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  #1  
Old 12-14-2017, 04:57 PM
nightflier nightflier is offline
 
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Default Percent power vs RPM

Trying to establish percent power for POH for RV9A, with 160 HP Catto prop. ANy ideas?
Thanks,
Sam
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  #2  
Old 12-14-2017, 05:32 PM
moosepileit moosepileit is offline
 
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http://www.vansairforce.com/communit...hp?t-8037.html searched for thread.

Searched for a Lyc image, I know the rpm is probably too low for a Catto.
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Last edited by moosepileit : 12-14-2017 at 05:38 PM.
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  #3  
Old 12-14-2017, 05:55 PM
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vlittle vlittle is offline
 
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Quote:
Originally Posted by nightflier View Post
Trying to establish percent power for POH for RV9A, with 160 HP Catto prop. ANy ideas?
Thanks,
Sam
Search the forums "Engine Power Percentage?"
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  #4  
Old 12-14-2017, 06:10 PM
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sirlegin sirlegin is offline
 
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Here's what I use in my 9A 160HP Catto 3 blade

POWER SETTING PERCENTAGE
RPM X 100 + MP (INCHES)
60=100%
57=95%
51=85%
48=75%
45=65%
42=60%
39=55%
36=50%
33=45%
30=40%
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  #5  
Old 12-14-2017, 06:55 PM
brad walton brad walton is offline
 
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Originally saw the manifold pressure plus rpm formula from the RVator. But I doubt its accuracy. I can run 24/24 at low altitude burning 9 gph. I don't think I'm getting 75% power at less than 10.5 to 11 gph
Mine is an io 360

Last edited by brad walton : 12-14-2017 at 07:15 PM. Reason: Add text re displacement
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  #6  
Old 12-15-2017, 08:20 AM
Rupester Rupester is offline
 
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The GRT EFIS installation manual just happens to have a MP-RPM-%power chart for an O-320. It's used to set up the EFIS for display of % power. I don't have access to my install manual at present, but I think you can access it at GRTs website under "documentation".
When I was doing the setup for mine, that was the best &clearest reference I found for % power. Further, when I checked it matched those mind-boggling Lyco graphs perfectly.
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  #7  
Old 12-15-2017, 01:15 PM
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sirlegin sirlegin is offline
 
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Quote:
Originally Posted by RV8JD View Post
I think you meant RPM/100 + MP.

Example: 2450/100 + 23.5 = 48 is approximately 75% power.
I'm glad you were paying attention. Thanks
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  #8  
Old 12-16-2017, 01:32 PM
nightflier nightflier is offline
 
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Default O320 % power

Thanks for you help guys, VAF comes through again!
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  #9  
Old 12-16-2017, 03:32 PM
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Jesse Jesse is offline
 
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I understand that the equation gives you an approximation, but Manifold Pressure plays a bigger part in power than does RPM, does it not? For example, to get 75% power, the number 48 assumes 24 squared, I guess. However, if you increase RPM to 2700 and reduce MAP to 21, the number 48 does not yield 75% power. Likewise, 30 of MAP and 1800RPM would likely yield more than 75% power (while not advisable to fly that far over squared. Is there an equation somewhere that gives a weightingvto RPM & MAP that are more true to life than the even weighting?
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  #10  
Old 01-12-2018, 06:24 AM
svyolo svyolo is offline
 
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Power is also a function of how fast you are producing work. So RPM definitely matters.

Anybody got a resource for what this all means LOP? 24/24 at SL is 75%. I think Lyc doesn't want you to lean above 70% or something like that. Lets take 65%. What is the "square" power setting for 65% ROP, and what is it LOP. I assume the 22/22 ROP is more power than 22/22 LOP. Or maybe I am wrong.
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