Dan Lloyd RV-10 "Factual" report out...

[islandmonkey]

What has come out of this thread so far for me is that I would not even consider an auto engine installation or any engine installation for that matter that relies on a constant application of volts and amps to an ECU or other non redundant system in my plane. Subaru engines are great engines in the environment that they were designed for. However for me the risk is too great. Lycoming development and improvements has come on leaps and bounds in the last few years. With new technology available from third parties in terms of electronic computerised magnetos that generate their own backup power and are now available for the experimental market, I feel there is no need to take the risk by going elsewhere. Some readers of this post my not agree with me and to be honest I do not care. If someone chooses to go down the auto engine conversion route thats their decision and lookout. I wish them luck and I hope they take sensible precautions to eliminate the risk of loosing power to the ECU or other vital non redundant systems.

I would like to know other peoples opinion on this and also I would like to know if sales of Subaru conversions have suffered because of this incident. Some of the comments in this thread so far do not put the Florida based supplier in such a good light.

[nucleus]

I have multiple ground paths from the engine to airframe, but only one from the battery to the airframe. If I lose that connection, will my system still work due to the polarity being set up with the alternator, right?

Hans

[kentb]

Originally Posted by islandmonkey

What has come out of this thread so far for me is that I would not even consider an auto engine installation that relies on a constant application of volts and amps to an ECU in my plane. Subaru engines are great engines in the environment that they were designed for. However for me the risk is too great. Lycoming development and improvements has come on leaps and bounds in the last few years. With new technology available from third parties in terms of electronic computerised magnetos that generate their own backup power and are now available for the experimental market, I feel there is no need to take the risk by going elsewhere. Some readers of this post my not agree with me and to be honest I do not care. If someone chooses to go down the auto engine conversion route thats their decision and lookout. I wish then luck and I hope they take sensible precautions to eliminate the risk of loosing power to the ECU.

I would like to know other peoples opinion on this and also I would like to know if sales of Subaru conversions have suffered because of this incident. The some comments in this thread so far do not put the Florida based supplier in such a good light.

I really think that what you should take away from this thread is:
1. Be prepared to fly you plane without the engine running.
2. Take you time with the build. Make sure all safety system are working.
3. Take your time with the phase I testing. Make sure that your planes flies correctly.
4. If you don't have the experience (and most of use don't), use an EAA flight adviser.
5. Don't take short cuts. See 2 and 3 above.



When I started building, I considered the Egg system, but decided against it because it would not save me any money and I didn't see where it would increase performance enough to warrant leaving traditional aircraft engine behind. I also thought that it would take me longer to get my plane flying. Any engine can fail, do what you can to minimize the chance.

I install only one EI and still have one mag. I have two alt., but only one battery.

I regularly practice stall recovery and engine out procedures.

Kent

[rv6ejguy]

Absolutely agree with Kevin here. Testing and practice are vitally important.

As far as automotive engines being used in aircraft, this has been discussed at length. The number of core engine failures on properly assembled and operated engines is extremely small. We have seen in the last year or so several failures due to things as small as spark plug heat range and inadequate fuel octane. These can be attributed to a lack of experience and indeed proper testing. But the general feeling that the Lycoming route is more proven is certainly true IMO.

Other failures recently have be attributed to insufficient bearing clearances and FOD internally. I rank these under improper assembly (for the intended application) and certainly has nothing to do with the engine design. Subaru engines in particular have demonstrated excellent core reliability in hundreds of thousands of hours of flight operations. Having been involved in this field for a number of years, electrical issues are the #1 cause of inflight power loss and fuel issues are #2 on auto conversions.

Relating back to this accident, had Dan's RV10 been equipped with an IO-540 and twin Jeff Rose EIs for instance, the result would likely have been the same. Indeed we have seen a number of twin EI failures/ issues on RVs over the last couple years. Pointing the finger at the Subaru engine in this case is simply illogical.

No matter which engine you have, if it has electrically dependent ignition and fuel components, address the potential for losing primary power to these.

As far as sales of Subaru conversions go, none of the current vendors have had the best of customer service or performance reviews lately so this has had much to do with a general cooling of interest towards these engines as of late. This is no surprise. IMO all vendors in this field do nowhere near enough ground validation and flight testing of their products before release for sale. This just comes back to haunt you. Any time vendors have delays in supplying equipment or poor customer service (either perceived or actual), the long term viability of the product line is in question. We can only hope that newcomers to this field address these concerns diligently.

[airguy]

Originally Posted by islandmonkey

What has come out of this thread so far for me is that I would not even consider an auto engine installation that relies on a constant application of volts and amps to an ECU in my plane.

I'm not an "alt engine" guy, though I would like to be if the right turbodiesel was available. Having said that - I think you should remove the "auto engine" part of your statement entirely, and let's focus on the core problem you have stated, that of having a critical flight parameter dependent on electrical power. In that case, it's not fair to pick on auto engines, or indeed even jet engines or Lycomings for that matter. There are very many certified Lycomings flying around that require constant power to keep turning, due to dual EI's and/or electric-only fuel systems.

More and more aircraft these days are being constructed to be electrically dependent, whether it's fuel, or nav, or spark - both VFR and IFR. Once you commit to having an aircraft that is electrically dependent, it DOES NOT MATTER which of the flight-critical components are electrically dependent, YOU MUST have a backup electrical system, in good working order, for reliability and safety. If you have that good working electrical backup, then there is no valid reason NOT to use the desired equipment and accept the electrical dependency.

The fact that an auto engine was installed (in this case) had nothing to do with it, and I would hate to see someone be scared away from an auto conversion for that reason. There may be reasons to choose NOT to do an auto conversion - but this is not one of them.

For the record, I am planning on a fully redundant electrical system (dual battery, dual alternator, dual buss) with glass panel, IFR capable, 2-axis AP, one mag and one EI, and dual electric-only fuel pumps, on a Lyclone. My aircraft will be electrically dependent. I accept that up front, and will plan the equipment appropriately.

[David-aviator]

Originally Posted by Kevin Horton

I'll add a few more:

4. If safety depends on backup systems, the response to failure of the primary system should be demonstrated. This testing should be done on the ground, if possible. I've participated in more than one test, on aircraft from multiple manufacturers, where the response to failure of a major primary system was different from what had been predicted. Some of these bad responses would probably have resulted in an accident had they occurred in service.

5. If safety depends on backup systems, the serviceability of those backup systems should be checked at some reasonable interval.

6. Emergency procedures should not only be reviewed, they should be practiced. Too many people are killed because the pilot mishandles an engine failure.

7. System failure procedures should not only be reviewed, they should be practiced. I'm aware of multiple fatal accidents where the accident was caused by poor pilot response to a switchover to a backup system.

I can say from experience the original Subby back up system designed by Gary Newsted with the famous "bus master" switch worked very well.

My H6 quit one day climbing through 6000' and selecting back up power restored engine operation immediately. (the poly fuse protection of the primary power source had tripped) The comfort level of the back up operation was not all that comfortable as I had no idea how long it would run, but it sure was better than a totally silent engine. It did get me to a runway without incident. That same system was checked occasionally on the ground by simply selecting it and pressing the start button and the engine came to life. No other switch had to be on. The system was not designed in a vacuum. I was involved in the original forum discussion with Gary and Jan and other early Subby guys - just about every conceivable problem was covered. Changes were made as we gained experience with the system and there were a few like when the H6 quit due to 02 sensor heaters kicking in, over loading the circuit.

It is a good system but not quite good enough to save Lloyds's RV-10. He must have had a back up feature very similar to the original design even though EXPBUS was gone. The NTSB report states "the "BUSS SELECTOR" switch was in the "ON/MAIN" position". If it had been moved to "EMERGENCY", the second battery would have kicked in and maybe kept the engine running assuming its cables were attached. With due credit to the EGG factory, they have preached since day one if there is any indication of engine trouble, select EMERGENCY (or BBAT as it was called in the beginning) immediately.

But no electric system will work if it is not wired properly. The report states there were many unconnected wires....that's not so good.

[islandmonkey]

Originally Posted by airguy

I think you should remove the "auto engine" part of your statement entirely, and let's focus on the core problem you have stated, that of having a critical flight parameter dependent on electrical power. In that case, it's not fair to pick on auto engines, or indeed even jet engines or Lycomings for that matter. There are very many certified Lycomings flying around that require constant power to keep turning, due to dual EI's and/or electric-only fuel systems.

Point taken airguy. Original post has been edited. However I still would not consider an auto engine conversion, especially one from Florida. Lets be careful however just in case we get "off topic" and have the posts pulled.

[rv6ejguy]

I think Greg is doing this in the most reliable and safest way possible. I approve if that counts for anything. My RV10 has 2 pumps, 2 batteries and 2 alternators.

When we sell EFI systems for Lycomings or Continentals, almost invariably redundancy of fuel and spark is discussed. My recommendation is generally to retain one mag for spark and a simple mechanical system with nozzles, the original carb or even the entire mechanical FI left in place for fuel backup. Just leave the mixture in idle cutoff.

Mike Dacey's Reno racer retains one mag and has fuel nozzles mounted in the intake manifold for backup along with a second battery and two pumps. It has been flight tested and runs pretty well at a fixed throttle setting. Simple, cheap and light.

Despite all this, we should not overlook the basic requirement of getting electrons to those backup systems if primary power fails for any reason. We warn people repeatedly about good wiring practices and good system design and keeping things simple. Your life may depend on it.

[N62XS]

Mike can rant, the NTSB can cloud the issue with pages and pages of paper, others can defend the "right to choose" any engine for their project, but the facts are that if an airplane engine were in use on the airplane in question, it would not have failed in the fashion it did. I know airplanes with airplane engines crash as well, but they would not have failed in this manner if a battery connection came apart.

FWIW

[Walt]

Originally Posted by rv6ejguy

Indeed we have seen a number of twin EI failures/ issues on RVs over the last couple years.

Just curious, what kind of failures of dual EI as I have not personally heard this before (as a dual LSI powered Lyc I am curious about this statement)