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07-08-2017, 05:48 PM
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Join Date: Dec 2007
Location: Peachtree City, GA
Posts: 144
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Quote:
Originally Posted by rv6ejguy
Interesting. Surprised at such high MAP in the descent. Certainly different from a turbo SI engine. Is there a minimum MAP they recommend in flight to keep the fires lit?
They don't have any FF signal available out of the FADEC?
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Remember, takeoff power is 83 to 90" depending on conditions, so 60" really isn't that high. They do recommend 30-45" MAP depending on OAT to insure auto ignition. I can tell you I have never seen it below 31" even at low idle on the ground.
This engine has no FADEC. Straight mechanical fuel injection unlike the CD-135/155 and no servo control function like its SMA cousin.
__________________
Scott Flandermeyer
Rv-10 TDI 300 hrs
Fayettevile, GA
2020 VAF Donation complete
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07-08-2017, 06:10 PM
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Join Date: Dec 2007
Location: Peachtree City, GA
Posts: 144
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Quote:
Originally Posted by rv7charlie
Hi Scott,
Have you looked at the older style FloScan sensors? They make them specifically for diesel engines (marine), and as far as I know, their K factor is similar to the gas version. Therefore, they should work with your gauge/EFIS, since (again, as far as I know), the FloScan & red cube sensors are supposed to interchange.
Just a thought,
Charlie
http://www.floscan.com/dnloads/floscanfinal.pdf
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Charlie,
I actually called the folks at FloScan to talk with them about their diesel systems. The engineer couldn't hang up the phone fast enough when I explained what type engine I was using.  It didn't matter that it would be a certified aircraft engine.
Most marine diesel FF meters that would work speak DIGITAL and aviation displays speak ANALOG. The problem aviation version of the FloScan and Red Cube have are that the Bosch mechanical injector pump introduces 3200 pulses/minute(idle) and 8800 pulses/minute(flight) into the incoming fuel stream. Think shockwaves or instantaneous microstops to the incoming fuel. This drives the turbine meter systems nuts. And yes I've looked into digital to analog convertors. I've yet to find one that can work with the few number of pulses per gallon the system would produce at idle. I actually found a system that was designed to account for these pulses, but again, its output was digital.
I knew when I committed to installing this engine, I would be on the cutting edge. I just didn't think I would be the FIRST one, I expected an OEM to get there first.
__________________
Scott Flandermeyer
Rv-10 TDI 300 hrs
Fayettevile, GA
2020 VAF Donation complete
Last edited by Flandy10 : 07-08-2017 at 06:46 PM.
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07-08-2017, 08:36 PM
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Join Date: May 2006
Location: Pocahontas MS
Posts: 3,884
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Hmmm...I always thought that the FloScans & red cubes output pulses, with the K factor related to how many pulses per gallon (or pound; whatever).
Oh, well.
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07-09-2017, 06:06 AM
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Join Date: Nov 2010
Location: Boston Area
Posts: 135
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Very interesting. Do you know if the certified version will be FADEC?
Tim
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07-09-2017, 07:22 AM
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Join Date: Mar 2005
Location: Calgary, Canada
Posts: 5,766
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I wrongly assumed this engine used a FADEC with backup mechanical system like the SMA engine. Thanks for the correction.
Last edited by rv6ejguy : 07-17-2018 at 09:02 PM.
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07-09-2017, 12:36 PM
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Join Date: Dec 2013
Location: SLC, UT (KBTF)
Posts: 240
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Pulse Damper
Scott,
Would a pulse damper (or two in series) between the FloScan sensor and the injector pump isolate the sensor from the pulses?
Cheers, David
RV-6A KBTF
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07-09-2017, 05:49 PM
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Join Date: Dec 2007
Location: Peachtree City, GA
Posts: 144
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Quote:
Originally Posted by rv7charlie
Hmmm...I always thought that the FloScans & red cubes output pulses, with the K factor related to how many pulses per gallon (or pound; whatever).
Oh, well.
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Charlie,
You understand them correctly. In fact, I verified the fuel flow of the duplex (supply and return) cube system prior to getting the engine. Its the injector pulses that introduce a stutter to the incoming fuel stream causing the flow through the cube to be jumpy. Its still flowing 48gph, just not a smooth flow that the turbine meters like.
__________________
Scott Flandermeyer
Rv-10 TDI 300 hrs
Fayettevile, GA
2020 VAF Donation complete
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07-09-2017, 05:58 PM
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Join Date: Dec 2007
Location: Peachtree City, GA
Posts: 144
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Quote:
Originally Posted by koupster
Scott,
Would a pulse damper (or two in series) between the FloScan sensor and the injector pump isolate the sensor from the pulses?
Cheers, David
RV-6A KBTF
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I was told, in France, they did some testing and found it took 3 spherical pulse dampeners to isolate the sensor. This was on a C182 with the SMA engine which has no return flow system. There is no room in the tunnel or under the cowl for that mess.
I am still in search of a better solution to this problem.
__________________
Scott Flandermeyer
Rv-10 TDI 300 hrs
Fayettevile, GA
2020 VAF Donation complete
Last edited by Flandy10 : 07-09-2017 at 06:50 PM.
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07-10-2017, 12:57 AM
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Join Date: Nov 2005
Location: KRTS
Posts: 1,798
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Quote:
Originally Posted by Flandy10
I was told, in France, they did some testing and found it took 3 spherical pulse dampeners to isolate the sensor. This was on a C182 with the SMA engine which has no return flow system. There is no room in the tunnel or under the cowl for that mess.
I am still in search of a better solution to this problem.
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What did Cessna use on the 172 and 182 diesels?
Not an elegant solution but what about wiring an on/off switch into the redcube? Turn it on as part of your takeoff check list... You know the fuel flow on the ground, anything short of an hour to taxi/takeoff is barely a rounding error for most top offs. Remember back in the day when you did it off the POH and then went to the fuel truck after a long flight to see if your math was accurate?
Tried talking to the EFIS manufacturers to see if there's a solution to using a digital box?
__________________
Next?, TBD
IAR-823, SOLD
RV-8, SOLD
RV-7, SOLD
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07-10-2017, 02:49 AM
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Join Date: Nov 2010
Location: Boston Area
Posts: 135
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To me a fuel totalizer is making up for bad fuel tank measurements. Would it not be easier to fix the problem of the fuel tank measurements then add one more bandaid?
Tim
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