Bear with me as I get my mind around the low pitch stop setting and see if my logic is correct. I have a 0-360, Hartzell C2YK-1/7666A-4 Propeller and a MT P - 420 - 3 governor. On takeoff, my engine data shows RPM increasing to 2730 for 1 second then decreasing to 2650 - 2670 during the roll. I apply throttle slowly. The propeller never gets to 2700 RPM except for the brief surge. At rotation and during climb fuel flow settles in at 17 - 17.5 gals/hr and MP at 29. The data would indicate the low pitch stop is set too low preventing the prop from achieving full RPM or is the governor is limiting the prop RPM? How do I determine which one?
I hesitate to do a tied down static test for all the reasons mentioned in this thread.
The Hartzell manual says "The propeller low pitch stop is set at Hartzell Propeller Inc. in accordance with the aircraft TC or STC Holder's requirements and should not require any additional adjustment".
From the Hartzell manual " Turning the low pitch stop in will increase blade pitch to reduce RPM, and turning the low pitch stop out will lower blade pitch and increase RPM. The low pitch stop has 24 threads per inch. a Turning the low pitch stop 3/4 of a turn equals 0.030 inch (0.76 mm) of linear travel, and will change the blade pitch by approximately one degree. One degree of blade pitch will change the engine RPM by approximately 140-150 RPM. Turning the low pitch stop screw one revolution equals 0.042 inch (1.06 mm) of linear travel, and results in approximately 1.4 degree blade angle change. A 1.4 degree blade angle change results in an RPM increase/decrease of approximately 200 RPM."
If the low pitch stop is limiting max RPM, then I should turn the low pitch stop OUT one third of a turn to increase RPM by 40 RPM.
Does this logic sound correct?