lostpilot28

lostpilot28

Well Known Member
OK, so in my haste to get my wings mated, I overlooked the fact that lower bolts need washers under the head of the bolt, not the nut. :mad:

Question #1: I've done a search and found numerous ways that folks have removed the lower bolts, but does anyone have a "best idea" to make this job easy? I'm considering buying a soft brass dowl (smaller diameter than the bolts) and using a rivet gun to gently tab the bolts out from the threaded side. Maybe also use a pry-bar under the head of the bolt to assist (fulcrum of wood to protect the center-section. Anyone have a better idea?

Question #2: How does one torque the nuts that are barely accessible because of the gear weldement?

My sincere appreciation for any advise offered!
 
You're not alone

I did the same thing when I mounted my wings a couple of months ago. At least I caught the error before I put in the 4 small bolts.

I called Vans and they said not to worry as long as I put the washers on the forward side to insure that the nuts would not bottom out. I sprayed some LPS-3 under the head of the bolts since you have the turn the bolt head to get them tight.

I torqued mine to the high end of the torque range since I was turning the head and not the nut. It's pretty darn hard even getting a wrench on the nuts, let alone a torque wrench. If I remember correctly, I used a screw driver jammed under one nut on each side 'cause there was no way to get a wrench on the nut.
 
any chance a short wrench would help?

I ended up going to SEARS and getting a SHORTY wrench,.. then grinding off some of the sides,... to get it to fit into the tight fit between fuse and nut,.. of course this is 9A,.. so don't know if or how it would translate for you
 
Leave 'em Be

Sonny,

Don't mess with it. Your nose-dragger mount replaces some need for washers to prevent bottoming of the nut. If all's snug, you'll only risk more damage under the head trying to "correct" it.

John Siebold
 
RV7ator said:
Sonny,

Don't mess with it. Your nose-dragger mount replaces some need for washers to prevent bottoming of the nut. If all's snug, you'll only risk more damage under the head trying to "correct" it.

John Siebold
Click to expand...

Hi John,
Thanks...I have to back them out a little bit, though because I don't have enough room to get the nut on. Doh! I like the idea posted above about lubing under the bolt-head so as not to cause damage to the center section.

Regarding torquing the head of the bolt, should I calculate the drag first? I'm guessing it'll be pretty high.
 
Rick_A said:
I did the same thing when I mounted my wings a couple of months ago. At least I caught the error before I put in the 4 small bolts.

I called Vans and they said not to worry as long as I put the washers on the forward side to insure that the nuts would not bottom out. I sprayed some LPS-3 under the head of the bolts since you have the turn the bolt head to get them tight.

I torqued mine to the high end of the torque range since I was turning the head and not the nut. It's pretty darn hard even getting a wrench on the nuts, let alone a torque wrench. If I remember correctly, I used a screw driver jammed under one nut on each side 'cause there was no way to get a wrench on the nut.
Click to expand...

Thanks, Rick...The 1/4" bolts were definitely a tighter fit on mine. I will have to back them out slightly to get the nut on, but I don't think I'll be taking them all the way out.
 
Ideally, you torque the nut, not the bolt. To torque bolts properly, measure the drag on the bolts without the nuts (or the nuts can be loose). If the nuts don't turn freely, measure the drag on them, too. You will probably need a beam type torque wrench to do this. Add those to the torque spec. I have had nuts showing as much as 15 inch pounds drag, when the spec was less than 30 pounds, so if I just torqued to spec I would only have half the designed torque.
 
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I made this dumb mistake tonight. Forgot the washer under the head of one of the lower bolts. It took about an hour with a wrench turning and pulling at an angle to get it back out. Hopefully I won't make the same mistake again.

Is the one washer sufficient for each bolt? It seems to tighten before bottoming out, but it's hard to be certain considering the bolts are in so tight to begin with.
 
One washer is all that is required... that is on the head side.


Lionclaw said:
I made this dumb mistake tonight. Forgot the washer under the head of one of the lower bolts. It took about an hour with a wrench turning and pulling at an angle to get it back out. Hopefully I won't make the same mistake again.

Is the one washer sufficient for each bolt? It seems to tighten before bottoming out, but it's hard to be certain considering the bolts are in so tight to begin with.
Click to expand...
 
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Those bolts are in shear...

So torque is not super critical. If you are reasonably close, and you have threads showing (smoke and mirrors may be required to see :) then you are good to go.
I also forgot to put the washer under the head. :eek: I concur with RV7ator, trying to remove them is more risk than leaving them alone.
One of my hangar mates (another 7A) has a ground down open end wrench that he let me borrow to hold the nuts. Not easy, but possible.
I super-glued the nuts to a strip of aluminum to hold them in place until the bolt got started in the nut.
 
I don't think you can accurately torque the fastener using the bolt. Subtracting the running torque without a nut helps somewhat, but as the nut tightens during the assembling, the friction will significantly increase from the bolt head. I think a more accurate tensioning will result if you do the following:

Either on another similar fastener or on a mockup assembly (if you cannot get a torque wrench on another fasterner of the same type/diameter, tighten the nut until the nut just contacts the spar or other component. You can determine the running torque of the nut prior to it contacting the surface while you do this. From the contact position, torque the nut to the required torque, adding the running torque to compensate. Lets say you're going to torque to 75 ft-lbs and the nut had a 5 ft-lb running torque. You'd then torque to 80 ft-lbs. Count the number of turns it takes to get from the contact point until you reached your required 80 ft-lbs of torque. Use this number of turns to correctly torque the fasteners that you can't get a torque wrench on.

This method is extremely accurate in properly tensioning the bolts. The major error that can be introduced is that the assembly needs to be properly fitted so that you are not using the initial turns to "compress" the assembly, resulting in a reduced torque on the fastener. To make sure the bolt is properly drawn (bottomed) when you start the count, you can tighten the assembly then loosen the nut and rebottom it prior to counting the turns.

Hope this helps!
 
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