Hi everybody,
thanks for all the responses.
Today we removed the prop, and the complete gearbox.
It was not the conic connection, crankshaft - flywheel. That came loose with a loud bang, this one, for sure, has not been slipping. Also the surfaces were nice and flat.
2nd suspect was the slipper on the outgoing axe to the prop.
We removed the big nut, M30x1.5, on the axe to the prop. It took 2 men to get is loose. Loctite is very strong...
Everything looked ok there as well. No sign of wear. We didn't take the gear off the axe, you need special tools for that, but it looked ok to us.
We removed the old Loctite, put on new and tightened it again, 250Nm, someone ever tried that?? It took again 2 men to do that. A lever of 1 meter!!
Next we assembled everything again.
Test run and all went well.
6400rpm, same as we had before. Nice.
They told us that the slipper system on the outgoing axe is for when the prop hits the ground.
Unconfirmed, but they also told us that it should slip at 300Nm, it seems to be a standard test for this slipper.
We didn't fly yet, to much wind and to bumpy but the weekend looks promising.
Again, thanks for all the responses.
If I find out how the slipper on the outgoing axe is tested I will post it here, just that you also know how it works.
Peter
