Any last minute tips for wing final installation?

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

tomcostanza said:

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

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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.

ArVeeNiner said:

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

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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.

Mike S said:

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.

Click to expand...

Good catch! Thanks!

Putting some sort of lube on the bolts is a good idea but I also swabbed some in the spar holes. I figured that if you only lubed the bolt, by the time it came through the last part of the hole all the lube sould be gone and that last inch would be dry.

FWIW I used DC33 low temp bearing grease, great stuff for a lot of applications.

Paul Danclovic
Jamestown NC
RV-8A N181SB

I recall that it was difficult to impossible to get a torque wrench on most of the bottom nuts because of the gear towers (maybe a crowfoot wrench would work?). While ideal to torque these, the exact value, if I recall correctly, is not as critical as in other areas, since these bolts are in shear and not tension.

greg

Wings on and torqued

OK, last weekend I got the wings installed with bolts in the holes in about 4 hours.

Today, I got all the nuts installed and everything torqued. Really, it wasn't all that difficult. Now, changing the water pump on our old Plymouth Grand Voyager under a blue tarp in the rain...THAT was miserable!!! (We sold that car a couple of years later after the water pump leaked again!) This was nothing even close to that. The hype was worse than the work. Getting things all set up and started took a little bit of time but the learning curve is steep.

NOTE: Some of what follows doesn't apply to taildraggers.

Here are some of the things I learned from dealing with the bottom 8 bolts (4 per wing):

-I didn't have to make any special tools. Nothing was ground down or welded together. Standard tools worked fine.

-I used white grease on each bolt and never tried the Boelube. Worked great.

-I tried using a rubber mallet to get the bolts in the holes with limited success. Using a block of wood between a hammer and the bolt eventually split the wood. What worked best was at first, LIGHTLY tapping the head of the bolts with a ball peen hammer. You don't damage the bolt if you tap lightly. Make sure you have a wing shaker at the end of the wing.

-After a point, you won't be able to use the hammer anymore because the aileron push tube gets in the way. This is where you use the rivet gun. I once again used it directly on the bolt head. Tap lightly and you won't damage anything.

I used a very short flush rivet set in my gun which made this all possible. I got it at the Arlington Fly-In years ago but it looks like Avery sells something similar. The swivel rivet set that Avery sells won't let you get everything in place. It's too long.

-Like we've already established, you don't want to tap the bolts all the way through the holes. You only want two or three threads showing through the hole. Now, I would venture to say that this only applies to the two larger diameter bolts in the middle and not the two on the end but I played it safe and was very conservative with tapping them in.

-Before you put any bolts in the holes, measure the running torque of the nuts. You are then going to have to measure the running torque of the close tolerance bolts in the holes once they are installed as well. I measured one or two and then used a rough average for the rest. You'll need to add these values to the final torque.

-First thing after installing the front spar bolts (less nuts), install and torque up the rear spar bolts (one each wing) for flight. This will allow you to step on the wing making egress easier.

-Either leave the flaps off or leave them disconnected (at least on the 9A) so you can move a small ladder or step stool closer to the wing. This is easier than stepping on the step many many times.

-I never had to glue the nuts to Popsicle sticks. The hemostat method described below worked great.

-As was mentioned, start with installing and torquing the nuts from the outermost bolt to the innermost bolt. This gives you some room to work.

-Outermost bolts-

Hold the nut with a long pair of hemostats. No need to lock the hemostats.

I used an air ratchet on the head of the bolts to turn them initially.

Hold the nut in place with the hemostat or you can even remove the hemostat and hold the nut in place with a flat bladed screw driver. Once you have the nut held next to the bolt fire up the ratchet. Once you get it started, you might be able to spin the nut on with the screwdriver. I actually was able to get a wobbly, thin walled socket on one of the nuts far enough to hold it while I turned the bolt with the air ratchet.

So, run the nut up, tap the bolt a little further, run it up more, etc. I think I used a screwdriver to hold the nut while I torqued from the bolt head side. Easy.

-Bolts 2 and 3 from the outermost bolts (these are the big bolts)-

Same deal using the hemostats to get the nuts started but I used a regular ratchet with an 11/16 socket to turn the bolt. It takes a while but the nut will start. My air ratchet didn't have enough power to turn the big bolts.

After the nuts started, I was able to spin the nuts on almost all the way using just a flat bladed screwdriver. I think I was able to turn bolt number 3 with the tip of my finger.

Same deal as before, run up, tap the bolts farther using the rivet gun, run the nuts up some more, rinse, repeat.

I kept each nut from turning during torquing by jamming it with a flat bladed screw driver.

NOTE: I assumed the nut on the large bolts used the same size socket as the bolt heads. NOT SO! This caused me a scare with the top bolts. I put the 11/16" socket on one of the top nuts and tried to torque it. That won't work so well since the nut requires a 5/8" socket. You'll swear (literally) that you've stripped the outside of the nut. Well, you did but not enough to render it useless. Just remove the 11/16" socket and replace it with the 5/8" socket and continue torquing.

Bottom line, for the large bolts, use an 11/16" socket for the bolt head and a 5/8" socket for the nut.

-The innermost bolt-

This is another of the small bolts. I was able to install the nut using my fingers. I was also able to turn it with a box end wrench and hold it with that wrench while I torqued it from the bolt side.

-The rest of the bolts that aren't blocked by the gear leg weldment are torqued the standard way from the nut side. They require no special treatment.

-I used a tool bag to transport all the tools in and out of the plane. You're probably going to grab everything including the kitchen sink until you find a winning combination so having them in a single place is a good thing. Plus, it makes you less likely to drop a tool on a newly installed wing.

-Having a knowledgeable helper outside the plane would be a good thing but not necessary. I did all the nut installations solo.

Thanks for all the advice! I literally printed out this post and referenced it as I did the work.

Bottom line, it's not bad at all. Don't sweat it! Good luck!!

Thanks for all the insight! I am not quite to the point of wing install, but I just printed out your post and will reference it when the time comes. Thank goodness for VAF and the wonderful input the members take the time to submit. It has helped so much with my 7A project. Thanks ARVEENINER!
Chad

hesty said:

Thanks for all the insight! I am not quite to the point of wing install, but I just printed out your post and will reference it when the time comes. Thank goodness for VAF and the wonderful input the members take the time to submit. It has helped so much with my 7A project. Thanks ARVEENINER!
Chad

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No problem. I like to share my experiences to make it easier for the next guy. Without VAF, I would have never attempted this airplane building stuff.