RE: DA50- Anybody Having Trouble?
I don't think rpm should cause a problem with the 50 -but I have not tried running one fast. (I am setting up a customer's plane at the moment with one).
If the engine is properly setup - having good fuel and cooling,correct timing and not overpropped or overheated, the actual loads on the cranks at higher revs ,are lower .
The "why" , is that the engine has a peak breathing rpm . (carb/ timing/porting etc..)
Once you exceed the peak breathing ability -- the piston pressures become lower--
Bearing loads happen two ways - radial speed and load.
In any bearing catalog, you see ratings expressed this way - you can push one or the other but not both.
If the bearing mount is not solid (metals move) then either load or rpm will kill em.
Look at the Zenoah etc., bearings -these are BIG-compared to our special purpose engines - they are engineered for very high revs and shock loads.
The engines get heavy in the process.
trade offs