Today's Message Index:
----------------------
1. 12:02 PM - Small aux battery with Z-13 (Geoff Evans)
2. 01:24 PM - Microprocessor based Fuel Gauge Linearizer (Eric M. Jones)
3. 05:24 PM - Re: Noise canceling headsets (Van Caulart)
4. 11:41 PM - Re: Microprocessor based Fuel Gauge Linearizer (Tom Schiff)
Message 1
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| Subject: | Small aux battery with Z-13 |
--> AeroElectric-List message posted by: Geoff Evans <hellothaimassage@yahoo.com>
Bob (and anyone else with a useful comment):
I'm considering a Z-13 architecture with an additional small (4.5 AH) battery
to support one side of a dual electronic ignition in the very unlikely event
that the main battery goes inop for whatever reason. I perfer this to two
full-sized batteries because it offers unlimited endurance and it weighs
less.
I'm making an assumption here, and that is that a 4.5 AH battery can support
the operation of either the SD-8 or a standard alternator like the L-40. If
this is *not* the case (e.g. I should only use a larger battery with the
larger alternator), then the below-proposed system is overly complicated and
I can slim it down somewhat. I just figured that if I am going to install a
second small battery just incase the main battery goes inop, it might as well
be able to make either of my alternators run as well.
Anyway, I propose connecting the 4.5 AH battery directly to the #2 ignition
with a fuesable link. I will also connect it to the always-hot side of the
main battery contactor through a S704-1 relay. I will call the switch for the
relay the "Aux Battery Bus Tie," and it will be open for starting and closed
for all other operations EXCEPT for when both alternators are inop. In that
case, I'd open the relay to split the batteries so I have more control over
battery endurance.
Additionally, the power to the coil in the relay will come from BOTH
batteries, via diodes. This will allow the relay to be powered from either
battery without allowing current to flow from one battery to the other unless
the relay is actually closed. I think this would be useful in the unlikely
event of a battery-inop situation (which is the only reason I'm installing a
second small battery in the first place). If the aux battery goes inop, I can
still use juice from the main battery to hold the relay closed and thereby
power the #2 ign from the main battery. Alternatively, if the main battery
goes inop, I can use juice from the aux battery to hold the relay closed and
thereby allow the aux battery to be available to support either the L-40 or
the SD-8 alternator.
With this architecture, the only time I'd be without electrical power on the
e-bus and powering only the #2 ign directly from the aux battery is if the
main battery and both alternators died -- highly unlikely.
Once again, I'm making the assumption that a small battery will support
either the SD-8 or the L-40 alternator. I'm also assuming that it's not "bad
practice" or otherwise unadvisable to power a relay from more than one source
via diodes. Please correct these assumptions if they are wrong.
What do you think?
-Geoff
RV-8
__________________________________
http://search.yahoo.com
Message 2
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| Subject: | Microprocessor based Fuel Gauge Linearizer |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Neil Hulin's comment about using a fuel totalizer instead of a fuel gauge linearizer
has been burning a hole in my brain. I believe he is right....
Here's the deal--
You only need one fuel totalizer meter if you take fuel from only one tank at a
time. The fuel quantity meter (and memory) for that tank is simply updated as
required. I trust in this system, totalizers really work well.
Consider too, that you wouldn't need fuel-level senders or gauges at all. Always
problematic devices. You also would not need anti-slosh electronic filters
either. My airplane just got a whole lot lighter!
There are a few practical concerns--how do we know the tank is at the level the
"gauge" says it is? Well, I always checked it visually with a wooden stick anyway.
So when tanks are refilled they must be filled to the top (ideally) and
visually checked. You really wanted the fuel flow rate anyway. Not a bad tradeoff.
Eric M. Jones
The whole difference between construction and creation is exactly this:
that a thing constructed can only be loved after it is constructed;
but a thing created is loved before it exists.
- Charles Dickens
Message 3
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| Subject: | Re: Noise canceling headsets |
--> AeroElectric-List message posted by: Van Caulart <etivc@iaw.on.ca>
--> AeroElectric-List message posted by: "Ian Scott"
<jabiru22@yahoo.com.au>
I was wondering if anyone had upgraded their normal headsets to active
noise reduction and what the results where like? I.e. the kit that
replaces the innards for your old headset.
Prices a paid & results and so on?
I've converted a Dave Clark headset and two others using the kit. They
work great and all three of us wouldn't change back. Highly recommended.
I paid the going rate about $150 US, the DC kit was slightly more. well
documented and good value. Took about 2hrs/set to complete.
PeterVC
Message 4
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| Subject: | Microprocessor based Fuel Gauge Linearizer |
--> AeroElectric-List message posted by: "Tom Schiff" <tomschiff@attbi.com>
The problem is that the FAA requires that there be a fuel gage but only
requires that is shows when the tank is empty. I have been using a fuel
flow in my C-150 for several months. I have been updating the amount
remaining every time I fill by the exact amount that I have filled. It
has been agreeing with the amount determined by sticking the tanks.
After many fills and over 100 gallons of fuel burned it is still within
.2 gallons. So you could probably get away with a fuel gage that is in
reality a fuel flow gage but if you got caught you would be in trouble.
My ideal fuel gage would be several sensors of the type where a led
shines a light through a prism. When the prism is submerged in gas the
light shines on a photo sensor and indicates that the sensor is below
the level of the fuel. The sensors would be at various levels in each
tank an they would light two sets of led indicators on in the cockpit
and another aggacent to the filler port. I this way I would know when I
was about to overfill the tanks. I saw a Money that had a fuel gage next
to the filler port and that is where I got the idea from. Because you
have absolutle freedom where you place the sensors you wouldn't have to
worry about the non linearitys of flat tanks that are inclined at an
angle
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Eric
M. Jones
Subject: AeroElectric-List: Microprocessor based Fuel Gauge Linearizer
--> AeroElectric-List message posted by: "Eric M. Jones"
<emjones@charter.net>
Neil Hulin's comment about using a fuel totalizer instead of a fuel
gauge linearizer has been burning a hole in my brain. I believe he is
right....
Here's the deal--
You only need one fuel totalizer meter if you take fuel from only one
tank at a time. The fuel quantity meter (and memory) for that tank is
simply updated as required. I trust in this system, totalizers really
work well.
Consider too, that you wouldn't need fuel-level senders or gauges at
all. Always problematic devices. You also would not need anti-slosh
electronic filters either. My airplane just got a whole lot lighter!
There are a few practical concerns--how do we know the tank is at the
level the "gauge" says it is? Well, I always checked it visually with a
wooden stick anyway. So when tanks are refilled they must be filled to
the top (ideally) and visually checked. You really wanted the fuel flow
rate anyway. Not a bad tradeoff.
Eric M. Jones
The whole difference between construction and creation is exactly this:
that a thing constructed can only be loved after it is constructed;
but a thing created is loved before it exists.
- Charles Dickens
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