YS 140DZ Fuel System

[Tomanek, Wojtek]

Troy 
 
Great and very informative write up - thanks from rest of us.  Yes, you are
completely correct with limiting of the engine RPMs - the cam has a
completely different shape it is pointy at the peak giving a quick response
thus the feel of a tractor (high torque) pull, but because of that you
cannot run it at high RMPs (but then you really do not need to be at the max
RPM too often <G>).  
 
Wojtek



The engine seems to have a timing that like torque and big props....On the
ground many of the props in the proper load range run close to the same RPM
but in the air they really are different and to motor responds different.
The best props we have found are the 16.5-12W APC this is superb for high
elevations and windy conditions..... the 17-12 APC is a great prop also but
up here where I fly at 6000ft it is just a little too much load...and during
high winds I liked the 16.5-12W better....These props are both able to run
in the noise limits for messing around the 16-12 APC works like a missile
but is too much speed and noise. DON't run the motor up in the 9000's it is
not timing wise setup for these higher Rpms....Keep it above 8000 and below
about 8800 these two props above do just that. The 16-12 will push to top of
the 88700-8800 the 16.5-12W is a good one in the 8400-8600 and the 17-12
reaches the 8100-8200 range....depends on your style of flying the
plane.....Planes really dictate the prop selection not the motor.. A heavier
plane will like the smaller diameter with its quicker acceleration the
lighter planes will like the bigger diameter as they can accelerate the
light planes quicker....
 
 
I hope this helps understand what's going on in the motor...This knowledge
lets you know why the heli fuel is used and why the motor doesn't like rich
mixture.
 
Troy Newman





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