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Prop pitch

H

Handclutch

Well Known Member
I have bought a 12 just out of its test phase. Big decision after flying twins for almost 30 years, but I am loving it. I have much to learn and expect to be asking many questions on this forum.

Performance is meeting expectations but I'm wondering if the proper pitch needs fine-tuning slightly. From research on this forum and elsewhere it seems that 4950 is about right for static rpm. Mine is 5000. The other recommendation is 5000 to 5600 WOT at cruising altitude with 5200 the absolute minimum. I'm getting 5700 at 4000 feet.

I suspect the pitch needs to be coarsened just a whisker but am interested in what others are finding (and plan to get a few more hours under my belt anyway before making changes).

John M
 
John your pitch is good where it is if you are interested in just a little bit extra climb performance.
You could increase the pitch just a tiny bit if you want just a bit better cruise, particularly if you tend to stay at lower altitudes.

BTW, even an ideal cruise pitch setting will require that you cruise at less than full throttle below about 8-10K
 
Thanks. The other number I forgot to mention is that I'm getting 5100 on take-off. My experience is still very limited. I need to do a few trips at different altitudes to get a better handle on performance before contemplating any changes.
 
Handclutch said:
Thanks. The other number I forgot to mention is that I'm getting 5100 on take-off. My experience is still very limited. I need to do a few trips at different altitudes to get a better handle on performance before contemplating any changes.
Click to expand...

For the 5100 RPM info to be of any value you would have to also say what airspeed is at that RPM, but it sounds like the set-up is pretty close.
After you have flown it more you will be able to decide on whether to tweak it a bit.
 
5100 rpm prior to rotation and at 65 - 75 kts during initial climb. I agree that any change that I might settle on should be tiny - the aircraft performs extremely well. Suspect I will come to the conclusion that it isn't worth worrying about!

John M
 
If you do decide to adjust the pitch, you will be surprised at just how little of a change is needed. Just a whisker will result in changes in static RPM. Also, you should check that both blades are twisted at the same angle. There is enough play in the adjustment that each blade can vary from the other. I bought an electronic angle finder and build a little jig that fits on the prop.

Just FYI, my static RPM is right at 4950 and I am happy with both the climb and the cruise performance.
 
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