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  #71  
Old 05-15-2018, 01:07 PM
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Mike S Mike S is online now
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Quote:
Originally Posted by Mark33 View Post
The way I’m planning on wiring it will incorporate some redundancy. On one relay I’ll have 87 connected to one pump and 87a connected to the other pump. On the second really I’ll do the exact same thing. This way the B.M. can do it’s thing with its automatic switching capabilities and if one of the paths of electricity is interrupted for any reason (C.B.,relay,etc.) the other C.B. and relay can take over full duty and continue to allow the B.M. to work as normal...including its automatic pump switching functions. So basically, 87 from both relays will go to one pump and 87a will go to the other pump....so I’ll have two relays and two different circuits/C.B. doing the job that one relay and one C.B. can do....but they will be a backup for each other in the event one of them were to fail. I’m also planning on incorporating an oil pressure sensor switch into the system so that while the toggle switch is in the pump1/auto position, and if there’s no oil pressure, the fuel pumps will automatically shut down. All modern automobiles have this safety feature built in, so that in an accident the fuel pumps don’t continue to run and possibly spray fuel everywhere. This safety feature/switch will only affect the system when the toggle switch is in the pump1/auto position. By flipping the switch into the pump 2 position everything will work as normal.

Mark
Although this was originally in reference to automobile racing-----it is often quoted in things aeronautical ........and rightly so.

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Rv-10, N210LM.

Flying as of 12/4/2010

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  #72  
Old 05-15-2018, 01:51 PM
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DanH DanH is online now
 
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Originally Posted by rcpaisley View Post
As far as I know:
1. Voltage regulator failure leading to over voltage, dual lithium battery installation melt down, electrical system failure.

2. Non standard wiring installation, too small of a circuit breaker used on the injector circuit, injector breaker popped during low level (river following flight), hard landing.
Robert
Thank you. So what can you help us learn?

RV-6: Voltage regulator failure is pretty obvious, based on the pilot report of hot batteries and 15.5V at last check. We've been told EarthX batteries disconnect from charging at around 16.5 volts (but still have an output, however strange that may seem). Let's assume both batteries disconnected at 16.5V, a fair assumption because a meltdown wouldn't happen until failure of the battery management system at 60V or more. How would a battery charging disconnect result in an "electrical system failure" which would kill an EFI/EI? And of course, how might it be prevented?

Airborne Extreme: If I understand correctly, you're saying there was only one circuit breaker for all injectors. There is no standard wiring diagram in the EFII-brand manual. What do you recommend?
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  #73  
Old 05-15-2018, 03:00 PM
Mark33 Mark33 is offline
 
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Quote:
Originally Posted by Mike S View Post
Although this was originally in reference to automobile racing-----it is often quoted in things aeronautical ........and rightly so.

Hey Mike,

Yes....my thoughts exactly!! I know that sometimes there can be a fine line and a hard balancing act between simplicity and added safety redundancy. In my description of how I plan on wiring up the fuel pumps, I “think” that I’ve achieved that balance. I basically analyze the “what if” situation and expanded my though process from there. I know that we can’t predict or prepare for every conceivable scenario, but this is how I visualized and hopefully rectified the possible weak links in the “all electric fuel pump” architecture by incorporating a little bit of redundancy without adding “too much” complexity. I won’t go into the strengths or weaknesses of the bus manager itself because there are many opinions...both good and bad, so I think it just boils down to ones own personal thoughts and opinions and comfort level with it. So, moving on past the B.M. itself, I asked myself these questions:

1. Q: What would happen if the single circuit/circuit breaker that “both” pumps rely upon were to fail?
A: I would be a glider.
So what’s the fix? Split things up and incorporate “two” circuits and “two” circuit breakers. That’s step one in adding redundancy without introducing too much complexity.

2. Q: What would happen if the “single” relay that “both” fuel pumps rely upon were to fail?
A: Same as above...I’d become a glider. So what’s the fix? The same answer as above regarding the C.B’s. I’ll incorporate one additional relay and run them in parallel with each other so that if one were to fail the other one will take over full duty without there even being so much as a hiccup in normal operations. Once again, incorporating redundancy without introducing too much complexity.

3. Q: What would happen in a crash if a fuel line were to rupture and there’s still full power being supplied to the fuel pumps?
A: If I weren’t already dead, I’d surly die a fiery painful death. So what’s the fix? Incorporate a simple oil pressure sensor switch that’ll shut the fuel pumps off automatically if there no oil pressure present...ie. sudden prop/engine stoppage. Once again, very little complexity added as compared to the added safety margins.

4. Q: But what happens if the oil pressure safety switch discussed above were to fail?
A: The above discussed safety switch feature is only operational in the pump 1/auto toggle switch position...which is the primary pump that’s used during normal operations. The oil pressure safety switch feature is completely bypassed when the fuel pump selector switch is in the pump 2 position. So, if that oil pressure switch were to fail during flight it will be a simple flip if the selector switch into the pump 2 position and the flight will continue as normal.

So, even though I’m firmly in the “keep it simple stupid” camp, I’m hoping that I’ve thought through a few possible “what if” scenarios and have hopefully managed to incorporate a few extra safety features without introducing “too much” complexity.

Mark
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  #74  
Old 05-15-2018, 03:39 PM
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Walt Walt is offline
 
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So.. to Mike's point, remind me again what real benefit does EFI/EI get you over standard Bendix style FI with lets say some Pmags?

Sounds to me like things are awfully complicated, kinda reminds me of the FADEC system that eventually got removed from my friends RV9 due to issues that couldn't seem to be resolved, airplane went back to std FI with EI, probably lost 10 lbs of "stuff" in the process, and ran perfectly after that.

I understand if you just love to "tweak", but personally I just like to be able to jump in the airplane and fly and not worry about the stuff under the cowl.
Simple, and it just works.
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Last edited by Walt : 05-15-2018 at 03:46 PM.
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  #75  
Old 05-15-2018, 03:49 PM
BillL BillL is offline
 
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Quote:
Originally Posted by DanH View Post
We've been told EarthX batteries disconnect from charging at around 16.5 volts (but still have an output, however strange that may seem).
So, they may NOT have output, hopefully, the NTSB investigation will provide some enlightenment on the chain of causes.
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  #76  
Old 05-15-2018, 04:19 PM
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DanH DanH is online now
 
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Originally Posted by BillL View Post
So, they may NOT have output, hopefully, the NTSB investigation will provide some enlightenment on the chain of causes.
Even if both EarthX batteries disconnected themselves, the alternator is still there, with voltage at some high level.

As for the NTSB, I wouldn't hold your breath. Not a problem, given Robert's kind offer.

Quote:
Originally Posted by rcpaisley View Post
Our only concern is safety. If we can help a few people avoid the mistakes that have been implemented before them, this is a well worthwhile effort in our estimation...A very good place to start is to get information directly from suppliers who have been down these roads many times before and know their products well.

Robert
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Last edited by DanH : 05-15-2018 at 04:23 PM.
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  #77  
Old 05-15-2018, 04:36 PM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by Walt View Post
So.. to Mike's point, remind me again what real benefit does EFI/EI get you over standard Bendix style FI with lets say some Pmags?

Sounds to me like things are awfully complicated, kinda reminds me of the FADEC system that eventually got removed from my friends RV9 due to issues that couldn't seem to be resolved, airplane went back to std FI with EI, probably lost 10 lbs of "stuff" in the process, and ran perfectly after that.

I understand if you just love to "tweak", but personally I just like to be able to jump in the airplane and fly and not worry about the stuff under the cowl.
Simple, and it just works.
While some people using certain brands of FADEC have had some or numerous problems, many due to poor design, severe complexity, software issues, wiring and lack of testing and fleet time etc., many using other brands of EFI have had few if any problems and have done no maintenance aside from checking spark plugs and fuel filter screens at annual. Some of these date back 20+ years now. http://www.vansairforce.com/communit...d.php?t=147345 Two of our high timers have over 2000 hours each in the flight instruction field and zero problems as far as I'm aware.

It's the same idea as EFI in cars which revolutionized reliability compared to points and carbs- no or minimal maintenance and years of trouble free operation.

You get precise timing and mixture (in all cylinders) under all conditions, less bore washing, less chamber deposits, better cold and hot starting, better idle quality, lower mission fuel burn and less pilot workload. There are no more periodic inspections as on P Mags.

It's not hard to build a good, simple, redundant electrical system.

System weight is comparable to Bendix FI and a couple of mags.

None of this is new as some people think. Homebuilders have been using our EFI as far back as late 1995 and not to sound like a broken record but there are over 1900 of our aviation ECUs and systems out there, both in civilian and military use.

Nobody needs $30K worth of glass to fly day VFR either but that is the preference these days.

The engine builders, cowling makers, hose fab shops etc. are all getting on board now to service the growing number of customers who are installing EFI these days.
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Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, RV6A C-GVZX flying from CYBW since 2003- 424.4 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
http://sdsefi.com/cpi.htm



Last edited by rv6ejguy : 05-15-2018 at 05:50 PM.
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  #78  
Old 05-15-2018, 04:37 PM
Mark33 Mark33 is offline
 
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Location: Baton Rouge, La.
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Quote:
Originally Posted by Walt View Post
So.. to Mike's point, remind me again what real benefit does EFI/EI get you over standard Bendix style FI with lets say some Pmags?

Sounds to me like things are awfully complicated, kinda reminds me of the FADEC system that eventually got removed from my friends RV9 due to issues that couldn't seem to be resolved, airplane went back to std FI with EI, probably lost 10 lbs of "stuff" in the process, and ran perfectly after that.

I understand if you just love to "tweak", but personally I just like to be able to jump in the airplane and fly and not worry about the stuff under the cowl.
Simple, and it just works.
Hey Walt,

Well, the best way that I know of how to answer your question is that I think that it just boils down to personal preferences and you just have to pick your poison. I think your question, which is VERY valid opens up a whole other discussion. I guess that I’m more in the “modern technology” school of thought VS. the more old school traditional style of doing things. Don’t get me wrong, there’s absolutely nothing wrong with old school. I think that the beauty of an EFII or SDS type of system is that once you have it dialed in, it should be fly and forget. A computer (ECU) is going to do EXACTLY the same thing every time...where as I can’t do that manually. It’s very true that it’ll take some tweaking to get it dialed in correctly, but once it’s done, it’s done. A few things come to mind when considering an EFII or SDS system:

1. No moving parts...(other than the fuel pumps). I really like solid state!!

2. Having the ability to tweak each injector individually to get EGT’s/CHT’s even and happy.

3. Having the ability to adjust the timing perfectly in accordance with various RPM’s and manifold pressures, and to be able to do this weather running AvGas or MoGas.

4. Vapor lock is a thing of the past.

5. Better LOP operations.

These are just a few things that I can think of, but I’m sure there’s more. Like I said, there’s absolutely nothing wrong with old school and it’s served us well for a very long time, but I think once you get one of these electronic fuel injection and ignition systems dialed in it’ll be hard to beat.

Mark
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  #79  
Old 05-15-2018, 07:18 PM
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Carl Froehlich Carl Froehlich is online now
 
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Originally Posted by Mark33 View Post
Hey Walt,

Well, the best way that I know of how to answer your question is that I think that it just boils down to personal preferences and you just have to pick your poison. I think your question, which is VERY valid opens up a whole other discussion. I guess that I’m more in the “modern technology” school of thought VS. the more old school traditional style of doing things. Don’t get me wrong, there’s absolutely nothing wrong with old school. I think that the beauty of an EFII or SDS type of system is that once you have it dialed in, it should be fly and forget. A computer (ECU) is going to do EXACTLY the same thing every time...where as I can’t do that manually. It’s very true that it’ll take some tweaking to get it dialed in correctly, but once it’s done, it’s done. A few things come to mind when considering an EFII or SDS system:

1. No moving parts...(other than the fuel pumps). I really like solid state!!

2. Having the ability to tweak each injector individually to get EGT’s/CHT’s even and happy.

3. Having the ability to adjust the timing perfectly in accordance with various RPM’s and manifold pressures, and to be able to do this weather running AvGas or MoGas.

4. Vapor lock is a thing of the past.

5. Better LOP operations.

These are just a few things that I can think of, but I’m sure there’s more. Like I said, there’s absolutely nothing wrong with old school and it’s served us well for a very long time, but I think once you get one of these electronic fuel injection and ignition systems dialed in it’ll be hard to beat.

Mark
While I understand repeating product literature is normally a good thing, I would not want builders to think the objective of cylinder mixture control is to achieve a specific CHT or EGT. This is exactly wrong.

As been discussed on multiple posts, the specific EGT value means little as compared to fuel flow for each cylinder when that cylinder's EGT peaks (GAMI spread). The CHT value, while affected by fuel flow, is best used to verify normal operations, effective engine cooling air, and verify drop when LOP.

If using an EFII and tweaking to achieve a specific EGT or CHT value you will have the cylinders way out of balance.

So other thoughts reflecting on my operation of a balanced AFP injection system and pMags:
- Never had vapor lock
- Never had a start problem, hot, cold or in between
- Had a GAMI spread of 0.1GPH (same as my RV-10)
- LOP operation was smooth down to engine stop (same with my RV-10 and it still had mags - new pmags arrive this month!).
- Resetting timing for 100LL or 91UL is simple.
- Moving parts - yep, the fuel pump and a part in the pMag. Don't forget the EFII crank sensor is itself a moving part. Also consider the moving parts needed to keep electrical power going to the EFII system.

I have asked a couple of times for any data to demonstrate that when compared to a balanced traditional fuel injection system and pMags if any EFII system provided more power or higher engine efficiency. I have not received it - other than claims that pMag timing is all wrong. If such data exists, I would love to see it.

So what? If you want EFII fine, go for it. As many people follow these threads please be cautious on how you state facts to support your case. We have so many aftermarket option of late that new builders may think that they must have them all or their plane will fall out of the sky.

Sorry if I stepped on any toes,
Carl
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  #80  
Old 05-15-2018, 09:01 PM
Mark33 Mark33 is offline
 
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Quote:
Originally Posted by Carl Froehlich View Post
While I understand repeating product literature is normally a good thing, I would not want builders to think the objective of cylinder mixture control is to achieve a specific CHT or EGT. This is exactly wrong.

As been discussed on multiple posts, the specific EGT value means little as compared to fuel flow for each cylinder when that cylinder's EGT peaks (GAMI spread). The CHT value, while affected by fuel flow, is best used to verify normal operations, effective engine cooling air, and verify drop when LOP.

If using an EFII and tweaking to achieve a specific EGT or CHT value you will have the cylinders way out of balance.

So other thoughts reflecting on my operation of a balanced AFP injection system and pMags:
- Never had vapor lock
- Never had a start problem, hot, cold or in between
- Had a GAMI spread of 0.1GPH (same as my RV-10)
- LOP operation was smooth down to engine stop (same with my RV-10 and it still had mags - new pmags arrive this month!).
- Resetting timing for 100LL or 91UL is simple.
- Moving parts - yep, the fuel pump and a part in the pMag. Don't forget the EFII crank sensor is itself a moving part. Also consider the moving parts needed to keep electrical power going to the EFII system.

I have asked a couple of times for any data to demonstrate that when compared to a balanced traditional fuel injection system and pMags if any EFII system provided more power or higher engine efficiency. I have not received it - other than claims that pMag timing is all wrong. If such data exists, I would love to see it.

So what? If you want EFII fine, go for it. As many people follow these threads please be cautious on how you state facts to support your case. We have so many aftermarket option of late that new builders may think that they must have them all or their plane will fall out of the sky.

Sorry if I stepped on any toes,
Carl
Hey Carl,

Points and counter points are always appreciated and well taken. Heck, I’m just a shade tree mechanic trying build something that’ll be safe and fun to fly and trying to incorporate a little bit of modern technology along the way. You are correct regarding balancing EGT’s/CHT’s by using fuel flows and equal and balance GAMI being the most important aspect. That’s really what I meant but I guess I just didn’t state it properly. Also, like I said, there’s absolutely nothing wrong with any other type of ignition or fuel injection system and there’s probably hardly any measurable performance difference between any of them....at least nothing that I know that I could measure. LOL!! One thing I am curious about is what you said about the crank sensor. It’s just a Hall effect sensor that senses the magnet position when the imbedded magnets that are in the flywheel passes in front of it....that’s what talkes to the ECU. Can you please elaborate more on what moving parts you’re referring to? Thanks for the good input.

Mark

Last edited by Mark33 : 05-15-2018 at 09:04 PM.
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