ekimneirbo
Well-Known Member
Question: Has anyone ever done any computation comparing the forces applied by the pistons in an aero engine and a similar sized automotive engine?
One of the big differences that come up for discussion in auto/aero discussions is that the auto engine isn't designed for aero use
and doesn't run at WOT like the aero engine. I've stated previously that 2700 rpms isn't WOT but the recommended maximum throttle setting of the manufacturer and propeller manufacturer.Without addressing that....the crux of my question is that one of
the main reasons an aero engine is limited is due to the large size of the pistons used and the much heavier rod assemblies.
I wonder if anyone has ever done any real investigation as to how much difference the mass of each piston/ring/rod assembly puts
on the crankshaft as compared to the lighter piston and rod assembly in a similar displacement V8 engine. Something like an O360
vs a 350 Chevy. The Chevy is naturally going to be lighter due to having 8 pistons vs 4 for the Lyc. I'm wondering how much more rotational force the Lyc applies at each individual journal than the Chevy (Ford etc).The point of the question is that the crankshaft
is going to subjected to elastic twisting forces with each combustion cycle compounded by the mass involved in transferring the power to the crank. I'm just curious as to how much difference each journal might see.
Anyone have an O-360 piston/rod/rings assembly handy that they can weigh?
One of the big differences that come up for discussion in auto/aero discussions is that the auto engine isn't designed for aero use
and doesn't run at WOT like the aero engine. I've stated previously that 2700 rpms isn't WOT but the recommended maximum throttle setting of the manufacturer and propeller manufacturer.Without addressing that....the crux of my question is that one of
the main reasons an aero engine is limited is due to the large size of the pistons used and the much heavier rod assemblies.
I wonder if anyone has ever done any real investigation as to how much difference the mass of each piston/ring/rod assembly puts
on the crankshaft as compared to the lighter piston and rod assembly in a similar displacement V8 engine. Something like an O360
vs a 350 Chevy. The Chevy is naturally going to be lighter due to having 8 pistons vs 4 for the Lyc. I'm wondering how much more rotational force the Lyc applies at each individual journal than the Chevy (Ford etc).The point of the question is that the crankshaft
is going to subjected to elastic twisting forces with each combustion cycle compounded by the mass involved in transferring the power to the crank. I'm just curious as to how much difference each journal might see.
Anyone have an O-360 piston/rod/rings assembly handy that they can weigh?
