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  #1  
Old 02-02-2019, 08:04 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
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Default Fuel Consumption

What are you guys seeing for fuel consumption at cruise? Iíve got a little over 800 hrs on my 912ULS and have seen the the burn rate creep up from4.5 GPH to 5.1 GPH at 4200 RPM AND 22Ē MAP over the last 300 hours. Is that what you guys are seeing?

Rich
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  #2  
Old 02-02-2019, 11:37 PM
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Piper J3 Piper J3 is offline
 
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Are you really flying around are 4200 RPM?

Look here for fuel burn rate... http://www.vansairforce.com/communit...5&postcount=34
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  #3  
Old 02-03-2019, 12:24 AM
NinerBikes NinerBikes is offline
 
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Are you running Mogas, and has it lately been winter blend? You will use more fuel in the winter time than summer time, air is more dense due to the lower average temperatures.
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  #4  
Old 02-03-2019, 09:38 AM
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DaleB DaleB is offline
 
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Our fuel burn was considerably higher than what others reported. During our last CI I did the carb inspection, which includes replacing the metering needle, float valves, etc. We also found a bad left choke cable that may have been keeping the left side starting carb from shutting off completely. Afterward our fuel consumption dropped by at least 1/2 GPH in cruise. We'll never know for sure, but think at least part of that was from replacing worn fuel metering parts.

About the only time I see 22" MAP is during descent and in the pattern, though. Couldn't tell you what the fuel consumption is then.
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  #5  
Old 02-03-2019, 08:04 PM
RFSchaller RFSchaller is offline
 
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Oops! I meant 5200. Math in public overloads my aging brain!😱😝
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  #6  
Old 02-04-2019, 04:45 AM
AirHound AirHound is offline
 
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Location: OFallon IL now, everywhere before
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Quote:
Originally Posted by DaleB View Post
Our fuel burn was considerably higher than what others reported. During our last CI I did the carb inspection, which includes replacing the metering needle, float valves, etc. We also found a bad left choke cable that may have been keeping the left side starting carb from shutting off completely. Afterward our fuel consumption dropped by at least 1/2 GPH in cruise. We'll never know for sure, but think at least part of that was from replacing worn fuel metering parts.

About the only time I see 22" MAP is during descent and in the pattern, though. Couldn't tell you what the fuel consumption is then.
Dale, what is MAP on take off and initial climb? Doug
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  #7  
Old 02-04-2019, 09:15 AM
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DaleB DaleB is offline
 
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Quote:
Originally Posted by AirHound View Post
Dale, what is MAP on take off and initial climb? Doug
Have never noticed, to be honest. On takeoff and climb I have the throttle wide open, eyeballs outside and occasionally glance at airspeed. If I EVER get to fly again (it's been a long, long month of cr@p weather here) I'll try to get a look and remember what it is.
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Previous RV-7 project (sold)
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  #8  
Old 02-04-2019, 02:36 PM
AndrewR AndrewR is offline
 
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Location: Ballarat, VIC
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Quote:
Originally Posted by RFSchaller View Post
Iíve got a little over 800 hrs on my 912ULS and have seen the the burn rate creep up from4.5 GPH to 5.1 GPH
At 800 hours I'd be tempted to replace the needles and needle jets in the carbs.

Cheap and easy, and a prime suspect if you are seeing increased fuel consumption.
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  #9  
Old 02-04-2019, 07:22 PM
RFSchaller RFSchaller is offline
 
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Andrew, I had my carbs overhauled at about 500 hours.

Rich
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  #10  
Old 02-04-2019, 11:30 PM
AndrewR AndrewR is offline
 
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Quote:
Originally Posted by RFSchaller View Post
Andrew, I had my carbs overhauled at about 500 hours.
Did they replace the needles & needle jets? (Probably, but not necessarily.)

Last 200 hour carb inspection on my Rotax was 400 hours, the comment was they'd maybe replace them next time (600 hours).

Even so, your overhaul was 300 hours ago... the manual calls for inspection every 200 hours. It could be worth a look.

Or maybe your flying style has changed? Air filters excessively oiled?
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