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  #141  
Old 07-30-2017, 11:00 PM
rv6ejguy's Avatar
rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,191
Default

Some more info from Dave flying back home from Osh:

"This was after leaving Great Falls Montana on the way home. Those are obviously incorrect winds and xw. Then look at 31.4 mpg at this low altitude at about 20” MAP at 2200 rpm, while truing 197mph. I love this system, you can full power or lean with no problems and it starts like a car, even on hot starts."





Dave says he's overcooling in cruise running LOP and will look at reducing the inlet ring size at some point.

The SDS programmer here shows the AFR at 16.7 which is well LOP.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 418.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 07-31-2017 at 09:16 AM.
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  #142  
Old 08-01-2017, 05:36 PM
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rv6ejguy rv6ejguy is offline
 
Join Date: Mar 2005
Location: Calgary, Canada
Posts: 4,191
Default SDS Digital Fuel Flow Accuracy

Some more feedback from Dave today showing the accuracy of our optional FF software. We generate a pulse train from the ECU to feed the engine monitor so no Red Cubes are required.

"Just wanted to let you know that the speed we did in the race was while burning 14.5 gph, confirmed by the max FF indication I was getting when using the SDS fuel signal was within 0.1gph and confirmed by the fuel added at the pump at the pit stop, so at that flow, the FF was accurate to within .227 gals of all the 32 gals in my tanks. During those conditions my engine was producing about 194 real hp at 2830 rpm. Also during the race I burned the left tank out until I saw the fuel pressure fluctuate 2-3 lbs off of max pressure then changed the selector to the tanks without even a hesitation in the engine operation.

hp = 14.5 gph x 5.9 lbs/gal / 0.44 bsfc"
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 418.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


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  #143  
Old 08-01-2017, 05:54 PM
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M McGraw M McGraw is offline
 
Join Date: Dec 2012
Location: Greenback, TN
Posts: 339
Default FF calc

I have been collecting a lot of data on my install. I do plan to publish it in the future after about 100 hours of use. Currently - at 50 hours - I am consistently within 0.1 gallons at fill up on my IO-390 using the SDSEFI system.
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Marvin McGraw, 5TN4
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  #144  
Old 08-01-2017, 06:11 PM
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rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
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Thanks Marvin. Barry will be happy to know all his hard work paid off writing this software. It was dead on in lab testing but nothing like these real world results on running engines to fully confirm.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 418.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


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  #145  
Old 08-01-2017, 08:01 PM
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Toobuilder Toobuilder is offline
 
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Location: Mojave
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Im very happy to hear the computed fuel flow of the SDS ECU is consistently accurate. I never liked that fuel flow meter clap trap on the engine and especially after Dan dissected one which revealed the miniscule flow passages. Good riddance!

I have just flow tested my new fuel system for the Rocket and am happy to report that it flows 60 GPH with the single pump and 90 with the second running. During the retrofit I went to great lengths to eliminate 90 degree fittings on the suction side, including changing the in tank pickup to a straight fitting. An interesting side note is that I also intended to run two Faccet cube pumps as "pushers" right at the wing roots thinking that my planned use of auto gas would need help to prevent vapor lock. I decided to only install one cube pump for the test period so that I could easily determine if I needed to add the second, or remove the first. During the FF test I noted that the "cube side" sounded more labored than the "non cube side" despite the fact that there was no measurable difference in delivered flow rate. Based upon this, I would not be surprised to find that the added restriction of the cube pump has actually increased my susceptibility to vapor related issues. Testing will determine.

At any rate, the less hardware in the loop, the better! Thanks Ross!
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WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
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Harmon Rocket II -SDS EFI instalation in work
RV-8 - Flying
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  #146  
Old 08-01-2017, 08:41 PM
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rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
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Very good numbers Brad. What timing are you running? Compression ratio? Airframe? Prop?
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 418.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


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  #147  
Old 12-08-2017, 09:34 AM
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rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
Posts: 4,191
Default Battery Update and Reserve Number Analysis

Dave just installed two Shorai LiFePO4 batteries.

"I decided that I didn't have a long enough reserve capacity in my aux battery. I put in brand new batteries at the time i installed the SDS then put in a larger aux batt when I put the injectors into their new locations on the heads. I looked at the failure voltages of the essential electric components, and the fuel pump is around 9V. Then after looking at the capacity of the aux batt and the voltage decrease as the lead acid battery draws down, I decided that I didn't have enough flying time before i got down to 9V.

With the old system (before i was all electric) I had the Plasma ignitions that would go down to 6V or slightly less. I actually tested that and if I had a total bus failure back then just after take off, I could switch to the aux batt and I would run out of fuel before I lost power to the ignitions. This is not the case now, because as I tested it, my minimum emergency current draw is about 7A.

You may remember that I have the fuel solenoid on the throttle body so all I need is 1 ignition, 1 fuel pump, and that fuel solenoid turned on. Now with the LiFEPO4 36 Ah lead acid equiv aux battery (which isn't really) I can get 1.2 hrs at voltages above 12.8V at a 7A draw.

I can test the batteries individually before I start, to see their voltages, and determine their capacity remaining based on their voltage. The aux batt charges through a Schottky diode so it's not going to get a totally maximum capacity charge but should charge to about 95% of capacity, which would still be enough flying time. If a total main bus and main battery failure occurred in flight, I would have a 320 mile diameter to find a place to land and that would be the worse case scenario. I monitor and alarm the buss minimum/maximum voltages, now set for the LiFePO4 batteries, through my Dynon Skyview.

More likely, an alternator failure may occur and the diameter of the circle increases to about 600 miles because you would use the main batt first. Also with the "indicated voltage/remaining capacity chart" you can actually kind of determine the time remaining as the capacity decreases while the voltage is drawn down.

It took a little work to get the batteries in. I had to reroute fuel lines in the compartment where the batteries are and insulate the batts from the fuselage skin. They were a net 14 lbs lighter."

__________________

Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 418.1 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm


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