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Z101 in an RV-10
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A Lumley

Joined: 12 May 2021
Posts: 10
Location: Ontario, Canada

Posted: Fri Sep 03, 2021 1:54 pm Post subject: Z101 in an RV-10

Good evening all,



I'm working away on an electrical architecture for my RV-10 based on Z-101B. I haven't started to install the system yet but I have a question about how I will actually install the electrical system.



In the RV-10, the battery and battery contactor are located in the tailcone. Looking at the schematic, I will need to run a large conductor (probably 2AWG) forward from the contactor to the starter. My concern is that the "fat wire tie point" for the battery bus, aux bus, and engine bus will need a second large conductor run forward (my aux and engine busses have decent loads due to IFR and EFII equipment). This seems like it will add considerable weight...



The only solution I can imagine would be to leave the battery in the tail and move the battery contactor forward to the firewall. This would leave a long length of unprotected wire but I would have that anyways with the second contactor coming forward to the tie point...



This might become more clear as I start to actually run wires but for now it seems less than ideal. Thoughts?



Andrew

jluckey(at)pacbell.net
Guest

Posted: Fri Sep 03, 2021 2:56 pm Post subject: Z101 in an RV-10

Andrew,

Why don't you mount the start solenoid on the firewall and run a #2 from the master solenoid in tail cone forward to start solenoid on firewall.

Then use the battery side of the start solenoid as the main terminus for the other loads.  It sounds like you have several sub-systems to feed so you may want to use an additional stud terminal mounted near the start solenoid, with a jumper to the battery side of the start solenoid, to handle the quantity of wires.

Are you in Canada?

-Jeff

                  

                                                                    On Friday, September 3, 2021, 03:05:13 PM PDT, A Lumley <andrew.lumley(at)sympatico.ca> wrote:                 

                 



                 



                 --> AeroElectric-List message posted by: "A Lumley" <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)>



Good evening all,



I'm working away on an electrical architecture for my RV-10 based on Z-101B. I haven't started to install the system yet but I have a question about how I will...



In the RV-10, the battery and battery contactor are located in the tailcone. Looking at the schematic, I will need to run a large conductor (probably 2AWG) forward from the contactor to the starter. My concern is that the "fat wire tie point" for the battery bus, aux bus, and engine bus will need a second large conductor run forward (my aux and engine busses have decent loads due to IFR and EFII equipment). This seems like it will add considerable weight...



The only solution I can imagine would be to leave the battery in the tail and move the battery contactor forward to the firewall. This would leave a long length of unprotected wire but I would have that anyways with the second contactor coming forward to the tie point...



This might become more clear as I start to actually run wires but for now it seems less than ideal. Thoughts?



Andrew



Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=503039#503039



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A Lumley

Joined: 12 May 2021
Posts: 10
Location: Ontario, Canada

Posted: Fri Sep 03, 2021 4:52 pm Post subject: Re: Z101 in an RV-10

Hey Jeff, I am in Canada. That is my plan for the loads downstream of the battery contactor. But the Z-101 schematic also has several loads connected to the battery side of the battery contactor (hot battery bus and alternate feeds for the aux and engine busses). It's these loads that I'm trying to prevent running a second 2AWG cable for.



Andrew

cluros(at)gmail.com
Guest

Posted: Sat Sep 04, 2021 12:07 pm Post subject: Z101 in an RV-10

Hi Andrew, where in Canada? I'm in Vancouver.



Have you done an Electrical Load Analysis on your hot battery loads? I'm finding it hard to believe that you would need anything close to 2 AWG for those combined loads. What continuous load are we talking about here?

On Fri, Sep 3, 2021 at 5:57 PM A Lumley <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "A Lumley" <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)>

 

 Hey Jeff, I am in Canada. That is my plan for the loads downstream of the battery contactor. But the Z-101 schematic also has several loads connected to the battery side of the battery contactor (hot battery bus and alternate feeds for the aux and engine busses). It's these loads that I'm trying to prevent running a second 2AWG cable for.

 

 Andrew

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=503041#503041

 

 

 

 

 

 

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A Lumley

Joined: 12 May 2021
Posts: 10
Location: Ontario, Canada

Posted: Sat Sep 04, 2021 1:06 pm Post subject: Re: Z101 in an RV-10

I'm in Belleville, 2 hours from Toronto.



The hot battery bus itself is only about 0.5 amps for a few overhead lights. The issue is that the Z-101 schematic has the ability to power the aux and engine busses through relays attached to the battery side of the battery contactor. My engine bus will draw 15-20 amps (SDS EFI) when both fuel pumps are running. The Aux bus includes the PFD, GPS, pitot heat, autopilot, and a few other small loads that will total another 15-20 amps with the pitot heat operating.



I'm thinking I'll need a separate cable of about 4 AWG running forward from the battery in addition to the 2 AWG starter cable. Just wondering if there is a better way, perhaps not.

cluros(at)gmail.com
Guest

Posted: Sat Sep 04, 2021 1:48 pm Post subject: Z101 in an RV-10

I think you could get away with 8AWG rather than 4 AWG for the loads you describe but let's think about this another way.



In case of a forced landing, we want to be able to disconnect the 2 AWG cable from the battery so that when we hit a fence post we don't have a leaking fuel line and a big spark 5 feet from our asses. Putting the relay as close to the battery accomplishes this. If we then run a 4 AWG wire along the same route with no way to disconnect it from the battery, are we any better off? If you're going to accept a large live wire running along the fuselage, will it help that the 2 AWG is cold and the 4 AWG is hot? Might as well just leave the 2 AWG hot and move the relay to the front as you first described.

The only other solutions I can think of are

1. Relays on both wires and dual fed engine and aux busses. In a forced landing you shut off both relays.

2. A second battery in the engine compartment.

3. A second alternator and feed your dual fed engine and aux busses from each alternator, dropping the battery feed.

On Sat, Sep 4, 2021 at 2:10 PM A Lumley <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "A Lumley" <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)>

 

 I'm in Belleville, 2 hours from Toronto.

 

 The hot battery bus itself is only about 0.5 amps for a few overhead lights. The issue is that the Z-101 schematic has the ability to power the aux and engine busses through relays attached to the battery side of the battery contactor. My engine bus will draw 15-20 amps (SDS EFI) when both fuel pumps are running. The Aux bus includes the PFD, GPS, pitot heat, autopilot, and a few other small loads that will total another 15-20 amps with the pitot heat operating.

 

 I'm thinking I'll need a separate cable of about 4 AWG running forward from the battery in addition to the 2 AWG starter cable. Just wondering if there is a better way, perhaps not.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=503043#503043

 

 

 

 

 

 

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Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Sat Sep 04, 2021 2:49 pm Post subject: Z101 in an RV-10

I think the real analysis is that you need two separate power sources 

for the fuel injection and the ignition. Using a single battery does not 

accomplish that, no matter how you wire it. I believe you would have to 

have two batteries, and probably should have two alternators.

However, that gets back to why do you want an aircraft for IFR that 

requires the complexity of two separate electrical systems and the 

electrical components to allow them to operate separately?

Simplicity is your friend, especially when IFR.

Regardless of advertising claims, a port fuel injection system with 6 

individual electrically operated solenoids does not significantly 

improve power or fuel economy over the mechanical fuel injection system 

the IO-540 is designed with or the Air Flow performance experimental 

fuel injection. They also eliminate the need for electrical fuel pumps 

to operate continuously, as the stock mechanical pump is adequate for 

almost all in-flight situations.

Having both ignitions systems electrically dependent again introduces 

complexity. You really want your engine to be able to run indefinitely 

without external power if all electrics fail.

You can still have the benefits of electronic ignition without the need 

for external power if you install 2 PMag systems, and they only need 

external power for starting.

  Even if the full SDS system gets you an extra 10 kts (unlikely) it 

only reduces the time to fly a 500nm flight by perhaps 10-15 minutes.



If you eliminate the need for external power for the engine to run, you 

can have adequate backup power for avionics without having to install 

dual electrical systems. Most EFIS have backup battery systems that 

allow shutting of the master and will continue to operate for 45 min or 

more. You can equip a Nav/com with similar backup battery.



Just my opinion with 40+ yrs of IFR flying and 5 years of flying my IFR 

RV-10.

Kelly



On 9/4/2021 2:47 PM, Sebastien wrote:

 	  Quote: 	
		   I think you could get away with 8AWG rather than 4 AWG for the loads you 

 describe but let's think about this another way.

 

 In case of a forced landing, we want to be able to disconnect the 2 AWG 

 cable from the battery so that when we hit a fence post we don't have a 

 leaking fuel line and a big spark 5 feet from our asses. Putting the 

 relay as close to the battery accomplishes this. If we then run a 4 AWG 

 wire along the same route with no way to disconnect it from the battery, 

 are we any better off? If you're going to accept a large live wire 

 running along the fuselage, will it help that the 2 AWG is cold and the 

 4 AWG is hot? Might as well just leave the 2 AWG hot and move the relay 

 to the front as you first described.

 

 The only other solutions I can think of are

 

 1. Relays on both wires and dual fed engine and aux busses. In a forced 

 landing you shut off both relays.

 2. A second battery in the engine compartment.

 3. A second alternator and feed your dual fed engine and aux busses from 

 each alternator, dropping the battery feed.

 

 On Sat, Sep 4, 2021 at 2:10 PM A Lumley <andrew.lumley(at)sympatico.ca 

 <mailto:andrew.lumley(at)sympatico.ca>> wrote:

 

     

     <andrew.lumley(at)sympatico.ca <mailto:andrew.lumley(at)sympatico.ca>>

 

     I'm in Belleville, 2 hours from Toronto.

 

     The hot battery bus itself is only about 0.5 amps for a few overhead

     lights. The issue is that the Z-101 schematic has the ability to

     power the aux and engine busses through relays attached to the

     battery side of the battery contactor. My engine bus will draw 15-20

     amps (SDS EFI) when both fuel pumps are running. The Aux bus

     includes the PFD, GPS, pitot heat, autopilot, and a few other small

     loads that will total another 15-20 amps with the pitot heat operating.

 

     I'm thinking I'll need a separate cable of about 4 AWG running

     forward from the battery in addition to the 2 AWG starter cable.

     Just wondering if there is a better way, perhaps not.

 

 

 

 

     Read this topic online here:

 

     http://forums.matronics.com/viewtopic.php?p=503043#503043

     <http://forums.matronics.com/viewtopic.php?p=503043#503043>

 

 

 

 

 

 

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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

A Lumley

Joined: 12 May 2021
Posts: 10
Location: Ontario, Canada

Posted: Sat Sep 04, 2021 4:07 pm Post subject: Re: Z101 in an RV-10

Thanks for the comments Kelly. For starters while I am planning for a single battery, I am definitely installing dual alternators. I believe a second battery would be of marginal benefit given the chance of dual alternator failure and subsequent battery failure.



I do appreciate the comments on the electronic fuel injection though. I'm quite set on electronic ignition but I'm not 100% set on electronic injection to go with it. I'll have to do some more research. It would certainly give me less electrical concerns to install a mechanical injection system.

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Sat Sep 04, 2021 5:32 pm Post subject: Z101 in an RV-10

I agree with the electronic ignition. There are definite advantages. 

However, there are trade-offs. AFAIK, only P Mag offers electronic 

ignition that isn't dependent on ship's power.

Electrical systems come down to what can fail that takes the system 

down. It takes effort to design a system that can't be brought down by 

say failure of the master relay, master switch, etc. There is a recent 

article of an RV-10 that was grounded by ignition switch failure, 

fortunately on the ground.

Kelly



On 9/4/2021 5:07 PM, A Lumley wrote:

 	  Quote: 	
		   

 

 Thanks for the comments Kelly. For starters while I am planning for a single battery, I am definitely installing dual alternators. I believe a second battery would be of marginal benefit given the chance of dual alternator failure and subsequent battery failure.

 

 I do appreciate the comments on the electronic fuel injection though. I'm quite set on electronic ignition but I'm not 100% set on electronic injection to go with it. I'll have to do some more research. It would certainly give me less electrical concerns to install a mechanical injection system.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=503046#503046

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

Voyager

Joined: 30 Jun 2020
Posts: 77

Posted: Sat Sep 04, 2021 5:42 pm Post subject: Z101 in an RV-10

I am currently finalizing my schematics for my S-21 and I am building a system based mostly on the Z-14 system.  I am planning on dual 40 amp alternators and two independent buses, but with crossfeed so that both batteries can be used for engine start and in the case that one alternator or battery fails I can run everything on the remaining battery or alternator.



I plan to run two fat wires from the baggage floor mounted batteries to the firewall.  I will probably use 2 AWG, but RANS lists 4 AWG in their schematic (for a single battery installation) so that may be adequate since the batteries share current during starting. Since I will have two battery buses in addition to the two main buses, I will probably run 14 AWG for each of those as that will handle 15 amps each and 30 amps is more than enough for the always hot accessories.



I am also leaning towards SDS for both ignition and EFI.  I have owned and driven a variety of cars and trucks and off-road and OTR equipment since the early 70s and I will tell you that magnetos, carbs, mechanical FI and mechanical fuel pumps are no more reliable than modern EFI and electronic ignition systems and I would argue much less reliable.  I have not had nearly the trouble with any of my cars in the last 20 years that have had EFI and EI as I had with cars equipped with carbs and points ignition or my 182 with carb and mags.  An SDS system with dual ECUs, and dual electric fuel pumps operated by two alternators and two batteries is probably 10X more reliable than a magneto equipped airplane with mechanical FI and mechanical fuel pump.  I’d love to see some real statistics from the aviation world, but using the auto world as a benchmark gives me good confidence that my 10X estimate isn’t far off.



Sent from my iPad



 	  Quote: 	
		   On Sep 4, 2021, at 8:11 PM, A Lumley <andrew.lumley(at)sympatico.ca> wrote:

 

 

 

 Thanks for the comments Kelly. For starters while I am planning for a single battery, I am definitely installing dual alternators. I believe a second battery would be of marginal benefit given the chance of dual alternator failure and subsequent battery failure.

 

 I do appreciate the comments on the electronic fuel injection though. I'm quite set on electronic ignition but I'm not 100% set on electronic injection to go with it. I'll have to do some more research. It would certainly give me less electrical concerns to install a mechanical injection system.

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=503046#503046

cluros(at)gmail.com
Guest

Posted: Sat Sep 04, 2021 6:49 pm Post subject: Z101 in an RV-10

Kelly it's not a single battery, it's a single battery and an alternator. If the alternator quits the battery gets you on the ground. Failures of properly maintained batteries are very rare, but if the battery fails in flight you won't notice because the alternator keeps going. A second alternator can greatly extend the time in the air, but most second alternators are 20A at most so for Andrew's requirements not enough for indefinite flight.



Where are you getting your data that EFI does not reduce fuel consumption? I haven't seen any real world data but the advertising shows significant reductions (though at $2.00 / liter, not enough to offset the purchase price)



On Sat, Sep 4, 2021 at 7:17 PM Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 

 I think the real analysis is that you need two separate power sources 

 for the fuel injection and the ignition. Using a single battery does not 

 accomplish that, no matter how you wire it. I believe you would have to 

 have two batteries, and probably should have two alternators.

 However, that gets back to why do you want an aircraft for IFR that 

 requires the complexity of two separate electrical systems and the 

 electrical components to allow them to operate separately?

 Simplicity is your friend, especially when IFR.

 Regardless of advertising claims, a port fuel injection system with 6 

 individual electrically operated solenoids does not significantly 

 improve power or fuel economy over the mechanical fuel injection system 

 the IO-540 is designed with or the Air Flow performance experimental 

 fuel injection. They also eliminate the need for electrical fuel pumps 

 to operate continuously, as the stock mechanical pump is adequate for 

 almost all in-flight situations.

 Having both ignitions systems electrically dependent again introduces 

 complexity. You really want your engine to be able to run indefinitely 

 without external power if all electrics fail.

 You can still have the benefits of electronic ignition without the need 

 for external power if you install 2 PMag systems, and they only need 

 external power for starting.

   Even if the full SDS system gets you an extra 10 kts (unlikely) it 

 only reduces the time to fly a 500nm flight by perhaps 10-15 minutes.

 

 If you eliminate the need for external power for the engine to run, you 

 can have adequate backup power for avionics without having to install 

 dual electrical systems. Most EFIS have backup battery systems that 

 allow shutting of the master and will continue to operate for 45 min or 

 more. You can equip a Nav/com with similar backup battery.

 

 Just my opinion with 40+ yrs of IFR flying and 5 years of flying my IFR 

 RV-10.

 Kelly

 

 On 9/4/2021 2:47 PM, Sebastien wrote:

 > I think you could get away with 8AWG rather than 4 AWG for the loads you 

 > describe but let's think about this another way.

 > 

 > In case of a forced landing, we want to be able to disconnect the 2 AWG 

 > cable from the battery so that when we hit a fence post we don't have a 

 > leaking fuel line and a big spark 5 feet from our asses. Putting the 

 > relay as close to the battery accomplishes this. If we then run a 4 AWG 

 > wire along the same route with no way to disconnect it from the battery, 

 > are we any better off? If you're going to accept a large live wire 

 > running along the fuselage, will it help that the 2 AWG is cold and the 

 > 4 AWG is hot? Might as well just leave the 2 AWG hot and move the relay 

 > to the front as you first described.

 > 

 > The only other solutions I can think of are

 > 

 > 1. Relays on both wires and dual fed engine and aux busses. In a forced 

 > landing you shut off both relays.

 > 2. A second battery in the engine compartment.

 > 3. A second alternator and feed your dual fed engine and aux busses from 

 > each alternator, dropping the battery feed.

 > 

 > On Sat, Sep 4, 2021 at 2:10 PM A Lumley <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca) 

 > <mailto:andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)>> wrote:

 > 

 >     --> AeroElectric-List message posted by: "A Lumley"

 >     <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca) <mailto:andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)>>

 > 

 >     I'm in Belleville, 2 hours from Toronto.

 > 

 >     The hot battery bus itself is only about 0.5 amps for a few overhead

 >     lights. The issue is that the Z-101 schematic has the ability to

 >     power the aux and engine busses through relays attached to the

 >     battery side of the battery contactor. My engine bus will draw 15-20

 >     amps (SDS EFI) when both fuel pumps are running. The Aux bus

 >     includes the PFD, GPS, pitot heat, autopilot, and a few other small

 >     loads that will total another 15-20 amps with the pitot heat operating.

 > 

 >     I'm thinking I'll need a separate cable of about 4 AWG running

 >     forward from the battery in addition to the 2 AWG starter cable.

 >     Just wondering if there is a better way, perhaps not.

 > 

 > 

 > 

 > 

 >     Read this topic online here:

 > 

 >     http://forums.matronics.com/viewtopic.php?p=503043#503043

 >     <http://forums.matronics.com/viewtopic.php?p=503043#503043>

 > 

 > 

 > 

 > 

 > 

 > 

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Voyager

Joined: 30 Jun 2020
Posts: 77

Posted: Sat Sep 04, 2021 7:46 pm Post subject: Re: Z101 in an RV-10

I will argue that the folks at GAMI have provided this data for many years now.  What they do in tuning injectors in mechanical systems is essentially what the ECU can do in real-time in an EFI system.  Now, I don’t know if the SDS ECU is that a sophisticated, but auto EFI systems can adjust the PWM of each individual injector to optimized each cylinder.  This absolutely improves both fuel economy and emissions performance.



So, if you believe GAMI’s data in regard to balancing mechanical injectors then you should believe that EFI will bring similar performance improvements if properly implemented.

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Sat Sep 04, 2021 7:47 pm Post subject: Z101 in an RV-10

I did not say that EFI did not reduce fuel consumption or increase 

power. What I said was electronically controlled port fuel injection is 

not going to reduce fuel consumption or increase power enough to give up 

the reliability of mechanical fuel injection. Electronic fuel injection 

is very reliable in cars, where an electrical failure just causes the 

engine to die. In an aircraft the electronic controller and injectors 

are a single point of failure. Electronic fuel injection has almost zero 

operating experience in aircraft, compared to 60 years of mechanical 

fuel injection. When Lycoming or Continental adopt electronic fuel 

injection, I might think about it. Aircraft applications are very 

different from automotive engines operating characteristics.

A single battery is a single battery no matter how many alternators you 

have. No different than a single master relay.



On 9/4/2021 7:48 PM, Sebastien wrote:

 	  Quote: 	
		   Kelly it's not a single battery, it's a single battery and an 

 alternator. If the alternator quits the battery gets you on the ground. 

 Failures of properly maintained batteries are very rare, but if the 

 battery fails in flight you won't notice because the alternator keeps 

 going. A second alternator can greatly extend the time in the air, but 

 most second alternators are 20A at most so for Andrew's requirements not 

 enough for indefinite flight.

 

 Where are you getting your data that EFI does not reduce fuel 

 consumption? I haven't seen any real world data but the advertising 

 shows significant reductions (though at $2.00 / liter, not enough to 

 offset the purchase price)

 

 On Sat, Sep 4, 2021 at 7:17 PM Kelly McMullen <kellym(at)aviating.com 

 <mailto:kellym(at)aviating.com>> wrote:

 

     

     <kellym(at)aviating.com <mailto:kellym(at)aviating.com>>

 

     I think the real analysis is that you need two separate power sources

     for the fuel injection and the ignition. Using a single battery does

     not

     accomplish that, no matter how you wire it. I believe you would have to

     have two batteries, and probably should have two alternators.

     However, that gets back to why do you want an aircraft for IFR that

     requires the complexity of two separate electrical systems and the

     electrical components to allow them to operate separately?

     Simplicity is your friend, especially when IFR.

     Regardless of advertising claims, a port fuel injection system with 6

     individual electrically operated solenoids does not significantly

     improve power or fuel economy over the mechanical fuel injection system

     the IO-540 is designed with or the Air Flow performance experimental

     fuel injection. They also eliminate the need for electrical fuel pumps

     to operate continuously, as the stock mechanical pump is adequate for

     almost all in-flight situations.

     Having both ignitions systems electrically dependent again introduces

     complexity. You really want your engine to be able to run indefinitely

     without external power if all electrics fail.

     You can still have the benefits of electronic ignition without the need

     for external power if you install 2 PMag systems, and they only need

     external power for starting.

        Even if the full SDS system gets you an extra 10 kts (unlikely) it

     only reduces the time to fly a 500nm flight by perhaps 10-15 minutes.

 

     If you eliminate the need for external power for the engine to run, you

     can have adequate backup power for avionics without having to install

     dual electrical systems. Most EFIS have backup battery systems that

     allow shutting of the master and will continue to operate for 45 min or

     more. You can equip a Nav/com with similar backup battery.

 

     Just my opinion with 40+ yrs of IFR flying and 5 years of flying my IFR

     RV-10.

     Kelly

 

     On 9/4/2021 2:47 PM, Sebastien wrote:

      > I think you could get away with 8AWG rather than 4 AWG for the

     loads you

      > describe but let's think about this another way.

      >

      > In case of a forced landing, we want to be able to disconnect the

     2 AWG

      > cable from the battery so that when we hit a fence post we don't

     have a

      > leaking fuel line and a big spark 5 feet from our asses. Putting the

      > relay as close to the battery accomplishes this. If we then run a

     4 AWG

      > wire along the same route with no way to disconnect it from the

     battery,

      > are we any better off? If you're going to accept a large live wire

      > running along the fuselage, will it help that the 2 AWG is cold

     and the

      > 4 AWG is hot? Might as well just leave the 2 AWG hot and move the

     relay

      > to the front as you first described.

      >

      > The only other solutions I can think of are

      >

      > 1. Relays on both wires and dual fed engine and aux busses. In a

     forced

      > landing you shut off both relays.

      > 2. A second battery in the engine compartment.

      > 3. A second alternator and feed your dual fed engine and aux

     busses from

      > each alternator, dropping the battery feed.

      >

      > On Sat, Sep 4, 2021 at 2:10 PM A Lumley

     <andrew.lumley(at)sympatico.ca <mailto:andrew.lumley(at)sympatico.ca>

      > <mailto:andrew.lumley(at)sympatico.ca

     <mailto:andrew.lumley(at)sympatico.ca>>> wrote:

      >

      >     

      >     <andrew.lumley(at)sympatico.ca

     <mailto:andrew.lumley(at)sympatico.ca>

     <mailto:andrew.lumley(at)sympatico.ca <mailto:andrew.lumley(at)sympatico.ca>>>

      >

      >     I'm in Belleville, 2 hours from Toronto.

      >

      >     The hot battery bus itself is only about 0.5 amps for a few

     overhead

      >     lights. The issue is that the Z-101 schematic has the ability to

      >     power the aux and engine busses through relays attached to the

      >     battery side of the battery contactor. My engine bus will

     draw 15-20

      >     amps (SDS EFI) when both fuel pumps are running. The Aux bus

      >     includes the PFD, GPS, pitot heat, autopilot, and a few other

     small

      >     loads that will total another 15-20 amps with the pitot heat

     operating.

      >

      >     I'm thinking I'll need a separate cable of about 4 AWG running

      >     forward from the battery in addition to the 2 AWG starter cable.

      >     Just wondering if there is a better way, perhaps not.

      >

      >

      >

      >

      >     Read this topic online here:

      >

      > http://forums.matronics.com/viewtopic.php?p=503043#503043

     <http://forums.matronics.com/viewtopic.php?p=503043#503043>

      >     <http://forums.matronics.com/viewtopic.php?p=503043#503043

     <http://forums.matronics.com/viewtopic.php?p=503043#503043>>

      >

      >

      >

      >

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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

Foghorn

Joined: 22 Jun 2020
Posts: 3
Location: Virginia Beach

Posted: Sun Sep 05, 2021 4:01 am Post subject: Z101 in an RV-10

Here is my dual alternator/single battery SDS schematic for my IFR RV8. The battery will be an EarthX 900 on the firewall. 

The primary ALT is set at 14.4, the AUX ALT is set at 13.9 and the ETX-900 is the final power source. Both ALTs and the AUX ENG BUS PWR will be on for all flight conditions. The AUX E-BUS will be open until needed.



This has now flown yet.



 

  Jeff Parker

757-817-4929



  

  	  Quote: 	
		  On 4Sep, 2021, at 17:06, A Lumley <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)> wrote:

--> AeroElectric-List message posted by: "A Lumley" <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)>I'm in Belleville, 2 hours from Toronto.The hot battery bus itself is only about 0.5 amps for a few overhead lights. The issue is that the Z-101 schematic has the ability to power the aux and engine busses through relays attached to the battery side of the battery contactor. My engine bus will draw 15-20 amps (SDS EFI) when both fuel pumps are running. The Aux bus includes the PFD, GPS, pitot heat, autopilot, and a few other small loads that will total another 15-20 amps with the pitot heat operating.I'm thinking I'll need a separate cable of about 4 AWG running forward from the battery in addition to the 2 AWG starter cable. Just wondering if there is a better way, perhaps not.Read this topic online here:http://forums.matronics.com/viewtopic.php?p=503043#503043

SINGLE_FWD_BATT_SDS_Rev9.pdf

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_________________
Jeff Parker

Voyager

Joined: 30 Jun 2020
Posts: 77

Posted: Sun Sep 05, 2021 4:43 am Post subject: Re: Z101 in an RV-10

 	  Kellym wrote: 	
		  I did not say that EFI did not reduce fuel consumption or increase 

power. What I said was electronically controlled port fuel injection is 

not going to reduce fuel consumption or increase power enough to give up 

the reliability of mechanical fuel injection. Electronic fuel injection 

is very reliable in cars, where an electrical failure just causes the 

engine to die. In an aircraft the electronic controller and injectors 

are a single point of failure. Electronic fuel injection has almost zero 

operating experience in aircraft, compared to 60 years of mechanical 

fuel injection. When Lycoming or Continental adopt electronic fuel 

injection, I might think about it. Aircraft applications are very 

different from automotive engines operating characteristics.

A single battery is a single battery no matter how many alternators you 

have. No different than a single master relay.

	




You are making the assumption that mechanical FI is more reliable than electronic FI and I don’t agree that this is a valid assumption.  I am not sure there is good data available to make such a decision, but I think it is incorrect to automatically assume that mechanical is more reliable than electrical.  I’d love to see real data on MFI vs EFI as my experience in the auto world is that EFI is one of the most reliable parts on an engine.  Then again, most cars did skip MFI and went straight from carbs to EFI as MFI would not have helped them pass the emissions regulations.



Yes, a single battery is a single point of failure, but what difference does that make other than when starting and, most of the time at least, that is done on the ground.  The EFI doesn’t care where the electrons come from.  So, with both alternators and battery, you have a redundant system and the odds of both failing on the same flight are low.  And batteries rarely fail suddenly.  I have had only one battery fail suddenly in 50+ years of owning vehicles.  That was on a new Chevy Equinox that just wouldn’t crank one morning.  It was only 4 months old and the battery apparently had a connection open internally, obviously due to a factory defect.  Every other battery has given plenty of warning (slow cranking generally) that it was on its last legs.  As long as you don’t ignore the warning, it is almost always possible to replace the battery before complete failure.

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Sun Sep 05, 2021 5:26 am Post subject: Z101 in an RV-10

On Sun, Sep 5, 2021 at 7:47 AM Voyager <m.whiting(at)frontier.com> wrote:



[quote] 

 >

 Kellym wrote:

 > I did not say that EFI did not reduce fuel consumption or increase

 > power. What I said was electronically controlled port fuel injection is

 > not going to reduce fuel consumption or increase power enough to give up

 > the reliability of mechanical fuel injection. Electronic fuel injection

 > is very reliable in cars, where an electrical failure just causes the

 > engine to die. In an aircraft the electronic controller and injectors

 > are a single point of failure. Electronic fuel injection has almost zero

 > operating experience in aircraft, compared to 60 years of mechanical

 > fuel injection. When Lycoming or Continental adopt electronic fuel

 > injection, I might think about it. Aircraft applications are very

 > different from automotive engines operating characteristics.

 > A single battery is a single battery no matter how many alternators you

 > have. No different than a single master relay.

 >

 You are making the assumption that mechanical FI is more reliable than

 electronic FI and I don’t agree that this is a valid assumption.  I am not

 sure there is good data available to make such a decision, but I think it

 is incorrect to automatically assume that mechanical is more reliable than

 electrical.  I’d love to see real data on MFI vs EFI as my experience in

 the auto world is that EFI is one of the most reliable parts on an engine

_________________
Charlie

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Sun Sep 05, 2021 6:39 am Post subject: Z101 in an RV-10

There is no question that mechanical fuel injection has been extremely 

reliable on aircraft engines. They have been employed since the early 

1960s. The Bendix variety generally goes to TBO with the engine. The 

Continental needs periodic pressure adjustments that affect mixture but 

not reliability. You just won't find aircraft accidents from mechanical 

fuel injection failures....just lack of fuel or fuel selector 

mismanagement. I've flown behind mechanical injection engines for 23 

years, behind carburetors for 24 years.

Automotive mechanical injection systems started in the late 50s, were 

widely used on more expensive autos from the late 70s (think Bosch), 

were very easy to adjust for mixture and generally needed nothing else. 

The early electronic injection systems used by VW and Porsche were 

terrible and resulted in many engine fires.

The current automotive systems are not just electronic, but are also 

direct injection, which you won't see in aircraft systems. Most of their 

advantages come from the direct cylinder injection, which came from 

diesel applications. Even those have fairly common failures...my 8 month 

old vehicle had to go to the dealer just last month with multiple 

electronic failures that were traced to a failure in the wiring 

harness...in a mass manufactured vehicle, not a hand wired aircraft. 

Fortunately it was designed with a limp home mode. Low power, limp home 

is ok for autos, not for aircraft.

While SDS may have dual controllers, they still only have one injector 

per cylinder. Yes electronic injectors fail. I had to have a set of 

diesel injectors replaced less than 10 years ago because of frequent 

failures, under a manufacturer service bulletin (not just my auto).

I've seen a dual electronic ignition fail on an aircraft, on takeoff, 

because of an intermittent failure of an automotive voltage regulator, 

fried the electronic ignitions, yes, both of them.

Automotive reliability simply does not translate directly to aviation. 

There are really only two automotive engines that have endured in 

aviation, and neither one normally has electronic anything.

Just my experience from 50 years of working on autos and 45 years 

working on aircraft.

Kelly

A&P/IA



On 9/5/2021 6:19 AM, Charlie England wrote:

 	  Quote: 	
		   

 

 On Sun, Sep 5, 2021 at 7:47 AM Voyager <m.whiting(at)frontier.com 

 <mailto:m.whiting(at)frontier.com>> wrote:

 

     

     <m.whiting(at)frontier.com <mailto:m.whiting(at)frontier.com>>

 

 

     Kellym wrote:

      > I did not say that EFI did not reduce fuel consumption or increase

      > power. What I said was electronically controlled port fuel

     injection is

      > not going to reduce fuel consumption or increase power enough to

     give up

      > the reliability of mechanical fuel injection. Electronic fuel

     injection

      > is very reliable in cars, where an electrical failure just causes

     the

      > engine to die. In an aircraft the electronic controller and

     injectors

      > are a single point of failure. Electronic fuel injection has

     almost zero

      > operating experience in aircraft, compared to 60 years of mechanical

      > fuel injection. When Lycoming or Continental adopt electronic fuel

      > injection, I might think about it. Aircraft applications are very

      > different from automotive engines operating characteristics.

      > A single battery is a single battery no matter how many

     alternators you

      > have. No different than a single master relay.

      >

 

 

     You are making the assumption that mechanical FI is more reliable

     than electronic FI and I don’t agree that this is a valid

     assumption.  I am not sure there is good data available to make such

     a decision, but I think it is incorrect to automatically assume that

     mechanical is more reliable than electrical.  I’d love to see real

     data on MFI vs EFI as my experience in the auto world is that EFI is

     one of the most reliable parts on an engine.  Then again, most cars

     did skip MFI and went straight from carbs to EFI as MFI would not

     have helped them pass the emissions regulations.

 

     Yes, a single battery is a single point of failure, but what

     difference does that make other than when starting and, most of the

     time at least, that is done on the ground.  The EFI doesn’t care

     where the electrons come from.  So, with both alternators and

     battery, you have a redundant system and the odds of both failing on

     the same flight are low.  And batteries rarely fail suddenly.  I

     have had only one battery fail suddenly in 50+ years of owning

     vehicles.  That was on a new Chevy Equinox that just wouldn’t crank

     one morning.  It was only 4 months old and the battery apparently

     had a connection open internally, obviously due to a factory

     defect.  Every other battery has given plenty of warning (slow

     cranking generally) that it was on its last legs.  As long as you

     don’t ignore the warning, it is almost always possible to replace

     the battery before complete failure.

 

 

 I've owned a MFI car, and I pray that I never have to own another. If 

 simple is the goal, a carb is the thing (single point of failure, 

 BTW...). But simple doesn't necessarily mean more reliable.

 

 A battery *should not* be a 'single point of failure' in the sense of 

 terminating a flight, as long as the system architecture is properly 

 executed. Look at any of the Z figures; the alt B-lead is connected to 

 the bus on the load side of the master contactor. If the battery simply 

 dies, everything still works until engine shutdown. If the battery 

 develops a dead short internally, then your problem is either a lot 

 (explosively) bigger than electron supply, or you turn off the master, 

 and everything continues to work until engine shutdown. That business 

 about field wound alternators being 'unstable' without a battery 

 attached is just old hangar tales. A bit more 'ripple' in the DC is just 

 about the only thing that changes.

 

 I don't know about every aftermarket EFI, but the SDS system does allow 

 tuning individual injector pulses, and they also make a fully redundant 

 system (two complete, independent controllers). Not available with any 

 'traditional' a/c system that I've ever seen. The aftermarket automotive 

 controllers also allow individual injector tuning, and it's possible to 

 configure a redundant system with those, as well.

 

 Charlie

 

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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Sun Sep 05, 2021 8:23 am Post subject: Z101 in an RV-10

Well, yeah; it takes effort. That's why most of us are here on this list. 

I'm really grateful for a place where we can 'spitball' all kinds of ideas, and still have a few highly experienced 'shepherds' to keep us from straying too far into danger.

Charlie

On Sun, Sep 5, 2021 at 10:38 AM Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:

 	  Quote: 	
		  --> AeroElectric-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 I agree with the electronic ignition. There are definite advantages. 

 However, there are trade-offs. AFAIK, only P Mag offers electronic 

 ignition that isn't dependent on ship's power.

 Electrical systems come down to what can fail that takes the system 

 down. It takes effort to design a system that can't be brought down by 

 say failure of the master relay, master switch, etc. There is a recent 

 article of an RV-10 that was grounded by ignition switch failure, 

 fortunately on the ground.

 Kelly

 On 9/4/2021 5:07 PM, A Lumley wrote:

 > --> AeroElectric-List message posted by: "A Lumley" <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)>

 > 

 > Thanks for the comments Kelly. For starters while I am planning for a single battery, I am definitely installing dual alternators. I believe a second battery would be of marginal benefit given the chance of dual alternator failure and subsequent battery failure.

 > 

 > I do appreciate the comments on the electronic fuel injection though. I'm quite set on electronic ignition but I'm not 100% set on electronic injection to go with it. I'll have to do some more research. It would certainly give me less electrical concerns to install a mechanical injection system.

 > 

 > 

 > 

 > 

 > Read this topic online here:

 > 

 > http://forums.matronics.com/viewtopic.php?p=503046#503046

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > 

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Charlie

Voyager

Joined: 30 Jun 2020
Posts: 77

Posted: Sun Sep 05, 2021 9:08 am Post subject: Re: Z101 in an RV-10

 	  Kellym wrote: 	
		  There is no question that mechanical fuel injection has been extremely 

reliable on aircraft engines. They have been employed since the early 

1960s. The Bendix variety generally goes to TBO with the engine. The 

Continental needs periodic pressure adjustments that affect mixture but 

not reliability. You just won't find aircraft accidents from mechanical 

fuel injection failures....just lack of fuel or fuel selector 

mismanagement. I've flown behind mechanical injection engines for 23 

years, behind carburetors for 24 years.

Automotive mechanical injection systems started in the late 50s, were 

widely used on more expensive autos from the late 70s (think Bosch), 

were very easy to adjust for mixture and generally needed nothing else. 

The early electronic injection systems used by VW and Porsche were 

terrible and resulted in many engine fires.

The current automotive systems are not just electronic, but are also 

direct injection, which you won't see in aircraft systems. Most of their 

advantages come from the direct cylinder injection, which came from 

diesel applications. Even those have fairly common failures...my 8 month 

old vehicle had to go to the dealer just last month with multiple 

electronic failures that were traced to a failure in the wiring 

harness...in a mass manufactured vehicle, not a hand wired aircraft. 

Fortunately it was designed with a limp home mode. Low power, limp home 

is ok for autos, not for aircraft.

While SDS may have dual controllers, they still only have one injector 

per cylinder. Yes electronic injectors fail. I had to have a set of 

diesel injectors replaced less than 10 years ago because of frequent 

failures, under a manufacturer service bulletin (not just my auto).

I've seen a dual electronic ignition fail on an aircraft, on takeoff, 

because of an intermittent failure of an automotive voltage regulator, 

fried the electronic ignitions, yes, both of them.

Automotive reliability simply does not translate directly to aviation. 

There are really only two automotive engines that have endured in 

aviation, and neither one normally has electronic anything.

Just my experience from 50 years of working on autos and 45 years 

working on aircraft. 	




I agree that aircraft MFI is very reliable.  I simply disagree with your assertion that EFI is somehow not reliable.



Early implementations of almost every new technology are less reliable than after they have a decade or so of service.  Auto style port injection EFI is hardly a new technology now with at least three decades of refinement.  GDI has some early teething troubles, but even that is pretty well proven now.



Fabric and tube is a reliable technology, but that doesn’t mean aluminum is not reliable even though many early aluminum airplanes had issues prior to fatigue being well understood.  And as good as aluminum is now, it doesn’t mean that composites are not good.  They had issues early on as the temperature dependence and resin to fabric proportions were sorted out.  Everything new goes through a period of learning and refining.



I am not saying the wholesale adopt auto technology, as the environments are certainly different, however, many systems such as alternators, fuel systems and such really are not significantly different.  High continuous power makes many auto engine installations challenging, but mostly from a cooling perspective.  Cooled properly, most auto engines will run as long as most airplane engines.  And high continuous power output really doesn’t matter for things like alternators and EFI.  An alternator only knows RPM and load placed on it and neither is a function of the engine’s power out.  Same for EFI.  The injectors don’t really much care how wide the PWM signal is and that is the main thing that changes with higher power output.  I actually suspect an airplane engine is a much nicer environment for an electronic fuel injector than is a car engine.  Cars often run at much higher RPMs that airplanes so the injectors have to fire much faster and more often and cars often sit idling in traffic with very high under hood temperatures that airplanes only see occasionally.



I will leave you to your carbs and magnetos and happily use my electronic ignition and fuel injection.  I do still have one carbureted motorcycle that often reminds me of just how much better EFI is on all of my other vehicles.

kenryan

Joined: 20 Oct 2009
Posts: 426

Posted: Sun Sep 05, 2021 9:57 am Post subject: Z101 in an RV-10

It seems to me that the issue of a reliable source of power has been confronted and fully addressed in Bob's work.

"I think the real analysis is that you need two separate power sources

for the fuel injection and the ignition."

On Sun, Sep 5, 2021 at 9:27 AM Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 

 I think the real analysis is that you need two separate power sources 

 for the fuel injection and the ignition. Using a single battery does not 

 accomplish that, no matter how you wire it. I believe you would have to 

 have two batteries, and probably should have two alternators.

 However, that gets back to why do you want an aircraft for IFR that 

 requires the complexity of two separate electrical systems and the 

 electrical components to allow them to operate separately?

 Simplicity is your friend, especially when IFR.

 Regardless of advertising claims, a port fuel injection system with 6 

 individual electrically operated solenoids does not significantly 

 improve power or fuel economy over the mechanical fuel injection system 

 the IO-540 is designed with or the Air Flow performance experimental 

 fuel injection. They also eliminate the need for electrical fuel pumps 

 to operate continuously, as the stock mechanical pump is adequate for 

 almost all in-flight situations.

 Having both ignitions systems electrically dependent again introduces 

 complexity. You really want your engine to be able to run indefinitely 

 without external power if all electrics fail.

 You can still have the benefits of electronic ignition without the need 

 for external power if you install 2 PMag systems, and they only need 

 external power for starting.

   Even if the full SDS system gets you an extra 10 kts (unlikely) it 

 only reduces the time to fly a 500nm flight by perhaps 10-15 minutes.

 

 If you eliminate the need for external power for the engine to run, you 

 can have adequate backup power for avionics without having to install 

 dual electrical systems. Most EFIS have backup battery systems that 

 allow shutting of the master and will continue to operate for 45 min or 

 more. You can equip a Nav/com with similar backup battery.

 

 Just my opinion with 40+ yrs of IFR flying and 5 years of flying my IFR 

 RV-10.

 Kelly

 

 On 9/4/2021 2:47 PM, Sebastien wrote:

 > I think you could get away with 8AWG rather than 4 AWG for the loads you 

 > describe but let's think about this another way.

 > 

 > In case of a forced landing, we want to be able to disconnect the 2 AWG 

 > cable from the battery so that when we hit a fence post we don't have a 

 > leaking fuel line and a big spark 5 feet from our asses. Putting the 

 > relay as close to the battery accomplishes this. If we then run a 4 AWG 

 > wire along the same route with no way to disconnect it from the battery, 

 > are we any better off? If you're going to accept a large live wire 

 > running along the fuselage, will it help that the 2 AWG is cold and the 

 > 4 AWG is hot? Might as well just leave the 2 AWG hot and move the relay 

 > to the front as you first described.

 > 

 > The only other solutions I can think of are

 > 

 > 1. Relays on both wires and dual fed engine and aux busses. In a forced 

 > landing you shut off both relays.

 > 2. A second battery in the engine compartment.

 > 3. A second alternator and feed your dual fed engine and aux busses from 

 > each alternator, dropping the battery feed.

 > 

 > On Sat, Sep 4, 2021 at 2:10 PM A Lumley <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca) 

 > <mailto:andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)>> wrote:

 > 

 >     --> AeroElectric-List message posted by: "A Lumley"

 >     <andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca) <mailto:andrew.lumley(at)sympatico.ca (andrew.lumley(at)sympatico.ca)>>

 > 

 >     I'm in Belleville, 2 hours from Toronto.

 > 

 >     The hot battery bus itself is only about 0.5 amps for a few overhead

 >     lights. The issue is that the Z-101 schematic has the ability to

 >     power the aux and engine busses through relays attached to the

 >     battery side of the battery contactor. My engine bus will draw 15-20

 >     amps (SDS EFI) when both fuel pumps are running. The Aux bus

 >     includes the PFD, GPS, pitot heat, autopilot, and a few other small

 >     loads that will total another 15-20 amps with the pitot heat operating.

 > 

 >     I'm thinking I'll need a separate cable of about 4 AWG running

 >     forward from the battery in addition to the 2 AWG starter cable.

 >     Just wondering if there is a better way, perhaps not.

 > 

 > 

 > 

 > 

 >     Read this topic online here:

 > 

 >     http://forums.matronics.com/viewtopic.php?p=503043#503043

 >     <http://forums.matronics.com/viewtopic.php?p=503043#503043>

 > 

 > 

 > 

 > 

 > 

 > 

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