What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Calling all IO-360-M1B and Hartzell operators. Smooth RPMs?

jcarne

Well Known Member
Patron
I typically cruise anywhere from 8500-11500 on my IO-360-M1B with a 74" Hartzell CS. I am curious what RPM others have found to be the smoothest. It would seem that mine really likes 2450 and above. I can certainly go lower than that but the feet buzz increases significantly. Around 2300 RPM and the feet buzz is annoying enough that I don't want to stay there for an entire flight. Anyone else find similar? What RPM do you like? Any tricks you found to reduce the feet buzz?
 
72" Hartzell

My experience has been the same, Jereme. Regardless of altitude, 2500 rpm is my normal setting; occasionally, 2600 rpm. YIO-360-M1B.

Merrill
 
I have a different engine in my -7 (IO-360-A1B6), but the same propellor. It seems to "like" 2500 RPM for higher power and airspeeds.

I've also found that 2100RPM is smooth and quiet, albeit much slower, and a Podracer like vibe...
 
Same experience as noted. The power stroke torque impulses are increased with higher power, so the vibration will be more intense with lower altitudes at the same RPM.

I can run down to 2350 if leaned if over 10k, but 2450 seems to be a comfortable place. I have the 72" composite Hartzell- M1B.
 
Thanks for the great replies everyone! Glad to see it's not something unique to mine. I will just keep on running her where she is happy. :)
 
could your feet buzz be lowered with dynamic prop balancing?

mine was balanced for 2200 and i find it very smooth at this RPM as long it isn't to much oversquare.
 
could your feet buzz be lowered with dynamic prop balancing?

mine was balanced for 2200 and i find it very smooth at this RPM as long it isn't to much oversquare.

I wondered about this too. I have heard it makes a difference, just haven't done it yet. I am still hoping to find a friend that has one so I can do it myself. :)
 
Back
Top