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7/16 or 3/8?

RV10Man

Well Known Member
I bought a prop from a VAF member for my RV9A. It's the exact prop form Van's for my engine and airplane. BUT, I didn't fully check out my prop flange. My flange is for 3/8" bolts, the prop is 7/16".

My question to the gurus is, can I use this prop and install bushings/spacers, and use 3/8" bolts?
 
Prop flange

The bolts should match your prop for security. New collets for your crankshaft are available. Use a home made removal and installation tool using ordinary sockets, washers, and a same threaded bolt (not one of the expensive prop bolts)
 
Crank flange drive bushing

Several times I have solved issues like this by replacing the bushings. I usually buy serviceable used bushings from Aircraft Specialties in Tulsa. Bob over there can set you up with what you need.

Don Broussard
RV9 Rebuild in Progress
57 Pacer
 
I'm not saying its right but when I bought i believe it was a prince prop for my old rv i was told it was ok to use bushings.
 
The answer is....

I bought a prop from a VAF member for my RV9A. It's the exact prop form Van's for my engine and airplane. BUT, I didn't fully check out my prop flange. My flange is for 3/8" bolts, the prop is 7/16".

My question to the gurus is, can I use this prop and install bushings/spacers, and use 3/8" bolts?

Marshall,
The answer is yes.
Keep the prop like it is and make the spacer match by drilling it out and using 7/16 bolts from Saber or whomever you choose. Bushings on a wood prop won’t work over time and the 7/16 bolts are far superior with an 0-320.
The older 4” spacers like mine on my RV4 had pressed bushings similar to Lycoming flange bushings that were difficult to remove so I drilled mine (and my prop) to 7/16. Reason for me is that 3/8 bolts didn’t hold torque more than 10hrs with my Sterba wood prop in the moist climes of my home state (FL).
You could drill the spacer yourself or send it to Saber mfg and have Sam drill it for you or just buy a new spacer from Saber.

V/R
Smokey
 
Last edited:
Marshall,
The answer is yes.
Keep the prop like it is and make the spacer match by drilling it out and using 7/16 bolts from Saber or whomever you choose. Bushings on a wood prop won?t work over time and the 7/16 bolts are far superior with an 0-320.
The older 4? spacers like mine on my RV4 had pressed bushings similar to Lycoming flange bushings that were difficult to remove so I drilled mine (and my prop) to 7/16. Reason for me is that 3/8 bolts didn?t hold torque more than 10hrs with my Sterba wood prop in the moist climes of my home state (FL).
You could drill the spacer yourself or send it to Saber mfg and have Sam drill it for you or just buy a new spacer from Saber.

V/R
Smokey


Thanks Smokey.
Problem is, it's the other way around. The prop, spacer, and bolts are 7/16, my crankshaft (prop) flange is 3/8.
 
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