Gregg Brightwell

Gregg Brightwell

Well Known Member
Just taking a poll..... How many -4 builders out there had their horizontal jigged perfectly, yet still ended up with a slight twist at one end or the other after skinning?

I have heard that it is fairly common. Anyone??

Gregg J. Brightwell
Independence, KS
Emp... Complete!
Saving $$ for wings
 
The HS .... :) Mine ended up 100% straight - with the 3rd skin. The problem is the manufacturing process at Van's bending the skin at an offset line not parallel to the trailing edges. This leaves the trailing edges skewed. Trying to make it correct by lining up the trailing edge as per the plans and manual will make the structure twisted because the leading edge bend will no longer be parallell to the aft spar center line.

When I got my last skins, I specifically asked them to pick out the best ones, they were better than the second pair that would not fit no matter how hard I tried, but still off by 1-2/16. The solution is simply to put them on so the leading edge bend is straight, and trim the trailing edges afterward. Also, according to Van's, it is very important to leave the HS in the jig when riveting.
 
mine is twisted a bit

My first HS was twisted pretty bad as a result of the reasons listed above. I rebuilt it and found it STILL had tiwst, although not much...maybe 1 degree at the tip. I dont think it will matter at all so im not going to mess with it.
 
mine has about 1/8 of twist at the tip. it flys straight and fast. i just don't set the elevators neutral at a fly in, i tie it back full up,so nobody can see it.
 
Check this link: http://www.vansairforce.com/community/showthread.php?t=28246&highlight=discostu . Bjornar and I had some discussion of this a while ago.

Here is the excerpt of my comments and a pic from that thread:

When I received my replacement HS skins from Van's, I was disappointed to see that they too were bent incorrectly - however, they weren't as bad as my originals.

http://www.flickr.com/photos/43008524@N00/2233115314/

Eventually, I pulled the skin a bit to make it fit 'close' without twisting the skeleton. I also moved the skin as far outboard as possible to try and get adequate overhang on the short side. For final trimming, this meant I had to file down a LOT of the trailing edge on the other side of the skins (crappy job to do) and even then, one side is slightly shy of the called for overhang.
 
You must log in or register to reply here.