Originally Posted by WestTexasKing
I wouldn't rely on the lock washer alone to hold torque, though it probably wouldn't hurt.
This is what I'd use to keep everything solid:
One problem I see is that most lock washers are irregular in shape so they might distort the back plate under torque from the nut.
In a normal situation, the lock washer is designed to distort from its original shape under pressure between the much stronger nut/bolt and whatever it's fastening.
In this case, the lock washer could distort the lightweight plastic long before washer itself distorts flat causing a wobbly prop.
Best choice would likely be an internal star lock washer (largest, far right in your link) as opposed to an external star (smaller ones to the left) or split washer (right above the star washers).
I'm sure you'll be able to figure something out that works well, surely there's no need for me to over-analyze it like I'm doing right now LOL
Yeah, on second thought, the lock washer idea is probably only going to tear up the backplate even more in the event of a prop strike, etc.
Up until know, I was just using el-cheapy GWS 3-blade 9x7 orange propellers without the spinner or backplate of the original airplane. That worked well, but it really looked dorky.
But I think I've figured out a combination of washers, etc, that should allow me to go back to using the old spinner and backplate and the master airscrew 3-blade props that I was using before my spinner broke. The whole assembly is based on your ideas.
Here's a little video to show yo what I finally ended up with:
Once the propeller is on, I should be able to bolt on the spinner to the backplate and it will look pretty stock once again.
At some point, I really just need to get some decent motors with some better shafts and the right sized prop adapter with a nice solid grub screw to hold the prop on correctly.
I'm using my first P38 as a platform for experimenting. When I get ready to build my other one (airframe only), it will incorporate all of the improvements that have been listed in this thread, along with some nice retracts, etc, etc.