Jig or no jig

wirejock · #1 06-09-2013, 07:19 PM

I am curious how many, if any, built tail feathers on a pre-punched kit without using a jig and were there any problems.
The plans don't mention using one. Given the size and match drilling, maybe it's not necessary.
It's probably too late to ask since the HS, VS & rudder are done. Better late than never.
The rudder ended up with about 1 degree of twist.
I need to check the HS & VS.
I will use one on the wings and fuse for sure.

wjb · #2 06-09-2013, 07:50 PM

I just finished my tail feathers for a 7 without a jig ... like you said, the plans didn't ask for one and it seemed the pre-punched ribs and skins constrain everything tightly ... except for the rudder, it only has two ribs ... tip and base. How did you measure the twist? Reference to a flat surface, or some other way?

blueflyer · #3 06-09-2013, 08:32 PM

no jig for me either

bruceh · #4 06-09-2013, 10:44 PM

The only jig you need, at least on the -9, is something flat to set the trailing edge of the rudder on when you match drill the wedge.

wirejock · #5 06-10-2013, 07:42 AM

Quote:

Originally Posted by wjb

I just finished my tail feathers for a 7 without a jig ... like you said, the plans didn't ask for one and it seemed the pre-punched ribs and skins constrain everything tightly ... except for the rudder, it only has two ribs ... tip and base. How did you measure the twist? Reference to a flat surface, or some other way?

I set the rudder up on my bench trailing edge up with blocks supporting it under the spar.
Then I used a plumb bob to center the root. The plumb bob revealed a tiny twist when moved to the tip end.

Thanks for the responses. I feel better about building on my bench sans jig.

rv9av8tr · #6 06-10-2013, 11:14 AM

Even though I used alum angle to hold the elevator trailing edges straight when I prosealed the wedge, I still ended up with some twist between the two elevators. I'm pretty sure it developed during the riveting of the trailing edge wedge. It was enough that I felt "concerned". Given the building technique, I honestly couldn't see how to ensure building it perfect.

As an engineer you quickly learn nothing is perfect... and that you can always tell a real engineer because we "Measure with a micrometer, mark with a crayon and cut with a chainsaw".

In the end, my airplane only needed a little rudder trim and that was because I found it difficult to establish the offset of the vertical stabilizer.

Do the best you can and build on....

fl-mike · #7 06-10-2013, 03:55 PM

there are a lot of 4's and 6's with a lot more twist that were built in jigs!

I was sure my -4 HS and elevators were perfect...until I mounted the elevators. It looked like the control horns were two legs taking a walk.

I am really liking this CNC punched jig-less -8 kit so far. I'll be interested to see how straight it comes out.

wirejock · #8 06-10-2013, 05:27 PM

Thanks everyone.
I'm going to build more and worry less.

Dave Taylor · #9 06-11-2013, 10:37 AM

But the biggest improvement ? some might call it revolutionary ? in Standard Kits is the introduction of "matched-hole" components. Made possible by advances in tools and techniques, components are now supplied with all the fastener holes punched ?and punched so accurately that the need for assembly jigs is eliminated. When the holes line up, the component must be straight!

http://www.vansaircraft.com/public/kits-standard.htm

Quote:

Originally Posted by wirejock

I am curious how many, if any, built tail feathers on a pre-punched kit without using a jig and were there any problems.
The plans don't mention using one. Given the size and match drilling, maybe it's not necessary.
It's probably too late to ask since the HS, VS & rudder are done. Better late than never.
The rudder ended up with about 1 degree of twist.
I need to check the HS & VS.
I will use one on the wings and fuse for sure.