Today's Message Index:
----------------------
1. 05:52 AM - Re: Batt and Alternator Switch (John M Tipton)
2. 06:07 AM - Re: Super-whizzy energy management systems (bcone1381)
3. 08:55 AM - Re: Re: Super-whizzy energy management systems (Robert L. Nuckolls, III)
4. 09:56 AM - Re: Re: DC clamp meter (Robert L. Nuckolls, III)
5. 10:22 AM - N88MV Accident Analysis (Robert L. Nuckolls, III)
6. 10:50 AM - Re: N88MV Accident Analysis (Charlie England)
7. 02:24 PM - Re: N88MV Accident Analysis (Robert L. Nuckolls, III)
8. 03:55 PM - Re: N88MV Accident Analysis (Charlie England)
9. 04:26 PM - Re: N88MV Accident Analysis (Alec)
10. 05:24 PM - Re: Re: Super-whizzy energy management systems (Charlie England)
11. 06:03 PM - Re: Super-whizzy energy management systems (johnbright)
12. 06:10 PM - OV push to test button, is there a hack for SB1B (johnbright)
13. 06:44 PM - Re: N88MV accident analysis (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Batt and Alternator Switch |
eBay item: UK listing - 163671102668
Sent from my iPad
----x--O--x----
> On 4 May 2020, at 9:18 pm, Robert L. Nuckolls, III <nuckolls.bob@aeroelect
ric.com> wrote:
>
> =EF=BB At 02:00 PM 5/4/2020, you wrote:
>> I have a Z16 with a rotax 914.=C3=82 I have two separate=C3=82 switches f
or Bat and Alt.
>>
>> The other day in turbulence while reaching for my GPS a bump caused me to
switch off the BAT while leaving the ALT on.=C3=82 I noticed and quickly=C3
=82 switched the BAT back on.=C3=82 =C3=82
>>
>> My interim=C3=82 solution is to make a switch guard.
>>
>> However I remember reading the that the way to avoid this is to have and O
FF ON ON switch.=C3=82 =C3=82
>>
>> Can someone suggest the appropriate switch please.
>>
>> thanks
>>
>> Will
>>
>> William Daniell
>> LONGPORT
>> +1 786 878 0246
>
> The switch depicted on Z16 does just that.
> It's a progressive transfer, Two-pole, Three-position,
> switch. Available from many sources under various
> part numbers, you can get one with fast-on tabs
> from B&C as S700-2-20.
>
> https://tinyurl.com/y7ay7lvj
>
>
>
> Bob . . .
Message 2
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| Subject: | Re: Super-whizzy energy management systems |
[/quote]My 1st question is whether that alternator ground wire was the only connection
between the engine and the airframe, as seems likely.
Charlie[/quote]
Throttle, mixture and prop cables will ground an engine. Its a mystery what other
grounds existed.
--------
Brooks Cone
Bearhawk Patrol Kit Build
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496205#496205
Message 3
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| Subject: | Re: Super-whizzy energy management systems |
At 08:06 AM 5/5/2020, you wrote:
>
>[/quote]My 1st question is whether that
>alternator ground wire was the only connection
>between the engine and the airframe, as seems likely.
>
>
>Charlie=C2 [/quote]
>
>Throttle, mixture and prop cables will ground an
>engine. Its a mystery what other grounds existed.
Yes . . . sort of . . . all those conductors
are steel, long and terminate on various
and widely separated mountings designed
for mechanical integrity, not electrical
conductivity.
It is not uncommon for those 'ground paths'
to suffer serious overheat events during
engine cranking when a mechanic inadvertently
fails to replace the crankcase-to-firewall
bond strap during maintenance. This very
event occurred on one of my rental airplanes
back about 1990 but it was double grounded
p-lead shields that smoked. This is why
the z-figures show p-lead termination that
is contrary to some legacy practice.
A ground lead to an alternator case is
not common practice. The crankcase-to-
firewall ground strap is generally 2AWG
equivalent or better and seeks good
electrical conductivity at locations
suited to that service.
We don't know where the other end of
the illustrated ground lead was terminated,
nor do we know if it was in addition to
another ground path. The overheating
observed in the picture does suggest
that the ground system on that engine
was inadequate by design or compromised
by error.
I'm hoping to get back to our hip-pocket
accident analysis but as participants
will note, there are more questions
than answers. Lacking a good schematic
for how the airplane was wired, we'll
never know how an engine became electrically
starved (assuming that's true) while
a data acquisition system RECORDED
the presence of voltage in the system.
This wasn't an electrical 'black out' . . .
The alternator output went to zero
but again, we're not privy to all the
hardware between the alternator and
the bus . . . the breaker was not open
so something caused the alternator
output to zero with what appears to
be simultaneous engine failure.
Bob . . .
Message 4
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| Subject: | Re: DC clamp meter |
At 12:12 PM 5/4/2020, you wrote:
<den_beaulieu@yahoo.com>
>
>"Help us out with your mission."
>
>Hi Bob, I simply want to put a typical inflight
>load on the fuly charged battery and perform the
>below method /test as my benchmark for battery
>capacity check and/or replacement. When at 80%
>of the benchmark, replace battery. I was going
>to use old style truck headlight bulbs for a
>resistive load. Cranking capacity is not a
>significant concern for my style of flying operation... (famous last
words?)
>
> >From the Earth FAQ's listing...
>
>Test Method #2 (with timer and DC current meter):
>
>a. Fully charge the battery with an appropriate charger.
>
>b. Turn on all electrical loads and start a
>timer. The same load must be used in subsequent years for accuracy.
>
>c. Measure and record the battery=99s discharge
>amps using a DC clamp-on current meter at the positive terminal of the
battery.
>
>d. Using the measured amps in the previous step
>and the battery=99s nameplate rated capacity (in
>Ah), calculate the time to discharge the battery to 80%.
>
>Time to Discharge 80% (Hours)=Rated Capacity in Ah * .8Measured Discharge
Amps
>
>For Example (16 Ah Rated Capacity, 5 amp measured discharge rate)
>
>Time to Discharge 80%=16 Ah * .85= 2.56 hours
If one is going to test the battery in-situ, i.e.
on the airplane with plan-b endurance loads running,
then the exact current demand is somewhat irrelevant
to the test. Just time the interval until electro-
whizzies shut down. That time represents the present
capacity-at-plan-b-load. You can do that with a
new battery to benchmark T1. The replacement
milestone would be at T0.80 of the as-new value.
You should measure or accurately calculate plan-b
loads to (1) predict plan-b endurance based on
battery specifications and (2) verify the battery's
capabilities at the time of your benchmark
test on a new battery.
You can easily measure plan-b loads by inserting
an ammeter in series with your battery lead and
turning on the plan-b compliment of electro-
whizzies. This is a good thing to do to verify
your load analysis values.
>e. Terminate the test after the number of hours
>calculated in the previous step has expired or
>if the battery is over-discharged (shuts off
>discharge current). If the battery is still
>supplying power at the termination of the test,
>then the battery=99s capacity is greater than
>80%. If the battery=99s capacity is greater than
>80% of it rated or capable of supporting the
>aircraft=99s emergency load for the required
>amount of time, then the battery has passed the test.
>
>f. Fully charge the battery with an appropriate charger.[/i]
The Earth-X testing is okay but I think
overly complicated. YOUR primary interest
as the guy sitting in the left seat is
"how long will the panel stay lit up"?
Doing the in-situ test tells you what the
battery will do right now. The 80% value
is a somewhat arbitrary number established
by convention and experience with rechargeable
batteries (when a battery drops to 80% of
as new capacity, it's on the down-hill-slide
toward useless).
Your multimeter probably has a 10 amp DC
current measurement capability that can be
used to quantify your real, plan-b loads.
You don't need to buy a special instrument
for this measurement.
Bob . . .
Message 5
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| Subject: | N88MV Accident Analysis |
Another interesting data point.
This flight didn't last very long. Further,
the DAS system reported only a short interval
of abnormal bus voltage before the
alternator output went to zero.
The narrative says the pilot 'noticed the
batteries overheating'. I wonder how
this was observed. Bad smell? Melting
plastic? Smoke?
Bob . . .
Message 6
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| Subject: | Re: N88MV Accident Analysis |
On 5/5/2020 12:17 PM, Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> Another interesting data point.
>
> This flight didn't last very long. Further,
> the DAS system reported only a short interval
> of abnormal bus voltage before the
> alternator output went to zero.
>
> The narrative says the pilot 'noticed the
> batteries overheating'. I wonder how
> this was observed. Bad smell? Melting
> plastic? Smoke?
Stock battery location in the RV6 is adjacent to the pilot's right foot
(passenger's left foot), almost touching the firewall. Mine has an
aluminum cover, but it's simple to just use a hold-down strap.
From the Katheryn's Report:
"At an altitude of about 4,000 ft, the pilot noticed that the airplane
batteries, located in the cockpit near his right foot, were getting hot. "
Charlie
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Message 7
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| Subject: | Re: N88MV Accident Analysis |
> From the Katheryn's Report:
>"At an altitude of about 4,000 ft, the pilot noticed that the
>airplane batteries, located in the cockpit near his right foot, were
>getting hot. "
>
>Charlie
Yeah, that's what I'm referring to. Suppose you're
flying along fat and sassy . . . and you 'notice'
that your batteries are getting hot. How
would that come to your attention?
Bob . . .
Message 8
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| Subject: | Re: N88MV Accident Analysis |
On Tue, May 5, 2020 at 4:30 PM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> From the Katheryn's Report:
> "At an altitude of about 4,000 ft, the pilot noticed that the airplane
> batteries, located in the cockpit near his right foot, were getting hot. "
>
> Charlie
>
>
> Yeah, that's what I'm referring to. Suppose you're
> flying along fat and sassy . . . and you 'notice'
> that your batteries are getting hot. How
> would that come to your attention?
>
>
> Bob . . .
>
The battery is within a couple of inches of the pilot's right foot; he
might even have his foot resting against if if he's taken his feet off the
pedals & slid them forward with a bit of 'man spreading'. If it got truly
'hot' (unquantified), it's not much of a stretch to believe he felt it with
his foot.
Charlie
Message 9
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| Subject: | Re: N88MV Accident Analysis |
Your shoe melts?
Sent from my iPhone
> On May 5, 2020, at 6:44 PM, Charlie England <ceengland7@gmail.com> wrote:
>
>
>
>> On Tue, May 5, 2020 at 4:30 PM Robert L. Nuckolls, III <nuckolls.bob@aero
electric.com> wrote:
>>> =46rom the Katheryn's Report:
>>> "At an altitude of about 4,000 ft, the pilot noticed that the airplane b
atteries, located in the cockpit near his right foot, were getting hot. "
>>>
>>> Charlie
>>
>> Yeah, that's what I'm referring to. Suppose you're
>> flying along fat and sassy . . . and you 'notice'
>> that your batteries are getting hot. How
>> would that come to your attention?
>>
>>
>> Bob . . .
>>
>
> The battery is within a couple of inches of the pilot's right foot; he mig
ht even have his foot resting against if if he's taken his feet off the peda
ls & slid them forward with a bit of 'man spreading'. If it got truly 'hot'
(unquantified), it's not much of a stretch to believe he felt it with his f
oot.
>
> Charlie
Message 10
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| Subject: | Re: Super-whizzy energy management systems |
On 5/5/2020 10:51 AM, Robert L. Nuckolls, III wrote:
> At 08:06 AM 5/5/2020, you wrote:
>> <bcone1964@gmail.com>
>>
>> [/quote]My 1st question is whether that alternator ground wire was
>> the only connection between the engine and the airframe, as seems likely.
>>
>>
>> Charlie [/quote]
>>
>> Throttle, mixture and prop cables will ground an engine. Its a
>> mystery what other grounds existed.
>
> Yes . . . sort of . . . all those conductors
> are steel, long and terminate on various
> and widely separated mountings designed
> for mechanical integrity, not electrical
> conductivity.
>
> It is not uncommon for those 'ground paths'
> to suffer serious overheat events during
> engine cranking when a mechanic inadvertently
> fails to replace the crankcase-to-firewall
> bond strap during maintenance. This very
> event occurred on one of my rental airplanes
> back about 1990 but it was double grounded
> p-lead shields that smoked. This is why
> the z-figures show p-lead termination that
> is contrary to some legacy practice.
>
> A ground lead to an alternator case is
> not common practice. The crankcase-to-
> firewall ground strap is generally 2AWG
> equivalent or better and seeks good
> electrical conductivity at locations
> suited to that service.
>
> We don't know where the other end of
> the illustrated ground lead was terminated,
> nor do we know if it was in addition to
> another ground path. The overheating
> observed in the picture does suggest
> that the ground system on that engine
> was inadequate by design or compromised
> by error.
>
> I'm hoping to get back to our hip-pocket
> accident analysis but as participants
> will note, there are more questions
> than answers. Lacking a good schematic
> for how the airplane was wired, we'll
> never know how an engine became electrically
> starved (assuming that's true) while
> a data acquisition system RECORDED
> the presence of voltage in the system.
>
> This wasn't an electrical 'black out' . . .
>
> The alternator output went to zero
> but again, we're not privy to all the
> hardware between the alternator and
> the bus . . . the breaker was not open
> so something caused the alternator
> output to zero with what appears to
> be simultaneous engine failure.
>
> Bob . . .
>
To the 'control cables will ground the engine': In the early 1970s, I
bought a brand new Fiat 128; the 1st commonly available front wheel
drive econobox in the USA. At some point, the dealership had to do some
work on it, and when I got it back, it would intermittently fail to
'turn over' well, as if the battery was going bad. I eventually quit
driving it, having purchased a 124 (a lot more fun). When a potential
buyer showed interest in it, I tried to get it running with a new
battery mounted, and with the hood up, I noticed smoke under the hood
while the starter was trying to turn. The car had a cable actuated
clutch, and the clutch cable was trying to go up in smoke. Looked under
the car, and the engine's ground strap was hanging loose on one end.
If the discoloration in the 'alternator ground' terminal really is due
to poor termination-induced resistance heating, that's a strong
indicator (to me, anyway) that it was the only ground *wire* connecting
the engine to the airframe. I'd expect a properly sized ground wire
attached anywhere else on the engine to carry effectively all the
current, with the high resistance 'alternator ground' being ignored by
the a/c.
The narrative of the engine shutting down *when the voltage climbed* but
the rest of the a/c continued to see battery voltage after the
alternator shut down really is....interesting.
The investigation does seem very typical of NTSB/FAA handling of
experimental a/c incidents/accidents. The never have staff experienced
with homebuilts (especially 'alternative' configurations), and very
rarely even make an attempt to find competent, knowledgeable
consultants. There's also rarely an *objective* opinion sought. They
frequently call on the mfgr of the device, a/c, etc that's in question
for failure analysis. If I built the widget, am I likely to take
responsibility for its failure in an accident?
Charlie
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Message 11
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| Subject: | Re: Super-whizzy energy management systems |
Would/could the loose alternator/engine ground wire fool the regulator into raising
the field current?
--------
John Bright, RV-6A, at FWF, O-360
Single batt dual alt SDS EM-5-F.
john_s_bright@yahoo.com, Newport News, Va
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496222#496222
Message 12
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| Subject: | OV push to test button, is there a hack for SB1B |
Hi Bob,
Seems like a nice feature that SB1B has an annunciatior light that it has come
online but unlike LR3C there is not an OV PTT... is there a way to hack into SB1B
for an OV PTT button?
Thanks
--------
John Bright, RV-6A, at FWF, O-360
Single batt dual alt SDS EM-5-F.
john_s_bright@yahoo.com, Newport News, Va
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=496223#496223
Message 13
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| Subject: | Re: N88MV accident analysis |
At 08:01 PM 5/5/2020, you wrote:
><john_s_bright@yahoo.com>
>
>Would/could the loose alternator/engine ground wire fool the
>regulator into raising the field current?
No. The built in regulator usually senses alternator
output voltage between b-terminal and alternator
case ground. The the DAS recorded voltage rise
suggests that while the alternator ground was
of poor integrity, it was still carrying a substantial
amount of current else the crank-case would have gone
negative as opposed to the observed rise in
bus voltage.
Hmmm . . . the crankcase had to be operating
at some point below ground if the ground-lead
crip was failing electrically. The various
control cable-grounds would have taken on
some of the engine ground duties too.
We are not told if this alternator was
fitted with a control input port under
crew control. The narrative speaks to
a brief attempt to restore power without
explaining what action was taken.
Bob . . .
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