Why I picked Subaru.

[Msletten]

Flying is not a right and with the attitude that any of us can endanger others because we choose to experiment with something that is IMHO, more expensive, unsafe and less reliable than what Vans recommends only adds to the public perception that the aviation community is ARROGANT!

Well then we should all scrap our "unsafe and less reliable" experimental aircraft and buy Cessnas.

I'm sorry, I don't intend to be flippant, but I'm bemused that you, as an EXPERIMENTAL aircraft builder/flyer (I assume, I haven't checked your profile) denigrate others who choose to EXPERIMENT with alternative engines.

I understand your point that making poor choices and crashing experimental aircraft all over the place won't endear our community to John Q. Public. But, do you honestly think the non-aviation public differentiates between the relative merits of "certified" vs "non-certified" engine choices when they hear about an experimental aircraft crash on the local news? After all, it's fairly obvious to me that many seemingly omniscient members of our own community don't take the time to read the full NTSB report on a particular accident before arguing about what caused it.

I will agree with one thing you said -- flying is not a "right" in our country, but that's because we've made it so. I wonder how Wilbur and Orville would answer if you asked if they believed they had a "right" to fly? I submit that we DO have a right to fly; what we don't have, what we've taken away from ourselves, is the freedom to do so -- and that's too bad, but it's also a different debate...

Back to my point: The scary fact is J.Q. Public (or his/her elected representative) could at any time decide experimental aviation is just too dangerous to allow to continue. IMHO, if that happens it won't be because a few of us chose to experiment with alternative engines.

I, for one, am thankful beyond words I live in a country where I HAVE alternatives, and the right and freedom to choose them...

Let us not, in the heat of debate, forget the things we have in common (EXPERIMENTAL aviation), or that what is "right" for one is not necessarily right for all.

Regards,

Mark Sletten

 

[janeggenfellner]

If the ECU, or the PSRU, or the triple boost pump, 8 relay 5 TPDT switches fail, all of which are required for these crazy systems, is that the same?

Not that complex You eally just need too connect the battery to the ECU and fuel pump.

Jan Eggenfellner

 

[Rotary10-RV]

Correct of course Jan

I am often amused by every one talking about fuel pumps and systems on alternate engine experimentals. I find this amusing because this is an RV forum, and all the current RVs are LOW WING AIRCRAFT. The point is that every one of these planes has an electric fuel pump be it Egg, Lyc or whatever. I don't know anybody running a LW plane that doesn't have 2 electric pumps, one for each tank and usually the ability to valve them to the other tank if one fails. So how different is that than the altenative system? We now have in-tank pumps available that provide EFI pressure so you don't even have to carry more pumps than a regular low wing. My dad once told me not to "go looking for trouble" and keep things simple. Good advice reguardless of what your engine choice is! Carburetors have a failure mode that EFI does NOT have and that is icing. Many crashes can be attributed to icing by people not remembering to pull the carb heat in decent. Other people forget to richen the mixture flying high to low. These are hardly what you would call difficult and complex systems. The point is that while the parts of EFI may be more complex than a typical carb, the OPERATION isn't. Sometimes you could make a very good case for the fact that it is simpler for the operator than a carburetor system. I would say that if you follow the engineering basics and keep the system as simple as you can there will be little difference to the end user. We are trying to grow a segment of a small market into a mature product. We all must do our best to be sure to design the best product we can. As some of the thread hijackers wail on I must leave you with the comments of Franklin after singing the Declaration of Independance, "Gentlemen we must now all hang together, or we will all surely hang separately!"

Bill J

 

[n5lp]

I am often amused by every one talking about fuel pumps and systems on alternate engine experimentals. I find this amusing because this is an RV forum, and all the current RVs are LOW WING AIRCRAFT. The point is that every one of these planes has an electric fuel pump be it Egg, Lyc or whatever. I don't know anybody running a LW plane that doesn't have 2 electric pumps, one for each tank and usually the ability to valve them to the other tank if one fails...

I have a very stock RV-6 and my system is very different than what you describe.

Like most RVs I have two fuel pumps in series, one mechanical and one electric. Either pump is able to pump fuel from either fuel tank. If both pumps are running, as they are during low altitude operations, they failure of either pump requires no action for the engine to remain running.

 

[Jconard]

Not that complex You eally just need too connect the battery to the ECU and fuel pump.

Well,

that is not how any wiring diagram or panel for an egg is wired or recomended by the factory....at least none that I have seen, and I have seen more than a few. Perhaps the recomended wiring is just extra 4 pole double throw switched and relays for nothing...

 

[Rotary10-RV]

Same thing different direction.

I have a very stock RV-6 and my system is very different than what you describe.

Like most RVs I have two fuel pumps in series, one mechanical and one electric. Either pump is able to pump fuel from either fuel tank. If both pumps are running, as they are during low altitude operations, they failure of either pump requires no action for the engine to remain running.

Larry,
I'm not being critical or sarcastic here, but the point is that you DO have two fuel pumps. The system can be simple in either case. A EFI could even be configured with a mechanical pump if you want. I have built both mechanical and electronic injected engines. There are differences on the engine end of course. Everybodys system will be slightly different, there is no reason to fight about it. You did cut off the remark that the EFI system won't ice up where a carb can. An EFI or FI system could ice over the filter element so if you run an air filter you need an alternate air source. You put in the level of redundancy that you feel safe with.

Bill

 

[DGlaeser]

Mine is simple...

Not that complex You eally just need too connect the battery to the ECU and fuel pump.
Well,
that is not how any wiring diagram or panel for an egg is wired or recomended by the factory....at least none that I have seen, and I have seen more than a few. Perhaps the recomended wiring is just extra 4 pole double throw switched and relays for nothing...

I didn't like a single 4PDT switch, so I went with a very simple architecture - 2 pump switches, 2 ignition switches, each set hooked to it's own battery.
see: http://ph.groups.yahoo.com/group/subaruaircraft/photos/view/df67?b=2

 

[janeggenfellner]

that is not how any wiring diagram or panel for an egg is wired or recomended by the factory....at least none that I have seen, and I have seen more than a few. Perhaps the recomended wiring is just extra 4 pole double throw switched and relays for nothing...

Not quite for nothing. It is one way to wire the stuff. It is unbelievable that these things are argued about in the first place? The engine needs fuel, turn on a pump. The engine need ignition, turn it on. If you have a problem, throw an emergency override switch for the fuel and ignition. These are very simple concepts. While you are at it, use high quality gas filled switches. If you do not want the fuel failover to be automatic, do it manually. In any case, these are not issues to be discussed as a reason for flying behind a Subaru or air cooled. You can tackle these any way you would like, as long as it is sound and has true redundancy. The real issues are what engine you will be happier flying behind during the next 30 years.

Jan
Jan

 

[rv8ch]

Gas filled switches?

... If you have a problem, throw an emergency override switch for the fuel and ignition. These are very simple concepts. While you are at it, use high quality gas filled switches. ...

I've never heard of gas filled switches - do you have any suggested part numbers or sources?

Thanks,
Mickey

 

[janeggenfellner]

I've never heard of gas filled switches - do you have any suggested part numbers or sources?

Thanks,
Mickey


I was referring to the Honeywell 4 pole switch someone mentioned from a wire diagram we post on the Installation pages / manual on our web site.

Jan Eggenfellner