You got to be kidding?

[SSDiv6]

Originally Posted by A56

What has been proposed and is pretty much is a simple wing tab kit with a nut and bolt. Originally I had proposed this with a lock nut, but it was rejected due to the fact that the lock nut could fall off. What has been decided on is to use the wing tabs and a nice aircraft bolt with possibly a castle style nut and a cotter key. This system will be in addition to our already existing spring tabs or A/B collector tabs. The actual Bolt / Nut / Cotter Key has not been decided on. I dont know if it will be a 1/4", if it will be a castle style, and what the clip or cotter key will have to look like. But what I do know is that it will be simple and inexpensive.

Mark Lelchook
D/ED F/SA

Mark,

The is not need to use a castellated nut with a cotter pin.
An aviation/aerospace specific quality locking nut should be more than sufficient.
The fasteners shown below are what you will find typically in any commercial aircraft flying in the skies everyday.

I suggest the following fasteners:

Bolt:
AN3-4A (Has drilled Shank for Cotter Pin)

Washer:
AN960-10

Locking Nut:
AN363-10
MS9321-10
NAS1587-3
MS21046C3 (High Temperature)

In the event NHRA decides to use a castellated nut and cotter pin, the part numbers are as follows:

Cotter Pin:
MS9245-22 (Corrosion Resistant/High Temperature)

Castellated Nut:
AN310-C3 (Corrosion Resistant)
MS17825-3 (Castellated, Corrosion Resistant Self Locking Nut)

If you need the technical specifications or data to substantiate the use of any of these fasteners, just let me know or send me a PM.

[Ed Wright]

I'm surprised steel self locking nuts aren't accepted. The recip airplanes (that's how old I am) that I used to work on used them to hold the exhaust on. Silver plated. I still have some. Our collectors don't get as hot, nor nearly as long as the header pipes did at the jugs on those engines (P&W 4360s). I have them on my car, have never had one loosen. Had castle nuts & keys a lot of places, but not at the jugs. I will probably just tig weld mine.

[SSDiv6]

Originally Posted by Ed Wright

I'm surprised steel self locking nuts aren't accepted. The recip airplanes (that's how old I am) that I used to work on used them to hold the exhaust on. Silver plated. I still have some. Our collectors don't get as hot, nor nearly as long as the header pipes did at the jugs on those engines (P&W 4360s). I have them on my car, have never had one loosen. Had castle nuts & keys a lot of places, but not at the jugs. I will probably just tig weld mine.

Ed,
The parts I listed are very affordable and the Silver plated ones are still available too.
I totally agree with you, a reciprocating engine generates a lot more vibration than a race engine would. I believe the use of castellated nut and cotter pin is an overkill.
In my years in the aviation business, I have never seen an aviation spec self locking nut come loose.