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  #11  
Old 12-23-2020, 01:22 PM
airguy's Avatar
airguy airguy is offline
 
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Quote:
Originally Posted by KatieB View Post
If it turns into a glider when you shut the master switch off, that's a problem.
Ehhh... maybe, but I'm not so sure about that. Let me tell you why I say that...

I have an electrically dependent airplane - I need voltage for fuel pressure and ignition, not to mention nav. In my airplane I have dual alternators and a large battery. Either alternator can take the full electrical load of the airplane, and the battery is good for about 30 minutes with both alternators offline, in an IFR flight condition. The Skyview EFIS has its own backup battery and happily proceed on its own for 45+ minutes. So far, so good - that covers my risk assessment for electrical redundancy, others will vary but this is mine. Alternator failures occur, but rarely - and if I have a single flight that has TWO of them, and I can't get it down in the time remaining on the battery, then Jesus loves me and I ain't gonna fight that.

I have redundant power paths to my fuel pumps and ignition, completely separate from the normal path through the master. I can power those items normally through the master or from a hot E-buss directly from the battery with the master off - but I do NOT have them set up for automatic transfer, intentionally. If something goes that far wrong in the cockpit such that there is an electrical fire/smoke, or worse yet a major fuel leakage in the cockpit, then I *DO* want to be able to hit the master and make everything go quiet, and then troubleshoot critical systems one by one as I bring them back online - and yes I'm including engine power in that statement. If I blow a fuel line at the fuel pumps and start dumping raw fuel in the cockpit, I'm going to go cold and deadstick it somewhere in the interest of not making ANY spark and turning myself into a shooting star.

I suppose it comes down to a comfort level with airborne "emergencies" of various levels and how we each deal with them. I've had a few over the last couple decades. I do NOT want to be in a situation where a device fails, the automatic failsafe takes over and puts the backup on line, and somehow I am not alerted to that fact or miss an indication of it. If I have to take positive action to bring the backup online then I know what I have operating and what I don't and there's not a question of whether I missed it or not. When things start to go "nonstandard" in the cockpit, in my mind I will treat it as "minor" which means "Huhhh, it shouldn't be doing that, let's see here...." or "major" which means too many things are going wrong to troubleshoot simultaneously or the issue is too major to troubleshoot immediately - in which case I want to kill the master, stop EVERYTHING, turn the airplane into a glider which follows the known physics of flight, and then take stock of what we know still works. Preferably prioritizing the engine first.

Everyone is different, and we have different risk profiles, this is mine. I've seen me react under pressure enough times to know what to expect. I know precisely how I will react when cruising along at 15,000' and the engine quits unexpectedly - because I've done it. YMMV.

But, I digress.... This is about UL Power, which is something I like and want to see succeed.
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N16GN flying 750 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, IFD440
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.

Last edited by airguy : 12-23-2020 at 01:31 PM.
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  #12  
Old 12-23-2020, 01:29 PM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by agent4573 View Post
The FADEC system is a closed loop EFI system.
I don't think their FADEC runs in closed loop. No mention of an O2 sensor on their website.
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Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 445.9 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
https://www.youtube.com/channel/UCiy...g2GvQfelECCGoQ


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  #13  
Old 12-23-2020, 01:38 PM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by KatieB View Post
What kind of guidance does UL have on how to set up a redundant electrical system for the FADEC system? Electrical dependency for engines gives me the willies.
There are quite a number of electrically dependent certified aircraft out there now- many of the Diamond diesels with FADECs for instance and some of the latest turbines have no mechanical backups for the FADECs either.

We've got a couple thousand people flying our EFI/ EI systems going out 25 years now. Not a big issue if you have a well thought out and constructed electrical systems.

I worry more about the reliability of the spinning ironmongery out front.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 445.9 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
https://www.youtube.com/channel/UCiy...g2GvQfelECCGoQ


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  #14  
Old 12-23-2020, 01:57 PM
Kuhtenia Kuhtenia is offline
 
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<< Just curious if they offer guidance on how to avoid that. >>

The short answer is "yes" - the UL Power installation manual includes various sample installation diagrams for single/dual ECU setups, etc.
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  #15  
Old 12-23-2020, 01:59 PM
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KatieB KatieB is offline
 
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Quote:
Originally Posted by rv6ejguy View Post
Not a big issue if you have a well thought out and constructed electrical systems.
Exactly. I just posted the question here to get people thinking about it. I think the technology is appealing because it's efficient and "modern," but unless it's either self-generating or installed along with a well-planned and executed redundant electrical system, it does add a significant layer of risk. Not only risking the builder, who may know their system inside and out, but also potentially risking subsequent owners who most likely won't have a clue about how it works and how it may fail. Just food for thought.
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  #16  
Old 12-23-2020, 02:14 PM
Andrew Anunson Andrew Anunson is offline
 
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Quote:
Originally Posted by agent4573 View Post
I would imagine the fuel burn would be the same or less than an equivalent power lycoming.
Pilots can run a Lycoming LOP (lean of peak) for high efficiency and clean running. That isn't an option with the UL Power engines since the FADEC controls the mixture. So far, Lycoming engines run better fuel burns.
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  #17  
Old 12-23-2020, 02:15 PM
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KatieB KatieB is offline
 
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Quote:
Originally Posted by rv6ejguy View Post
There are quite a number of electrically dependent certified aircraft out there now- many of the Diamond diesels with FADECs for instance and some of the latest turbines have no mechanical backups for the FADECs either.
One of the Diamond diesel twins a while back had both engines quit after takeoff because the pilots jump-started the plane after leaving the master on and it didn't have enough electrical power to run the ECUs... so it can happen with certified aircraft too. The pilots lack of knowledge/ignoring the POH didn't help...

https://www.aviationconsumer.com/ind...ate-1-fadec-0/
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CFII/A&P
EAA Homebuilt Advisory Council
Rebuilt most of SNF tornado victim RV-3B Tony Boy II (had to sell him, but he's flying!)
RV-9 93281 tail kit has arrived... here I go again!
VAF Dues Paid 2021!
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  #18  
Old 12-23-2020, 03:11 PM
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rv6ejguy rv6ejguy is offline
 
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Quote:
Originally Posted by KatieB View Post
One of the Diamond diesel twins a while back had both engines quit after takeoff because the pilots jump-started the plane after leaving the master on and it didn't have enough electrical power to run the ECUs... so it can happen with certified aircraft too. The pilots lack of knowledge/ignoring the POH didn't help...

https://www.aviationconsumer.com/ind...ate-1-fadec-0/
Yes, that was a famous one but you can't blame the system design there any more than you can blame the fuel system for someone running out of fuel, forgetting to switch tanks or failing to use carb heat properly. All can lead to a power loss at an inconvenient time.

Ignore proper training, systems understanding, POH warnings and checklists at your peril...

Not having solid backup power and proper low voltage warning systems can bite you with electrically dependent aircraft. We suggest all our clients have such things installed.
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Ross Farnham, Calgary, Alberta
Turbo Subaru EJ22, SDS EFI, Marcotte M-300, IVO, Shorai- RV6A C-GVZX flying from CYBW since 2003- 445.9 hrs. on the Hobbs,
RV10 95% built- Sold 2016
http://www.sdsefi.com/aircraft.html
https://www.youtube.com/channel/UCiy...g2GvQfelECCGoQ


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  #19  
Old 12-23-2020, 03:34 PM
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Mel Mel is offline
 
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Quote:
Originally Posted by KatieB View Post
That's fine, but how are they powered? What about the rest of the wiring, redundant batteries, dual alternators, etc. If it turns into a glider when you shut the master switch off, that's a problem. Just curious if they offer guidance on how to avoid that.
Why would you wire the engine computer through the master switch? You don't wire other ignition switches through the master.

The internal alternator feeds the CPU.
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  #20  
Old 12-23-2020, 05:18 PM
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KatieB KatieB is offline
 
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Quote:
Originally Posted by Mel View Post
Why would you wire the engine computer through the master switch? You don't wire other ignition switches through the master.

The internal alternator feeds the CPU.
What I meant was, what happens when electrical power is killed to the aircraft. Say you have to shut off the master due to smoke in the cockpit, for example. Will it keep running as if it had mags/carb? Looks like it will if you use their special buffer capacitor, since the ECU is wired to the regulator/rectifier and alternator.

It's a single-alternator, single-battery system, according to the UL Power website. If you have an alternator failure, it will run until the battery dies, about an hour on the battery they tested. If the battery dies first, it runs "as long as necessary" on alternator power... or until the alternator burns out. That's fine for a VFR airplane, but if you're putting one of these in an RV intended for IFR, is that battery or alternator going to last until you're in a position to land? These engines were modeled after Jabiru engines. The alternators are basically motorcycle stators. The drawing on the UL site is identical to a Jabiru system with the stator and rectifier/regulator. I've seen them fail quite a bit. They burn out, regulators go bad. Maybe UL has improved them? People need to be prepared, is all I'm saying. I don't have a dog in the engine fight anymore, thank God. In fact, my old friend/colleague sells both Jabiru engines and UL Power. Those ULs do look sexy. But I cringe when people get all starry-eyed over the new technology and assume that it won't fail. I'd want a dual-alternator, dual-battery setup on one of these, personally. It would help offset the weight difference, too...
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EAA Homebuilt Advisory Council
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RV-9 93281 tail kit has arrived... here I go again!
VAF Dues Paid 2021!
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