Governor, RPM limit

455 Bravo Uniform

455 Bravo Uniform

Final Approach
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455 Bravo Uniform
I used my optical tach on my latest takeoff and it registered 2650’ish RPM. The “redline” is 2620. Yes, my optical tach is reading accurately.

How involved is the calibration/adjustment of the governor? In other words, how much equipment and testing (time & money)? Or is it a matter of the A&P “just” turning a screw in one direction and going for a flight/ground run with a certified tach?

If this has been happening unbeknownst to me for however long it’s been happening, should I be worried about prior damage or component fatigue? Or is 30 rpm considered within acceptable error?
 
Adjusting every Governor I’ve ever seen is just a turn of a screw.

However: some can be VERY difficult to access

One complete turn usually about 25 RPM

YMMV

My personal belief is 30 RPM over red line is not an issue.

Contact the engine mfg Customer Service to get Official.
 
455 Bravo Uniform said:
I used my optical tach on my latest takeoff and it registered 2650’ish RPM. The “redline” is 2620. Yes, my optical tach is reading accurately.

How involved is the calibration/adjustment of the governor? In other words, how much equipment and testing (time & money)? Or is it a matter of the A&P “just” turning a screw in one direction and going for a flight/ground run with a certified tach?

If this has been happening unbeknownst to me for however long it’s been happening, should I be worried about prior damage or component fatigue? Or is 30 rpm considered within acceptable error?
Click to expand...
1.1% over? I wouldn't sweat it. A couple extra HP in the climb might be useful anyway. Besides, the blue knob is a vernier, right?
 
455 Bravo Uniform said:
Or is it a matter of the A&P “just” turning a screw in one direction and going for a flight/ground run with a certified tach?
Click to expand...

Could be slightly worn hardware, etc. Consider checking security and linkage first. Yes, it might be a little difficult to access.
 
asicer said:
1.1% over? I wouldn't sweat it. A couple extra HP in the climb might be useful anyway. Besides, the blue knob is a vernier, right?
Click to expand...

Correct. Good thought.

One of the docs I looked at said to fly it at prop full forward and then pull rpm back to where it should be, and land that way then check for clearance between the lever and the stop screw.
 
Is this the famous screw? It’s accessible with the cowl on. In the pic, the prop is to the left, cylinder to the right.

F72EE8FA-E1BB-4773-AE18-0C73910CFBB7.jpeg
 
455 Bravo Uniform said:
I used my optical tach on my latest takeoff and it registered 2650’ish RPM. The “redline” is 2620. Yes, my optical tach is reading accurately.

How involved is the calibration/adjustment of the governor? In other words, how much equipment and testing (time & money)? Or is it a matter of the A&P “just” turning a screw in one direction and going for a flight/ground run with a certified tach?

If this has been happening unbeknownst to me for however long it’s been happening, should I be worried about prior damage or component fatigue? Or is 30 rpm considered within acceptable error?
Click to expand...

30 RPM is no problem,
 
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