I have never used variable pitch props in fixed wing aviation so I am not entirely sure if I am using them right. My understanding was that you still flew them with the throttle, and only adjusted the pitch at cruise altitudes for faster revolutions in the thin air (and of course feathering them in an engine out situation) But when I enable pitch control in my simulator, it takes over and the throttles become useless.
Now, in helicopters, you fly them with pitch control, and the engine stays at a constant 100% (unless you are flying an Enstrom or an old Bell where you have to manage pitch and prop simultaneously.)
So if anyone has variable pitch propeller experience, let's hear from you.
Flying variable pitch props
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Peter Grey
- Posts: 5716
- Joined: Tue Oct 12, 2010 3:21 pm
Re: Flying variable pitch props
Hello,
Variable pitch props are a very unique tool in airplanes and are designed to maximize efficiency. First off I recommend reading chapter 11 of the Airplane Flying Handbook (the part on constant speed propellers, which is another term for the same thing), however until then here is a primer.
For takeoff and other situations that require high power setting a high RPM (which is a low pitch/blade angle) is used, this has 2 benefits:
It better aligns the prop with the airflow for maximum efficiency.
Each blade deals with less air which put less strain on the engine.
Imagine a car/bike in low gear, this is the basic analogy.
In cruise you bring back the RPM to twist the blade a bit towards the movement of the aircraft to compensate for the faster forward motion. This is the same idea as going to a high gear on a bike. This also lowers the noise profile of the aircraft.
So with that in mind here is a basic profile to use for prop management, the specific RPMs are from 2 aircraft I have flown with constant speed props (The C182 and the PA44):
Takeoff: Full forward (high RPM) for maximum RPM: ~ 2700
500' AGL: Bring back the prop 100-200 RPM, this lowers the noise profile.: ~ 2500
Cruise: Bring back the prop another 200 RPM: ~2300
Before landing: Prop full forward in the event of a go around. ~ 2700 (note at low power you may not get max prop RPM)
I can't speak to the simulator disabling the throttle, this should not happen.
Let me know if you have any other questions on this system.
Variable pitch props are a very unique tool in airplanes and are designed to maximize efficiency. First off I recommend reading chapter 11 of the Airplane Flying Handbook (the part on constant speed propellers, which is another term for the same thing), however until then here is a primer.
For takeoff and other situations that require high power setting a high RPM (which is a low pitch/blade angle) is used, this has 2 benefits:
It better aligns the prop with the airflow for maximum efficiency.
Each blade deals with less air which put less strain on the engine.
Imagine a car/bike in low gear, this is the basic analogy.
In cruise you bring back the RPM to twist the blade a bit towards the movement of the aircraft to compensate for the faster forward motion. This is the same idea as going to a high gear on a bike. This also lowers the noise profile of the aircraft.
So with that in mind here is a basic profile to use for prop management, the specific RPMs are from 2 aircraft I have flown with constant speed props (The C182 and the PA44):
Takeoff: Full forward (high RPM) for maximum RPM: ~ 2700
500' AGL: Bring back the prop 100-200 RPM, this lowers the noise profile.: ~ 2500
Cruise: Bring back the prop another 200 RPM: ~2300
Before landing: Prop full forward in the event of a go around. ~ 2700 (note at low power you may not get max prop RPM)
I can't speak to the simulator disabling the throttle, this should not happen.
Let me know if you have any other questions on this system.