Today's Message Index:
----------------------
1. 03:10 AM - Z-14 implementation for SDS (Krea Ellis)
2. 05:53 AM - Re: Z-14 implementation for SDS (Robert L. Nuckolls, III)
3. 07:04 AM - Re: Z-14 implementation for SDS (Ernest Christley)
4. 07:19 AM - This doesn't seem right, but what do I know (Paul Zimmer)
5. 07:38 AM - Re: This doesn't seem right, but what do I know (Robert L. Nuckolls, III)
6. 07:42 AM - Z-14 implementation for SDS (Krea Ellis)
7. 08:04 AM - Re: Z-14 implementation for SDS (Charlie England)
8. 08:28 AM - Re: Plan-B fuel flow . . . (Robert L. Nuckolls, III)
9. 08:49 AM - Re: This doesn't seem right, but what do I know (Paul Zimmer)
10. 11:05 AM - Re: This doesn't seem right, but what do I know (Charlie England)
11. 05:01 PM - To Krea: the Q. you haven't asked yet :-) (Charlie England)
12. 05:29 PM - Re: Proposed Z-14 implementation (johnbright)
13. 06:18 PM - Re: Plan-B fuel flow . . . (johnbright)
14. 07:47 PM - Re: Replacing an EGT Probe (Art Zemon)
Message 1
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| Subject: | Z-14 implementation for SDS |
Ive tried to register to log in, but no luck - so I have to post a new thread.
Sorry.
Z14 architecture. As with John Bright, the issue is powering the injectors. All
other components are redundant (ECU, fuel pump, 6 cylinder coil pack) and can
be powered by an individual hot battery bus - protected by CBs and controlled
by a Honeywell TL switch.
My dilemma for the injectors is whether or not to power them from a Schottky diode
protected injector bus, fed by each hot battery bus - or power them through
a double pole triple throw switch. Normal position - 3 injectors powered by
their respective hot battery bus, or all injectors powered by either A or B hot
battery bus - with all power running through the TL switch.
If the injector bus loses power for whatever reason, the engine dies.
Trying to decide which architecture is the most reliable.
Thank you.
Message 2
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| Subject: | Re: Z-14 implementation for SDS |
>If the injector bus=9D loses power for whatever reason, the engine dies.
>
>Trying to decide which architecture is the most reliable.
But what might be the reason? 99.999% of the time,
when a bus looses power, it's because the source of
power for that bus was lost . . .not because of
any catastrophic failure of wiring and/or
bus structure.
This is a good topic for conducting an
artful FMEA. I posed the question earlier:
Assume all injectors are powered from
the z-14 aux bus. What failure of a device
would bring down the bus in a manner that
had no handy mitigation i.e. a plan-B?
Bob . . .
Message 3
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| Subject: | Re: Z-14 implementation for SDS |
On Tuesday, January 28, 2020, 6:10:55 AM EST, Krea Ellis <krea.ellis@gm
ail.com> wrote:
If the =9Cinjector bus=9D loses power for whatever reason, the
engine dies.
The Wright brother had an engine that dripped fuel into a bowl at the intak
e.=C2- That method doesn't give a lot of control, but it still works.=C2
- If you can gravity feed fuel, you might consider running a line to some
place on the intake and control it with a needle valve.
Message 4
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| Subject: | This doesn't seem right, but what do I know |
I use and monitor two Hall effect current sensors on my RV. One measures
the current flow on the "B" lead from the main alternator, and the other
measures the current flow to/from the main battery.
What doesn't make sense to me is there are periodic and frequent current
flows to/from the battery (1 to 5 amps) during normal cruise operations,
this during periods of static and relatively light load (12-15 amps) on the
electrical system, much smaller than the capacity of the 60A Plane Power
alternator. I would expect all power to be supplied directly from the
alternator as it is supplying the current at a higher voltage (~14.5v or
so) than the battery. These periods of flow to/from the battery are short
in duration normally lasting only a few seconds.
Is this normal and to be expected, or does it suggest a problem with the
internally regulated alternator, or perhaps with the current sensor itself?
Any insight explaining what I am seeing will be appreciated.
Thanks
Message 5
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| Subject: | Re: This doesn't seem right, but what do I know |
<snip>
>These periods of flow to/from the battery are short
>in duration normally lasting only a few seconds.
>
>Is this normal and to be expected, or does it
>suggest a problem with the internally regulated
>alternator, or perhaps with the current sensor itself?
>
>Any insight explaining what I am seeing will be appreciated.
The battery's physics reacts to BUS VOLTAGE.
Any period battery energy outflow MUST be
paired with a drop in bus voltage to something
below the battery's present open-circuit
voltage.
The voltage doesn't have to drop to
the battery's natural delivery
level (~12.5 volts for SVLA) . . .
a battery across an operating bus
will support small outflow currents
at voltages higher than 12.5.
What is your normal bus voltage and do
you notice any depression of voltage
that corresponds to battery outflow
events?
Bob . . .
Message 6
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| Subject: | Z-14 implementation for SDS |
Ive tried to register to log in, but no luck - so I have to post a new thread.
Sorry.
Z14 architecture. As with John Bright, the issue is powering the injectors. All
other components are redundant (ECU, fuel pump, 6 cylinder coil pack) and can
be powered by an individual hot battery bus - protected by CBs and controlled
by a Honeywell TL switch.
My dilemma for the injectors is whether or not to power them from a Schottky diode
protected injector bus, fed by each hot battery bus - or power them through
a double pole triple throw switch. Normal position - 3 injectors powered by
their respective hot battery bus, or all injectors powered by either A or B hot
battery bus - with all power running through the TL switch.
If the injector bus loses power for whatever reason, the engine dies.
Trying to decide which architecture is the most reliable.
Thank you.
Message 7
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| Subject: | Re: Z-14 implementation for SDS |
On 1/28/2020 5:08 AM, Krea Ellis wrote:
>
> Ive tried to register to log in, but no luck - so I have to post a new thread.
Sorry.
>
> Z14 architecture. As with John Bright, the issue is powering the injectors.
All other components are redundant (ECU, fuel pump, 6 cylinder coil pack) and
can be powered by an individual hot battery bus - protected by CBs and controlled
by a Honeywell TL switch.
>
> My dilemma for the injectors is whether or not to power them from a Schottky
diode protected injector bus, fed by each hot battery bus - or power them through
a double pole triple throw switch. Normal position - 3 injectors powered by
their respective hot battery bus, or all injectors powered by either A or B
hot battery bus - with all power running through the TL switch.
>
> If the injector bus loses power for whatever reason, the engine dies.
>
> Trying to decide which architecture is the most reliable.
Well, most safety related analysis techniques I've read about tend to
assign 'reliable' to stuff we can't make redundant or for which we can't
supply an alternative, like wings and other structure.
If it's reasonably possible to provide an alternative for a safety of
flight item, we *assume* that it can fail, *regardless of its
reliability*, and provide an alternative (ex: pitch trim backs up direct
pitch control from the stick).
If you route all power for the injectors through a single multi-section
switch, a mechanical failure of the switch (no matter how 'reliable')
can take out all power to all injectors. In my opinion, it fails failure
mode analysis, since there's no 'plan B' for a mechanical switch failure.
Charlie
Message 8
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| Subject: | Re: Plan-B fuel flow . . . |
At 09:00 AM 1/28/2020, you wrote:
>On Tuesday, January 28, 2020, 6:10:55 AM EST,
>Krea Ellis <krea.ellis@gmail.com> wrote:
>
>If the =9Cinjector bus=9D loses power for whatever reason, the
engine dies.
>
>
>The Wright brother had an engine that dripped
>fuel into a bowl at the intake. That method
>doesn't give a lot of control, but it still
>works. If you can gravity feed fuel, you might
>consider running a line to someplace on the
>intake and control it with a needle valve.
Speaking of redundant fuel delivery systems,
I'm recalling a conversation from waaayyy back
in the dark ages . . . I think it was prompted
by the John Denver crash in a LongEz. The
investigators theorized that he ran a tank
dry and may have stood on a rudder pedal
trying to reach a fuel tank selector handle
causing loss of control under engine-out
conditions.
The conversation debated a desire by some
Ez owners not to have to run three fuel
lines the length of the cockpit to a more
conveniently located selector valve.
I suggested an alternative, no-valve,
all electric approach to fuel management
on canard-pusher aircraft.
Emacs!
The suggestion also provided an alternative,
completely independent, fuel delivery system.
4-port primer systems were a functional possibility
for most Ez engines. I had recalled several
"I leaned about flying from that" stories
wherein a pilot brought his ship to a
comfortable landing using a primer pump
to keep the engine delivering useful power.
So why not install an on-purpose, primer/run
system? The pump driven, primer system would
feed from one tank, the main fuel supply from the
other tank. A third pump would transfer fuel
from the left tank to the right tank.
A needle valve in the primer line would be
used to calibrate primer fuel flow to approximate
that needed for 70% or so power.
Don't know how many of these system were
installed but I did get a report from
one reader that did a calibrated,
4-port installation and flight tested
it. He said it worked nicely. This arrangement
had a high probability of enabling a
graceful return to earth in case of
problems in the primary fuel delivery
system.
Light, cheap, low energy requirements and
completely independent of primary system.
Bob . . .
Message 9
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| Subject: | Re: This doesn't seem right, but what do I know |
I can=99t say that I=99ve noticed a bus voltage drop during the
se times of
battery outflow, but before I say one way or the other, I=99ll need t
o pay a
little closer attention, and perhaps record the engine monitor parameters
during a flight which would allow for an after the fact thorough analysis
of what actually went on. I=99ll circle back at a later date. Thank
s
On Tue, Jan 28, 2020 at 10:43 AM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> <snip>
>
> These periods of flow to/from the battery are short
> in duration normally lasting only a few seconds.
>
> Is this normal and to be expected, or does it
> suggest a problem with the internally regulated
> alternator, or perhaps with the current sensor itself?
>
> Any insight explaining what I am seeing will be appreciated.
>
>
> The battery's physics reacts to BUS VOLTAGE.
> Any period battery energy outflow MUST be
> paired with a drop in bus voltage to something
> below the battery's present open-circuit
> voltage.
>
> The voltage doesn't have to drop to
> the battery's natural delivery
> level (~12.5 volts for SVLA) . . .
> a battery across an operating bus
> will support small outflow currents
> at voltages higher than 12.5.
>
> What is your normal bus voltage and do
> you notice any depression of voltage
> that corresponds to battery outflow
> events?
>
>
> Bob . . .
>
Message 10
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| Subject: | Re: This doesn't seem right, but what do I know |
If you were using a shunt, I'd suggest checking any fuseholders used to
protect the sense wires. Any minor variations in resistance in the sense
lines can cause significant instrument error, showing discharge.
Charlie
On 1/28/2020 10:46 AM, Paul Zimmer wrote:
> I cant say that Ive noticed a bus voltage drop during these times of
> battery outflow, but before I say one way or the other, Ill need to
> pay a little closer attention, and perhaps record the engine monitor
> parameters during a flight which would allow for an after the fact
> thorough analysis of what actually went on. Ill circle back at a
> later date. Thanks
>
> On Tue, Jan 28, 2020 at 10:43 AM Robert L. Nuckolls, III
> <nuckolls.bob@aeroelectric.com <mailto:nuckolls.bob@aeroelectric.com>>
> wrote:
>
> <snip>
>
>> These periods of flow to/from the battery are short
>> in duration normally lasting only a few seconds.
>>
>> Is this normal and to be expected, or does it
>> suggest a problem with the internally regulated
>> alternator, or perhaps with the current sensor itself?
>>
>> Any insight explaining what I am seeing will be appreciated.
>
> The battery's physics reacts to BUS VOLTAGE.
> Any period battery energy outflow MUST be
> paired with a drop in bus voltage to something
> below the battery's present open-circuit
> voltage.
>
> The voltage doesn't have to drop to
> the battery's natural delivery
> level (~12.5 volts for SVLA) . . .
> a battery across an operating bus
> will support small outflow currents
> at voltages higher than 12.5.
>
> What is your normal bus voltage and do
> you notice any depression of voltage
> that corresponds to battery outflow
> events?
>
>
> Bob . . .
>
Message 11
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| Subject: | To Krea: the Q. you haven't asked yet :-) |
I installed these in my RV6. The '2 seats with 5Lv' model will give you
what you're looking for.
https://www.ebay.com/itm/Car-Seat-Heater-Kit-Carbon-Fiber-Universal-Heated-Cushion-Warmer-2-level-5-level/253250702661?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
Hope that helps,
Charlie
Message 12
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| Subject: | Re: Proposed Z-14 implementation |
nuckolls.bob(at)aeroelect wrote:
> At 02:29 PM 1/27/2020, you wrote:
>
> Okay, riddle me this . . . suppose all injectors were
> powered from the aux bus of Z14. Deduced and cite the
> failure that would bring the aux bus down . . . and
> what would be the mitigating action?
>
>
> Bob . . .
Thanks Bob,
The feed to the bus itself could be interrupted resulting in engine stoppage. It
is unlikely to lose a bus feed but not impossible; probably due to poor craftsmanship
which in my anecdotal experience occurs too often. Also in an electrical
fire in the cockpit scenario the crew would take the main and aux power buses
down.
I took a shot a bus config trade study for electronic injection + ignition; attached
as a gif and in my filespace linked from my signature.
--------
John Bright, RV-6A, at FWF, O-360, dual SDSEFI EM-5-F
<a href="https://drive.google.com/drive/folders/1u6GeZo6pmBWsKykLNVQMvu4o1VEVyP4K">Dual
Batt Dual Alt RV-6A SDS dual EM-5-F</a>
john_s_bright@yahoo.com, Newport News, Va
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=494516#494516
Attachments:
http://forums.matronics.com//files/bus_config_trades_for_electronic_injection__ignition_rev_01282020_819.jpg
Message 13
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| Subject: | Re: Plan-B fuel flow . . . |
Dave Anders did something like this on his SDS EFI RV-4:
http://www.vansairforce.com/community/showpost.php?p=1191654&postcount=140
Some photos of his RV-4:
http://www.sdsefi.com/dave.htm
--------
John Bright, RV-6A, at FWF, O-360, dual SDSEFI EM-5-F
<a href="https://drive.google.com/drive/folders/1u6GeZo6pmBWsKykLNVQMvu4o1VEVyP4K">Dual
Batt Dual Alt RV-6A SDS dual EM-5-F</a>
john_s_bright@yahoo.com, Newport News, Va
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=494517#494517
Message 14
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| Subject: | Re: Replacing an EGT Probe |
Thanks, folks. I'll try one of the old EGT probes and see if it works.
Cheers,
-- Art Z.
--
https://CheerfulCurmudgeon.com/
*Love the stranger for you yourselves were strangers in Egypt. *Deut. 10:19
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