Is electronic injection ?there??

[SinCityJets]

I know electronic ignitions have come a long way, and are almost the “standard” now, but with some cutting edge companies like SDS and EFII (maybe others??), electronic injection is also on the scene now.

Is this technology ready to be placed at the pointy end of our lifeline in the sky? This is not so much an SDS vs EFII thread, as it is an electronic ignition vs Bendix thread.

For me, I love the dual ECU redundancy of an automotive like injection system, with no mixture knob, however I am not a fan of no mechanical fuel pump.

It seems like these full electronic systems DEMAND a back up alternator and battery for true redundancy.

I appreciate your thoughts and responses.

Chad

[maniago]

As a bad parody....."To have electricity or not have electricity, that is the question."

The quality of the equipment is really no longer an issue IMHO. Choose your poison, and build to suit.

[Toobuilder]

The equipment itself is automotive based and as such has proven itself far beyond the legacy systems by virtually any measure. Add redundancy and I think it would be hard to argue a scenario where the EFI system is any less reliable than a mechanical system, and in all likelyhood much higher.

Electrical delivery systems likewise are very well proven. Again, with billions of hours of service history to calculate MTBF.

The rub is the installation variability of each builder. For example, fuel systems are very simple, yet look at their role in E-AB accidents. Poor (re)design, substandard workmanship and lack of attention to detail all conspire to take down more homebuilts than just about any other mechanical cause. Now apply that same standard to a far more complex electrical system. Install a proper electrical system feeding your EFI and you are likely to increase reliability over the legacy stuff.

I think the real advance to pave the way for EFI is the fact that our panels are becoming increasingly complex and are forcing robust and reliable electrical systems. Once we finally let go of the concept that electricity is "optional", and really figure out a robust and redundant power system, then adding a fuel pump and ECU is an easy step to take.

[RandyAB]

Originally Posted by Toobuilder

...
The rub is the installation variability of each builder. For example, fuel systems are very simple, yet look at their role in E-AB accidents. Poor (re)design, substandard workmanship and lack of attention to detail all conspire to take down more homebuilts than just about any other mechanical cause. Now apply that same standard to a far more complex electrical system. Install a proper electrical system feeding your EFI and you are likely to increase reliability over the legacy stuff....

How best to design the electrical system to accommodate the level safety required? This has been the most difficult part of the decision making process for me. I'm reading as much as I can but there is lots of different and sometimes conflicting bits of advice. I have yet to see a solution that looks simple to me. I asked Ross at SDS for his recommendation which he shared. With that schematic, there is a master switch for the engine which will turn off the engine if it failed or was inadvertently closed. Granted, that design had a backup battery and switch to mitigate the risk. Perhaps I'm over thinking it but I still had my reservations.

[Walt]

I was just talking to a friend about a local Columbia (Cessna) 400 owner that I know that had smoke in the cockpit from an electrical fault, he's now scared to fly the plane and his wife won't go near it.

So with that in mind it got me thinking what would I do in that scenario and what would I have left if I killed the master due to an electrical fault.

Eng: should keep running, Electroair and Pmag, std AFP FI with mechanical fuel pump.

Avionics: I have a backup battery bus but not knowing where the smoke is coming from I'd probably shut that off too, that would leave me with the G5 and 660 (if I was IFR I'd have the Ipad in my lap), that plenty to keep me aviating and navigating.

Anyway something to consider.

[rv8ch]

Originally Posted by RandyAB

How best to design the electrical system to accommodate the level safety required? This has been the most part of the decision making process for me. I'm reading as much as I can but there is lots of different and sometimes conflicting bits of advice. I have yet to see a solution that looks simple to me. I asked Ross at SDS for his recommendation which he shared. With that schematic, there is a master switch for the engine which will turn off the engine if it failed or was inadvertently closed. Granted, that design had a backup battery and switch to mitigate the risk. Perhaps I'm over thinking it but I still had my reservations.

Hi Randy, You probably already know about the aeroelectic connection http://www.aeroelectric.com/ - if not, you might consider reading that book. It greatly demystified the aircraft electrical systems for me, and this understanding has given me the confidence that I would need for an all electric aircraft. A solid design, good installation practices, and understanding of how it all works will go a long way to making sure the fan up front keeps spinning.

[n82rb]

no, they do not demand it. the first question that must be answered is what is the mission of the aircraft. it amazes me how much redundancy that people cram in a VFR aircraft. if you are going to be flying IFR, or in the west where airports are farther apart then more redundancy will be required. for a basic VFR aircraft a single alternator with a single battery in an aircraft with a single EI and one mag is perfectly fine. for a VFR aircraft with two EI's then I would, and have in mine, installed a small dedicated backup for the EIs. a 5 a/hr battery should power an EI for a couple of hours in the event of a total electrical failure. for an IFR aircraft I would probably add a backup alternator to power the important stuff. now start adding EFI and you add more issues.

bob burns
RV-4 N82RB

[RandyAB]

Originally Posted by rv8ch

Hi Randy, You probably already know about the aeroelectic connection http://www.aeroelectric.com/ - if not, you might consider reading that book. It greatly demystified the aircraft electrical systems for me, and this understanding has given me the confidence that I would need for an all electric aircraft. A solid design, good installation practices, and understanding of how it all works will go a long way to making sure the fan up front keeps spinning.

I am familiar yes Mickey. I've read good chunks of it but have not gotten all of way through it. I find it quite verbose and overloaded making it less than a captivating read. Ausman's book is good but perhaps not quite comprehensive enough. I will plod through. What I have found very helpful is looking through and understanding the solutions others have posted.

[RandyAB]

Originally Posted by Walt

....So with that in mind it got me thinking what would I do in that scenario and what would I have left if I killed the master due to an electrical fault....

That is what was concerning me as well Walt. Correct me if I am wrong but my understanding is that the engine should be on it's own master and isolated from the other systems.

[rvbuilder2002]

Properly designed (and fully understood) support systems are critical.

I am aware of an RV (I think it is likely that the majority of it was contract built) that had a power problem away from home.

The owner had wanted newest tech. and best of everything in his airplane. The result is an airplane that is over his head in complexity. Not necessarily when every thing is working correctly, but as soon as something goes wrong..... it can go wrong in a very bad way, very quickly.

The owner had an alternator failure away from home. He flew the (entirely electrically dependent) airplane home on only battery power, with seemingly little understanding of how close he came to disaster.

This is the type of scenario that gives me the most concern these days regarding the direction that the experimental community is headed.
Some are able to engineer reliable systems and do a well thought out installation, but many are not. Even worse is when RV's with complex systems are being sold to second owners who have zero understanding of how the systems work.

If you build an entirely electrical dependent airplane, be sure you are aware of all of the potential failure modes you need to have contingency for.

Number one on the list of design priority's should be to assure you be able to make a decision and execute a plan in just a few seconds, that will remove power from a failed portion of your electrical system, but still keep the engine running........
And please, produce some documentation so that people other than the builder can learn how the systems work.