Today's Message Index:
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1. 09:10 AM - Re: Re: Wig Wag difficulties (Ed)
2. 06:00 PM - Re: Re: Wig Wag difficulties (Robert L. Nuckolls, III)
3. 09:09 PM - Re: Re: Wig Wag difficulties (Ed)
Message 1
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Subject: | Re: Wig Wag difficulties |
Howdy Bob,
It behaved the same with two different flashers, both EL 13A-2, one
Tridon brand the other Novita which appears to be the follow on to
Tridon. Maybe 75 ohms would work at 14.4v, but I'm testing in the garage
at more like 12.6 with a power supply supporting a battery. When cold,
it would sometimes flash for a few and then stop. My guess is that the
resistance went up with heat and the current was reduced below the
threshold that the flasher would work with.
The mountable and heat sinked resistors seem like a good idea. Better
than zip tying a hot resistor to the wires for sure.
I am not worried about .3A as long as the alternator is running. If it
is offline, so will be my main buss and the exterior lighting. My load
analysis shows me at 26.4A for night VFR while wigwaging. That's 66% of
my 40A alternator capacity. When I designed and built my electrical
system, I was planning to use 100w halogens as I have in my other
airplane. I've dropped at least 4 amps with the LEDs. I'm also going
with LED position/strobe lights for an additional current and weight
savings of around 9 amps and 2 1/2 pounds.
Ed
On 8/10/2016 8:17 PM, Robert L. Nuckolls, III wrote:
> At 01:09 PM 8/10/2016, you wrote:
>>
>> To update where I'm at - I paralleled two 75 ohm, 5w resistors on each
>> light and got solid flashing for the 20 minutes that I tested it. The
>> resistors are too hot to grip between fingers but not too hot to touch
>> lightly. I calc about .33A loss and about 4.16 watts. I might try some
>> 50 ohm, 10w resistors which should save me a tenth of an amp and run
>> slightly cooler.
>
> A power resistor running at rated dissipation
> will sizzle-spit . . . over 100C surface
> temperature. They just do that.
>
> Your experiment suggests that the flasher
> in hand is a bit more demanding of a low-
> as-practical resistance to ground on the
> OFF lamp.
>
> I've had a couple builders use resistors
> much like this
>
> *http://tinyurl.com/jroz29g*
>
> while rated at many more watts . . . if
> not mounted to a heat sinking surface,
> it too would be too hot to touch. The
> handy thing about these guys is that
> they're easy to mount on metal surface
> that sharply reduces their operating
> surface temperature.
>
> And . . . of course . . . you can change
> out the flasher for one more specific
> to the application.
>
> I've opened several versions of those
> devices. One particular model was easily
> converted to a 4-wire device by cutting
> a trace on the board and soldering
> on a ground wire to bring out of the case.
>
> Then the need for 'grounding resistors'
> goes away. But if the externally added
> resistors is not a source of heartburn,
> then I suspect the devices cited above
> will do the job . . . and the price is
> right.
>
>
> Bob . . .
>
Message 2
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Subject: | Re: Wig Wag difficulties |
At 11:05 AM 8/11/2016, you wrote:
>
>Howdy Bob,
>
>It behaved the same with two different flashers, both EL 13A-2, one
>Tridon brand the other Novita which appears to be the follow on to
>Tridon. Maybe 75 ohms would work at 14.4v, but I'm testing in the
>garage at more like 12.6 with a power supply supporting a battery.
>When cold, it would sometimes flash for a few and then stop. My
>guess is that the resistance went up with heat and the current was
>reduced below the threshold that the flasher would work with.
>
>The mountable and heat sinked resistors seem like a good idea.
>Better than zip tying a hot resistor to the wires for sure.
>
>I am not worried about .3A as long as the alternator is running. If
>it is offline, so will be my main buss and the exterior lighting. My
>load analysis shows me at 26.4A for night VFR while wigwaging.
>That's 66% of my 40A alternator capacity. When I designed and built
>my electrical system, I was planning to use 100w halogens as I have
>in my other airplane. I've dropped at least 4 amps with the LEDs.
>I'm also going with LED position/strobe lights for an additional
>current and weight savings of around 9 amps and 2 1/2 pounds.
>
>Ed
Good moves. Why would you run wig-wags with
an off-line alternator?
First, such an occurrence is rare.
When it does occur, the design goal is
NOT to run everything including the kitchen
sink . . . but to keep really USEFUL things
running until the airport of INTENDED DESTINATION
is in sight. In the earliest days of the implementation
of an e-bus, EN ROUTE operating loads were often
reduced to 3 amps or less.
Certainly, running any form of exterior lighting
does not improve significantly on your probability
of comfortable termination of flight.
Adding the SD-8 in Z-13/8 was a quantum jump
in options for EN ROUTE energy consumption. A
Plan-B could consider continuous consumption
of 8A or more . . . with total independence
on the battery's contained energy.
Once the airport was in sight, you could
fire up everything, kitchen sink and all,
for descent and approach to landing.
The through process in this particular
Failure Modes Effects Analysis is to deduce
electrical demands for sustained flight
sans main alternator. For myself, the
design goal would be to sustain useful/
necessary electro-whizzies, battery only
for duration of fuel aboard.
I.e. your ELECTRICAL endurance should be
equal to or greater than FUEL endurance.
In no scenario can I imagine that exterior
lighting of any kind is a significant factor
in the equation for comfortable termination
of flight at airport of intended destination.
Back when LongEz was king, a nav/com, transponder,
turn-coordinator and minimal panel lighting
was easily power up for 4 hours or more by
a rather small battery.
Your own demands for comfortable EN ROUTE
operations without a main alternator are
undoubtedly different. It's a good thing
to KNOW what they are and then design
for meeting those demands for what ever
ENDURANCE value you choose . . . perhaps
an hour is okay in your book . . . but 3+
hours would not be a bad thing.
Energy consumption for exterior lighting
doesn't figure into that consideration.
Bob . . .
Message 3
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Subject: | Re: Wig Wag difficulties |
Howdy Bob,
Yeah, I had an alternator fail in our 6A and just kept going. I had cap
checked the RG-25 battery at the most recent annual using a 4 amp load
with a West Mountain Radio CBA, and got 8 hours out of it to 10.5v so I
knew that the situation wasn't critical. We flew on for a couple of
hours, landed for gas, and flew another hour and a half to our intended
destination. Replaced the alternator the next day and still had plenty
of pop in the battery for engine start.
My new plane will pull a little over 6 amps at minimum load with 2
electronic ignitions, another 2 amps if I don't kill the MFD. I have two
PC680s which I will cap check before I fly and at each annual so I will
know my endurance. I can power the E-bus with either or both batteries
so I can run one and hold the other in reserve if I so choose. Using the
Odyssey discharge charts, I'm reading about 5 hrs. endurance, if I'm
careful. I may still put on an SD-8 for belt and suspenders.
Ed
On 8/11/2016 5:58 PM, Robert L. Nuckolls, III wrote:
> At 11:05 AM 8/11/2016, you wrote:
>>
>
>
> Good moves. Why would you run wig-wags with
> an off-line alternator?
>
> First, such an occurrence is rare.
>
> When it does occur, the design goal is
> NOT to run everything including the kitchen
> sink . . . but to keep really USEFUL things
> running until the airport of INTENDED DESTINATION
> is in sight. In the earliest days of the implementation
> of an e-bus, EN ROUTE operating loads were often
> reduced to 3 amps or less.
>
> Certainly, running any form of exterior lighting
> does not improve significantly on your probability
> of comfortable termination of flight.
>
> Adding the SD-8 in Z-13/8 was a quantum jump
> in options for EN ROUTE energy consumption. A
> Plan-B could consider continuous consumption
> of 8A or more . . . with total independence
> on the battery's contained energy.
>
> Once the airport was in sight, you could
> fire up everything, kitchen sink and all,
> for descent and approach to landing.
>
> The through process in this particular
> Failure Modes Effects Analysis is to deduce
> electrical demands for sustained flight
> sans main alternator. For myself, the
> design goal would be to sustain useful/
> necessary electro-whizzies, battery only
> for duration of fuel aboard.
>
> I.e. your ELECTRICAL endurance should be
> equal to or greater than FUEL endurance.
> In no scenario can I imagine that exterior
> lighting of any kind is a significant factor
> in the equation for comfortable termination
> of flight at airport of intended destination.
>
> Back when LongEz was king, a nav/com, transponder,
> turn-coordinator and minimal panel lighting
> was easily power up for 4 hours or more by
> a rather small battery.
>
> Your own demands for comfortable EN ROUTE
> operations without a main alternator are
> undoubtedly different. It's a good thing
> to KNOW what they are and then design
> for meeting those demands for what ever
> ENDURANCE value you choose . . . perhaps
> an hour is okay in your book . . . but 3+
> hours would not be a bad thing.
>
> Energy consumption for exterior lighting
> doesn't figure into that consideration.
>
>
> Bob . . .
>
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