[simpits-tech] Aircraft power question

Sat Dec 28 18:39:46 PST 2013

Even on relatively small aircraft there is an amazing amount of power
available.  Big fat hairy Amps that you probably don't want in a sim.  If I
recall correctly, each of the alternators on our J41 can deliver something
like 750A continuous.  With this amount of power available, just about
everything on board is high power. Even the cabin lighting.  I've dumped it
all in favour of LED's where possible.

I suspect you are correct in assuming that the bus control is elsewhere and
in your shoes I would certainly be re-wiring the pit rather than trying to
make sense of the existing (yet butchered) loom.

Even with the wiring diagrams, aircraft are an absolute bitch to trace.

Roy.

On 29 December 2013 00:47, Matt Bailey <dabigboy at cox.net> wrote:

> Good point about the buses. Am I correct that a huge batch of terminal
> blocks would be considered a bus? Or are we talking about something a
> little fancier? (I have very little experience poking around the
> innards of aircraft in any detail). I *do* see some odd rectangular
> looking relays in the nose. On the back of the cockpit, there are over a
> dozen individual terminal blocks. There are several big wire bundles
> coming off them and going aft, which of course are just cut off now.
> Unfortunately, a bunch of wires also go back into the cockpit, and they
> got cut because they are right along the inside of the outer skin. I am
> worried that power delivery for the cockpit goes up to that bunch of
> terminal blocks for organization purposes. Does this make sense? Or
> perhaps I am just not getting the right relays energized to tie
> everything into power....
>
> I still have two of the three "big" inverters in the nose, as the
> previous owner was unable to figure out how to remove those. That
> leaves me with inverter #1 and a "750va" inverter (not sure what that
> monster is for).
>
> I played with it today. I figured out some of the power delivery stuff
> for the #1 and #2 inverters. My problem right now is I don't have a good
> 28v DC power source. I series'd two 12v batteries together and was able
> to power up inverter #1 for a few minutes. It appears to work (and
> makes quite an intimidating sound!), but I got absolutely no reaction
> inside the cockpit. Even the load/volt/CPS indicators did not budge.
> Then I tried tying the power lead that is supposed to go to inverter
> #1, into my 24v battery rig also. There were some interesting noises
> inside the cockpit, but then my little batteries wore out (this thing
> draws a TON of current). I am HOPING this means that I just have to
> have the 28v supply leads connected to power to engage some relays or
> something to tie in all the necessary buses, but I won't know for sure
> until I work out a better DC power source (I am actually thinking of
> using a couple of my cars in series with jumper cables and the engines
> running).
>
> Interestingly, there don't seem to be any bus tie-in controls in the
> cockpit. I guess it all happens "under the hood".
>
> Matt
>
> On Fri, 27 Dec 2013 15:05:47 +0000
> Roy Coates <roy at flightlab.liv.ac.uk> wrote:
>
> > Remember that there will be multiple buses which can be shed or
> > cross-linked.  I know zip about the Sabreliner but even our baby J41
> > has 5 (maybe 6?) buses. A very basic 737 has eleven.  So, the wiring
> > won't be as simple as you might like.
> >
> > >From my limited experience - the battery master does indeed operate
> > >a relay
> > but then the battery power is fed to the bus controller which is
> > likely another box full of relays hidden away somewhere.
> >
> > Also, not all the gubbins in the cockpit will be fed from the same
> > bus. Essential vs Non-Essential items, left or right side, there are
> > many permutations.
> >
> > Test meter out... and lots of patience!
> >
> > Roy.
> >
> >
> >
> > On 27 December 2013 04:59, Matt Bailey <dabigboy at cox.net> wrote:
> >
> > > I got a chance to poke around the Sabreliner a little bit with a
> > > multimeter and a cable checker/sound'r-out'r and tried figuring out
> > > the wire routing for cockpit power. I am a little perplexed...as
> > > far as I can tell, none of the wires going to the battery master
> > > actually exit the cockpit directly. Do aircraft normally have only
> > > a relay connected to the battery master switch? I would think that
> > > at least the common lead should trace out to the wire going to the
> > > negative terminal of the aircraft's batteries. I assume I need to
> > > dig in the forward nose/avionics bay some more for relays or
> > > terminal blocks.
> > >
> > > I want to use as much of the plane's original wiring as possible.
> > > Any particular pointers you guys could offer in tracking down the
> > > power delivery circuits to the cockpit? The wiring diagram for the
> > > entire plane from Sabreliner Corp is over $700.....a little more
> > > than I can spend when I am trying to save up to build a shop for
> > > this thing this summer!
> > >
> > > --
> > > Matt Bailey
> > >
> > > Keeping It Real:
> > > Sabreliner 60 Flight Simulator
> > > Serial # 306-61 - N1JX
> > > http://sabrelinersim.com
> > > _______________________________________________
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> > > http://www.simpits.org/mailman/listinfo/simpits-tech
> > > To unsubscribe, please see the instructions at the bottom of the
> > > above page.  Thanks!
> > >
>
>
>
> --
> Matt Bailey
>
> Keeping It Real:
> Sabreliner 60 Flight Simulator
> Serial # 306-61 - N1JX
> http://sabrelinersim.com
> _______________________________________________
> Simpits-tech mailing list
> Simpits-tech at simpits.org
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> page.  Thanks!
>
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