I would suspect the main culprits to be vibration and fatigue. As soon as one of the supports cracks then the others will follow quickly as they are now overstressed from the lost support of the broken mount.
I would suggest you get the prop balanced as this is a telltale sign of excessive vibration. I would aslo look closely at your baffling and exhaust system, these are also very succeptable to excessive vibration.
Dan, I don't remember how much weight. Screw, nut, and a couple washers? I can remove and weigh in a couple days. Yes, attached to the spinner buikhead flange. Whatcha thinking? Thx, -Jim
engine prop balance weights get bolted to the starter ring gear. Spinner back plate cracking is most likely due to centrifigual forces from the spinner not being perfectly centered.
engine prop balance weights get bolted to the starter ring gear. Spinner back plate cracking is most likely due to centrifigual forces from the spinner not being perfectly centered.
I'm trying to visualize the ring gear on the -540 for the RV-10...where would it bolt to? Drill a new hole? Guess I'll have to take another look when I return from this business trip.
Yep, these are highly stressed parts with lots of vibration and centrifugal forces trying to tear them apart. Looks like old age finally took it's toll. Get a new one, rebalance the prop and don't worry about it. Whenever I do a prop balance I closely inspect the spinner and attaching parts for exactly what you found.
Good thing you caught it though, it was getting ready to end up in someones yard
