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08-09-2011, 05:43 PM
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Join Date: Dec 2005
Location: Sweden, 67" North
Posts: 68
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My 5 Swedish cents
For fuel effiency and power, mixing different ignition system can`t be a good thing unless they have exactly the same timing curve, runnin a Mag together with a EI system is working "good enough" below around 2400rpm, the EI system alone ignites the Air/fuel mixture way before the magneto, and after 2400rpm the mag starts to mess with the Air/Fuel Mixture before the EI wants to ignite it...
Redundancy is a good thing, but to be fair, how often do you have a ignition problem on a car with CDI? As long you have power to the systems at least one of them will work, lets say your generator quits... Your battery will provide power to the systems long enough to get you down safe...
On the SAAB 2000 Airliner i curretly working with, it is a Fly By Wire aircraft, it has got a back up system on the back up system and so on, but in case of total AC power loss, you have 40min on the batteries, thats it...
=) /Dennis
__________________
Dennis Isaksson
G?llivare, Sweden
Grew up with an RV-4, SE-XIO
Now: RV-8, Showplanes Fastback. #83218 Under construction, SE-XXO
Engine and avionic installation in progress
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08-09-2011, 09:48 PM
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Join Date: Dec 2006
Location: Arroyo Grande, CA
Posts: 938
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Anyone flying with a battery-powered ignition should resolve to get the airplane on the ground with a failure of the main power even though they have a back-up battery. The LSE should have a minimum 4AH back-up, and should the main power fail in a dual EI, the back-up battery should support one EI for at least 1/2 hour to 1 hour at 1.6A at 2700 rpm drain on a four cylinder or at least 1/2 hour in 2.4A/EI six cylinder. A 4AH battery's capacitance drops off at higher load, so it will not support 2 hours at 2A. The one remarkable thing about the LSE is it will keep giving full spark power down to 6V +/- 0.5V. Everything else in the electrical load will have long-ago died before the LSE. That's really great when starting with a weak barrery because if the battery has at least 8V when the switch is turned on, the LSE will still operate down to 6V! Always play it safe!
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08-10-2011, 07:32 AM
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Join Date: Oct 2009
Location: Victoria, BC, Canada
Posts: 3,932
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Elippse, isn't the PMag, with it's internal alternator, insurance against battery/electrical failure? I understood that the design was such that it created it's own power like a conventional mag...
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Rob Prior
1996 RV-6 "Tweety" C-FRBP (formerly N196RV)
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08-10-2011, 02:03 PM
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Join Date: Mar 2007
Location: Sonoma County
Posts: 3,821
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Quote:
Originally Posted by elippse
Anyone flying with a battery-powered ignition should resolve to get the airplane on the ground with a failure of the main power even though they have a back-up battery. The LSE should have a minimum 4AH back-up, and should the main power fail in a dual EI, the back-up battery should support one EI for at least 1/2 hour to 1 hour at 1.6A at 2700 rpm drain on a four cylinder or at least 1/2 hour in 2.4A/EI six cylinder. A 4AH battery's capacitance drops off at higher load, so it will not support 2 hours at 2A. The one remarkable thing about the LSE is it will keep giving full spark power down to 6V +/- 0.5V. Everything else in the electrical load will have long-ago died before the LSE. That's really great when starting with a weak barrery because if the battery has at least 8V when the switch is turned on, the LSE will still operate down to 6V! Always play it safe!
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My back-up EI battery is 5.0 AH. 3.5 lbs. 4"X3.5X2.75". It lost .20 volts sitting on my bench for 8 months. $18.00 each.
http://www.mouser.com/ProductDetail/...5HNrGVBw%3d%3d
That gives me three sources of power for my Lightspeed IGN. without needing a built in power source (more parts).
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08-10-2011, 11:41 PM
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Join Date: Sep 2009
Location: Aloha, or
Posts: 282
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EFII
What Lycoming models can the FlyEFII system be used with? Looking at O320's and O360's. It isn't clear if the system is designed to adapt a Lycoming with a fuel injection system already or a carburetor model...
I mean, if your relying on electricity for spark anyways then might as well go for electronic fuel injection also.
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James Bagley Jr
RV6A flying
RV6 #2 tail done and wings done
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08-11-2011, 12:25 AM
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Join Date: Jun 2006
Location: tucson, az
Posts: 104
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EFII
Does anyone know how much the EFII-1 Complete Electronic Fuel Injection and Ignition System costs?
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Bill Finnell
RV-8 Fuselage
Tucson AZ
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08-11-2011, 02:20 AM
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Join Date: Mar 2007
Location: Sonoma County
Posts: 3,821
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Quote:
Originally Posted by wfinnell
Does anyone know how much the EFII-1 Complete Electronic Fuel Injection and Ignition System costs?
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http://www.aircraftspruce.com/catalo...ges/ptefii.php
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Description Part No. Price Buy
EFII ELECTRONIC FUEL ENJ SYS 07-01849 $4995.00
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08-11-2011, 09:56 AM
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Join Date: Jan 2008
Location: Upland, CA
Posts: 286
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EFII applications
Hi James,
The EFII-1 kit can be used on any of the 320 or 360 Lyc engines.
Personally, I agree with you about switching to the complete electronic engine management. Once you have flown behind a Lyc with modern engine control, you'll never want to go back.
Robert Paisley
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08-13-2011, 01:05 AM
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Join Date: Mar 2005
Location: SE Florida
Posts: 1,499
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Fuel pumps for fuel injection versus carburetor
Quote:
Originally Posted by jbagley
What Lycoming models can the FlyEFII system be used with? Looking at O320's and O360's. It isn't clear if the system is designed to adapt a Lycoming with a fuel injection system already or a carburetor model...
I mean, if your relying on electricity for spark anyways then might as well go for electronic fuel injection also.
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FYI,
Carburetor engines require anywhere from 0.5 to 6 psi to be output from both the mechanical and the electric boost pumps. Any more pressure than that, will cause the carb to flood. The mechanical fuel injection used by Bendix [aka Precision] & Airflow Performance need 25 psi [10 to 40 psi is allowable] to operate.
I can not comment on whether FlyEFII has a variant of their fuel pump designed for the low pressure needs of a carb. Actually, only the fuel pressure relief valve would need to be different.
Using electronic fuel injection would GREATLY increase the number of amps that your aircraft would need to supply in an "alternator out" situation. This would require the use of an electrical design such as Bob Nuckholls suggests in his book AEROELECTRIC CONNECTION.
http://www.aeroelectric.com/Catalog/pub/pub.html
See his Z13 wiring schematic. If you do not already own this book, I STRONGLY suggest you read it, so that you can understand the issues involved with electrically dependent engines. Electronic EFI will also add a control computer to the system. This adds another "single point of failure" to the system. Computer failure in autos is not common, but it does happen occasionally.
Perhaps Mr. Paisley can comment knowledgeably regarding the fuel pressure requirements of their EFI system. My 25 years experience with automotive port fuel injection is that they require fuel pressures in the 30 to 60 psi range.
Charlie
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08-13-2011, 06:22 AM
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Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,514
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Quote:
Originally Posted by chaskuss
FYI,
Carburetor engines require anywhere from 0.5 to 6 psi to be output from both the mechanical and the electric boost pumps. Any more pressure than that, will cause the carb to flood. The mechanical fuel injection used by Bendix [aka Precision] & Airflow Performance need 25 psi [10 to 40 psi is allowable] to operate.
I can not comment on whether FlyEFII has a variant of their fuel pump designed for the low pressure needs of a carb. Actually, only the fuel pressure relief valve would need to be different.
Using electronic fuel injection would GREATLY increase the number of amps that your aircraft would need to supply in an "alternator out" situation. This would require the use of an electrical design such as Bob Nuckholls suggests in his book AEROELECTRIC CONNECTION.
http://www.aeroelectric.com/Catalog/pub/pub.html
See his Z13 wiring schematic. If you do not already own this book, I STRONGLY suggest you read it, so that you can understand the issues involved with electrically dependent engines. Electronic EFI will also add a control computer to the system. This adds another "single point of failure" to the system. Computer failure in autos is not common, but it does happen occasionally.
Perhaps Mr. Paisley can comment knowledgeably regarding the fuel pressure requirements of their EFI system. My 25 years experience with automotive port fuel injection is that they require fuel pressures in the 30 to 60 psi range.
Charlie
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My understanding of how these systems work is the computer controls the fuel/air ratio by varying the time the injector is open. The proper F/A ratio is then a function of injector time open AND fuel pressure. If fuel pressure varies, so does the F/A ratio. A reliable pressure regulator is essential.
Ross Farnham at
http://www.sdsefi.com/
probably knows as much about these systems as anyone on the planet. Before making a move in this direction be sure to check out what is going on with his company.
I believe the most sophisticated systems come from the auto manufactures. The original Subaru ECU that came with the 4 cylinder engines was excellent, its only short coming was lack of pilot control of the F/A ratio, which was somewhat conquered by Robert and Jan by adjusting fuel pressure. The pressure regulator that was adjusted by MP was a great idea and worked reasonably well. That regulator also had an adjustable needle valve to reset basic pressure. Mine was lowered from about 40 to 32 to get fuel flow down to a reasonable level. This adjustment has to be monitored with a F/A meter. The systems marketed by Robert and Ross I believe include such an instrument. It is essential if the pilot has the capability to set F/A ratio in flight.
There are a number of Lycoming engines operating in the field with ECU systems but I do not know of any personal reports on their success or problems. Such reports are essential before spending the kind of money we are looking at, not only for the system but for that lost getting rid of an existing system. (I suppose one could buy a Lycoming kit without a fuel system or mags and go from there, it would make sense financially.)
I've been down this road and spent a ton of money along the way. The results were mixed. Some of it was fun, some not. But I learned a lot and I guess that's worth something.
As you know, I am back to Lycoming and mags with the AFP injection system. The package works so well, I am a bit bored but that's not all bad. 
__________________
RV-12 Build Helper
RV-7A...Sold #70374
The RV-8...Sold #83261
I'm in, dues paid 2019 This place is worth it!
Last edited by David-aviator : 08-13-2011 at 06:25 AM.
Reason: ...editing..
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