How to repair stiffeners showing through skin?

Ok, let me elaborate. I bought this tail kit partially completed, the previous builder appears to have done good work (ok, I'm a amateur myself but I don't see anything really wrong) except for a couple little things. The biggest one to me is on the rudder skin, he had forced it closed using clecos before he bent the trailing edge. Because of this every third stiffener has a little mark on the skin, visible from the outside. I was hoping when I bent it, that maybe they'd go away... well I was wrong. Do you think a small padded hammer could massage them down? I really want to polish my bird when she's all done. It doesn't slap you in the face, but it not being right keeps eating away at me.

Here's an example;


Am I just being to anal about this, or what do you think?

Thanks,
Jeff

Could it be the tip of the opposite stiffener poking up. If so, you can't bump them down without trimming the stiffener ends a touch.

I'm thinking that since he didn't have the trailing edge bent at all, when he forced the skin closed the stiffeners were pushing hard into the skin. They resisted hard enough that they put a permanent dent on it. Now that I have the trailing edge bent to shape I can't imagine them touching anymore.

In my opinion, this is very minor. It was common on the early kits for the opposite stiffener to slightly crease the skin WHEN folded. This was a sign of doing the bend "right". The skins where also .016.
However, I agree with you in that this crease is not offset but in line with the end of that stiffener.
I do not believe there is anything you can do. The risk of making it worse far out weighs this minor flaw in my opinion.

Ditto

I agree with Jon, sometimes you will shot yourself in the foot by picking at the small bumps, that will not make a lot of difference. If a good pair of seaming pliers will not roll the edge closed without the two sides coming in contact, you may be asking for more bumps to show up. I have seen a lot of these flows out on the ramp and none have reported any bad effect on flying or life of the item in question.. You can always make another one and get it to come out perfect. But nothing lasts long in a perfect state. Its your call. I would leave it alone and go fly when you get it together, if you don't like it after 100-200 hours, make another. Hope this helps. Yours as always. R.E.A. III #80888

JeffM said:

....The biggest one to me is on the rudder skin, he had forced it closed using clecos before he bent the trailing edge....
Am I just being to anal about this, or what do you think?

Thanks,
Jeff

Click to expand...

The trailing edge of the rudder has to be bent right, if it isn't the aircraft will be unstable in yaw control. It is not difficult to fix as the trailing edge can be bent properly between the stiffeners.

My elevators and ailerons were bent perfectly but for some in explicable reason I did not do it with the rudder. That showed up during flight test with the thing not settling down after kicking the rudder. You could stop the oscillations with rudder pedals but it would not dampen itself.

I would not worry about the slight imperfection of the stiffeners not being trimmed properly, but I would be concerned about the bend.

I'm very pleased with how my bend of the trailing edge turned out, I used the 2" surface of a couple 2x6s with a small gap between and a 1/8 dowel inside the skin for the majority of the bend. That got it 95% of the way, the remaining 5% was done carefully with the seaming pliers.

I have a tendency to want to make things perfect, I just know that sometimes picking away will do more bad than good. I'll heed to your advice and leave it be. Thanks guys.

JeffM said:

I'm very pleased with how my bend of the trailing edge turned out, I used the 2" surface of a couple 2x6s with a small gap between and a 1/8 dowel inside the skin for the majority of the bend. That got it 95% of the way, the remaining 5% was done carefully with the seaming pliers.

I have a tendency to want to make things perfect, I just know that sometimes picking away will do more bad than good. I'll heed to your advice and leave it be. Thanks guys.

Click to expand...

Excellent. Now, what you want to insure is the skin lays flat or nearly so naturally on the spar, with little tension to cleco it in place. After clamping in place lay a straight edge from the spar to the trailing edge. It should lay flat almost all the way to the trailing edge. No bulbous protrusion near the trailing edge.
I would lay odds that yours is perfect.

I haven't put the spar in it yet, hoping to do that tonight. I kept bending until the natural size of the gap was the same size or smaller than the spar (i did the same for the lh elevator). I'm amazed how much it flattened out, looks really good.