Coviper

Coviper

Active Member
I began installing the landing gear mounts in my 9A this morning. Everything went well, but I have a question for those of you who have already done this. The bolts that go to the wing carry-though bulkhead (F-904) and though the thick alum bar are called out as -12A. I torqued these properly, but the threads just barely come out to the edge of the lock nuts. I thought you should see at least a couple of threads on a tight bolt. Has anyone else noticed this and is it OK to leave it as is, or should I be using a longer bolt? :confused:
 
Coviper said:
I began installing the landing gear mounts in my 9A this morning. Everything went well, but I have a question for those of you who have already done this. The bolts that go to the wing carry-though bulkhead (F-904) and though the thick alum bar are called out as -12A. I torqued these properly, but the threads just barely come out to the edge of the lock nuts. I thought you should see at least a couple of threads on a tight bolt. Has anyone else noticed this and is it OK to leave it as is, or should I be using a longer bolt? :confused:
Click to expand...

I know that my DAR preferred to see a couple of threads, so I changed the bolt. However, it was actually a RV6A and the horizontal stab.

L.Adamson
 
Short bolts

You may borrow my bolt stretcher if you would like. I ran into this problem prior to pre punched a few times. I just put in longer or shorter bolts as needed. One thing I did was to Put in thinner washers or low profile bolts (providing the bolt was in shear, not tension).
 
Vans figured this out... but didn't tell you

Hi Joseph - I just did this last week and the exact same thing happened to me. I tried thin washers and it was "almost OK".... but not good enough.

In a stunning turn of events, I noticed that Vans had included (10) AN4-13 bolts as well as the (10) -12 bolts. This is not referenced on the plans but you will find them in your hardware packing lists. I can't remember the bag number but they were there. I pulled out the -12 bolts, put in the -13 bolts with regular washers and all was done.

Now if I could get my fuel / brake / vent lines done that easy...
 
Coviper said:
I began installing the landing gear mounts in my 9A this morning. Everything went well, but I have a question for those of you who have already done this. The bolts that go to the wing carry-though bulkhead (F-904) and though the thick alum bar are called out as -12A. I torqued these properly, but the threads just barely come out to the edge of the lock nuts. I thought you should see at least a couple of threads on a tight bolt. Has anyone else noticed this and is it OK to leave it as is, or should I be using a longer bolt? :confused:
Click to expand...
A couple of points. Make certain the threads of the bolt completely clear the hole. It is not good practice to allow bolt threads to come into contact with any portion of the bearing surface of a hole. That will happen if the bolt is too short. If that is the case, install a longer bolt. If that is not the case and the bolt shank does clear the entire hole, here are the guidelines my former employer required. The Engineering Department established minimum thread protrusion allowed after a nut was torqued to be 2?. That may have just been company policy as I'm told 2 or even 1? threads protruding is generally considered acceptable. In addition to company minimums, assuming an installed bolt was slightly long and needed to be shimmed to account for its extra length, no more than 2 AN960 washers were ever allowed to be installed under a nut. With all that stuff in mind, I have never encountered a situation in which I could not comply with a self imposed 2 thread minimum.
 
Thanx!

Thanks Guys! I will pull the -12A's and install -13A's....Better to be safe than sorry.
 
I asked Vans

and got the "Oh not THAT again"..:)

At that time they were installing 12A and 13A bolts in the kits just in case.

Frank
7a
 
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