What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Prop Bolt Pattern. O-360

Kahuna

Moderatoring
Cant find the answer in the archives.
Looking for the bolt pattern for an 0-360 A1A.
Gotta drill a prince prop that came off an IO-0360, it had a spacer to adjust for a funky bolt pattern.

Cant find a template or a diagram of the bolt pattern.
Can someone point me to a diagram?

I have most all the lycoming manuals and sb's and things on DVD but all be darned if I can find the answer.

Please no safety police on drilling a prop.
Thanks for you help.
 
Last edited:
Mike,
An O-360 is probably an SAE2, six .375" bolts on a 4.750" diameter bolt circle. Typical bushing counterbores are 5/8".

We're both hard-headed SOB's, so you'll understand if I ignore your request to not be told double drilling a wood prop hub is a bad idea.

The largest hub load by far is tension across the hub due to centrifugal force. Don't know your blade weight so I can't calculate yours, but I can offer an example. Centrifugal force for the 84" maple prop I carved last year is about 10 tons.

WWII flight training resulted in a huge service experience database for wood props. One design realization was the importance of maintaining enough uncut wood fiber from blade to blade across the hub. It's in the ANC prop design handbook.

Here's what you have when you drill both an SAE1 (4.375" bolt circle) and SAE2 (4.750" bolt circle) bolt pattern in the same hub. The green hatch is uncut wood fiber.



You can ignore this detail in one circumstance. If the Prince prop has a structural composite sheath capable of carrying all the hub loads by itself, without contribution from the wood, you're good to go.
 
Mike,
An O-360 is probably an SAE2, six .375" bolts on a 4.750" diameter bolt circle. Typical bushing counterbores are 5/8".

O-360 uses 0.5" bolts.

And I have to agree with Dan about the uncut wood fibers.
 
Last edited:
Both Mel. and Don are correct. I have a Prince drop tip carbon that is drilled to an SAE #2 with 1/2 inch bolts.. Please if you drill this one two times the money. Give some thought to marking it un-airworthy and put it on the wall.
I do not know you but I like you for now!!!!! I like prop wall clocks, its a good place to retire one that been good to you.
 
Back
Top