Lowest Governed RPM?

[BillL]

I am about half way through phase I and found that the my Hartzell prop gov won't regulate the speed lower than 2400 rpm. What do the other governors (for the 360-M1B) have for a lower limit? This seems a bit high.

[dlloyd3]

During your runup, when you cycle the prop do you get an rpm drop? If so, it is likely not the governor but the high pitch stops in the prop.

[BillL]

Originally Posted by dlloyd3

During your runup, when you cycle the prop do you get an rpm drop? If so, it is likely not the governor but the high pitch stops in the prop.

Yep drops and jumps just fine on the run up, but in cruise I can dial it back to 2250 if it is at a low MAP. Increase the MAP and it will go up to about 2350-ish and that is about it.

So - how low can YOU go? And what prop do you have?

[nigelspeedy]

My Whirlwind 74RV governs down to 1800 RPM in flight with the Jihstrol governor on a parallel valve IO-360.
Cheers
Nige

[rzbill]

Bill,
I have the Hartzell aluminum BA prop and Johostroj governor. I frequently cruise oversquare at 2300 and 25". Have run as low as 2200 in cruise.

If memory serves, you have the Hartzell composite. And that one has a close approach to the cowl when at high pitch. If adjusting high pitch stop (which I have no clue how or where), don't forget to check that cowl clearance again.

[BillL]

Originally Posted by nigelspeedy

My Whirlwind 74RV governs down to 1800 RPM in flight with the Jihstrol governor on a parallel valve IO-360.
Cheers
Nige

This is what I had expected! Thanks

Originally Posted by rzbill

Bill,
I have the Hartzell aluminum BA prop and Johostroj governor. I frequently cruise oversquare at 2300 and 25". Have run as low as 2200 in cruise.

If memory serves, you have the Hartzell composite. And that one has a close approach to the cowl when at high pitch. If adjusting high pitch stop (which I have no clue how or where), don't forget to check that cowl clearance again.

Yes I do have that Hartzell composite, something is just not right. I did not change the prop pitch stops. I sent a note to Hartzell and will follow with a call today. When I took the top off the gov during the clocking process, it seems there is no magic, just a flyball governor. I just wonder if the pressure/flow requirement is different for that wide blade.

What is weird is RPM changing when remaining at the same altitude and everything fixed. I was doing some 3 leg ASI testing and the RPM would wander. I just increased to a stable point and flew on.

I'll contact Team Aerodynamics, they had this prop, maybe Hartzell gov's too. Maybe Kahuna has some knowledge of this.

Update: 5/31/18 Emailed Kahuna, no issues with the Team! So, not likely the prop demand. It would make sense that H would design all props with the same range of pressure demand.

[vic syracuse]

What do you get as a max static RPM? If your brakes won't hold that, what do you get as max RPM right about the time you are lifting off?

If you aren't getting 2650-2700 RPM you may not have the stops set correctly on the propeller. The manual tells you how to do this.

Of course, do make sure you have the prop governor set full forward in the right direction at the governor.

Vic

[BillL]

Originally Posted by vic syracuse

What do you get as a max static RPM? If your brakes won't hold that, what do you get as max RPM right about the time you are lifting off?

If you aren't getting 2650-2700 RPM you may not have the stops set correctly on the propeller. The manual tells you how to do this.

Of course, do make sure you have the prop governor set full forward in the right direction at the governor.

Vic

It usually is right at 2700 on TO and climb or cruise when requested. It started a little low (2650) and I adjusted it up (2700). I will be checking the static RPM of the prop tomorrow. With a density altitude of 3200' on the ground (540 ASL), I am not sure what I should expect for static rpm with the governor out of the picture. I suppose I'll just run to 2700 and note the MAP.

I did reclock the RPM stop suggested by Hartzell and it lowered the set point from 2400 to 2300. It stopped there.

I did check the pitch range of the prop when installed using air pressure. It was the same as the Hartzell test sheet.

Any governor experts, please provide some insight, thanks.

[schaplerrh]

Check the pop control cable at the governor end. I recently encounter similar prop control issues and discovered that the metal sleeve on the prop control cable had separated permitting the cable to flex. It took several close inspections to discover the problem ? reach in and try moving he sleeve because it looked attached but wasn?t.

[lr172]

Originally Posted by BillL

This is what I had expected! Thanks



Yes I do have that Hartzell composite, something is just not right. I did not change the prop pitch stops. I sent a note to Hartzell and will follow with a call today. When I took the top off the gov during the clocking process, it seems there is no magic, just a flyball governor. I just wonder if the pressure/flow requirement is different for that wide blade.

What is weird is RPM changing when remaining at the same altitude and everything fixed. I was doing some 3 leg ASI testing and the RPM would wander. I just increased to a stable point and flew on.

I'll contact Team Aerodynamics, they had this prop, maybe Hartzell gov's too. Maybe Kahuna has some knowledge of this.

Update: 5/31/18 Emailed Kahuna, no issues with the Team! So, not likely the prop demand. It would make sense that H would design all props with the same range of pressure demand.

Just had a long discussion with hartzell on something similar. Did you take off the top off the governor? If so, you have to be precise in how you hook the spring back on during reassembly. They happened to mention that they had recently got a call from a guy with the same symptoms. They ultimately found that was off by one flat on the spring clocking when he reassembled his governor.

That top plate isn't supposed to come off for lever clocking. Only the screws get loosened to rotate the cover, then re tightened.

Hartzell tells me that governor should control down to 1600 or so.

Larry