How to explain a CS prop to an A&P?

OK, I’ll see if I can help out coloradobluesky.
I’m assuming you have a Hartzell constant speed propeller.
If you have a “typical” Hartzell constant speed propeller in a single engine aircraft, you have what Hartzell calls a “-1” propeller. A “-1” uses oil under pressure from the governor to coarsen the blade pitch (prop to high blade angle, low RPM). On the other hand, oil is removed from the propeller cylinder to move the propeller to a low blade angle (high RPM).
OK so far?
When you are sitting on the ramp with the prop control full forward and the throttle full forward, brakes locked, you are in the “Static RPM” condition. This means that there is NO oil being pumped up to the prop, and the prop is on the low pitch stop. This should be at, or slightly below max RPM. This is a mechanical stop internal to the propeller. It is the lowest blade angle the propeller can reach.
When you are on the low pitch stop, and start to lean the mixture, you will eventually reduce the available engine power. Because you propeller is already at the lowest pitch it can reach, the prop cannot adjust pitch any lower to maintain RPM, and RPM will begin to drop, simply because there is not enough available engine power to spin the propeller, even at its lowest available pitch setting.
 
That's pretty cool. On the G-1, the propeller a throttle are linked together. The manual actually says the propeller controls engine speed.
 
GlennAB1 said:
That's pretty cool. On the G-1, the propeller a throttle are linked together. The manual actually says the propeller controls engine speed.
Click to expand...

Your old G-1 (TC-4C) mech, says they are a real pleasure to rig.
 
You must log in or register to reply here.
Back
Top