Prop vrs RMP/MP

09-20-2012, 05:00 PM

Mike | Prop vrs RPM/MP

How does one figure out the blade angle at 24/24?

09-29-2012, 02:24 AM

jar59nh | Blade angle variable

Hi Mike,

It depends on many factors, airspeed, temperature & pressure altitude. Not sure you can nail it down easily. One possible way would be to read the prop governor pressure being sent to the prop. I don't know if that's possible with the governor on the front. Probably could do on IO-360 setup with gov on back of engine.

For a given govenor pressure the oil pushes against the prop spring and gives a certain blade angle. The govenor is using its speed sensing system to change the blade angle to maintain a constant RPM, i.e. 2400.

That's about the only way I could think it would be possible. Although a set of high speed photos from a chase plane abeam the prop might reveal the angle too.

Food for thought,

John