Propeller Governor

[garrylundberg]

Using P3D V4.3.

Just completed first full flight. Tried to set up 65% cruise at 8,000 ft., which calls for 21.8" mp @ 2200 rpm. Could not get rpm's below about 2350 no matter what I did with the levers. Lowered mp to 15" than could reduce rpm's...but not at cruise settings. Went down to 6,000 ft. and tried 21.6" @ 2100 rpm...again could not reduce below about 2300 rpm. Checked my CH Throttle Quadrant setting and re-calibrated...no help. Moving levers in the VC also no help.

Thanks.

[wells]

There are several valid power settings given for 65% at 8000 ft. You could also use 20.5" @ 2400 RPM. It will depend on OAT and density altitude. At higher true speeds, the prop will hit the high pitch limit. At lower density altitude and TAS, you can use a lower RPM setting. The prop control was adjusted to give 1850 RPM on the ground with the lever at MIN RPM, as per the service manual. In the aircraft config file, in the propeller section, you can increase the max_beta a few degrees. This will allow you to drop RPM a little more.

[N918JC]

Hi Folks,

I was intrigued by this discussion since I had also noticed the behavior discussed by the op. So, I went looking for a bit more information on the topic and found this interesting article: https://www.avweb.com/news/maint/propel ... 565-1.html

After reading and some experimentation and test flights in P3Dv4 I have settled into using Beta_Max=32 . It seems to fit pretty well for me but, not sure what else it may effect so I'm still waiting for the other shoe to drop.

I also suspect that P3D is modeling this setting similarly to the article's description of a single engine aircraft. Not sure I understand why a difference between single engine and twins in this context but it seemed to me that's what they were saying. And the single engine description seemed to fit with what I was seeing in P3D.

Just thought I would share this for consideration for anyone who may be interested. I am far from knowledgeable about these things so please consider this worth only as much as you paid for it. All I know about airplanes is how to drive them and that not well.

Hope it is helpful,

Jesse Cochran

Edit: To update, after a bit more testing I have pulled the Beta_Max back to Beta_Max=31. Just seems a better all around result.

[garrylundberg]

Jesse,

Good read and very thorough. Also never heard about single vs. multi engine being different...but it's been since the 70's that I have been out of the GA business.


I ended up setting mine at 34...that seemed the best for my set-up. Did a two hour flight yesterday and did not notice any adverse effects.