Discussion Yak 85inch main wing spar to tight.

[Danny-II]

Hi all

A new plane has landed on my door step today and I have a little (Big) problem as follows.

The main carbon wing rod seems very tight when trying to install the wings onto it.

The rod goes into the hole in the fuse ok. Has anyone else had this problem before.

I feel like if I push to hard, something will break...

For your info if other are interested, it's the 85inch yak from peakmodel.com $361 Aus dollars delivered to the front door in 8 days from China to Tassie (Wahoooo!)

Pics will come later when I start to build it.

Cheers Danny-II

[Siko_Flyer]

My Slick was the same way,per a friend,I put some baby powder on it,rubbed it in,then wiped it off,
wing tube went in much easier.DO NOT leave the baby powder on as I did this first and thought I
would never get the dang thing back out.Also,from what I have been told,DO NOT sand a carbon fiber
wing tube,it will fail.I have no ideal if this is true,nor do I want to find out.I did see in another thread
of sanding the tube inside the wing and fuse by using a homemade round sander,that wouldn't be
too hard to make.After a short period of time,they will loosen up some also.Hope one of these
ideals helps.

[MODE 1]

Talcum powder should be your first attempt to see if it helps the tube slide in the socket easier. If this doesn't work a similar size tube (not the original) with some sand paper glued to the end and used to hone the wing socket out would be my next solution.
Work in stages a little at a time around the sockets inner face and re try the original tube for fit.


LOL Siko posted the same time I did.

Yeah that.s right Siko never sand the CF tube, Scratches in the surface cause weak spots and early failure

[Siko_Flyer]

	Quote: Originally Posted by MODE 1
	Talcum powder should be your first attempt to see if it helps the tube slide in the socket easier. If this doesn't work a similar size tube (not the original) with some sand paper glued to the end and used to hone the wing socket out would be my next solution. Work in stages a little at a time around the sockets inner face and re try the original tube for fit. LOL Siko posted the same time I did. Yeah that.s right Siko never sand the CF tube, Scratches in the surface cause weak spots and early failure

Thanx for the confirmation Mode.How long you think before this turns into an argument over
what brand of powder works best?

[Evenbigger D]

The difference between tight and loose is about 0.005". I spent ages sanding on a 50mm tube to get it to fit and finally it did but the reduction in diameter was almost negligible. If the tube is made properly you will be sanding away resin not fiber and bear in mind the final step in their manufacture is sanding.
One point of interest was how consistent the carbon tube was compared to the aluminum tube I replaced (when measuring with a caliper), the metal tube was all over the place.

[vmceachern]

If you wax the tube first and then powder this works great. Most guys no how to wax their tube pretty well.

[Danny-II]

Thanks all, I will try your ideas and see how it goes.

Rgds Danny-II

[MODE 1]

May or may not be of use to you but I make my own tube sockets up from glass or cardboard tube soaked in thinned resin when ever I have an odd size wing tube that I cant match up.
I find sanding flap wheels reduced to the right size on a long extension, run off a pistol drill on slow speed gives a very uniform finish in diameter and is much faster than hand sanding.

Depending on how the socket is fixed in the wing could give you a problem on the last 1/4" when hand sanding. As this is where I have found the wing tube gets stuck and is difficult to remove the excess material. The flap wheel does a better job of reaching all the way down the socket's length.