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Re: VT Rib Issue - beware??

Posted: Sat Sep 20, 2014 7:08 am
by Greg Pixley
I think I've found a way to say the VT and for those who have yet to start, I offer the following lessons learned:
1. Use the metal yardstick clamped to your hinge every time you drill a hinge! I learned that too late and may have to redo my rudder.
2. For the VT, I'd adjust the center rib until the lower rib fits flush. Cut the end and rivet a plate to adjust to fit or just build a new one.
3. Use -4 hinges on the VT. They offer more edge distance in case you need to make adjustments or drill a hole slightly off center. -4 fits between the stiffener and the star with plenty of room. I also used about 8" of -4 on the tips of the HT.

With the center rib removed the tail still retained some of its original shape but now I'm left with only about 1/16" gap at the bottom and a 1/32" at the top of the aft spar. I plan on taking that gap out by drilling another -4 hinge.

Greg Pixley

Re: VT Rib Issue - beware??

Posted: Fri Sep 19, 2014 10:33 pm
by Greg Pixley
Dan,

I wish it was as simple as putting the stiffener on the wrong side of the spar but they are IAW plans. I was able to save the photos to a smaller format (less than 256K) so they should post here.

Thanks
Greg

Re: VT Rib Issue - beware??

Posted: Fri Sep 19, 2014 8:23 am
by danweseman
Greg
A 3/16 bow is not acceptable. It sure seems like a stiffener may be on wrong side. Verify the 3/16 stiffener is on aft side of aft spar and forward side of forward. A small amount of tension on the hinge is likley fine but not this much.
Some pics would be great!
Dan

VT Rib Issue - beware??

Posted: Fri Sep 19, 2014 5:56 am
by Greg Pixley
When building the VT I came across an issue I don't know how to resolve. The bottom rib appears to be about 3/16" short! At first I thought I had a spar on the wrong side but they are correct. So instead of asking the question I pressed on, certainly many tail kits have been built before mine! Thinking the skin would define the straight trailing edge, I added the skin. The result is, as one would expect, a bowed rear spar (off by about 1/8").

Here's the hard question; how do I fix this, or do I fix it? Adding a spacer to the rib would have messed up the trailing edge of the skin and change the dimensions of the attach point at the aircraft. I can attach the rudder currently, it just takes some force and once the hinge pin go in, it's there to stay.

Thanks for your help/opinions in advance!
Greg Pixley
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