Dbro172

Dbro172

Well Known Member
Im bolting my flaps to the wings and come across my first castellated nuts / cotter pins on the project.

I have not found any specific information pertaining to the torque value for the castellated nuts.

Based on size, are the castellated nuts to be torqued to the same values as the standard AN bolt / locknut combination (say, 20-25 inch lbs. for an AN3, etc.)

Thanks
 
Yes, same values

The final values are the same, but you also have to be able to get the slots in the nut to line up with the hole in the bolt.

Start with the torque at the low end of the range and check to see if you can get the cotter pin in. If not, continue to torque up to the maximum torque but DO NOT exceed the maximum.

If you were not able to get the cotter pin in anywhere between the min & max torque range, add or remove washers and try again.
 
castellated

Who cares?! Castle, castellated, nutplate, platenut???!!!
 
Across the pond!

Across the pond I have seen them called crown nuts.
Not important, just a little trivia.;)
 
castellated nuts

When was the last time you saw a self-locking castellated nut? What torque?
Hawker uses them. What I want to know is why a cotter pin secured nut needs to be self locking. Maybe it should also be drilled for safety wire.
 
Leaving aside the issue of what they're called...

If the nuts in question are the 3 per flap that secure the flaps to the hinges below the wing, I don't believe they are torqued to the standard value -- they are there simply to act as a pivot point for the flap's up/down motion. Torquing them to the AN value would cause the hinge to be very difficult to move...bad for the flap motor.

I put the nut on finger tight, then backed off until the previous slot aligned with the hole in the bolt. Insert cotter pins, then test to be sure the motion of the flap is smooth and not binding. You'll come across the same thing when connecting the rudder cables/pedals.
 
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No binding here

jwyatt said:
Leaving aside the issue of what they're called...

If the nuts in question are the 3 per flap that secure the flaps to the hinges below the wing, I don't believe they are torqued to the standard value -- they are there simply to act as a pivot point for the flap's up/down motion. Torquing them to the AN value would cause the hinge to be very difficult to move...bad for the flap motor.

I put the nut on finger tight, then backed off until the previous slot aligned with the hole in the bolt. Insert cotter pins, then test to be sure the motion of the flap is smooth and not binding. You'll come across the same thing when connecting the rudder cables/pedals.
Click to expand...


These were the three in question. I did end up torquing these to about 22 inch lbs. and there is no binding whatsoever; flaps swing freely. Remember, there is a brass bushing squeezed into the wing side flap bracket, (1/64" inch wider on each side of bracket) preventing a bind issue here.
 
I did not and will not torque my flap hinge or rudder cable hardware. On my control sticks, I have steel and bronze with grease in between as a bearing surface. On my flaps I have aluminum and bronze. I don't want a groove wearing into hinges and yes mine did bind up if torqued. I doubt either way will cause flap to depart, but why Van's did not use the same setup as elevators/rudder with a spherical ball I have no idea.
 
It's already been said, but the application matters. For pivoting points, you want the nuts snug but not restrictive. Don't go way loose, either, or the bolts will tend to 'work' and elongate the holes they are in. For other applications where the cotter pin is a safety feature (the engine mount bolts leap to mind), torque to the minimum value and then continue until the nut's castellations are lined up with the hole in the bolt or you reach the maximum torque value, whichever comes first. You can adjust with washers, including thin washers, as necessary remembering to adhere to the three washer maximum rule. And, if three washers is still too loose, use a shorter bolt; similarly, use a longer bolt if the body of the nut covers the hole in the bolt to the point where a cotter pin cannot be easily inserted.
 
nuts

Self locking castle nuts are used in helicopters and other critical applications. Aircraft Spruce has limited sizes.
 
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