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scrockard 10-01-2017 10:18 PM

Installing Wings Notes
For anyone mounting their wings on a RV-9a, this is what worked well for me:
(I wanted to write this up while it's still fresh on my mind)

Inserting the wings (the first time):
I pre-lubed the inside spars with Permatex aluminum style anti-seize so the wing spars slid in easier. Go easy on this stuff because a little bit goes a long way.

I built a table that was to the level of the bottom of the fuselage skin and then used a moving blanket and a fellow builder to teeter totter the wing up and down as it was inserted. The moving blanket was the fulcrum. This arrangement allowed this to be done with the help of only one person while I sat in the cockpit ready to pin the wing. That table also allowed me to work on the wing and even turn it upside down myself after wing removal for its nut plate fitting.

I used drift pins donated from a fellow builder which were turned down to a .003 smaller diameter. These slid easily into the 7/16" bolt holes if everything was aligned properly. Thank you Philip Groelz!
I inserted the top pin first because it was the most accessible. The bottom pin slid in easily when the dihedral on the wing was rather high as compared to the table below. I only pinned one top and one bottom with the .003 smaller pins. That is good enough for the first fitting.

Close tolerance bolts and final wing fitting: I used STP oil treatment on the shank only (keeping it off the threads). This helped a lot with the insertion. Have patience because these close tolerance bolts take time to tap and turn in. (I cheated a little bit here sometimes with an aviation hammer... :) )

Note: the bottom bolts have the washer on the head side and not on the normal nut side. This is because the side that does the turning is the one you protect with the washer. If you put two washers on those bolts, then you just may not get enough threads protruding from the nuts. Follow the plans carefully here.

Don't put in the 1/4" hardware until the AN365-720A nuts are installed in order to have more room down there.

Someone on a different thread said to use a crowsfoot for the bottom bolts. This was a great idea! The crowsfoot would drop into place and lock there as I torqued things into place. It took an extension bit and sometimes a very slight turn on the crowsfoot to get it to release but it did! I could turn the bottom bolt heads with both hands and not worry about the crowsfoot side with was holding the bottom AN365-720A nut nice and snug in there.

I used a 1" diam x 14" long pvc for a lever arm on the wrench handle for the final torque. (37.5-41.7) ft lbs or so and a little wrench handle is just too much force so the the lever arm made this final tightening easy.

I tried using various torque wrenches on the bottom bolts but what worked well was a torque adapter inline with the extension bits and sockets. I also had a nice 100W equivalent LED light shinning on the area for good lighting without generating too much extra heat. I used a small inspection mirror to help align the holes during the wing insertion and pinning process.

I used a combination of multiple extensions and sockets for the AN7 bolts: 6" & 3" extensions, 11/16" sockets of various lengths and a 5/8" crowsfoot. In my case, I had an overall socket, extension and/or torque adapter hardware length stackup of around 8" from bolt head to the wrench. This cleared the aileron push tube well.

Good luck to anyone doing this. It takes some time so you must have patience.

tgmillso 10-02-2017 12:36 AM

Great timing. I'm just this moment about to put those bolts in, so thanks for the additional pointers.

tgmillso 10-02-2017 02:27 AM

Worked a treat. I had the NAS bolts in the freezer for a few hours today in individually sealed zip lock bags (the ones you get small parts from Vans in) with all the air squeezed out so when I pulled them out of the freezer moisture would not start accumulating on the bolt, and only took them out of the bag just before lubricating and putting them in the hole. I lubed with just engine oil as it was all I had available, and they went in fine just tapping them lightly with a one pound hammer, working one at a time as I removed the existing hardware store bolt. The most time consuming thing about the whole ordeal was running the 50 yards back and forth to the freezer.

scrockard 10-02-2017 09:08 AM

I knew about the temperature trick. It seemed more of a bother so I didnt go that route.

The stp lube was passed onto me as a tip from an old school mechanic. The stuff in stp seems to work well because it seems to leave a slippery film. Other lubricants I'm sure will work well too. I felt that since the cad layer was taking a beating, putting some film onto the bolt seemed like a good idea. It also helped a lot when turning the bolt from the head side too.

ALagonia 10-02-2017 09:17 AM

Years ago during an inspection of a Lear 24 that I owned a bolt had to be removed from the T Tail in order to remove the tail. The guys in the shop sprayed the bolt with liquid nitrogen. Bolt came out with absolutely no problem. I stood there watching and was extremely impressed.

wilddog 10-02-2017 01:31 PM

Auto parts stores now carry canned spray on stuff that freezes bolts.

Gizmos 06-02-2018 10:02 PM

Final installation of wings?
Was this going to be final installation of wings before flying? I am to that point of mating my wings but I will have to remove them before I fly, need to move it to the airport. Any suggestions on whatbolts/how many needed to be used to drill the back bolt on rear spar? Is it easy to remove the close tolerance bolts ones installed?

Flying Canuck 06-02-2018 10:38 PM

I sure never want to remove those close tolerance bolts. It took a week to get them in there and getting them out would be nearly impossible. Use hardware store bolts for the first fit and drilling the rear spar. They move quite a bit easier and they line up the same. It also protects your final install bolts, the removal of the hardware store bolts was hard enough on them. You can grind down the threads on the tip to give them a little taper and they go in easily - you'll appreciate having those bolts later when you go to do your final assembly, use them to get the holes lining up before you put the close tolerance bolts it.

Gizmos 06-02-2018 11:18 PM

I will buy some bolts,I am within a week or so on installing wings. I just finished my Kitfox 5 and waiting on paperwork. Need to get DAR for inspection. Thanks for the info

sglynn 08-14-2018 10:15 AM

Wing Bolts - How to get them in
Day 2 and I still can't get any wing bolts in. I have bullet bolts in two large holes on top for alignment. By bullet bolts I just mean a hardware store bolt with the threads cut off and the end tapered. I froze and lubed one 1/4 bolt but it wouldn't go into wing spar. I used rubber hammer and tried rivet gun but it hung up on something.

What other ideas are there for getting the close tolerance bolts to go in?

Should I slightly taper the thread ends of the production bolts to help slide them in?

I'm assuming reamer of any kind is a no no.

I will get an assistant tonight and try wriggling the wing while I insert bolt, but with two large bullet bolts in wouldn't that line up the holes plus prevent much affect from wiggling?

I also used a 22 caliber barrel brush to clean out dust and apply a little lube inside the bolt holes.


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