Thelert & Austro have a clutch between the engine and reduction gear box that limits the load transmitted to the engine……….. But the gearbox has to be replaced after a shock load.
It won’t help with the loads transmitted into the crankcase if you smash the prop on something, however. The “equal and opposite reaction” still stresses the crankcase, the engine mounting flanges, etc.
I don’t know about Thielert/Austro but in the Lyco/Conti world there are plenty of cracked crankcases. Usually they are found in good time, merely leaking oil. Usually a prop strike is a suspect.
The gearbox is much weaker than the crankcase, in the most severe prop strike I have seen with a Thielert engine the gearbox case failed with the prop and forward half of the gearbox departing the aircraft.
Aeroplus: I can’t imagine a less convenient place than Helgoland to get a prop strike! I’ve flown over it a couple of times but avoided landing there for the very reason of what to do if anything goes wrong, eg flat tyre, etc. etc. What did your friend do?
Aveling wrote:
eg flat tyre
In a dire emergency, you can stuff it full of grass.
