Today's Message Index:
----------------------
1. 06:46 AM - Through-panel ATO fuses ()
2. 07:55 AM - Re: Through-panel ATO fuses (rockyjs)
3. 10:04 AM - Encoder Certification (Steve Thomas)
4. 11:14 AM - Re: Encoder Certification (Bob Lee)
5. 12:27 PM - Re: Encoder Certification (Bruce Gray)
6. 03:55 PM - Re: 28v to 14v (Eric M. Jones)
7. 07:43 PM - Wires, wires, so many choices . . . (Robert L. Nuckolls, III)
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Subject: | Through-panel ATO fuses |
1/16/2010
Hello Matt, You wrote: "As has been discussed at length recently, mounting
the fuses in the panel
pretty much means that you also have to provide the pilot with replacement
fuses, or demonstrate to the DAR that none of the fuses are critical to
continued flight."
If the aircraft is to be flown at night or IFR I don't understand how a
decision by a DAR (documented or undocumented) could override the required
wording in the aircraft's Operating Limitations and the resulting applicable
wording in 14 CFR 91.205.
>From the Operating Limitations:
"After completion of Phase I flight testing, unless appropriately equipped
for night and/or instrument flight in accordance with 91.205, this aircraft
is to be operated under VFR, day only."
>From 14 CFR 91.205
"(c) Visual flight rules (night). For VFR flight at night, the following
instruments and equipment are required:
(6) One spare set of fuses, or three spare fuses of each kind required, that
are accessible to the pilot in flight."
and
"(d) Instrument flight rules. For IFR flight, the following instruments and
equipment are required:
(1) Instruments and equipment specified in paragraph (b) of this section,
and, for night flight, instruments and equipment specified in paragraph (c)
of this section."
The requirement regarding placement of fuses and circuit breakers
"..essential to safety in flight.." comes from 14 CFR 23 which provides the
airworthiness standards for type certificated aircraft.
14 CFR 23.1357 Circuit protective devices reads:
"(d) If the ability to reset a circuit breaker or replace a fuse is
essential to safety in flight, that circuit breaker or fuse must be so
located and identified that it can be readily reset or replaced in flight."
and
"(e) For fuses identified as replaceable in flight-
(1) There must be one spare of each rating or 50 percent spare fuses of each
rating, whichever is greater; and
(2) The spare fuse(s) must be readily accessible to any required pilot."
14 CFR 23 does not apply to experimental amateur built aircraft.
I conclude that if an experimental amateur built aircraft has ANY of the
fuses installed in ANY of its electrical systems accessible to the pilot in
flight then the pilot must carry the 91.205 regulatory required spare fuses.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
=======================================================
Time: 10:52:50 AM PST US
Subject: Re: AeroElectric-List: Through-panel ATO fuses
From: "Matt Prather" <mprather@spro.net>
Unrelated to your question....... skip........
As has been discussed at length recently, mounting the fuses in the panel
pretty much means that you also have to provide the pilot with replacement
fuses, or demonstrate to the DAR that none of the fuses are critical to
continued flight. It also means that should someone suffer an electrical
malfunction (which might or might not be related to an opened fuse), they
may spend time diagnosing the problem in flight instead of flying the
airplane - increasing risk.
..................... skip.................
Regards,
Matt-
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Subject: | Re: Through-panel ATO fuses |
I was also interested in placing some fuses through the panel. In searching I
found these. You would have to manufacture a stand off, but I like the compactness.
I also attempted to find the ones used in the RV-12 and was told it was
proprietary.
http://www.delcity.net/store/8!way-fuse-block/p_10823.a_1
Rocky
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=281802#281802
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Subject: | Encoder Certification |
A message to Stan Sutterfield:
You wrote last June:
> This may not be the ideal forum for asking this question, but I'll try
it
> anyway.
>
> I want to certify my RV-8 for IFR flight. I know the FARs - I've
looked at
> them.
>
> I have the Blue Mountain EFIS One as primary instrumentation.
> I have the Blue Mountain EFIS Lite as a backup.
> Both EFISs are on different electrical busses - the main and the
standby.
> -
> which can be tied together, if needed.
>
> I asked a local avionics guy about doing a pitot-static and
transponder
>
> check for IFR. He said I would have to install a separate altimeter
and
>
> encoder in order to get IFR certification. The EFIS has a built-in
encod
> er.
>
> Has anyone else encountered this obstacle?
>
> Stan Sutterfield
There were several replies that mostly focused on finding the right
avionics guy. I have the exact same setup in my panel as do you and am
ready for certification. Can you share your experience? Are you
certified and flying? Who did you use for your certification and how
did you go about getting it?
I am in Southern California, and anyone else who can offer any advice on
this topic will be welcome. My local shop mostly deals with biz jets
and large non-jets. I don't think they will be very helpful with an
experimental. Also, exorbitantly expensive. Do I need a transponder
cert for my DAR inspection? Can I fly somewhere else to get it done
once I have flown off my hours?
Steve Thomas
________________________________________________________________________
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Subject: | Encoder Certification |
Steve,
You wrote: << My local shop ... I don't think they will be very helpful
with an experimental. Also, exorbitantly expensive. >>
Never let what you think prevent you from asking. If you don't ask your
local shop it's a 0% chance they will calibrate your system at a reasonable
price. If you do ask them all they can say is yes or no so you've got a 50%
chance they will help you at a reasonable price. Your odds of success are
50 times better if you ask!
Regards,
Bob Lee
N52BL KR2
Suwanee, GA USA
92% done only 67% to go!
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Subject: | Encoder Certification |
I would advise you to check with the EAA. This subject has been aired
before. I essence, by passing the certification criteria (ramp test), it
meets the FAA's standards. No TSO or separate encoder/altimeter is
required. The EAA has chapter and verse. I would also suggest you find
another shop who work on experimentals. Those heavy iron types are
rather inflexible to new ideas.
Bruce
www.Glasair.org
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Bob
Lee
Sent: Saturday, January 16, 2010 2:13 PM
Subject: RE: AeroElectric-List: Encoder Certification
Steve,
You wrote: << My local shop ... I don't think they will be very
helpful with an experimental. Also, exorbitantly expensive. >>
Never let what you think prevent you from asking. If you don't ask your
local shop it's a 0% chance they will calibrate your system at a
reasonable price. If you do ask them all they can say is yes or no so
you've got a 50% chance they will help you at a reasonable price. Your
odds of success are 50 times better if you ask!
Regards,
Bob Lee
N52BL KR2
Suwanee, GA USA
92% done only 67% to go!
Message 6
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Try Astrodyne for great low cost power supplies that will do what you want.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones@charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=281851#281851
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Subject: | Wires, wires, so many choices . . . |
>
>It seems that sometimes people size the wire simply based on the
>Volts, current draw of the device, and the length of the wire. You
>give some lengthy example calculations that go deeper to include
>resistance of various devices in the circuit. How do i know when
>it's ok to "grab any wire chart and hook things up accordingly"?
It's not that random a process. In EVERY wire sizing task
one starts with design goals. For example, the case for
navigation lights (used to be the most energy hungry
system on the airplane - before LEDs), we consider
a high-duty cycle system where we want the bulbs to
operate close to their design values. Here, voltage
drop rules-of-thumb for 5% sort of drive the decisions.
For getting the engine started, its a very low duty
cycle, highest POWER task on the airplane with
variables such as temperature of engine oil and
battery, potential for partially discharged battery,
mixture management for lighting off the fires, no
alternator to help out, installed weight, etc.
Now our design goal is to minimize the time it takes
to get the engine running irrespective of how much
loss is tolerated. If we were to obsess over losses,
perhaps AWG 0 wire would make us feel better, but
that wire's ability to perform is only taxed while
cranking the engine . . . the rest of the time it's
dead weight on the airframe.
For establishing design goals, you STILL want to be
aware of where the energy comes from (chemical and/or
electro-mechanical), who needs it and how you're going
to use the various ingredients for success to get it
all wired up while always aware of the holy grail of
airframe systems design . . . minimum WEIGHT to still
get the job done.
>I hadn't noticed Z-32 before. Is that the standard for a rear
>battery? I hadn't considered using a relay. If the bulk of the ebus
>load is resistive, shouldn't a switch be able to handle the 10 amps
>that the #14 wire can cary? Wouldn't a relay just be another
>possible point of failure? I'll go that route if it's necessary, but
>I would rather keep it simple at this point.
The relay becomes a 'mini-contactor' for driving a remotely
mounted bus. The rule-of-thumb for always hot wires in
airplanes is 5A breakered, 7A fused and MINIMUM length
for wires that carry more than that. LONG fat wires that
attach to batteries get protected with a contactor at
the battery. Your 14AWG feeder to a "heavy duty" e-bus
is too fat and too long to be allowed to run always
hot.
The history of the e-bus began before we had SD-8 standby
alternators and all electric panels. An e-bus load back
then was 4-5 amps max . . . no contactor necessary.
As the e-bus got bigger (supported by an 8A engine
driven alternate power source) it looks more like
the main bus in terms of feeders between the battery
bus and the e-bus . . . and the mini-contactor
is called for.
>Ok, I'll use #2 wire to the starter, but why #4 at the battery? That
>seems strange. Won't that negate the benefit of the longer piece of
>#2? Let me guess at your answer: Is it because you're worried about
>fatiguing the battery terminals and the voltage drop of those short
>pieces of #4 is not very significant to the overall circuit, and the
>temp rise is not really an issue?
YES!
>Is fatigue as much of an issue with more flexible welding cable?
>The picture I have in my mind though is those pieces of #4 acting
>like a traffic-jam to electron flow. is that incorrect?
Yes, the voltage drop is greater . . . but if your
battery were up front, you would wire the entire
the entire suite of fat wires with 4awg. The batteries
really like 4awg mechanically so there's a reason
to retain them even if you up-size to 2awg for a remote
battery.
Actually, there are a lot of all metal airplanes with
rear mounted batteries that use 4AWG, I've even
seen a few Eze type aircraft with round-trip 4AWG
wiring . . . but these are 'warm weather' airplanes.
Now, could you use 2AWG battery jumpers . . . sure
and they're probably fine too in WELDING cable.
But I've seen two failures of the battery connector
tabs when the batteries were wired with 2AWG, 22759
wire.
Bob . . .
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