Today's Message Index:
----------------------
1. 07:58 AM - Re: Size of Fuse vs. Circuit Breaker - (Robert L. Nuckolls, III)
2. 09:01 AM - Re: Size of Fuse vs. Circuit Breaker - Corrected (Bob C.)
3. 11:00 AM - Wing wiring grounds (Jay Brinkmeyer)
4. 11:57 AM - Re: Toggle switch - both master/battery and starter (Mitch Faatz)
5. 11:57 AM - Pitot Tubes (Eric M. Jones)
6. 12:15 PM - Re: Pitot Tubes (BobsV35B@aol.com)
7. 12:18 PM - Re: Wing wiring grounds (John Schroeder)
8. 01:40 PM - Advice about 24V systems (Nigel Harrison)
9. 02:15 PM - How do you carry the braid from a shielded wire past the molex connector. (cecilth@juno.com)
10. 02:21 PM - Relays for heated pitot tube circuit question ()
11. 03:26 PM - Re: Advice about 24V systems (Ken)
12. 04:29 PM - Re: Size of Fuse vs. Circuit Breaker - Corrected (Mike Nellis)
13. 05:40 PM - Re: Pitot Tubes (Charlie England)
14. 05:43 PM - Re: How do you carry the braid from a shielded wire (Eric M. Jones)
15. 05:53 PM - Re: How do you carry the braid from a shielded wire past the molex connector. (Bob C.)
16. 06:15 PM - Re: Size of Fuse vs. Circuit Breaker - Corrected (Jim Stone)
17. 07:53 PM - Re: Wing wiring grounds (Dean)
18. 08:17 PM - Re: Re: How do you carry the braid from a shielded wire (Wayne Sweet)
19. 10:07 PM - Coax crimper / stripper question (Jay Brinkmeyer)
20. 10:19 PM - Re: Advice about 24V systems (Robert L. Nuckolls, III)
21. 10:21 PM - Re: How do you carry the braid from a (Robert L. Nuckolls, III)
22. 11:09 PM - LSE Ign Power Wire (Tinne maha)
23. 11:34 PM - Taxi/Landing Lights (Tinne maha)
Message 1
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| Subject: | Re: Size of Fuse vs. Circuit Breaker - |
Corrected
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
Corrected
At 06:29 PM 2/11/2005 -0600, you wrote:
>--> AeroElectric-List message posted by: "Bob C. " <flyboy.bob@gmail.com>
>
>Bob,
>
>What's you conclusion on the pitot heater example . . . what would the
>appropriate wire size be 14, 16 or 18?
How big a pitot heater? They come in 100, 150 and 200 watt sizes
or more. How much wire does it take to wire up the pitot tube? If
you have a plastic airplane, remember that TOTAL path length includes
a return ground wire. If you want the 99.9% UNIVERSAL answer, you can
wire with 10AWG protected with a 30A fuse with a very high probability
of satisfactory operation. Recall that fuses/breakers protect wire,
wire needs to be of sufficient size that voltage drops and temperature
rises are tolerable. So, wiring up with some configuration that
many folks would consider overkill, it is not incorrect. Voltage
drops and temperature rises will be very acceptable and the wire
run is adequately protected. If you went with the 14AWG/30A
example I cited earlier, you're going to have a 99.0 or
better probability of success.
Cookbook wiring philosophies tend conservative and assume that
your selection of parts and operation of the airplane is not
out of the ordinary. As a designer, I make it a goal to understand
the performance characteristics of all the parts so that the
installation is well considered and not overly heavy or expensive.
My decisions can affect the condition of hundreds of airplanes
over decades of future usage. You're only building one airplane
so the total impact of the conservative solution is measured
at worst in a few dollars and a pound or two.
The vast majority of OBAM aircraft builders are doing this
because they desire the performance and maintenance alternatives
to over-regulated, technically-stagnated commercial products.
Most builders are installing Van's or Tony B's suggestions
that duplicate what's sold out of the spam can factories.
They will probably be perfectly happy with their decision.
I presume folks on this list server are interested in looking
beyond the "norm" to consider ideas that my compatriots in
the certified side can only dream about. Forgive me if this
isn't the answer you were looking for but please understand
that I can't give you the considered answer without having
more data about the parts you've selected and the machine you're
building. I'll suggest further that after you've gathered
all the information needed, you'll be 95% of the way
to a goal of answering the question yourself. The discovery
process of gathering data is always the most time consuming.
Analysis of the discoveries for the purpose of fine-tuning
a design is simple.
Bob . . .
Message 2
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| Subject: | Re: Size of Fuse vs. Circuit Breaker - Corrected |
--> AeroElectric-List message posted by: "Bob C. " <flyboy.bob@gmail.com>
Bob,
The reason I asked . . . I'm building a RV-8 that was partially
completed by another builder . . . he had installed a Gretz Aero
AN5812 heated pitot. The installation instruction say it will draw
from 6.4 to 8.0 amps which would put it in the 100W range. The
predecessor builder had run 16AGW from the pitot to the wing root . .
.
I was planning on finishing the circuit with 16 and putting a 10A
switch/breaker in to feed this device. Sounds like it "could be" a
little light on start up?
I learn a lot from this list!?
Thanks,
Bob Christensen
On Sat, 12 Feb 2005 09:57:19 -0600, Robert L. Nuckolls, III
<b.nuckolls@cox.net> wrote:
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
Corrected
>
> At 06:29 PM 2/11/2005 -0600, you wrote:
>
> >--> AeroElectric-List message posted by: "Bob C. " <flyboy.bob@gmail.com>
> >
> >Bob,
> >
> >What's you conclusion on the pitot heater example . . . what would the
> >appropriate wire size be 14, 16 or 18?
>
> How big a pitot heater? They come in 100, 150 and 200 watt sizes
> or more. How much wire does it take to wire up the pitot tube? If
> you have a plastic airplane, remember that TOTAL path length includes
> a return ground wire. If you want the 99.9% UNIVERSAL answer, you can
> wire with 10AWG protected with a 30A fuse with a very high probability
> of satisfactory operation. Recall that fuses/breakers protect wire,
> wire needs to be of sufficient size that voltage drops and temperature
> rises are tolerable. So, wiring up with some configuration that
> many folks would consider overkill, it is not incorrect. Voltage
> drops and temperature rises will be very acceptable and the wire
> run is adequately protected. If you went with the 14AWG/30A
> example I cited earlier, you're going to have a 99.0 or
> better probability of success.
>
> Cookbook wiring philosophies tend conservative and assume that
> your selection of parts and operation of the airplane is not
> out of the ordinary. As a designer, I make it a goal to understand
> the performance characteristics of all the parts so that the
> installation is well considered and not overly heavy or expensive.
> My decisions can affect the condition of hundreds of airplanes
> over decades of future usage. You're only building one airplane
> so the total impact of the conservative solution is measured
> at worst in a few dollars and a pound or two.
>
> The vast majority of OBAM aircraft builders are doing this
> because they desire the performance and maintenance alternatives
> to over-regulated, technically-stagnated commercial products.
> Most builders are installing Van's or Tony B's suggestions
> that duplicate what's sold out of the spam can factories.
> They will probably be perfectly happy with their decision.
>
> I presume folks on this list server are interested in looking
> beyond the "norm" to consider ideas that my compatriots in
> the certified side can only dream about. Forgive me if this
> isn't the answer you were looking for but please understand
> that I can't give you the considered answer without having
> more data about the parts you've selected and the machine you're
> building. I'll suggest further that after you've gathered
> all the information needed, you'll be 95% of the way
> to a goal of answering the question yourself. The discovery
> process of gathering data is always the most time consuming.
> Analysis of the discoveries for the purpose of fine-tuning
> a design is simple.
>
> Bob . . .
>
>
>
>
Message 3
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| Subject: | Wing wiring grounds |
--> AeroElectric-List message posted by: Jay Brinkmeyer <jaybrinkmeyer@yahoo.com>
I'm building an RV and priming... Perhaps this question is obvious to some, but
not to me. Is it good practice to ground landing lights, heated pitot and
position lights to the airframe or are return wires required for each? If
airframe ground is okay then how does one do that to insure safe and secure
contact?
Anyone know how many folks use 14v power versus 24v? I ran across a power
supply board design that could output both. Seems like a neat idea, but the
converter hw is an additional point of failure.
Thanks,
Jay
=====
__________________________________
Message 4
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| Subject: | Re: Toggle switch - both master/battery and starter |
--> AeroElectric-List message posted by: "Mitch Faatz" <mitchf@skybound.com>
> I have been looking for a switch guard that returns the switch to the
> center position. Can you post the source and p/n?
http://www.vickers-systems.com/pdfs/power/accessories.pdf#search='ms25221'
Switch Guard Code Numbers 3, 13, and 14 work this way, looks like 13 or 14
are the type I would want (they only differ in location of Keyway tab, which
I haven't figure out the correct orientation of yet).
Mitch Faatz RV-6A Finish Kit Auburn, CA
Message 5
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--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Pitot tubes use a huge amount of power. The last time this matter seems to
have been studied in small aircraft at subsonic speeds
was....ah....1928...and they determined that Pitot tubes along with
wing-wires can collect ice! There is so little information online about the
subject that a Google search of heated pitot tubes come up with "Do you
mean...Heated Pilot tubes"? Now there's an image....Hey Bob, I think I feel
some rain.
Could you build a Pitot tube that remained ice-free and had no
heater---Certainly. It's not even very hard.
Could you spritz Miracle-Spray on the tube to stave off ice
accumulation?---Certainly.
Could you use an iced Pitot tube to tell you to get the heck out of there
'cause you aren't delivering the anti-toxin?---Oh man....Yes.
Could you use slip a sock over the metal tube to conserve warmth and turn
down the current? Why not.
I have a little write-up on my own thermostatic heated pitot tube which I
can immodestly claim is light years ahead of AN5812. See
http://www.periheliondesign.com/downloads.htm
Imagine what a Pitot tube actually does--It keeps a tiny little space warm
enough to keep a hole open and ice-free in the direction of flight. The
surrounding air cools it off and it reaches some temperature equilibrium
determined by the heater and cooling by the air flow.
Could you build a Pitot tube that remained ice-free and had no
heater---Certainly. It's not even very hard.
Could you spritz Miracle-Spray on the tube to stave off ice
accumulation?---Certainly.
Could you use an iced Pitot tube to tell you to get the heck out of there
'cause you aren't delivering the anti-toxin?---Oh man....Yes.
Could you use slip a sock over the metal tube to conserve warmth and turn
down the current? Why not?
Could you put a current regulator into the circuit and only crank it up if
needed? Sure!
More than most other aircraft parts, Pitot tube design is dragged down by
the rules and regulations. But if you don't have to use the old dog-leg,
bring it up to modern times.
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
Message 6
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--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 2/12/2005 1:58:41 P.M. Central Standard Time,
emjones@charter.net writes:
Could you build a Pitot tube that remained ice-free and had no
heater---Certainly. It's not even very hard.
Good Afternoon Eric,
In the For What It Is Worth department, Beech used an Ice Resistant Non
Heated pitot tube on the early Bonanzas. The heated Pitot tube was an option that
was not often installed.
I found that I would have a half inch to an inch of ice on the wings before
I would lose the airspeed indications.
Remember, this was in the days when it may not have been wise to be flying
when that much ice would be accrued, but it was not illegal.
By judicious planning, I have often had that much ice on a 1947 straight 35
Bonanza. I was a copilot flying the DC-3 in those days and I felt the Bonanza
did just about as good as did the DC-3 at lower altitudes. I would use
the same techniques in icing conditions when flying the Bonanza as the
captains did when we were flying the DC-3.
Obviously, the DC-3 could handle it for a longer period of time and it could
handle ice at higher altitudes, but it was amazing how well we all got by
with a little knowledge of what was happening. The modern pilot never gets the
education to do that. All he is told is to stay out of it. Pity!
Do Not Archive
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
Message 7
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| Subject: | Re: Wing wiring grounds |
--> AeroElectric-List message posted by: "John Schroeder" <jschroeder@perigee.net>
Jay -
Check the archives. Bob has answered this several times. As I recall, it
is OK to do this for these systems, but I'd check for sure.
John
> I'm building an RV and priming... Perhaps this question is obvious to
> some, but not to me. Is it good practice to ground landing lights,
> heated pitot and
> position lights to the airframe or are return wires required for each? If
> airframe ground is okay then how does one do that to insure safe and
> secure contact?
Message 8
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| Subject: | Advice about 24V systems |
--> AeroElectric-List message posted by: "Nigel Harrison" <naharrison@manx.net>
Dear All,
I am a Europa builder and am planning to install an all-electric set up with
a Grand Rapids EFIS etc. Reading Greg Richter's artlcle on Aircraft wiring,
he is of the opinion that a 24V electrical system will provide much more
safety margin tha a 12V system in the event of generator failure. My
aircraft will have a Rotax 912S. The engine manufacturers have advised me
that "Unfortunately the Rotax electrical system is only 12 V DC.The internal
alternator gives an AC voltage above 24 V at a speed of about 3000 rpm,
which may possibly be suitable, but you would have to design or procure a
rectifier/regulator for 24 V." Can someone advise me whether this alternator
would be suffiiciently powerful to charge 2 x 12V 16Ah batteries in series.
Rotax also mention a rectifier/regulator. Advice on this too would be
useful.
I have little in the way of electrical knowledge/knowhow, so simple
explanations would be most helpful.
Thanks
Nigel Harrison
****************************************************************
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Message 9
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| Subject: | How do you carry the braid from a shielded wire past |
the molex connector.
--> AeroElectric-List message posted by: cecilth@juno.com
I need to carry the braid from a shielded wire past the molex connector.
What is the correct way to do this?
Just carry it through as one of the pins in the connector?
Cecil
Message 10
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| Subject: | Relays for heated pitot tube circuit question |
was Size of Fuse vs. Circuit Breaker - Corrected
--> AeroElectric-List message posted by: <chaztuna@adelphia.net>
> >Bob,
> >
> >What's you conclusion on the pitot heater example . . . what would the
> >appropriate wire size be 14, 16 or 18?
>
> How big a pitot heater? They come in 100, 150 and 200 watt sizes
> or more. How much wire does it take to wire up the pitot tube? If
> you have a plastic airplane, remember that TOTAL path length includes
> a return ground wire. If you want the 99.9% UNIVERSAL answer, you can
> wire with 10AWG protected with a 30A fuse with a very high probability
> of satisfactory operation. Recall that fuses/breakers protect wire,
> wire needs to be of sufficient size that voltage drops and temperature
> rises are tolerable. So, wiring up with some configuration that
> many folks would consider overkill, it is not incorrect. Voltage
> drops and temperature rises will be very acceptable and the wire
> run is adequately protected. If you went with the 14AWG/30A
> example I cited earlier, you're going to have a 99.0 or
> better probability of success.
>
> Cookbook wiring philosophies tend conservative and assume that
> your selection of parts and operation of the airplane is not
> out of the ordinary. As a designer, I make it a goal to understand
> the performance characteristics of all the parts so that the
> installation is well considered and not overly heavy or expensive.
> My decisions can affect the condition of hundreds of airplanes
> over decades of future usage. You're only building one airplane
> so the total impact of the conservative solution is measured
> at worst in a few dollars and a pound or two.
>
> The vast majority of OBAM aircraft builders are doing this
> because they desire the performance and maintenance alternatives
> to over-regulated, technically-stagnated commercial products.
> Most builders are installing Van's or Tony B's suggestions
> that duplicate what's sold out of the spam can factories.
> They will probably be perfectly happy with their decision.
>
> I presume folks on this list server are interested in looking
> beyond the "norm" to consider ideas that my compatriots in
> the certified side can only dream about. Forgive me if this
> isn't the answer you were looking for but please understand
> that I can't give you the considered answer without having
> more data about the parts you've selected and the machine you're
> building. I'll suggest further that after you've gathered
> all the information needed, you'll be 95% of the way
> to a goal of answering the question yourself. The discovery
> process of gathering data is always the most time consuming.
> Analysis of the discoveries for the purpose of fine-tuning
> a design is simple.
>
> Bob . . .
Bob,
I have a Piper style heated 12 volt pitot. This unit has 2 heating elements. Each
element draws 5 amps and has 16 AWG leads to each element. I would like to
a 2-2 style switch to control the heater. Each heater element would have it's
own fused circuit running 16AWG wire.
Your previous advice has been that relays are not needed to protect the switch
when current draw does not exceed 5 amps. Since this double pole switch will
limit warmed up current to 5 amps per set of contacts in the switch, will this
be sufficient? Will the high "in rush" current overwhelm the contacts in my Carling
Technologies switch? Do I need the added complexity of relays? Would 14
AWG wire be needed or preferable?
Charlie Kuss
RV-8A cockpit wiring
Message 11
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| Subject: | Re: Advice about 24V systems |
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
If I may be so bold -
A pound of battery is a pound of battery and it is silly to suggest that
there is more energy or safety margin in arranging it into 24 volts
rather than 12 volts. Your 12 volt accessories will drain just as much
energy as 24 volt accessories for all practical purposes. IMO there is
however a real safety margin advantage to sticking with tried and proven
12 volt components such as supplied for use with the stock 912S. THere
is more discussion on this in the archives.
Ken
Nigel Harrison wrote:
>--> AeroElectric-List message posted by: "Nigel Harrison" <naharrison@manx.net>
>
>
>Dear All,
>I am a Europa builder and am planning to install an all-electric set up with
>a Grand Rapids EFIS etc. Reading Greg Richter's artlcle on Aircraft wiring,
>he is of the opinion that a 24V electrical system will provide much more
>safety margin tha a 12V system in the event of generator failure. My
>aircraft will have a Rotax 912S. The engine manufacturers have advised me
>that "Unfortunately the Rotax electrical system is only 12 V DC.The internal
>alternator gives an AC voltage above 24 V at a speed of about 3000 rpm,
>which may possibly be suitable, but you would have to design or procure a
>rectifier/regulator for 24 V." Can someone advise me whether this alternator
>would be suffiiciently powerful to charge 2 x 12V 16Ah batteries in series.
>Rotax also mention a rectifier/regulator. Advice on this too would be
>useful.
>
>I have little in the way of electrical knowledge/knowhow, so simple
>explanations would be most helpful.
>
>Thanks
>
>Nigel Harrison
>
>
Message 12
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| Subject: | Re: Size of Fuse vs. Circuit Breaker - Corrected |
--> AeroElectric-List message posted by: Mike Nellis <mike@bmnellis.com>
Bob,
A few years ago I tested the 5814 pitot/static tube which is basically
the same as the one you have. You can see the graphed results here
http://www.bmnellis.com/pitotcurrent.htm along with raw data link in the
middle of the page.
--
Mike Nellis
Austin, TX
CMRA #32 Honda RC51
'00 YZ426F
'97 YZF1000
RV6 (Fuselage)
'47 Stinson 108-2(Sold)
http://bmnellis.com
Bob C. wrote:
>--> AeroElectric-List message posted by: "Bob C. " <flyboy.bob@gmail.com>
>
>Bob,
>
>The reason I asked . . . I'm building a RV-8 that was partially
>completed by another builder . . . he had installed a Gretz Aero
>AN5812 heated pitot. The installation instruction say it will draw
>from 6.4 to 8.0 amps which would put it in the 100W range. The
>predecessor builder had run 16AGW from the pitot to the wing root . .
>.
>
>I was planning on finishing the circuit with 16 and putting a 10A
>switch/breaker in to feed this device. Sounds like it "could be" a
>little light on start up?
>
>I learn a lot from this list!?
>
>Thanks,
>Bob Christensen
>
>
>On Sat, 12 Feb 2005 09:57:19 -0600, Robert L. Nuckolls, III
><b.nuckolls@cox.net> wrote:
>
>
>>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
Corrected
>>
>>At 06:29 PM 2/11/2005 -0600, you wrote:
>>
>>
>>
>>>--> AeroElectric-List message posted by: "Bob C. " <flyboy.bob@gmail.com>
>>>
>>>Bob,
>>>
>>>What's you conclusion on the pitot heater example . . . what would the
>>>appropriate wire size be 14, 16 or 18?
>>>
>>>
>> How big a pitot heater? They come in 100, 150 and 200 watt sizes
>> or more. How much wire does it take to wire up the pitot tube? If
>> you have a plastic airplane, remember that TOTAL path length includes
>> a return ground wire. If you want the 99.9% UNIVERSAL answer, you can
>> wire with 10AWG protected with a 30A fuse with a very high probability
>> of satisfactory operation. Recall that fuses/breakers protect wire,
>> wire needs to be of sufficient size that voltage drops and temperature
>> rises are tolerable. So, wiring up with some configuration that
>> many folks would consider overkill, it is not incorrect. Voltage
>> drops and temperature rises will be very acceptable and the wire
>> run is adequately protected. If you went with the 14AWG/30A
>> example I cited earlier, you're going to have a 99.0 or
>> better probability of success.
>>
>> Cookbook wiring philosophies tend conservative and assume that
>> your selection of parts and operation of the airplane is not
>> out of the ordinary. As a designer, I make it a goal to understand
>> the performance characteristics of all the parts so that the
>> installation is well considered and not overly heavy or expensive.
>> My decisions can affect the condition of hundreds of airplanes
>> over decades of future usage. You're only building one airplane
>> so the total impact of the conservative solution is measured
>> at worst in a few dollars and a pound or two.
>>
>> The vast majority of OBAM aircraft builders are doing this
>> because they desire the performance and maintenance alternatives
>> to over-regulated, technically-stagnated commercial products.
>> Most builders are installing Van's or Tony B's suggestions
>> that duplicate what's sold out of the spam can factories.
>> They will probably be perfectly happy with their decision.
>>
>> I presume folks on this list server are interested in looking
>> beyond the "norm" to consider ideas that my compatriots in
>> the certified side can only dream about. Forgive me if this
>> isn't the answer you were looking for but please understand
>> that I can't give you the considered answer without having
>> more data about the parts you've selected and the machine you're
>> building. I'll suggest further that after you've gathered
>> all the information needed, you'll be 95% of the way
>> to a goal of answering the question yourself. The discovery
>> process of gathering data is always the most time consuming.
>> Analysis of the discoveries for the purpose of fine-tuning
>> a design is simple.
>>
>> Bob . . .
>>
>>
>>
>>
>>
>>
>
>
>
>
Message 13
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--> AeroElectric-List message posted by: Charlie England <ceengland@bellsouth.net>
Eric M. Jones wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
>Pitot tubes use a huge amount of power. The last time this matter seems to
>have been studied in small aircraft at subsonic speeds
>was....ah....1928...and they determined that Pitot tubes along with
>wing-wires can collect ice! There is so little information online about the
>subject that a Google search of heated pitot tubes come up with "Do you
>mean...Heated Pilot tubes"? Now there's an image....Hey Bob, I think I feel
>some rain.
>
>Could you build a Pitot tube that remained ice-free and had no
>heater---Certainly. It's not even very hard.
>Could you spritz Miracle-Spray on the tube to stave off ice
>accumulation?---Certainly.
>Could you use an iced Pitot tube to tell you to get the heck out of there
>'cause you aren't delivering the anti-toxin?---Oh man....Yes.
>Could you use slip a sock over the metal tube to conserve warmth and turn
>down the current? Why not.
>
>I have a little write-up on my own thermostatic heated pitot tube which I
>can immodestly claim is light years ahead of AN5812. See
>http://www.periheliondesign.com/downloads.htm
>
>Imagine what a Pitot tube actually does--It keeps a tiny little space warm
>enough to keep a hole open and ice-free in the direction of flight. The
>surrounding air cools it off and it reaches some temperature equilibrium
>determined by the heater and cooling by the air flow.
>
>Could you build a Pitot tube that remained ice-free and had no
>heater---Certainly. It's not even very hard.
>Could you spritz Miracle-Spray on the tube to stave off ice
>accumulation?---Certainly.
>Could you use an iced Pitot tube to tell you to get the heck out of there
>'cause you aren't delivering the anti-toxin?---Oh man....Yes.
>Could you use slip a sock over the metal tube to conserve warmth and turn
>down the current? Why not?
>Could you put a current regulator into the circuit and only crank it up if
>needed? Sure!
>
>More than most other aircraft parts, Pitot tube design is dragged down by
>the rules and regulations. But if you don't have to use the old dog-leg,
>bring it up to modern times.
>
>Regards,
>Eric M. Jones
>www.PerihelionDesign.com
>113 Brentwood Drive
>Southbridge MA 01550-2705
>Phone (508) 764-2072
>Email: emjones@charter.net
>
Or you could do what Rutan did on one of his unmarketed designs (maybe
the Catbird?) & make the pitot a little bump on top of the wing near the
trailing edge.
A friend plumbed a 2nd airspeed indicator to the back engine baffle in
his RV-6A; it always agreed exactly with his primary ASI.
No heat in either case.
FWIW, YMMV, ETC, ETC
Charlie
Message 14
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| Subject: | Re: How do you carry the braid from a shielded wire |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
--> AeroElectric-List message posted by: cecilth@juno.com
>I need to carry the braid from a shielded wire past the molex connector.
>What is the correct way to do this?
>Just carry it through as one of the pins in the connector?
>Cecil
Okay so I had a triple espresso........
Almost nobody does shield termination correctly. Allow me to explain:
A shield-- braid, tape or foil is a kind of perfect partner--a little
Faraday cage around the wires that acts as a ground plane in reference to
the wires running through it. When some charge moves on the internal wires,
the shield supplies the opposite charge--on loan from ground. Well sort
of......
The right way of terminating the shield is coaxially--like a coaxial
bulkhead connector does. The absolutely wrong way is to separate the inner
wires from the shield and twist the shield into a wire and attach it to
ground as if it were just another wire. Holy Moley! Now that you have
strangled the little baby shield it develops a bad case of impedance at
frequencies that otherwise would have been grounded--depending on the fine
and random details of the high impedance "pigtail".
This makes terminating a shield a task that calls for special care. A way to
understand how to do this properly is to imagine a grounded metal wall that
the wire goes through. The shield is teased open and electrically bonded to
the wall around the circumference of the hole. That's the way to do it. Any
technique that approximates this is better than a "pigtail"
Oink,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
"I thoroughly disapprove of duels. If a man should challenge me, I would
take him kindly and forgivingly by the hand and lead him to a quiet place
and kill him." -- Mark Twain
Message 15
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| Subject: | Re: How do you carry the braid from a shielded wire |
past the molex connector.
--> AeroElectric-List message posted by: "Bob C. " <flyboy.bob@gmail.com>
That's what I would do . . . I don't see how that would be a problem?!
On Sat, 12 Feb 2005 14:13:57 -0800, cecilth@juno.com <cecilth@juno.com> wrote:
> --> AeroElectric-List message posted by: cecilth@juno.com
>
> I need to carry the braid from a shielded wire past the molex connector.
> What is the correct way to do this?
> Just carry it through as one of the pins in the connector?
> Cecil
>
>
>
Message 16
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| Subject: | Re: Size of Fuse vs. Circuit Breaker - Corrected |
--> AeroElectric-List message posted by: "Jim Stone" <jrstone@insightbb.com>
All this talk about heated pitot tubes reminds me that I need one. Anyone
got a AN-5812 for sale?
Contact me directly please.
Do not archive
Jim
----- Original Message -----
From: "Mike Nellis" <mike@bmnellis.com>
Subject: Re: AeroElectric-List: Size of Fuse vs. Circuit Breaker - Corrected
> --> AeroElectric-List message posted by: Mike Nellis <mike@bmnellis.com>
>
> Bob,
>
> A few years ago I tested the 5814 pitot/static tube which is basically
> the same as the one you have. You can see the graphed results here
> http://www.bmnellis.com/pitotcurrent.htm along with raw data link in the
> middle of the page.
>
> --
> Mike Nellis
> Austin, TX
> CMRA #32 Honda RC51
> '00 YZ426F
> '97 YZF1000
> RV6 (Fuselage)
> '47 Stinson 108-2(Sold)
> http://bmnellis.com
>
>
> Bob C. wrote:
>
>>--> AeroElectric-List message posted by: "Bob C. " <flyboy.bob@gmail.com>
>>
>>Bob,
>>
>>The reason I asked . . . I'm building a RV-8 that was partially
>>completed by another builder . . . he had installed a Gretz Aero
>>AN5812 heated pitot. The installation instruction say it will draw
>>from 6.4 to 8.0 amps which would put it in the 100W range. The
>>predecessor builder had run 16AGW from the pitot to the wing root . .
>>.
>>
>>I was planning on finishing the circuit with 16 and putting a 10A
>>switch/breaker in to feed this device. Sounds like it "could be" a
>>little light on start up?
>>
>>I learn a lot from this list!?
>>
>>Thanks,
>>Bob Christensen
>>
>>
>>On Sat, 12 Feb 2005 09:57:19 -0600, Robert L. Nuckolls, III
>><b.nuckolls@cox.net> wrote:
>>
>>
>>>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
>>><b.nuckolls@cox.net> Corrected
>>>
>>>At 06:29 PM 2/11/2005 -0600, you wrote:
>>>
>>>
>>>
>>>>--> AeroElectric-List message posted by: "Bob C. "
>>>><flyboy.bob@gmail.com>
>>>>
>>>>Bob,
>>>>
>>>>What's you conclusion on the pitot heater example . . . what would the
>>>>appropriate wire size be 14, 16 or 18?
>>>>
>>>>
>>> How big a pitot heater? They come in 100, 150 and 200 watt sizes
>>> or more. How much wire does it take to wire up the pitot tube? If
>>> you have a plastic airplane, remember that TOTAL path length includes
>>> a return ground wire. If you want the 99.9% UNIVERSAL answer, you can
>>> wire with 10AWG protected with a 30A fuse with a very high probability
>>> of satisfactory operation. Recall that fuses/breakers protect wire,
>>> wire needs to be of sufficient size that voltage drops and temperature
>>> rises are tolerable. So, wiring up with some configuration that
>>> many folks would consider overkill, it is not incorrect. Voltage
>>> drops and temperature rises will be very acceptable and the wire
>>> run is adequately protected. If you went with the 14AWG/30A
>>> example I cited earlier, you're going to have a 99.0 or
>>> better probability of success.
>>>
>>> Cookbook wiring philosophies tend conservative and assume that
>>> your selection of parts and operation of the airplane is not
>>> out of the ordinary. As a designer, I make it a goal to understand
>>> the performance characteristics of all the parts so that the
>>> installation is well considered and not overly heavy or expensive.
>>> My decisions can affect the condition of hundreds of airplanes
>>> over decades of future usage. You're only building one airplane
>>> so the total impact of the conservative solution is measured
>>> at worst in a few dollars and a pound or two.
>>>
>>> The vast majority of OBAM aircraft builders are doing this
>>> because they desire the performance and maintenance alternatives
>>> to over-regulated, technically-stagnated commercial products.
>>> Most builders are installing Van's or Tony B's suggestions
>>> that duplicate what's sold out of the spam can factories.
>>> They will probably be perfectly happy with their decision.
>>>
>>> I presume folks on this list server are interested in looking
>>> beyond the "norm" to consider ideas that my compatriots in
>>> the certified side can only dream about. Forgive me if this
>>> isn't the answer you were looking for but please understand
>>> that I can't give you the considered answer without having
>>> more data about the parts you've selected and the machine you're
>>> building. I'll suggest further that after you've gathered
>>> all the information needed, you'll be 95% of the way
>>> to a goal of answering the question yourself. The discovery
>>> process of gathering data is always the most time consuming.
>>> Analysis of the discoveries for the purpose of fine-tuning
>>> a design is simple.
>>>
>>> Bob . . .
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>
>
>
Message 17
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| Subject: | Re: Wing wiring grounds |
--> AeroElectric-List message posted by: "Dean" <dvanwinkle@royell.net>
John and Jay
The best way to insure a good structural ground is by use of abrasive
bonding brushes to remove the primer and any anodize coating. I obtained
mine from The Yard in Wichita. A 4 piece set, P/N 14706, is $3.95 in the
current catalog. They have a 1/4 inch shaft and 3/32, 1/8, 5/32, and 3/16
pilots. They have a much more expensive set that is more suited to avionics
shop or production line use. Try 1-800-888-8991 or www.yardstore.com.
Finish with an appropriate ring terminal, bolt, and locknut.
Dean Van Winkle
RV-9A Fuselage/Finish
----- Original Message -----
From: "John Schroeder" <jschroeder@perigee.net>
Subject: Re: AeroElectric-List: Wing wiring grounds
> --> AeroElectric-List message posted by: "John Schroeder"
<jschroeder@perigee.net>
>
> Jay -
>
> Check the archives. Bob has answered this several times. As I recall, it
> is OK to do this for these systems, but I'd check for sure.
>
> John
>
>
> > I'm building an RV and priming... Perhaps this question is obvious to
> > some, but not to me. Is it good practice to ground landing lights,
> > heated pitot and
> > position lights to the airframe or are return wires required for each?
If
> > airframe ground is okay then how does one do that to insure safe and
> > secure contact?
>
>
Message 18
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| Subject: | Re: How do you carry the braid from a shielded |
wire
--> AeroElectric-List message posted by: "Wayne Sweet" <w_sweet@comcast.net>
Don't quite get the picture. Is this equivalent; bare the shield around the
circumference, letting it retain it's structure and form, then soldering a
bare wire around that shield's circumference and taking that wire to the
ground lug?
Wayne
----- Original Message -----
From: "Eric M. Jones" <emjones@charter.net>
Subject: AeroElectric-List: Re: How do you carry the braid from a shielded
wire
> --> AeroElectric-List message posted by: "Eric M. Jones"
> <emjones@charter.net>
>
> --> AeroElectric-List message posted by: cecilth@juno.com
>
>
>>I need to carry the braid from a shielded wire past the molex connector.
>>What is the correct way to do this?
>>Just carry it through as one of the pins in the connector?
>>Cecil
>
> Okay so I had a triple espresso........
>
> Almost nobody does shield termination correctly. Allow me to explain:
>
> A shield-- braid, tape or foil is a kind of perfect partner--a little
> Faraday cage around the wires that acts as a ground plane in reference to
> the wires running through it. When some charge moves on the internal
> wires,
> the shield supplies the opposite charge--on loan from ground. Well sort
> of......
>
> The right way of terminating the shield is coaxially--like a coaxial
> bulkhead connector does. The absolutely wrong way is to separate the inner
> wires from the shield and twist the shield into a wire and attach it to
> ground as if it were just another wire. Holy Moley! Now that you have
> strangled the little baby shield it develops a bad case of impedance at
> frequencies that otherwise would have been grounded--depending on the fine
> and random details of the high impedance "pigtail".
>
> This makes terminating a shield a task that calls for special care. A way
> to
> understand how to do this properly is to imagine a grounded metal wall
> that
> the wire goes through. The shield is teased open and electrically bonded
> to
> the wall around the circumference of the hole. That's the way to do it.
> Any
> technique that approximates this is better than a "pigtail"
>
> Oink,
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge MA 01550-2705
> Phone (508) 764-2072
> Email: emjones@charter.net
>
> "I thoroughly disapprove of duels. If a man should challenge me, I would
> take him kindly and forgivingly by the hand and lead him to a quiet place
> and kill him." -- Mark Twain
>
>
>
I am using the free version of SPAMfighter for private users.
It has removed 715 spam emails to date.
Paying users do not have this message in their emails.
Try www.SPAMfighter.com for free now!
Message 19
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| Subject: | Coax crimper / stripper question |
--> AeroElectric-List message posted by: Jay Brinkmeyer <jaybrinkmeyer@yahoo.com>
Would this tool crimp RG-142/400? Perhaps -400 is size equivalent to others? If
so, which size?
http://www.mytoolstore.com/klein/t1720.html
Also, would someone be so kind as to recommend a good coax stripper?
Thanks!
Jay
=====
__________________________________
http://info.mail.yahoo.com/mail_250
Message 20
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| Subject: | Re: Advice about 24V systems |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
At 09:38 PM 2/12/2005 +0000, you wrote:
>--> AeroElectric-List message posted by: "Nigel Harrison"
><naharrison@manx.net>
>
>
>Dear All,
>I am a Europa builder and am planning to install an all-electric set up with
>a Grand Rapids EFIS etc. Reading Greg Richter's artlcle on Aircraft wiring,
>he is of the opinion that a 24V electrical system will provide much more
>safety margin tha a 12V system in the event of generator failure.
With all due respect to Greg's accomplishments as a manufacturer
of EFIS systems, the article you cited is rife with errors and
offers no understanding of the simple-ideas in physics that support
good design decisions. If you're interested in the details you can
check out:
http://aeroelectric.com/articles/richter/richter.html
>My aircraft will have a Rotax 912S. The engine manufacturers have advised me
>that "Unfortunately the Rotax electrical system is only 12 V DC.The internal
>alternator gives an AC voltage above 24 V at a speed of about 3000 rpm,
>which may possibly be suitable, but you would have to design or procure a
>rectifier/regulator for 24 V." Can someone advise me whether this alternator
>would be suffiiciently powerful to charge 2 x 12V 16Ah batteries in series.
>Rotax also mention a rectifier/regulator. Advice on this too would be
>useful.
I aware of no compelling explanation of system operation
and design that makes a case for 24 volt systems replacing
12 volt systems in small aircraft. The owner built and maintained
aircraft industry is seeking best return on investment
(i.e. VALUE) for component selection and system architecture.
The automotive world provides us with many low cost,
robust alternatives to 24 volt devices which are uniquely
aircraft in nature. The high cost of certification and relatively
low production numbers makes aircraft parts a very poor
value.
>I have little in the way of electrical knowledge/knowhow, so simple
>explanations would be most helpful.
May I suggest a source of information on a variety
of small aircraft electrical systems topics? Look
over the offerings at:
http://aeroelectric.com/articles.html
Further, please stay with us here on the AeroElectric-List.
There are many folks among the 1300+ subscribers who
will be pleased to share their experiences and insight
as they apply to your task.
Bob . . .
Message 21
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connector.
| Subject: | Re: How do you carry the braid from a |
shielded wire past the molex connector.
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
shielded wire past the molex connector.
At 02:13 PM 2/12/2005 -0800, you wrote:
>--> AeroElectric-List message posted by: cecilth@juno.com
>
>
>I need to carry the braid from a shielded wire past the molex connector.
>What is the correct way to do this?
>Just carry it through as one of the pins in the connector?
This is what's usually done. Since you're talking about
"molex" connectors, are you working with the shielded
wire in a strobe system? Also see:
http://aeroelectric.com/articles/pigtail/pigtail.html
This shows how to deal with multiple shielded wires
in a bundle.
Bob . . .
Message 22
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| Subject: | LSE Ign Power Wire |
--> AeroElectric-List message posted by: "Tinne maha" <tinnemaha@hotmail.com>
I installed a single LSE ignition in my project a while back and, for some
unknown reason, ran an AWG 14 wire from the battery bus to the control
module. Two hours ago, I'd have sworn up & down that the installation
manual required that big of a wire, but now I can't find any reference to it
in the manual or on the web page.
The web page shows a current draw of 1.2 amps @ 13.8 volts for my Plasma
II/4 cylinder set up: This would only require an AWG 20 or so wire.
Will listers with operating LSE systems please tell me if I'm cracking up?
How did you size the power wire on your project?
Thanks,
Grant
Message 23
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| Subject: | Taxi/Landing Lights |
--> AeroElectric-List message posted by: "Tinne maha" <tinnemaha@hotmail.com>
Bob/List,
I finally found the time/equipment/etc. needed to measure the current used
by my taxi & landing lights. 4.4 amps each. Thanks for your suggestions on
that. The measurement may not have been necessary, but I couldn't calculate
theoretical values 'cuz I didn't have any data: 'Sides that, I'm a 'seeing
is believing' kinda guy & it was a good exercise for me. Satisfied my
curiosity.
Now the question becomes how to wire these two lights (together in one
housing, but able to be controlled separately) for optimum use. I'm
inclined to set it up with a 3 position switch - down is 'Off', middle is
taxi light only & up is both landing & taxi lights on. I've thought of
other possble set ups (2 separate, 'on-off' switches or a 3 position switch
that doesn't allow both lights to be on at the same time), but I can't think
of a reason NOT to have the taxi light on whenever the landing light is on.
The only difference between the two lights, as far as I can tell, is the
angle at which the light is directed.
Any comments, sugestions or criticisms would be appreciated.
Thank You Again,
Grant Krueger
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