Thoughts on buying prop strike rotax 912uls

[rhkennerly]

Can’t help but be wary of a plane that has had a prop strike. Seller passes it off as no big deal after new prop & gearbox tear down.

I’m not so sure. Thoughts?

 

[Capt. Geoffrey Thorpe]

After a prop strike there should be a gearbox teardown and inspection.
The 912 ULS should have the slipper clutch that prevents impacts from reaching the crank. The 912 UL may not have the slipper clutch (mine does not) and in that case I would be somewhat concerned about the pressed together crank.
All of the 912s also have a dog clutch to reduce torsional vibrations at the prop.

 

[rhkennerly]

After a prop strike there should be a gearbox teardown and inspection.
The 912 ULS should have the slipper clutch that prevents impacts from reaching the crank. The 912 UL may not have the slipper clutch (mine does not) and in that case I would be somewhat concerned about the pressed together crank.
All of the 912s also have a dog clutch to reduce torsional vibrations at the prop.

thanks. It is a 912uls, with the slip clutch. There was a tear down & inspection of the gearbox & the prop was replaced. It’s flown 24 hrs since then.

I want to get to ‘yes’ too badly to think clearly about this. I have convinced myself that I trust the clutch system & the ‘break away’ fiberglass prop. But that’s a $20k error if it all comes apart on me.

but I need to build my risk into the price. I was hoping to see if anyone had insight into prop strikes with the 912uls who later had good or bad outcomes.

 

[Capt. Geoffrey Thorpe]

There is a check you can make for crankshaft twist - but it involves pulling the gearbox (not that huge a deal, but the seller may balk). I have no personal experience with an engine after a prop strike (that I am aware of ).

 

[Stan Cooper]

What was the prop material when the prop strike occurred? Wood? Composite? Aluminum? One of the advantages of wooden props is if it is just the tips that struck, the wood splinters and the impact of the strike on the gearbox and engine could be minimal to none. The wood acts sort of like a fuse, protecting the gearbox and crank.