Identify this nut!

[SMRacer]

While working in the tail cone of my RV8 (which I did not build) installing the pitch servo, I found a AN310-3 castle nut. It appeared as though it had been rolling around for quite awhile. There also appeared to be some metal in the threads of the nut indicating that it was not just a spare that dropped, but rather it had been installed somewhere.

For you RV8 builders, where could this nut have come from? I have searched through some of the plans for the empennage, but I cannot find any castle nuts in this area.

Thanks,
Jim
RV8 N37PK

[paul330]

The RV-10 has such a nut which is used to secure the leading edge of the VS....

[PaigeHoffart]

It was probably a temporary fastener. There have been occasions where the builder used temporary hardware without a locking feature, forgot to install the permanent hardware, and finally discovered it years later when the nut fell off.

The important AN3 bolts that come to my mind are on the elevator pushrods. Check all of the rod ends.

AN3s are also used to attach the empennage. The toughest ones to inspect run through an angle that attaches the front spar of the horizontal stab to the upper longerons.

Paige

[Doug]

First place I would check are around the rudder pedals, brake cylinder and rudder cable attachment to the pedals. Aeros can redistribute items like this into obscure parts of the airframe.

[Robert Anglin]

It is very common for a builder to use non nylock to fit and size everything as you build. Then once everything is ready to put together that last time use the called for locking nut or whatever. It is very good that you found this nut and are checking to see if anything is out of place. I will most likely find 4-5 that I have dropped and rolled into a place I could not get to at the time of building. "BUT" will always check for lose and out of place blots, nut, washers and anything I can every time I open a panel. You are correct. Better to be safe than sorry. Good work. Yours as always, R.E.A. III #80888

[Ron B.]

Originally Posted by Robert Anglin

It is very common for a builder to use non nylock to fit and size everything as you build. Then once everything is ready to put together that last time use the called for locking nut or whatever. It is very good that you found this nut and are checking to see if anything is out of place. I will most likely find 4-5 that I have dropped and rolled into a place I could not get to at the time of building. "BUT" will always check for lose and out of place blots, nut, washers and anything I can every time I open a panel. You are correct. Better to be safe than sorry. Good work. Yours as always, R.E.A. III #80888

For this reason I will spend a considerable amount of time finding a dropped item even down to a small washer. If I find something during inspection I'm quite sure it's something that has fallen off and needs to be found.

[SMRacer]

Does Van's have the capability electronically to search for an item. In other words, if they put "RV8" and "AN310-3" in a search, would it bring up all the uses in the airplane for this part?

Or, is their computer disc of plans searchable?

Jim

[SMRacer]

This was an AN310-4 castle nut.
I don't think this size is used as much as the -3 on the RV8, might make it easier to identify.
Jim

[cjhammes]

Used to attach seat belts to bracket.

[BillL]

Originally Posted by SMRacer

Does Van's have the capability electronically to search for an item. In other words, if they put "RV8" and "AN310-3" in a search, would it bring up all the uses in the airplane for this part?

Or, is their computer disc of plans searchable?

Jim

The disc plans are not searchable, I just tried. Frankly, it is most likely to be a dropped part, but to be safe, I would strip off all the inspection plates and do a tail to nose inspection of all the vital fasteners. On the 7 (and 8 likely) the HS spar is attached with -3 (10-32) fasteners. Lots of them around in vital places. Then an academic search is moot, and you are flying safe.