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  #31  
Old 09-15-2021, 08:48 AM
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charosenz charosenz is offline
 
Join Date: Aug 2009
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Quote:
Originally Posted by toninialex View Post
I do remember well a Lyc 360/190 HP on a Falco,2 bld hydraulic prop sized 74" model GT2-V29 had 26/28° 175 kts . Measures were recorded by a special equipment homade that we still positively use on different planes/engines/ tests combo .

https://www.facebook.com/GtProp/photos/1203278443110230

Hope this can help.

K regards Alex

www.instagram.com/gtpropellers/
This is very interesting. I looked at the link but cannot find the pages that have the pitch data. Can you provide a link to that? Either here or PM.

Thanks.
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  #32  
Old 09-15-2021, 10:53 AM
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rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by birddog486 View Post
I'm not exactly sure what your saying here but If you have a constant speed Hartzell and you haven't adjusted the low pitch stop on the prop, the governor is controlling your RPM on takeoff.

If your climbing out at 2700 and the governor fails with a correctly set low pitch stop you wont notice any RPM change until you reduce the climb rate or gain speed both of which will increase RPM.

On the other hand, If your climbing out and the governor fails and you haven't adjusted the low pitch stop, the engine over revs and can destroy itself.

My new hartzell was so far off in adjustment if my governor would have failed the engine would have potentially been close to 3800 RPM in the climb. I cant imagine what the RPM could climb to in cruise at that setting with a governor failure but I'm betting if you dont catch it in time the engine is junk.

The low pitch stop is an easy adjustment and I believe it's recommended in the manual for all new installations
The Hartzel manual has a procedure for confirming that the low pitch stop is set correctly, but it only needs to be adjusted if that check shows that it is not within spec (This should be checked on every new installation). I think I have only had to adjust one propeller out of many installations on RV's... they are usually spot on.

As others have said, the test / adjust procedure is setting the stop relative to a static RPM. Once the airplane begins to gain airspeed the RPM would increase if it was only the low pitch stop controlling RPM in climb (just like a fixed pitch prop does). Because of that, it is not the low pitch stop regulating the RPM once the airplane is moving. That is handled by the gov.
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  #33  
Old 09-15-2021, 11:13 AM
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charosenz charosenz is offline
 
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Quote:
Originally Posted by rvbuilder2002 View Post
The Hartzel manual has a procedure for confirming that the low pitch stop is set correctly, but it only needs to be adjusted if that check shows that it is not within spec (This should be checked on every new installation). I think I have only had to adjust one propeller out of many installations on RV's... they are usually spot on.

As others have said, the test / adjust procedure is setting the stop relative to a static RPM. Once the airplane begins to gain airspeed the RPM would increase if it was only the low pitch stop controlling RPM in climb (just like a fixed pitch prop does). Because of that, it is not the low pitch stop regulating the RPM once the airplane is moving. That is handled by the gov.
Thanks Scott....
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  #34  
Old 09-16-2021, 08:52 PM
birddog486 birddog486 is offline
 
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Quote:
Originally Posted by rzbill View Post

With your 3800 rpm failure scenario, what was your static rpm? What performance feedback did you use to adjust your fine stop?
The static RPM before adjustment was 2710 ( the governor was doing it's job) It took 5 full turns on the low pitch stop to reduce the RPM to 2600 static. Hartzell and lycoming have different specs out there from 2600-2650 static for a constant speed, I've also seen a couple as high as 2690.

I choose to be more conservative at about 2550 static which gives me 2700 at VX. It's possible the governor is having an influence even at that speed

Last edited by birddog486 : 09-16-2021 at 08:56 PM.
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  #35  
Old 09-17-2021, 12:44 AM
BobTurner BobTurner is online now
 
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Quote:
Originally Posted by birddog486 View Post
The static RPM before adjustment was 2710 ( the governor was doing it's job) It took 5 full turns on the low pitch stop to reduce the RPM to 2600 static.
I choose to be more conservative at about 2550 static which gives me 2700 at VX. It's possible the governor is having an influence even at that speed
Per the Hartzell manual, 1 turn should have changed rpm by 200 rpm. Something isn’t right here.
As to ‘being conservative’: True, you’ve lessened the risk of an overspeed if the governor fails and you’re at Vx (How much time do you spend there?). But you’re starting every takeoff with 5% less than full power. I’m not sure which is a greater risk.
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  #36  
Old 09-17-2021, 04:39 AM
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I see that you have chosen to operate the prop as a fixed pitch unit from takeoff to Vx. As you are the first person i have talked with to choose that route, i had not considered it in the previous operation comments. To each his own. I prefer the improved TO acceleration of full CS operation.
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