Help: aileron hinge AN bolt unthreaded

Camillo · #1 04-09-2007, 01:05 PM

Hallo to everybody. I just encountered a big problem.

I'm finishing up my QB wings. I was mounting the aileron bellcrank torquing two of the four AN bolts which attach the aileron bellcrank hinge to the main spar. I set my torque wrench to 110 because bolts arrived at this setting with QB wing kit (I emailed Van's a few months ago complaining of this overtorquing...and they told me to unscrew them and set to the proper torqing values...I just let them there until I needed to assemble the bellcrank I took out bolts and remembered the torquing value). I started torquing and...they begun loose all of a sudden. I think the threading broke. The fact is that I tried unwrenching and they don't come out. I tried with other instruments but...nothing. Now bolts are gone; bolt heads are nearly ruined.

I'm also worried about the platenut threading: if it is unthreaded, too, how would I replace them, since they are UNDER the main spar? Any suggestions?

I hope I was clear. I'm italian and my technical english is bad...

Thank-you.

scard · #2 04-09-2007, 01:13 PM

Yikes. Way over torqued indeed. It does sound like the platenuts are stripped and should be replaced. Us slow build people reached in there to buck the rivets that hold the nose ribs on the main spar. You should be able to get in there to rivet new platenuts.

frankh · #3 04-09-2007, 01:24 PM

Is there a hole in the spar that you can reach through? I thought it was solid??

Anyway if its just the bolt that is stripped (one can hope) take a pair of wire cutters and grip under the bolt head...In other words use the wire cutter blade to put tension on the bolt.

At the same time use a socket wrench to unscrew the bolt...You might get lucky and the remaining thread will re-engage and allow you to unscrew the bolt.

Then try inserting a new bolt and torquing up very gently.

Frank 7a

Camillo · #4 04-09-2007, 02:04 PM

To scard:

No, main spar does not have any hole for rivets. Platenuts are attached to the tie down bar and tiw down bar is attached to spar with bolts. I think I can take out tie down bar simply unscrewing the four bolts, but...I'm not sure that I would be able to mount it again, without enough space to reach that place.

To frankh:

Yes, I hope that bolt is stripped and not platenut. I already tried in your way with a screwdriver and the torque wrench. I will try again with a narrower blade which fits between bolt head and washer.

I regret Van's didn't tell me to careful tighten bolts not more than 50 pound/inch. I thaught manual settings would only a suggestion and that philippines specialist knew their job. Now I know that they overtightened bolts and I...made the same error.

scard · #5 04-09-2007, 02:23 PM

Alright, I'm looking at the plans now. My opinion is that the nutplate should be replaced if this assembly has been over torqued so much as to have stripped anything. If you really have to get a hand in there to get the tie-down bar off or back on, you can remove the tank and reach in there. Otherwise, I would think that you could rig up some kind of arm extension with a wad of duck tape on the end or something to reach in from the wing tip end to the fourth leading edge bay with the tie down bar in it for retrieval after all the bolts are out, or positioning upon reassembly. Then, capture the tie down bar with the tie down bolt hole through the bottom skin for stability while reinstalling the bolts that hold it on.

CraigC · #6 04-09-2007, 02:55 PM

Camillo,

Don't worry about removing the bolt with the torque wrench right now. Just use a regular wrench or socket/ratchet combo to remove it. With a pair of diagonal cutters under what is left of the bolt head turn the bolt to remove it. Once removed use a new longer bolt the same size as the removed one to check the threads on the nutplate. If the nutplate is stripped the new bolt should not start or engage the threads at all.

rv8guy · #7 04-09-2007, 04:38 PM

I would defenitely remove the tank, and check all of the material back there. Easy to get to with he tank off, at least on my antique slow build.

frankh · #8 04-09-2007, 05:54 PM

as long as the bolt torques up without stripping then there is no reason to remove the nut plate.

Basicalliy if the thread is torqued it will not see any additional tension in service...It just a question of did the bolt strip, the platenut or both.

The diagonal cutters (or wire cutters) under the head are much better than just a screwdriver because you can get way more tension on the bolt to start what is left of the threads than you can with just a screwdriver.

If your wintip is removed I bet you can get your tie down in and out with less work than if you removed the tank.

Try this.....Remove all but one of the bolts.....Pass a long piece of electrical wire through one of the top bolt holes from underneath.

pass a whole bunch of wire through into the nose...Reach in from the wing tip with a long stick/hook to grab the other end of the wire

Do the same again through the other top bolt hole.

Have a helper pull the wires taught from the wing tip, now use you hook stick to guide the plate along the length of wires.

To replace...Tie a knot in the middle of each wire that will prevent the knot going through the plate nuts...now pull the wire from underneath and I bet eventually the tie down plate will end up back here it came from.

Worth a try!..

Frank

Camillo · #9 04-10-2007, 04:20 AM

Thank-you to everybody. To Frankh: your technique looks good, but...how would I reinsert four AN bolts which attach tie down to mai spar, since their heads are below the main spar? Tie down has eight bolts: four (heads down) for attaching it to the spar and four (heads up; the ones ruined) for attaching aileron hinges to the spar.

I think that disassembling tank would be better (quicker?).

However, first of all I will remove bolts and check for platenuts threads integrity. Maybe they are all right (but I know Murphy's rule...).

Bye.

godspeed · #10 04-10-2007, 05:39 AM

Pull the tank and install new nutplates and get it over with as soon as
you can do it safe and clean, otherwise you will always wonder about the
threads.. its not worth it.. fix it and move on.. don't torq anything till
you get the torq list for each bolt size and application.. store the tail and wings and get going on the fuse.. if your not sure about the proper
inch pounds then ask on here , I have done this many times and these
guys are awesome helping with that stuff.. just my take on it..
I don't want to worry about these things everytime I am flying along
having a great time..

Danny..