Don Patrick

Don Patrick

Well Known Member
I'm sending an email off to Van's tomorrow to confirm my mistake will result in a new flap skin being ordered, BUT, I'll throw it out to everyone here.

The flap spar needs to be countersunk so that the dimple of #40 skin hole can sit in the spar (stronger joint) and then the flap hinge sits flush on the spar.

I don't have a clue why I started countersinking the SKIN!!! I finished perfect countersinks all the way down the left flap skin on the spar with the hinge in place...then realized what I did...:mad:

So can I rivet countersunk skin to the spar and the flap...I don't think that's going to cut it, or am I wrong? Is the strength compromsied? If I have to buy a new skin, so be it, but what a doofus!!! I still can't believe I did that!

Thanks


Don
 
countersink

How thick is the skin? You probably have a knife edge in the skin. I get a new one if that's the case.
 
skin

Generally speaking, 0.032" is the thinnest sheet you can successfully countersink.
 
I would personally not use a countersunk flap skin.

Remember, the flaps carry more flight loads than any other control surface. They are the only control surface that are pulled down into the airstream and remain there continuously.
 
skin

I find it amazing that you can get a airplane part for that kind of money. Needed a spring to comply with a Monney AD, it was $625.
 
Verdict is in.

I spoke with Scott today at Van's and told him what I had done. He indicated that since the skin was .032" thick, it shouldn't be a problem, with a caveat.

I did ask him about the strength of the joint as the dimpled skin into the countersunk spar should be stronger. He said it was probably negligable and build on.

So there's the word from Van's. Now the caveat. If the countersinks in the .032" skin are not perfect, don't do it. My countersinks are very good and are close to perfect....

I'm ordering a new skin for the peace of mind, it's cheap, and the loads I think are significant when the flaps are down and dirty and the plans provide for a stronger joint.

Thanks for the input!
 
You must log in or register to reply here.