Constant Speed Propeller

What! No thoughts/advice on this one???

I believe Rotax says 75% power is 5000 rpm. That’s a good cruise setting.

Hi all, the answer is simple.  Peak torque is at 5200.  Below that you are behind the power curve.  Above that you are on the right side to have good throttle response.  Anything below that you have to climb the pressure point to get it over the hump for acceleration.  Overpitch an engine and it is not good for performance and also it is difficult to respond to acceleration.  Flying with a constant speed should be following the manual to not overload the engine. 

You can see all the power curves in the operators manual from Rotax and their recommendation on setting a "normal" constant speed.  I believe the airmaster is similar but has only steps and not an infinite range.  Should be fine when set correctly. 

Cheers

Hi Sean

I realize this slightly off topic but bare with me.

I have a Sling 2 with Rotax 912 is Sport with airmaster whirlwind prop, electric  constant speed controller.

Different power curve so  try not compare power curves.

I set 5300 rpm for cruise. Works well. 

Nice becsuse you can cruise climb without having to change mode from cruise to climb on prop controller. If you want slightly better climb performance you can always select climb on controller.

Rotax engines like higher RPM. For my combination of engine and airframe considerations, I find there is a noticeable "smoothness" in vibration.

Try   during cruise at higher altitudes like 8000 ft , manually selecting different RPM for cruise. Find that sweet spot RPM and set that RPM for cruise.

Happy landings 

Glenn

( South Africa)

Hi Sam,

"I believe Rotax says 75% power is 5000 rpm. That’s a good cruise setting."

Good?

What is is the rationale, for a 5000 rpm Cruise setting, in the context of an Airmaster Auto Cruise ?