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Permalink Reply by Larry Ward on January 29, 2019 at 8:33pm

I have a 350i engine and it did not come with red cube flow meters.  So I just connected the white/red wire from the ECU to P14 on the EMS.  Once this was done I had to calculate the new K factor to put in Skyview.  Since 170 pulses/second was equal to 48L/hr, I converted liters to gallons and 170 pulses/second to pulses/hr and doing the math it came out that 1 gal/hr was equal to 48265 pulses/hr.  Once I had this number, I went it Skyview and entered the new number.  So far it seems to be giving me an accurate flow rate.  However this is based on ground runs and taxi tests only.  I just completed my airworthiness inspection yesterday and it will be at least a couple of weeks before I can fly and get some flying data.  Hope this helps.

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Permalink Reply by Doug Malloy on January 30, 2019 at 12:08am

Thanks Larry, that is what I needed. Congrats again on your airworthiness inspection. Now the fun begins! Let me know how it goes. I am doing my first taxi checks this week, so it won't be long for my Airworthiness as well.

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Permalink Reply by John Bell on May 11, 2022 at 4:42pm

Hi Larry. How did your K factor number work out in real world flying? Where did you get the pulse per litre info from? I have the 350is.

Just got my C of A and have an hour and a half on it but fuel flow on is way off. 

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Permalink Reply by Douglas Kupersmith on May 16, 2022 at 7:17am

Hi John. I'm not sure what "way off" is on your fuel flow, but using the same method as Larry (above), I find my fuel flows seem appropriate.  I confirm this by jotting down the Skyview fuel consumption numbers at the end of each flight and comparing them to the amount of fuel added back in to refill each tank. It's always within one or two tenths of a gallon.

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Permalink Reply by John Bell on May 16, 2022 at 3:17pm

The 12 gallons an hour includes flow return, correct?
My first few fills show consumption of around 6 gallons per hour which is what I’d expect.

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Permalink Reply by Douglas Kupersmith on May 17, 2022 at 10:19am

No, it does not include fuel return.  The 12 gal/hour is converted from the ULPower installation manual where it says the maximum fuel flow possible with the engine's fuel injection system is 48 liters/hour.  From that point, it's a straightforward mathematical reduction to determine pulses/liter or, for the case of the Dynon Skyview EMS, pulses per gallon.  At the maximum (theoretical) listed fuel flow, the injection system is outputting 170 pulses per second.  Lower throttle settings will result in lower pps and therefore lower fuel flow. 

So as Larry Ward wrote above, when the white/red lead from the ULPower ECU cockpit loom is connected to the Dynon EMS Pin 14, it reads the pulses from the motor and applies the pulses per gallon factor you input in setup to derive a real time gallons per hour reading.  From my experience, my max fuel flow tops out in the high 8s (8.7 - 9.0 gph during takeoff and early climb), cruises around 5.5 - 7.0 gph (depending on altitude, speed, weight, etc), and idles around 1.3 - 1.8 gph.  Using the Skyview performance data recording capability, I have detailed spreadsheets of my first 30 flights.  The spreadsheets contain ~ 80 columns of individual data points of up to 20,000 rows recording at 2 samples per second.

I also pull out max, min and average for many of those categories as a quick look at potential issues.  One of those averages is average fuel flow for the flight which includes taxi (basically fuel flow while the Hobbs is running). While this number can vary widely by mission, I generally get 4.2 to 5.4 gph as the overall average, which is clearly low due primarily to time spent taxiing ... but I'm mainly watching that metric for my wallet!

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Permalink Reply by John Bell on May 17, 2022 at 2:42pm

That all makes perfect sense to me now. It was the 12 g/hr out of context that had me head scratching.

Looks like I’m in the same ball park as you.

Thanks.

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Permalink Reply by Tom Sullivan on April 17, 2019 at 10:04pm

Guys, Thanks very much for this info. I had it wrong and never would have figured it out without your input. Tom (old not very computer savvy guy)

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