Any last minute tips for wing final installation on a 9A? (Update)
 

Hi all:

I think I'm going put the wings on for good this weekend. I've been studying the posts and I think I have a pretty good handle on what gotchas I should look out for. This is what I understand:

-Don?t forget to install the 4 each AN4-13A bolts.

-Don?t forget to put washers under the heads of the bottom 4 bolts on each side, and under the nuts of the top 4 bolts.

-Lube each bolt with Boelube or white grease but avoid lube on the threads.

-Tapping the bolts into place using a rivet gun is the ticket. CAREFUL, only put each bolt just far enough in each hole to get the nuts started. Too far and you won?t be able to get the nuts on.

-The bottom nuts are a pain to start. Gluing them to a Popsicle stick helps.

-Using an air ratchet to turn the heads of the bottom bolts while holding the nuts via the Popsicle stick is the bomb.

-The torque value of the close tolerance bolts: ?? bolts: 50-70 in/lbs, 7/16? bolts: 450-500 in/lbs all plus running torque.

-The bottom fasteners must be torqued from the bolt head end due to the inaccessibility of the nuts.

-The close tolerance bolts on the 9A shows the nuts facing forward but any orientation is fine with Vans. Installing per print appears to work fine for most people.

-The rear spar attach bolt is shown installed with 3 washers under the nut and none under the bolt head. Van?s says one washer could go under the head if you want. I like that much better.

-Putting the bolts in the freezer won?t hurt and may make it better. Vans suggested this to me today.

-I thought I read that there is a preferred installation order for the close tolerance bolts but I cannot find it. It had something to do with nut accessibility. Anybody know?

So, what have I forgotten? Are there any more tips that I've missed?

Thanks

lube the spar for insertion...
 

much easier to insert the wing spar after lubricating it with some stick boelube.

Employ a "shaker" :) A person holding the tip of the wing should fine shake it on your signal during spar bolts installation. Really helps to slide those big ones in.

If you want to use cold to shrink the bolts, go buy a block of dry ice, and put it in a box with the bolts in the freezer overnight. If you're going to go "cold", go all the way! (Just did this today on the -3. Did it make a difference? Can't tell you - I've always done it with cold bolts....)

Paul

But...
 

1) If you freeze the bolts before inserting, doesn't that make it impossible to ever remove them?

2) If you can't get the bolts in without freezing them, and you do freeze them, what would you do if you got them 1/2 way in and they warmed-up. Now you can't get them in, and you can't get them out.

In my freshman high school science class, there was a classic experiment with a ball and a ring. Both were on a metal rod. At room temp, it was obvious that the ball count NEVER go through the ring. The teacher put the ball in dry ice, and put the ring in the flame from a bunsen burner for a few seconds. The ball then easily went through the ring. The instructor cautioned that if they got stuck, you could throw them away, because you would never get them apart.

I thought I remember reading somewhere (possibly in the RVator ?) that if you couldn't get the bolts in, it was best to use an adjustable reamer, and ream a few hundred-thousandths. The bolts should need a light tap to insert, but no more.

Understand I'm not challenging anyone. Just asking.

wing installation
 

I recollect that there is some fuselage skin that projects out and under the wing as the wing goes in. I extended this skin with some thin plastic to keep it under the wing skin and not catch the wing as it moves in. You get focused on getting the wing in the right place and this is underneath and you do not want to bend it wondering what the wing is hung up on.

I'm not convinced of the cold bolt theory, but I suppose every bit helps. By my calculation, the difference in a half-inch bolt from room temperature to -346F (temperature of liquid nitrogen, which is what I used) is about 1.5 thousandths of an inch, which is much smaller than the tolerance on "close-tolerance" bolts. And, Tom, no this does not make them impossible to get back out (I had to back them out a bit to remove the gear towers when I converted to tailwheel).

Be careful what wrench you use on the nuts. If you use a box-end wrench on some of them, you may end up with a flying wrench (that is, flying with the airplane!) because they can get trapped between the end of the bolt and the gear tower. I also found that it was easier to get an open-end wrench on (and off) the nuts in the corner if you grind down the wrench a bit.

What Vlad said about someone to move the wing around a bit makes a huge difference in ease of installation.

It is indeed a good idea to have a washer under the bolt heads, as it makes it easier to get them back out if ever required.

Make sure that you have already installed the nutplates for the wing-root fairings, otherwise you will be taking the wings off again!

Congrats on a big step forward!

cheers,
greg

Nope. They're a royal pain to remove regardless whether or not you froze them before installation.

The rivet gun method can be used to remove them too, if you have room/space to get the rivet gun in there at all. A piece of brass or soft steel dowel rod may help you get into the tight spaces to drive the bolt back out.

I've never had to remove an RV's wing bolts, but once helped a friend remove the wing bolts from his Sidewinder and without the rivet gun and some "Mouse Milk" penetrating oil, they never would've come out. It was a slow and difficult process.

Kelly-

Just got my wings on permanently a couple weeks ago.

AC43.13 says using a mallet is OK on close tolerance bolts. FWIW, I found no need to freeze them. A bit of engine oil (per plans) and all but one of 16 went in quite easily with the mallet. The last took a bit more persuasion using light taps of a hammer. If you do tap it with a rivet gun or hammer, use a block of wood or something to protect the bolt head and/or your rivet set. Boelube is a bit thick I would think for these close tolerance bolts.

Also recommend using drift pins in ALL 8 holes per side. My bolts went in much easier after I used drift pins in all holes.

I think I remember reading someone saying they needed to torque each bolt as it was installed, starting from outboard going inboard in order to have enough room to get a wrench on the head or nut. Not sure, but this was NOT an issue with tailwheel versions where you can get a socket on either end.

Remember to rivet those nutplates on the fwd side of the tank attach brackets.

Remember to send a string through your wing conduit, if installed, for future wire additions.

If you need to drill an extra hole through the fuselage at the tank for a EFIS/EMS fuel level sender wire, do it now while you can do it from the outside. That way you can drill it close to the spar carry through and underneath the covers that go over the fuel lines along the front of the spar. (Your options may be different on a 9A, not sure.)

Make sure you've done the fuel tank SB, if applicable, and fit the wing root fairings, including the drilling of the bottom fuselage skin.

Good luck.

Did you mean to give one value in FT/LB, and the other in IN/LB???

50-70 ft/lbs seems like a lot for a 1/4" bolt.

Good luck.