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Propeller drive lugs

Av8torTom

Well Known Member
My Whirlwind propeller requires that 2 of the drive lugs on the flywheel (starter ring) be flush. Is there a tool for removing/replacing drive lugs?
 
I used a bolt, Tube/sleeve/socket and a brass hammer. To remove, thread the bolt through the socket or tube that had an ID slightly larger than the base flange and through the lug. Tighten aggressively and tap on the front of the lug with the brass hammer. If you did it right, the bolt will be a looser and able to be re-tightened. Repeat until removed. Installation is pretty much the same. I imagine there is some variability in the interference clearance and this may not work for some. I worked well for me.

The short lugs were expensive, so I just cut the long one down on a lathe.

I did this with the crank on the bench, so cannot speak to the clearance issues involved when done in situ. You may need to make an S shaped bar to tap during installation if you can't tap the back side. The lugs may also go in just fine without tapping.

Larry
 
Last edited:
Are you threading that bolt in from the back?
My engine is built and on the airplane - don't think I want to be hammering on anything
 
Last edited:
Are you threading that bolt in from the back?
My engine is built and on the airplane - don't think I want to be hammering on anything

I’ve done this a number of times using a bolt, washers, nut, and large socket, and never had to tap on anything with a hammer - just use the force generated by turning the nut on the bolt. Note that I am not using the drive lug bolt is small enough diameter to go straight through.
 
I’ve done this a number of times using a bolt, washers, nut, and large socket, and never had to tap on anything with a hammer - just use the force generated by turning the nut on the bolt. Note that I am not using the drive lug bolt is small enough diameter to go straight through.

Then reverse the process from the front side to press in the new lug?
 
Nothing wrong with not using a brass hammer. Just be certain that the flange is fully seated against the hub on installation. If it is not fully seated, your prop bolt could lose its torque over time. If the interference fit is tight, you may struggle to get it fully seated on with just a 3/8 bolt / nut.
 
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