Guys how much do you torque the prop nuts on the 170 ? I pretty much go as tight as I can without having smoke come off the nut and this had work fine until the last contest where the prop had loosened inflight and had to abort the round. The spinner backplate showed signs of wear just like the trust washer did. Maybe I should go even tighter and for that I ordered an extra long 13mm Snapon box wrench;hopefully this will help. One thing I've noticed is that the YS trust washer has grooves machined in the front face where it contacts the spinner back plate but I don't think they work at all because they do not match the groove pattern in the spinner backplate. Any ideas-suggestions ???

2 recommendations

1) replace driver hub - best solution
2) Glue a dics of coarse sand paper (60, 80 grit) cut to shape of the drive hub to the rear of the spinner back plate - good solution

Caution about tightening the prop-nut particularly the jam nut if using the tru-turn version with a long leverage advantage type wrench. It is possible to sheer off the threaded tip of the prop shaft. Don't ask me how I know that....

I think you may be a few clicks lean if your spinner is getting loose!

I'm nearly ready to replace my YS drive again, the #1 original chewed up quick, #2's taken a bit longer to chew up, 3rd time lucky? I tried a disk of emery cloth and it helped but it wasn't a permanent fix for me, but I didn't glue it in (didn't think of it at the time).

The next one I fit will either get some drive pins fitted or I will JB weld the spinner backplate to the drive disk.

I don't think the YS drive washer is up to the task.

The sand paper works the best, you don't need to glue it to the backplate.

I use a Craftsman 1/2" socket wrench & hold the very top end of the wrench when tightening. If you use a double jam nut, you can tighten the first one fairly tight but not the second one. I never have one come loose except when running too lean & back fired.

Adrian

Replace the drive hub. That fixed it for me.

Tanks for the suggestions, I am going to use the sandpaper until I replace the trust washer and by the way I've already replaced it once for the same reason. A fellow modeler at my field drilled his trust washer and spiner backplate and inserted a rolled pin into it, this is yet another idea I might do if the problem persists !

It only takes 1 or 2 leans runs to ruin a backplate. I always used the sand paper idea and it worked great for me.

Arch

I take a razor saw and create a star pattern of grooves on the back of the prop. Get a cloth rag to hold the prop with when you tighten. I never try to take the prop on or off without a rag on the prop, and sometimes one on the wrench. Get the system snug, but where you predict another 1/4 turn or so to make it "really" tight. Turn the prop so on this last turn you have good leverage and angle between the end of the prop you are holding and the wrench handle. A small end wrench isn't going to do the trick. Get a long end wrench, use a towel so that you don't slip and slice your hand, use good angles to push the prop, and pull the wrench together on the final turn.

I just snug up the jam nut, not especially tight, but the mechanical stop is reached.

At some point it might still slip, then the sand paper is necessary as suggested above.
Thanks,
Jim

Sounds like its lean to me. richen it up a little bit. i have a whole cabinet full of jacked up backplate

The problem arises because the spinner backplates are a hard alum. whilethe YS drive washer is amuchsofter material. The addition of the roll pins is a very good solution. Analternative method, which may be easier to implementis to use 2 small 4x40 allen headbolts to secure the spinner backplate.I have used the bolt method forover20 years. The props stay tight with only normal tighting of the prop nuts.

John W.
Scottsdale, AZ

I agree with Adrian on the sand paper; it works fine and if you do it the way I do it, it works with chewed up drive washers too. The way I prepare the sand paper disc is to use the sticky back type and glue two pieces back to back.....sandpaper is exposed on both sides. One side against the drive washer and the other against the spinner back plate. I've also done this with regular sandpaper without the sticky back, and simply ca'd the two paper discs together. FWIW 2U