Friday, November 27, 2009

Fitting the rear fuselage top skin. - Part2

While my wife toiled away at preparing a great Thanksgiving meal, I worked on my CX4 project. It was time to put the trimmed top skin back on and drill the holes in the stringer. Before I put the skin back on, I marked out the hole locations in the stringer and then drilled them with a #40 drill. This way I could replace the skin and hold it tight to the stringer with the straps and 1"x2" boards, reach up underneath and use the previously drilled holes as guides for drilling the skin. This technique worked great.

Click on image to enlarge

I occassionally drilled a little deeper into the 1"x2" board and used a cleco to temporarily secure things.

One of my concerns leading into drilling these holes was how to secure the stringer where it butts against the forward longeron. If you remember, I chose to do my splice differently than the plans call for. I'm doing this splice from the outside with screws instead of the inside with consunk rivets. So, at this point I have to undo my splice to drill my holes. This means that nothing is holding the two peices together where the stringer butts against the forward longeron. So, I carefully held the stringer and skin in place with a clamp and twisted it inward (because the top skin wants to bow outward) until everything lined up and then drill the first hole nearest my splice and installed a cleco.  I also used a couple of wood clamps after this first hole was drilled to twist everything into alignment. This really wasn't as hard has it sounds. Just take care and drill that first hole carefully. Everything else falls into place after that.

So, once all the holes are drilled, you can remove the clecos from the underside, loosen the straps and clamps carefully and install clecos on the outside. It is one of those times you can look at your project and see that you have accomplished something of significance.

By this time, the turkey was done and I had one more thing to be thankful for!

1 comment:

  1. Wow Doug you are moving along. Really starting to look like a plane now. I bet you can not wait till you can get it on the gear. Got a question for you. The splice joint you have on the outside. Dont you want to put it on the inside to keep the lines clean or is there a structural reason for the change. Just curious looks like you will need to take it off again to install the side skins. Just a thought