lml@lancaironline.net Mailing List Archive

This issue was a topic of discussion amongst some of the attendees at the Continental/Lancair maintenance clinic this past weekend. While I do have a Hartzell prop and governor on my Lancair Legacy, I am not sure if I have the S series governor you refer to. I have used 2000 RPM as my setting to check my prop during run-up as that is what I was advised to do when I bought my flying Legacy. Admittedly, I had not been concerned about the engine out ramifications of such a high required setting. As such I went out yesterday to check for the lowest possible RPM setting for prop control occur. I found that I had to go to 1900 RPM to have control on the ground. I have no reason to believe it will be any better in the air but I will check that out on my next simulated engine out opportunity.

Clearly this issue is genuine cause for some level of concern...not sure how much just yet.

Berni Breen

Sent from my iPhone

On Mar 24, 2014, at 9:06 PM, "Valin & Allyson Thorn" <thorn@starflight.aero> wrote:

I was surprised to learn recently that the Hartzell propeller governor (S Series) cannot adjust the blade pitch with an engine speed below about 1800 rpm. Seems like that could be a problem in an engine out glide scenario, where the prop stays at flat pitch, high drag.

I talked to a guy at Hartzell Technical Support and he confirmed that’s how their S series governors work. He said it’s not a problem and that they are on all the Cirrus airplanes. But, with the Cirrus’ single lever control linkage, I don’t think Cirrus pilots can adjust the blade pitch in an engine out scenario anyway.

For the Legacy flyers out there flying with the Hartzell governor, when you’re at best glide speed of 120 KIAS, are you able to get enough engine rpm to get maximum blade pitch (low drag) or not…?

Thanks,

Valin Thorn
Legacy Project
Boulder, Colorado USA