Wing Attach Bolts

Dan Cullman

Dan Cullman

New member
The wing attach bolts on light aircraft and Bellancas rarely wear out. If you are careful during installation and removal, they can be replated if necessary and reused. If you need the AN9 or AN 10 bolts, the best place to get them has been B&B Aircraft Supply of Gardner, Kansas. Apparently, they are going to sell out their remaining inventory and close the doors. I'm going to order a set for another, future project. Dan
 
It's really sad and frightening. America is losing its industrial base to China.
I bought a new set for 392, but now wonder if I shouldn't invest in a second set...
 
This thread sparked my memory, and I went looking thru old notebooks. About 10 years ago I purchased a set of wing bolts and nuts from a supply house in Florida. I managed to find the phone number and called it this week and the owner is retired, but still has over 100 tons of AN hardware. He has some of what we need for wing bolts. The Cruisair owners manual calls for AN9-51, and AN9-41 bolts. The owner told me he has AN9-53 bolts. They are a little long, but an easy shim job. He doesnt have the -41s, but he has plenty of the AN310-9 nuts. I just ordered 4 AN9-53 bolts at $20 each, and 8 AN310 nuts at $2.50 each. He also said that he has AN10-53 bolts, that I think would fit Cruismasters. Im not at all sure on Cruismaster part numbers, maybe someone else can chime in on those? The Gents name is Greg Cubbage, phone number 352-787-5128. His answering machine is hard to understand but I left a message and he got back to me in less than a day. He could have lots of other hardware that Bellanca owners need? _____I hope this helps.___Grant.
 
Oops, I just talked to one of our Gurus (Larry L) and he says you can only use a max, of 3 washers for shimming. I know there are different thickness washers but Im not sure if three of the thick ones would be enough. Does someone know? ____Grant.
 
Grant:

Harold McMurrin (my IA on this project) says I should use the -53 bolts with the "appropriate" number of shim washers. Something about when the original part isn't available you can use the next best fit?
I KNOW there's something in the 43.13 about this, but I can't remember nuthin' no more.
If I find it, I'll post it. :D

Happy Landings,
 
Wow, I have hit the Gurudom...very undeserved! I am still trying to find out how to lift the gear in these things!

After reading Dave's comment, I thought I ought to be able to back up what I say. So, Grant, I am sorry 'cause I did look in 43-13-1B (and even an old copy of 43-13-1A) and the FAA A&P General Handbook, and there was nothing there regarding number of washers. So I did consult a REAL Guru. Larry Davis is a Charles Taylor Award Mechanic at Creswell and has been an A&P for well over 50 years. I asked him where that number came from, and he said it was just an established tradition..just like how you orient fasteners. So I wasn't hallucinating regarding the number, but there is no hard and fast rule. As he said, sometimes you just have to make do and do what is necessary. So looks like you might need to shim the -53 up 1/4 inch. Looks like 4 NAS1149-0963 washers would do that.
 
I just received my shipment of bolts from B&B -AN-42s and AN-52s. Depending on the wing, it looks like I'll have to shim 1/8 to 3/16 inch. I was able to get thick and thin aluminum washers to match. Dan
 
Ref: CAM 18, (a) Bolts. (2) Grip Length. "In general, bolt grip lengths should equal the material thickness. However, bolts of slightly greater grip length may be used provided washers are placed under the nut or the bolt head. In the case of plate nuts, shims may be added under the plate. For proper washers refer to section 18.30-6 (e)". "Washers. - The types of washers used in aircraft structure are: Plain washers, lock washers, and special washers."

Wing attach bolts are in shear. A longer bolt with washers is not compromising anything.

CAR 18 and CAM 18 govern the maintenance and modifications of our airplanes.

Kent
 
Thanks, Grant!
It does help because I spent about three hours going thrugh old Bellanca parts at Webers today. I found lots of wing atttach bolts that were the right diameter but were either too short or too long. I probably could shim one of the longer ones but I'll need to get Kevin's OK. Incidentally, Caroll at Alexandria Aircraft has a new bolt that is the right diameter and length but isn't exactly like mine from the 14-13. It's price is $35.00 so I told him that he needed to save it for someone with deep pockets. :)
Gary
 
The standard rule of thumb is a maximum of two washers under the nut and two washers under the head of the bolt in order to keep the nut on the threaded area of the bolt in the case of a longer-than-necessary bolt. A maximum of four washers. I think I know why this is...
A stack of washers can compress more than just one or two. If washers are stacked and then the bolt torqued, it is possible for the stacked washers to crush and cause the bolt to lose it's torque and tension. This is especially critical in tension applications which may be subjected to adverse loads such as engine mount bolts. A loose bolt can shift and flex slightly. This induces work-hardening which will then be followed by cracking and then bolt failure. A Stearman in South Africa recently had it's engine separate from the aircraft because of cracked mount bolts. The pilot was killed in the ensuing crash. The cracking was caused by washers that were too soft and crushed, reducing the applied tension of the bolts enough to allow them to flex. I believe a stack of washers could do the same thing. That's why we don't stack more than two washers under a bolt head or nut.
 
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