Today's Message Index:
----------------------
1. 05:01 AM - Re: Re: Z101 in an RV-10 (Jeffrey Parker)
2. 05:44 AM - Re: Z101 in an RV-10 (Voyager)
3. 06:26 AM - Re: Re: Z101 in an RV-10 (Charlie England)
4. 07:39 AM - Re: Re: Z101 in an RV-10 (Kelly McMullen)
5. 09:23 AM - Re: Re: Z101 in an RV-10 (Charlie England)
6. 10:09 AM - Re: Z101 in an RV-10 (Voyager)
7. 10:57 AM - Re: Re: Z101 in an RV-10 (Ken Ryan)
8. 01:48 PM - Re: Re: Z101 in an RV-10 (Kelly McMullen)
Message 1
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| Subject: | Re: 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
> On 4Sep, 2021, at 17:06, A Lumley <andrew.lumley@sympatico.ca> wrote:
>
<andrew.lumley@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
>
>
>
>
>
>
>
>
>
Message 2
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| 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 dont 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. Id 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 doesnt 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 wouldnt 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 dont ignore
the warning, it is almost always possible to replace the battery before
complete failure.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=503053#503053
Message 3
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| Subject: | Re: Z101 in an RV-10 |
On Sun, Sep 5, 2021 at 7:47 AM Voyager <m.whiting@frontier.com> wrote:
m
> >
>
>
> 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 u
p
> > 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 zer
o
> > 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=99t 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 tha
n
> electrical. I=99d love to see real data on MFI vs EFI as my experi
ence 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=99t care where the elect
rons 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=99t crank one morning. It was only 4 months old and the bat
tery
> 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=99t ig
nore 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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Message 4
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| Subject: | Re: 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:
>
>
> On Sun, Sep 5, 2021 at 7:47 AM Voyager <m.whiting@frontier.com
> <mailto:m.whiting@frontier.com>> wrote:
>
> <m.whiting@frontier.com <mailto:m.whiting@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 dont 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. Id 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 doesnt 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 wouldnt 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
> dont 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
>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon>
> Virus-free. www.avast.com
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>
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Message 5
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| Subject: | Re: 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@aviating.com> wrote:
> kellym@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:
> andrew.lumley@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
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
Message 6
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| 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 doesnt 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 doesnt 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 doesnt matter for things like alternators
and EFI. An alternator only knows RPM and load placed on it and neither
is a function of the engines power out. Same for EFI. The injectors dont
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. :-)
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=503057#503057
Message 7
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| Subject: | Re: 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@aviating.com> wrote:
> kellym@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@sympatico.ca
> > <mailto:andrew.lumley@sympatico.ca>> wrote:
> >
> > <andrew.lumley@sympatico.ca <mailto:andrew.lumley@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>
> >
> >
> >
> >
> >
> >
> > ==========
> > -
> > Electric-List" rel="noreferrer"
> > target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
> > ==========
> > FORUMS -
> > eferrer" target="_blank">http://forums.matronics.com
> > ==========
> > WIKI -
> > errer" target="_blank">http://wiki.matronics.com
> > ==========
> > b Site -
> > -Matt Dralle, List Admin.
> > rel="noreferrer" target="_blank">
> http://www.matronics.com/contribution
> > ==========
> >
> >
> >
>
>
Message 8
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| Subject: | Re: Z101 in an RV-10 |
Agreed, however, in most cases it is to deal with two electrically
dependent ignition systems, and/or an essential bus for avionics. I
don't believe the case of electrically dependent fuel system has come
up, at least not recently.
Given your engine needs air, spark and fuel vapors, do you really want
fuel and spark to be dependent on the electrical system?
With the fuel system you both have to have the controllers powered and
both fuel pumps powered, and a means to cross feed power to them.
I'm more comfortable with a plane set up so that if there is any
electrical problem I can just shut off the master and get to nearest
suitable airport without needing electrics. Can only recall one time in
47 years of flying that I needed to do that, but was comforting to be
able to do. Just as limiting power to just an essential bus expands your
options to deal with situation.
Somewhat overlooked in the discussion is that the aircraft is to be
based in Canada, and there are times when the temperatures don't allow
work on an electrical system (ever pulled a battery at -40?) and
locations where spare parts might take a fair amount of time and money
to obtain. Likely remoteness and extreme temps can greatly influence
risks and your choices.
Kelly
On 9/5/2021 10:55 AM, Ken Ryan wrote:
> 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."
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