Today's Message Index:
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1. 08:40 AM - Re: was "Contactor Questions" now battery in the trunk (Jeff Luckey)
2. 11:20 AM - Re: was "Contactor Questions" now battery in the trunk (Charlie England)
Message 1
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| Subject: | Re: was "Contactor Questions" now battery in the trunk |
Hey Bob,
It sounds like you're asking the right questions...
The master contactor should be close enough to the battery so that the fat
positive cable from the batt to the solenoid can be 18 inches or less.=C2
- Then run the fat wire from the other side of the solenoid forward.
Then, just before the crash, when you're running the just-before-I-hit-the-
ground checklist, you shut off the master --- just like we were all taught
as student pilots.=C2- That makes the length of cable running forward ine
rt (obviously) and therefore, if it gets damaged in the crash, it won't cau
se a fire.
(This scenario requires a bit more engineering in modern aircraft where all
the flight instruments are electric (EFIS) and you might want to be watchi
ng airspeed as you try to reduce your kinetic energy before impact without
stall/spinning.=C2- But, with your instrumentation it is moot.)
BTW - this is exactly how my 1965 Cherokee is wired.
-Jeff
On Wednesday, May 19, 2021, 10:05:21 PM PDT, Bob Verwey <bob.verwey@gma
il.com> wrote:
This is kinda related to contactors...
On the BD4 that I am rebuilding, the battery is behind the baggage compartm
ent, with a really fat wire running up to the firewall.=C2-
IO 470 engine so lots of amps required for start.
Is there a recommended contactor placement/battery disconnect=C2-protocol
out there?I'm thinking safety in the event of an incident which might shor
t out the fat wire to the fuselage.
My setup is very rudimentary (steam 8 pack), conventional engine gauges, pe
rhaps a mini EFIS.=C2-=C2-I did try the Forum search but struggled a li
ttle....
Best Regards,Bob Verwey082 331 2727
=C2- =C2- =C2-=C2-
On Fri, 14 May 2021 at 05:46, A Lumley <andrew.lumley@sympatico.ca> wrote:
o.ca>
Thanks to you both for the quick feedback. I'll include the jumper from the
contactor "I" terminal to the starter with the extra diode.
You are correct that B&C no longer sells the crowbar module so I was going
to build my own from your crowbar schematics.
Thanks again, I'm sure I'll have lots more questions...
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=501914#501914
-
Electric-List" rel="noreferrer" target="_blank">http://www.matronics.co
m/Navigator?AeroElectric-List
FORUMS -
eferrer" target="_blank">http://forums.matronics.com
WIKI -
errer" target="_blank">http://wiki.matronics.com
b Site -
=C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin.
rel="noreferrer" target="_blank">http://www.matronics.com/contribution
Message 2
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| Subject: | Re: was "Contactor Questions" now battery in the trunk |
Rest of the story is that the starter contactor can be on the firewall.
That way, only one long fat wire from the back is needed. The
source-side terminal of the starter contactor becomes the distribution
point for all your master contactor-controlled 'stuff' in the forward
cockpit, etc. Any required 'E-bus' feed can be much smaller, & protected
with either a fusible link or appropriate sized slow acting fuse. You
should be able to find the concepts detailed in the Z drawings.
Charlie
On 5/20/2021 10:39 AM, Jeff Luckey wrote:
> Hey Bob,
>
> It sounds like you're asking the right questions...
>
> The master contactor should be close enough to the battery so that the
> fat positive cable from the batt to the solenoid can be 18 inches or
> less. Then run the fat wire from the other side of the solenoid forward.
>
> Then, just before the crash, when you're running the
> just-before-I-hit-the-ground checklist, you shut off the master ---
> just like we were all taught as student pilots. That makes the length
> of cable running forward inert (obviously) and therefore, if it gets
> damaged in the crash, it won't cause a fire.
>
> (This scenario requires a bit more engineering in modern aircraft
> where all the flight instruments are electric (EFIS) and you might
> want to be watching airspeed as you try to reduce your kinetic energy
> before impact without stall/spinning. But, with your instrumentation
> it is moot.)
>
> BTW - this is exactly how my 1965 Cherokee is wired.
>
> -Jeff
>
>
> On Wednesday, May 19, 2021, 10:05:21 PM PDT, Bob Verwey
> <bob.verwey@gmail.com> wrote:
>
>
> This is kinda related to contactors...
>
> On the BD4 that I am rebuilding, the battery is behind the baggage
> compartment, with a really fat wire running up to the firewall.
>
> IO 470 engine so lots of amps required for start.
>
> Is there a recommended contactor placement/battery disconnectprotocol
> out there?
> I'm thinking safety in the event of an incident which might short out
> the fat wire to the fuselage.
>
> My setup is very rudimentary (steam 8 pack), conventional engine
> gauges, perhaps a mini EFIS.
> I did try the Forum search but struggled a little....
>
> Best Regards,
> Bob Verwey
> 082 331 2727
>
>
> On Fri, 14 May 2021 at 05:46, A Lumley <andrew.lumley@sympatico.ca
> <mailto:andrew.lumley@sympatico.ca>> wrote:
>
> <andrew.lumley@sympatico.ca <mailto:andrew.lumley@sympatico.ca>>
>
> Thanks to you both for the quick feedback. I'll include the jumper
> from the contactor "I" terminal to the starter with the extra diode.
>
> You are correct that B&C no longer sells the crowbar module so I
> was going to build my own from your crowbar schematics.
>
> Thanks again, I'm sure I'll have lots more questions...
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=501914#501914
> <http://forums.matronics.com/viewtopic.php?p=501914#501914>
>
>
> ==========
> -
> 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
> ==========
>
>
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