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Prop pitch adjustment?

kbalch

Well Known Member
While conducting a full-power runup today prior to first flight, I determined that, with 2650 RPM indicated, I still had about two inches of throttle travel left to go. Clearly, going to full throttle on takeoff would result in overspeeding the engine.

This is a -14A with the standard IO-390 and Hartzell scimitar setup. My G3X is set for the P-mag?s required 2 pulses. I used the Van?s-supplied control cables and all were setup per the manual.

Do I need to adjust the prop?s low pitch screw to achieve 2650 RPM on full-throttle static runup or is this a governor issue?
 
It sounds like you need to adjust the low pitch stop on the propeller. Pretty common. I had to do it on my RV-7 as well. I was getting 2800 or so WOT.
 
You need to do both. First, adjust the prop?s fine pitch stop so the RPMs just reach red-line as the throttle is full forward (sea level, no wind). Then adjust the governor until the rpms come down to 2640, then re-adjust to barely get back to 2650.
 
You need to do both. First, adjust the prop?s fine pitch stop so the RPMs just reach red-line as the throttle is full forward (sea level, no wind). Then adjust the governor until the rpms come down to 2640, then re-adjust to barely get back to 2650.

Sorry to revive an old thread, but this technique is wrong.. you want to have he prop limited to approx 2650 statically b he low pitch stops, then as you build airspeed, the Governor limits it to 2700rpm. If you were to limit the governor to 2640, you will always have a rpm surge on takeoff.
 
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Sorry to revive an old thread, but this technique is wrong.. you want to have he prop limited to approx 2650 statically b he low pitch stops, then as you build airspeed, the Governor limits it to 2700rpm. If you were to limit the governor to 2640, you will always have a rpm surge on takeoff.

An A&P ditto to Tom. This is the standard method for dialing in a CS prop.

Also, the governor can't hide an engine deficiency such as running on one mag or whatever. A glance at the revs at the beginning of the roll will show that all is well - or not. The prop resting on the low pitch stop at that point serves as an excellent dyno check .

ron
 
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