Today's Message Index:
----------------------
1. 01:36 AM - Re: Batteries (Ami McFadyean)
2. 06:25 AM - Batteries (Fergus Kyle)
3. 09:57 AM - Re: Batteries (Fred Fillinger)
4. 09:58 AM - Re: Batteries (Fred Fillinger)
5. 10:23 AM - Re: Batteries (DJA727@aol.com)
6. 02:20 PM - Fiberglass repair (Gary R. Roberts)
7. 07:09 PM - Re: LEDs (Fred Fillinger)
Message 1
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--> Europa-List message posted by: "Ami McFadyean" <ami@mcfadyean.freeserve.co.uk>
"........ if there's two independent
> sources of power (spelled batteries)......"
Possibly, under the FARs.
JAR-E is more relaxed and only calls for two independent sources of
electrical power; there is nothing that explicitly prohibits one of these
being the engine-driven generator, so long as the electrical system can
allow each to operate independently of the other
Duncan McF.
> --> Europa-List message posted by: Fred Fillinger
<fillinger@ameritech.net>
>
> > I am not one bit convinced of the need for a spare
> > battery. The plane carries on flying without a blink if you switch off
> > master and alternator switches!
>
> That's because it's wired as it's supposed to be! It's picking off
> regulator current before fed to the bus, but it's not redundant. If one
> has a battery relay, and the alternator/regulator fails, and the overall
> problem is such the battery must be disconnected, the engine will quit.
> There's no way to wire the 914 pumps to any single electrical system
> which would meet current FAA rules, were this a production A/C. It's
> also interesting to note that this is a relaxation of the rule prior to
> 1965, since way back then one pump must have been engine-driven. Now
> redundant electrical pumps are permitted if there's two independent
> sources of power (spelled batteries).
>
> One partial solution is to wire one pump "off-master" - direct to
> battery. Satisfactory if one will never leave the A/C with it still
> switched on. Not an independent source of power, but redundant if the
> rest of the electrical system has failed and battery still good.
>
> For full compliance the FAA has approved, as a separate independent
> power source, a simple pack of dated alkaline "D" cells. I believe this
> will provide enough alternate power to a pump to get to some nearby
> airport if the main electrical system has smoked.
>
> Not trying to convince; just suggestions for any builder considering
> options.
>
> Fred F.
Message 2
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--> Europa-List message posted by: "Fergus Kyle" <VE3LVO@rac.ca>
Fred,
"There's no way to wire the 914 pumps to any single electrical system
which would meet current FAA rules, were this a production A/C. It's
also interesting to note that this is a relaxation of the rule prior to
1965, since way back then one pump must have been engine-driven. Now
redundant electrical pumps are permitted if there are two independent
sources of power (spelled batteries)."
Given that requirement, are not "two independent sources" a
battery and an alternator, just as an engine-driven pump and an electric one
are two independent sources of pressure?
What am I missing?
Cheers, Ferg
Message 3
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--> Europa-List message posted by: Fred Fillinger <fillinger@ameritech.net>
>> "........ if there's two independent
>>sources of power (spelled batteries)......"
>
> Possibly, under the FARs.
> JAR-E is more relaxed and only calls for two independent sources of
> electrical power; there is nothing that explicitly prohibits one of these
> being the engine-driven generator, so long as the electrical system can
> allow each to operate independently of the other
>
> Duncan McF.
JAR-E would then be loose! In again reading our old and new regs, I see
now that the artful change in wording is now such that the 914 probably
can't be certified at all either. It may be significant in that the
only such approval here has been on a motorglider.
My only question is if the alternator or regulator fails, AND there's
the smell of smoke and abnormal readings on amps/volts, one should
disconnect the battery at the battery relay, not just disconnect the
alternator and wait to see if the smoke goes away. What then will cause
the engine to continue to run? If one doesn't have a relay, and the
smoke is electrical but no circuit protector pops, there's no way to
stop the smoke without waiting for the battery to discharge or a
necessary circuit to go open through heating. Then the engine quits.
Fred F.
Message 4
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--> Europa-List message posted by: Fred Fillinger <fillinger@ameritech.net>
> ...are not "two independent sources" a
> battery and an alternator, just as an engine-driven pump and an electric one
> are two independent sources of pressure?
> What am I missing?
> Cheers, Ferg
I believe FAA's answer would be not if one can affect the other. An
overcharging alternator can ruin the battery, especially an RG type. A
failed battery can ruin the alternator regulator. Even if there's
adequate means to notify the pilot, who can promptly switch to battery
only, there's no way to know if the capacity in that battery will be
sufficient to keep the pump running long enough, in addition to holding
the battery relay closed, to avoid an off-airport landing...or whatever
better term local TV news will use to describe the event!
Regards,
Fred
Message 5
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--> Europa-List message posted by: DJA727@aol.com
In a message dated 6/22/2003 9:58:14 AM Pacific Standard Time,
fillinger@ameritech.net writes:
> My only question is if the alternator or regulator fails, AND there's
> the smell of smoke and abnormal readings on amps/volts, one should
> disconnect the battery at the battery relay, not just disconnect the
> alternator and wait to see if the smoke goes away. What then will cause
> the engine to continue to run? If one doesn't have a relay, and the
> smoke is electrical but no circuit protector pops, there's no way to
> stop the smoke without waiting for the battery to discharge or a
> necessary circuit to go open through heating. Then the engine quits.
>
Fred,
I have designed mine with a rather complicated arrangement of busses, and I
have my pumps on a "hot" bus for each of two electrical systems. In the event
of electrical smoke/fire -- the procedure is to shut down the electrical
system, except for the fuel pumps. The hot busses are protected by slow blow fuses.
I would be able to get rid of everything except the pumps in the event of an
electrical fire, and not lose the engine at the same time. I suppose I got
carried away with all this, but I have to keep my mind working on an involved
electrical system reminiscent of the Boeing days.
Dave
Message 6
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| Subject: | Fiberglass repair |
--> Europa-List message posted by: "Gary R. Roberts" <grroberts3@juno.com>
Whoops! I have a small puncture wound in one of my flaps. The
fiberglass is cut about 1/4 inch deep and 1/4 inch wide. Flap is microed
and Superfilled, but not yet painted.
What is the proper repair? Can I fill the hole and scab patch over it or
do I need to cut out the damaged fiberglass?
G Roberts
A187
Message 7
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--> Europa-List message posted by: Fred Fillinger <fillinger@ameritech.net>
Fergus Kyle wrote:
> ...but will tolerate an Average current which permits us to
> forestall their early intolerance by modulating the time constants.
Above referring to pulsing the LEDs with square wave circuitry, to make
the appear brighter to the brain. This is obsolete by now, and may give
you RF interference. For panel indicators, you can get super brights
cheaply now that will put spots on the retina, requiring cutting back
the current or buying fewer millicandles. Diffused clear LEDs to me are
the most attention getting.
For area illumination as you described, the realities of viewing angle
(i.e., beam width) similarly means multiple very super brights, so
adding extra(s) makes up for not having the pulse enhancement.
Regards,
Fred F.
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