside of the cup with the rivet gun not the backside and do it gently with reduced pressure checking progress often. Always use a well supported flat surface to work out any waves this way.
 
Steel strip

My neighbor and I used a length of steel approx 3/8" thick by 2" wide and the full length of the rudder. This was clamped into place and the riveting done. Turned out great.

I further finished mine by block sanding the trailing edge to get it perfectly trued up. Then I taped in 1" from the TE and block sanded the skins to remove any high points. (There were only a couple from poor shots with the rivet gun). This area was cleaned with acetone then a mixture of epoxy and micro filler used to fill the rivets and any other low spots.

The tape was removed and the rudder retaped to 1.25". The micro filler was sanded and blended into the skin. Rage auto body filler was used to touch up any areas necessary.

After getting this perfect I used 1" glass cloth tape and epoxy and sealed the trailing edge. All necesssary filling and sanding was completed. The result is perfect rudder trailing edge that is dead nuts straight and a very clean appearance. The process added roughly 3 hours of work to the process.
 
Rudder Trailing Edge

Steve,



Mine turned out absolutely straight by doing the following:



1) Clecoed the trailing edge to a piece of 1/4" aluminum angel (easy to match drill and stiff enough to keep it straight) 1/8" may be good enough if straight and backed up by a board. Use just one skin to match drill the angle and don't go through both and the V strip at one time or you will get egg shape holes in the bottom.

2) Taped off the trailing edge on the inside surface and scuffed it up good with Scotch Brite where it meets the V strip

3) Cleaned with MEK

4) I epoxied with JB Weld (not too much) and clecoed to the alum angle- Proseal may be better, I just don't know for sure and the JB weld worked so well for me.

5) Let it be for 48 hours (BTW- you will need to clean out the holes before setting with a Qtip dipped in thinner) I was really stiff after it set and never moved while riveting.

6) Mill a flush set to the angle of the trailing edge, I think it is 9 degrees

7) Squeeze riveted the trailing edge starting in the middle and skipping 5-8 holes in both directions and then I came back and added a rivet in the middle of the pattern and then did it again. You get the idea.



This is one of those things that people make a big issue of and I just didn't find it very difficult after setting with the JB Weld and using the angled flush die. I think the curved trailing edge develops when builders over drive the rivets on the trailing edge via bucking and it stretches the metal.



Good luck, take your time and continually check your progress and it will turn out good results. Carl

 
airplanepics031fw5.jpg
I didn't use any glue what so ever and mine turned out perfect. I just used 2 stair steps that I bought at home depot to make the mechanism to crease the trailing edge of the elevators. They are over an inch thick and very straight. Stacked them on top of each other and layed the rudder edge over it with just enough room for the bucking bar to hit the rivets. I didn't use any angle iron but had all the holes clecoed at once. Had a buddy lay his arms along the edge to hold them down tight against the wood. This insured the edge stayed as straight as the board. Just worked every other rivet half way first then finished off with the other ones. Once they were done, went back and final bucked them all. Took 10 minutes and it looks great. I was panicking when I read posts on how to do it and how tough people made it sound. Actually one of the easier parts yet.
 
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Two More Suggestions...

Flying Scotsman said:
Sometime shortly after returning from the Reno Air Races :) I'll be doing the rudder trailing edge. I want a razor-sharp, perfectly straight trailing edge here...any suggestions?

I see in the instructions to use a piece of angle aluminum as a sort of backing material, and match-drill everything including the AA, cleco it together and use fuel tank sealant. So far, so good, that makes sense. What about perhaps using a second piece of angle on the *other side*, to make a sort of "sandwich" to hold the sucker squoze up tight and straight?

And any suggestions to avoid getting a nice straight edge that is twisted with respect to the rest of the airfoil?

Or other tips?
Click to expand...


I only have a couple of things to add ...

1) If you're going to proseal the trailing edge, get a helper! Proseal is a non-issue if you have someone helping you out.

2) The caulk-like tube looks attractive (at least it did to me), but be aware you'll have about ten times as much proseal as you'll need, and you won't be able to use it on anything else. Get the 1oz size from Vans instead.

I too was a bit worried about this, but like most other 'difficult' tasks, it wasn't really that bad...

Good Luck,

Luis
RV7A - SuperSlowBuild(tm) Wings
 
Another suggestion...

I wasn't sure how to get the proseal slathered wedge in without making a big mess or scraping it off trying to slide it in between the skins where they come together. I saw on someone's website (sorry, I can't remember or I'd give credit) a good idea. Tie string through a few rivet holes in the top skin and tie the other end off to something on the ceiling. It holds the skin up just enough to slip the wedge in easily, then you just snip the string and the skin falls into place. Almost no mess in my case.

Still have to rivet, so reading this thread with interest. As usual, there seems to be more than one way to skin this cat...
 
C-J said:
Steve,



Mine turned out absolutely straight by doing the following:



1) Clecoed the trailing edge to a piece of 1/4" aluminum angel (easy to match drill and stiff enough to keep it straight) 1/8" may be good enough if straight and backed up by a board. Use just one skin to match drill the angle and don't go through both and the V strip at one time or you will get egg shape holes in the bottom.

2) Taped off the trailing edge on the inside surface and scuffed it up good with Scotch Brite where it meets the V strip

3) Cleaned with MEK

4) I epoxied with JB Weld (not too much) and clecoed to the alum angle- Proseal may be better, I just don't know for sure and the JB weld worked so well for me.

5) Let it be for 48 hours (BTW- you will need to clean out the holes before setting with a Qtip dipped in thinner) I was really stiff after it set and never moved while riveting.

6) Mill a flush set to the angle of the trailing edge, I think it is 9 degrees

7) Squeeze riveted the trailing edge starting in the middle and skipping 5-8 holes in both directions and then I came back and added a rivet in the middle of the pattern and then did it again. You get the idea.



This is one of those things that people make a big issue of and I just didn't find it very difficult after setting with the JB Weld and using the angled flush die. I think the curved trailing edge develops when builders over drive the rivets on the trailing edge via bucking and it stretches the metal.



Good luck, take your time and continually check your progress and it will turn out good results. Carl

Click to expand...

This sounds like a couple of excellent suggestions. First, drilling only through a single skin into the angle to keep the hole in the AA from oblonging.

Second, and I really like this idea, milling down a flush set and *squeezing* the rivets instead of pounding them. Anyone else try this?

I've got no problem grinding on tools and reshaping them to make a part come out better...
 
txnbuilder said:
The caulk-like tube looks attractive (at least it did to me), but be aware you'll have about ten times as much proseal as you'll need, and you won't be able to use it on anything else. Get the 1oz size from Vans instead.
Click to expand...

Dang! I was swindled into buying the tube from Spruce - the guy at the counter pushed it onto me. Maybe I can still return it and just buy the kind that comes in a can.
 
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