Today's Message Index:
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1. 08:18 AM - Re: Re: Primary Power Diagram RV-14 (Robert L. Nuckolls, III)
2. 08:34 AM - Re: Re: Primary Power Diagram RV-14 (Ken Ryan)
Message 1
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| Subject: | Re: Primary Power Diagram RV-14 |
>Two B/U=C2 batteries - I want to be able to maintain flight attitude and
>navigation capabilities, as normal as possible, if I need to secure
>ships battery and pri/stby alternators due to electrical smoke/fire.
Electrically promoted fire exterior to an appliance
is exceedingly rare and almost always caused by
a failure in craftsmanship.
Think about it. Smoke generally comes from overheated
insulation on wires. Circuit protection is provided
to prevent such issues.
Then there is smoke from combustion of some OTHER
material . . . okay. I'll give you choice of any
tools you like . . . whack away at any part of your
ship's electrical system to (1) create a spark
of sufficient heat to (2) ignite some flammable material
without (3) opening the circuit protection.
I would hope that by design and fabrication, your wiring
is mechanically secure, thoughtfully sized and protected
and your airplane is also free of materials that would promote
an in flight fire should an ignition source become available.
Most in flight fires are in front of the firewall
feed by fuel or oil. Shutting down the DC power is
effective only if the fire is fuel-fed and fuel
is electrically transported from tank to engine. If
it's oil fed . . . well . . . that's an especially
bad day in the cockpit.
>First sign of electrical smoke, I switch off main battery and alternators.
>The B/U bats activate automatically providing power to PFD, GTN650,
>and a few other nice to have items.=C2 =C2 If smoke continues, I switch
off
>B/U batts one at a time starting with the GTN650 and then PFD if smoke
>continues.=C2 Then I'm left with AV30 SFD and Ipad.
That's a busy plan-A to plan-B transition check list.
We know that smoke in the cockpit most
likely originates from inside a failed piece of
avionics . . . and it's generally limited to some
small component that does not pose risk of fire
to the rest of the airplane.
Further what's your planned maintenance protocol for the
batteries. How often cap-checked and with what
tools? What conditions for air-worthiness call for
replacement? Remember, batteries are like potted
plants. They need constant attention to maximize
performance.
I suggest you are building a fire-wall against a situation
that seldom if ever happens. I'm unaware of any effort to add such
features to TC aircraft . . . and I slogged through that
regulatory tar-pit for decades.
DIY OBAM system designers are fond of adding mitigation
for a constellation of in-flight problems that are
not demonstrated in practice. Mitigations that add
complexity to the Plan-A-to-Plan-B transition are
to be avoided in a time of elevated pucker-factor'
A fine example is what happened to crews in 737MAX
aircraft faced with unintended, commands from
software that was DRIVING the nose down with a MOTOR.
They were trained to drag out the check list!
PUNCH OFF the MOTOR DRIVEN flight control features and
fly the airplane . . . takes what . . . two, maybe
three seconds?
Your two-alternator, single battery system is about
a bullet-proof as you can get. Everything added
only drives up cost, weight and adds operational
complexity.
Bob . . .
////
(o o)
===========o00o=(_)=o00o=======
=
< Go ahead, make my day . . . >
< show me where I'm wrong. >
========================
========
In the interest of creative evolution
of the-best-we-know-how-to-do based
on physics and good practice.
Message 2
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| Subject: | Re: Primary Power Diagram RV-14 |
Regarding cap checking batteries, I recently became aware of this tool:
https://www.amazon.com/dp/B07F3NHHST?psc=1&ref=ppx_yo2ov_dt_b_product_d
etails
On Thu, Mar 23, 2023 at 7:23=AFAM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> Two B/U=C3=82 batteries - I want to be able to maintain flight attitude
and
> navigation capabilities, as normal as possible, if I need to secure
> ships battery and pri/stby alternators due to electrical smoke/fire.
>
>
> Electrically promoted fire exterior to an appliance
> is exceedingly rare and almost always caused by
> a failure in craftsmanship.
>
> Think about it. Smoke generally comes from overheated
> insulation on wires. Circuit protection is provided
> to prevent such issues.
>
> Then there is smoke from combustion of some OTHER
> material . . . okay. I'll give you choice of any
> tools you like . . . whack away at any part of your
> ship's electrical system to (1) create a spark
> of sufficient heat to (2) ignite some flammable material
> without (3) opening the circuit protection.
>
> I would hope that by design and fabrication, your wiring
> is mechanically secure, thoughtfully sized and protected
> and your airplane is also free of materials that would promote
> an in flight fire should an ignition source become available.
>
> Most in flight fires are in front of the firewall
> feed by fuel or oil. Shutting down the DC power is
> effective only if the fire is fuel-fed and fuel
> is electrically transported from tank to engine. If
> it's oil fed . . . well . . . that's an especially
> bad day in the cockpit.
>
> First sign of electrical smoke, I switch off main battery and alternators
.
> The B/U bats activate automatically providing power to PFD, GTN650,
> and a few other nice to have items.=C3=82 =C3=82 If smoke continues, I s
witch off
> B/U batts one at a time starting with the GTN650 and then PFD if smoke
> continues.=C3=82 Then I'm left with AV30 SFD and Ipad.
>
>
> That's a busy plan-A to plan-B transition check list.
> We know that smoke in the cockpit most
> likely originates from inside a failed piece of
> avionics . . . and it's generally limited to some
> small component that does not pose risk of fire
> to the rest of the airplane.
>
> Further what's your planned maintenance protocol for the
> batteries. How often cap-checked and with what
> tools? What conditions for air-worthiness call for
> replacement? Remember, batteries are like potted
> plants. They need constant attention to maximize
> performance.
>
> I suggest you are building a fire-wall against a situation
> that seldom if ever happens. I'm unaware of any effort to add such
> features to TC aircraft . . . and I slogged through that
> regulatory tar-pit for decades.
>
> DIY OBAM system designers are fond of adding mitigation
> for a constellation of in-flight problems that are
> not demonstrated in practice. Mitigations that add
> complexity to the Plan-A-to-Plan-B transition are
> to be avoided in a time of elevated pucker-factor'
>
> A fine example is what happened to crews in 737MAX
> aircraft faced with unintended, commands from
> software that was DRIVING the nose down with a MOTOR.
> They were trained to drag out the check list!
> PUNCH OFF the MOTOR DRIVEN flight control features and
> fly the airplane . . . takes what . . . two, maybe
> three seconds?
>
> Your two-alternator, single battery system is about
> a bullet-proof as you can get. Everything added
> only drives up cost, weight and adds operational
> complexity.
>
> Bob . . .
>
> ////
> (o o)
> ===========o00o=(_)=o00o======
==
> < Go ahead, make my day . . . >
> < show me where I'm wrong. >
> =======================
=========
>
> In the interest of creative evolution
> of the-best-we-know-how-to-do based
> on physics and good practice.
>
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