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Wing installation after adding seal

Jcurry

Well Known Member
Hi All,
I'm going to be installing my wing root seals soon. I know this has been discussed alot in the past. Someone had mentioned using an expander from northern tool to draw the wings on. I have been unable to locate a pic of this in the previous post. Can someone post a pic please? I don't want to clamp C Clamps to my spar so looking for other options. Thanks
 
Harbour Freight search for tail pipe expander 2 sizes med=1.2 to 2.5 and Lg. 2.5 to 3.5

Thank you. I wasn't sure of what type of expander. I'm worried about damaging the bushings. Has anyone used a hardwood tapered dowel with success?
 
Last edited:
Jack,
I see you’re an A&P, so some of my offerings below may be stating the obvious for you. Still, I’ll share observations from my build in hopes of benefit to you and others, assuming no major design or material changes to the seals since I built 6 years ago. Also, I share your concern about damaging the bushings! I believe I did use a piece of hardwood to gently lever the wing spars into alignment a time or two.

It seems to me in that those seals only serve to fill the gaps and prevent airflow in/out, turbulence and drag at the wing roots. They may also reduce cold drafts on your keister! In my opinion they should be firmly and uniformly (but not too tightly) compressed between the wing skin edges and the fuse skins which are unsupported. We’re not trying to seal a pressure vessel here.

So, before using a LOT of force (such as pipe expanders) to align the wing pins, check a couple of things…(ok 5 things ��)
1- Make sure it’s not something else interfering with proper alignment and seating of the spars. I had some proud wing spar rivets that would hang up against the fuse skins. Took me a while to find ‘em.
2 - make sure the gaps between the wing skins and fuse sides are uniform all around ie top, bottom, leading and trailing edges. Carefully and gradually trim tight spots further as needed.
3 - be sure the seals are placed exactly according to the KAI procedure. The seals have a beveled edge, so a little bit out of position one way or the other makes a difference in how they fit the gaps.
4 - once other obstacles have been eliminated, consider additional trimming on the inboard edges of wing skins if needed rather than applying excessive force to line up the pins. I had to do two iterations of this on my early kit #121.
5 - I used a Scotch Bright wheel on each spar pin to slightly round and polish the edge line where the tip bevel and pin barrel surface intersect.

Note: when all is said and done, it still sometimes requires wiggling at the wingtips, cajoling, light lube, gentle hammer taps and appeals to the dark forces to get the pins fully seated.

Perhaps our friend DBRuth can shed light on how to make it go more smoothly since he is able to get his bird off a trailer and ready to launch pretty darned quick!

Lastly I suppose some sort of caveat/disclaimer is in order…my build was an early one. Many changes and improvements have been incorporated in the kits, materials, and KAI procedures. If any of the above conflicts with current KAI, follow the kit instructions!

All the Best and Merry Christmas!
 
Has anyone used a hardwood tapered dowel with success?

Yes, it works but the expander is better. I use a piece of empty silicone sealant tube cut down to fit as a sleeve inside the bushing to prevent the expander from directly contacting the bushing.
 
Another option is to use nylon Ratchet Tie Down strap(s) from
wingtip to wingtip over the cockpit rails to pull the wings together.
 
I tried everything,then I tried the expander and that solved everything in about 30 seconds, that's the way to go.
 
Jack check out the medium expander in Post #3 That is what I’ve used for years to complete my re-installation after annual.
 
Wing seals

I must confess that I have not installed the wing root seals yet. I was thinking of painting the fuselage before installing them. After seeing the latest service bulletin regarding the seals and the effect on stall characteristics, I will put the seals on soon. Hopefully I can still get the wings on quickly after that.
 
If I needed to install RV12 wings and needed a little extra persuasion, I would make an install pin from aluminum round bar and cut the end at about 45*and round off the sides of the cut and polish.

Push into the bushing that you want to align and rotate till it stops. With a 12inch pipe wrench, rotate the bar 180*and the bushings will be aligned.

This will also work to align engine mounts, using a hardware store bolt and ratchet.
 
The Harbor Freight version is too large you need the small - Small expander 1-1/8" to 1-3/4". Plenty of sellers on Amazon.
 
Before people start using tailpipe expanders, and potentially expanding the brass bushings for the spar pins (vs. helping to align things for inserting the pin into the other hole).. I ran into this exact problem after the plane came out of the paintshop this week..

Before painting, the fit was "snug", and usually one or both spar pins required 1 "medium" tap with a rubber mallet. I could feel the bushings misaligned by about a fingernails width...

After painting and applying the wingroot seals, the misalignment was about 1/8". It was too much even for two guys to overcome by pushing the wing in farther. We decided to leave the wing in place and use it as a template for using an X-Acto knife to create a slice in the seal... so that the wingskin would slide into it. We tried it on one wing, removed and re-inserted the wing.. and the bushings were able to line up "close enough" again to use 1 tap of a mallet.
 
Wing install

Similar to Joe, I use ratchet straps, but around the wing tie down rings. Not though the rings but adjacent to the wing skins where there is less bending moment. And then under the fuse. After a couple of attempts you learn how much to tension the ratchets. And after a dozen goes, the seals take a permanent set, and you don't need so much tension. Has worked for 10 years, and typically only takes two people about 5 minutes to shuggle the wings into place.
 
Before people start using tailpipe expanders, and potentially expanding the brass bushings for the spar pins (vs. helping to align things for inserting the pin into the other hole).. I ran into this exact problem after the plane came out of the paintshop this week..

Before painting, the fit was "snug", and usually one or both spar pins required 1 "medium" tap with a rubber mallet. I could feel the bushings misaligned by about a fingernails width...

After painting and applying the wingroot seals, the misalignment was about 1/8". It was too much even for two guys to overcome by pushing the wing in farther. We decided to leave the wing in place and use it as a template for using an X-Acto knife to create a slice in the seal... so that the wingskin would slide into it. We tried it on one wing, removed and re-inserted the wing.. and the bushings were able to line up "close enough" again to use 1 tap of a mallet.

Excellent problem solving!
 
RV12 Stabilator rubber channel

Does anyone know where to get the rubber channel for the RV12 horizonal stabilator and what gule to use.

Thanks,
Joe
 
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