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  #1  
Old 12-03-2015, 06:35 PM
8 ball 8 ball is offline
 
Join Date: Dec 2014
Location: hilltop lakes' Texas
Posts: 135
Default Fuel flow takeoff power

I have an o-320 that has 9.37:1 cr. (measured). It turns a metal Senchenich 72x75 2280 shortly after takeoff. Fuel flow is 11.5 gph. How does this sound? Lean? On hot Texas days I have to keep it
above 140 mph up to about 4000 ft. to keep cht's. below 425 f. The baffeling is very tight (all holes and cracks filled). It has the air exit ramp between the dual exhaust.
RV 8. 1155 lbs
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  #2  
Old 12-03-2015, 06:45 PM
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bobbyhargrave bobbyhargrave is offline
 
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I see 19 gph on takeoff and climb at full throttle and 2700 rpm. O-360-A1A, Hartzell c/s, Marvel M5 carb., 120kias climb speed with no CHT exceedance.
Sounds lean to me.
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  #3  
Old 12-03-2015, 07:11 PM
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N941WR N941WR is offline
 
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Check the Lycoming operating manual for your O-320. Your numbers sound about right but I really don't know for sure.

The (I)O-360 can drink some fuel. When I was breaking in my O-360 I was planning on between 16 and 17 GPH at full throttle and full rich.
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  #4  
Old 12-03-2015, 07:29 PM
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n82rb n82rb is offline
 
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The lycoming chart showed about .58lbs/bph/hr that's about 15 gal/hr full rich,full power, standard sea level day.l

Bob burns n82rb rv-4
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  #5  
Old 12-03-2015, 07:53 PM
8 ball 8 ball is offline
 
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Location: hilltop lakes' Texas
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Default Takeoff fuel flow

Thanks folks, anyone have experience with jet size? Just open it up a few thousandths?
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  #6  
Old 12-03-2015, 09:45 PM
rv7charlie rv7charlie is offline
 
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Quote:
Originally Posted by n82rb View Post
The lycoming chart showed about .58lbs/bph/hr that's about 15 gal/hr full rich,full power, standard sea level day.l

Bob burns n82rb rv-4
Time out; he's got a fixed pitch prop. .58-.60 is likely a good number range, but you need to find power at his actual takeoff rpm (2200) & full throttle, not full power (2700rpm).

I see around 13-14 gph with an O-320/160 hp. I'm suspicious that it runs a bit richer than Lyc spec at full throttle.

What does the chart say at sea level MAP & 2200rpm?

Charlie
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  #7  
Old 12-03-2015, 10:19 PM
Beancounter Beancounter is offline
 
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8 Ball
I have 9:1 comp o-320, 72" fixed pitch sensenich prop combination and get very similar RPM's after take off. I see 11.1 gph at that RPM. Not saying that this is good just a data point.

From the Lycoming chart I calculate aprox 110hp at 2300 rpm or 69% of 160 rated power. Using .6 BFSC x 110hp = 66 lbs/hr or 11gph. If I am reading the chart correctly at 2300 rpm and between 24-28"mp the flow is 9.5-12gph.
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  #8  
Old 12-04-2015, 04:42 AM
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swisseagle swisseagle is offline
 
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I see at full power on ground this:

IO-320 / 160HP
Sensenich metall FP
2200 RPM
79% Power
12.2 GPH

Hope it helps!
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  #9  
Old 12-04-2015, 05:40 AM
8 ball 8 ball is offline
 
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Location: hilltop lakes' Texas
Posts: 135
Default Takeoff fuel flow

Bean counter sounds like a fairly close comparison.
I am definitely in the 9 to12 range. I have had the timimg all over between 20 to 30 degrees. 20 helps some but costs over 50 rpm at altitude.
Thanks for all the help fellows.
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  #10  
Old 12-04-2015, 07:00 AM
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Sam Buchanan Sam Buchanan is offline
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Quote:
Originally Posted by 8 ball View Post
I have an o-320 that has 9.37:1 cr. (measured). It turns a metal Senchenich 72x75 2280 shortly after takeoff. Fuel flow is 11.5 gph. How does this sound? Lean? On hot Texas days I have to keep it
above 140 mph up to about 4000 ft. to keep cht's. below 425 f. The baffeling is very tight (all holes and cracks filled). It has the air exit ramp between the dual exhaust.
RV 8. 1155 lbs
Those are about the same numbers (rpm and flow) that I see with my RV-6 (O-320, Sensenich 70x80).
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