Today's Message Index:
----------------------
1. 03:04 AM - Re: combining a PM and conventional alternator (James Foerster)
2. 03:46 AM - Re: Oil Pressure Switch (KITFOXZ@aol.com)
3. 08:46 AM - Fuel pressure automatic switch? (richard@riley.net)
4. 09:05 AM - Re: 10736 Gissendanner (Robert L. Nuckolls, III)
5. 09:05 AM - Re: Fuel pressure automatic switch? (Trampas)
6. 09:38 AM - Re: Re: combining a PM and conventional (Robert L. Nuckolls, III)
7. 09:38 AM - Re: Fuel pressure automatic switch? (Neville Kilford)
8. 09:47 AM - Re: Fuel pressure automatic switch? (Canyon)
9. 11:05 AM - Re: Fuel pressure automatic switch? (Robert L. Nuckolls, III)
10. 11:09 AM - Re: Oil Pressure Switch (Robert L. Nuckolls, III)
11. 06:11 PM - Re: Fuel pressure automatic switch? (Eric M. Jones)
12. 06:36 PM - Re: Re: Fuel pressure automatic switch? (Steve Richard)
Message 1
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| Subject: | Re: combining a PM and conventional alternator |
--> AeroElectric-List message posted by: "James Foerster" <jmfpublic@comcast.net>
Bob,
Thanks for your help. You were right about the relays: I meant to refer to the
S704-1 units with the minimal power draw.
Unfortunately, I cannot use Z13 because I need a second battery on the e-bus to
maintain the EFIS during startup. Also, I need both alternators operational.
The SD-20 alternator puts out 12 amps at 2000 rpm, 18 amps at 2500, and 22 amps
at 3000. It is directly driven from the crankshaft at crankshaft rpm. The
PM alternator built in to the 3300 Jabiru engine is also limited to 18-22 amps.
I am stuck with a Z14 type of system. Both alternators must run all the
time for adequate output capacity. In essence, I have two buses: the main or
lighting-starting bus, and the instrument-radio bus.
Because the PM alternator is reputed to be noisier than the conventional, I have
arbitrarily elected to use it for the lighting-starting main bus, and use that
B&C SD-20 for the e-bus. Both alternators will have cooling for their regulators
in the form of tiny centrifugal fans, which cost a few dollars on the industrial
surplus market.
As the Jabiru engines are getting popular in the experimental market, I intend
to share my circuit diagram with anyone who wants it, as soon as I feel confidant
that is works well. I hope to make my mistakes on paper, rather than in copper!
Jim Foerster
Message 2
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| Subject: | Re: Oil Pressure Switch |
--> AeroElectric-List message posted by: KITFOXZ@aol.com
In a message dated 8/21/2003 4:50:22 PM Eastern Standard Time,
ripsteel@edge.net writes:
Howdy A-list-
I have the switch from B & C and you'd think this has got to be a
pretty simple device. However, I am mystified at it's operation.
Terminals are P S & I (cute). P appears to be common. With no
pressure, I read anywhere between 120 & 2 to 3+ M ohms from P to S
(wandering around sometimes on my Fluke 87, sometimes stable at around
130-140 ohms), then when pressure applied, infinity. P to I acts like
normal NO connection, switching properly when pressure is applied. I am
using air- maybe it needs oiling? Or is it defective? Maybe the
internal processor or kadink muffler is defective, or it needs
shielding? 8
)
Thanks- Mark do not archive
Hello Mark,
I was going to reply to you privately but then I thought "Hey, Mark has a
great sense of humor and would really appreciate this to be shared with all!"
Your pressure switch problem is kind of like the story about the blonde who was
asking the car parts guy for a "lio" cap casket for her shinny new red
convertible. She was reading the "part number" upside down.
I am betting that oil pressure switch from B & C is a simple dry contact type
device. The terminals are probably not marked at all and what you are
reading is "PSI" with a second paper sticker that read: "100 lb.. Max" that has
fallen off. Digital voltmeters tell us much more than we need to know at times.
They are very high input impedance instruments and use a very tiny current to
check resistance. If all you had at your disposal was a simple test light,
you would have figured out which contacts are which. 8 )
John P. Marzluf
Columbus, Ohio
Kitfox Outback (out back in the garage)
Message 3
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| Subject: | Fuel pressure automatic switch? |
--> AeroElectric-List message posted by: richard@riley.net
I'm thinking of using a fuel pressure switch, like the oil pressure switch
that's used to run a hobbs meter. It would energize a relay and turn on
the electric fuel pump if the fuel pressure drops below, say, 15 lbs
(injected engine).
I'd have it light a warning light at the same time. I'd have to come up
with a way to defeat it prior to engine start.
Comments? Ideas?
Message 4
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| Subject: | Re: 10736 Gissendanner |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
> Hello again Bob,
>
>I am mounting a gps antenna on the fiberglass top deck on my GlaStar. I
>plan to use a copper ground plane. What diameter ground plane is
>recommened for gps antennas?
The unique nature of GPS antenna patterns makes them relatively
free of ground plane effects. A disk on the order of 4" diameter
would be fine . . . and it would work about as well with no
ground plane.
Bob . . .
--------------------------------------------
( Knowing about a thing is different than )
( understanding it. One can know a lot )
( and still understand nothing. )
( C.F. Kettering )
--------------------------------------------
Message 5
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| Subject: | Fuel pressure automatic switch? |
--> AeroElectric-List message posted by: "Trampas" <tstern@nc.rr.com>
You would have to put some kind of latch in the system.
Fuel pressure drops, pump comes on
Fuel pressure high, pump goes off
Fuel pressure low, pump comes on
Etc.
Trampas
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
richard@riley.net
Subject: AeroElectric-List: Fuel pressure automatic switch?
--> AeroElectric-List message posted by: richard@riley.net
I'm thinking of using a fuel pressure switch, like the oil pressure
switch
that's used to run a hobbs meter. It would energize a relay and turn on
the electric fuel pump if the fuel pressure drops below, say, 15 lbs
(injected engine).
I'd have it light a warning light at the same time. I'd have to come up
with a way to defeat it prior to engine start.
Comments? Ideas?
Message 6
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| Subject: | Re: combining a PM and conventional |
alternator
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 02:49 AM 8/22/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "James Foerster"
><jmfpublic@comcast.net>
>
>Bob,
>
>Thanks for your help. You were right about the relays: I meant to refer
>to the S704-1 units with the minimal power draw.
>
>Unfortunately, I cannot use Z13 because I need a second battery on the
>e-bus to maintain the EFIS during startup. Also, I need both alternators
>operational. The SD-20 alternator puts out 12 amps at 2000 rpm, 18 amps
>at 2500, and 22 amps at 3000. It is directly driven from the crankshaft
>at crankshaft rpm.
Hmmm . . . forgot that engined doesn't have a gear-reduction
drive . . .
> The PM alternator built in to the 3300 Jabiru engine is also limited to
> 18-22 amps. I am stuck with a Z14 type of system. Both alternators must
> run all the time for adequate output capacity. In essence, I have two
> buses: the main or lighting-starting bus, and the instrument-radio bus.
>
>Because the PM alternator is reputed to be noisier than the conventional,
>I have arbitrarily elected to use it for the lighting-starting main bus,
>and use that B&C SD-20 for the e-bus. Both alternators will have cooling
>for their regulators in the form of tiny centrifugal fans, which cost a
>few dollars on the industrial surplus market.
The SD-20 regulator requires no cooling. PM alternator regulators
DO run very hot as they have to carry and control full alternator output.
Bob . . .
Message 7
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| Subject: | Re: Fuel pressure automatic switch? |
--> AeroElectric-List message posted by: "Neville Kilford" <nkilford@etravel.org>
How about linking the affair through an oil pressure switch, i.e. the
autofuel-switch wouldn't work until after the engine was running.
Cheers.
Nev
--
Jodel D-150 in progress
UK
----- Original Message -----
From: <richard@riley.net>
Subject: AeroElectric-List: Fuel pressure automatic switch?
> --> AeroElectric-List message posted by: richard@riley.net
>
> I'm thinking of using a fuel pressure switch, like the oil pressure switch
> that's used to run a hobbs meter. It would energize a relay and turn on
> the electric fuel pump if the fuel pressure drops below, say, 15 lbs
> (injected engine).
>
> I'd have it light a warning light at the same time. I'd have to come up
> with a way to defeat it prior to engine start.
>
> Comments? Ideas?
>
>
Message 8
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| Subject: | Re: Fuel pressure automatic switch? |
--> AeroElectric-List message posted by: Canyon <steve.canyon@verizon.net>
richard@riley.net wrote:
>I'd have it light a warning light at the same time. I'd have to come up
>with a way to defeat it prior to engine start.
---
Sounds good, but I'd be concerned with automatically feeding an engine
fire. If you're sure you can defeat it properly, maybe a good
idea. Many have thought about it for autos but backed off after
thinking about an accident and possible fire.
Steve
Message 9
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| Subject: | Re: Fuel pressure automatic switch? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:45 AM 8/22/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: richard@riley.net
>
>I'm thinking of using a fuel pressure switch, like the oil pressure switch
>that's used to run a hobbs meter. It would energize a relay and turn on
>the electric fuel pump if the fuel pressure drops below, say, 15 lbs
>(injected engine).
>
>I'd have it light a warning light at the same time. I'd have to come up
>with a way to defeat it prior to engine start.
What is the failure mode you're addressing and how does the
new feature mitigate the failure with any more assurance
than what's been done in the past. Does the new feature
insert new failure modes or undesirable behaviors?
Right now, if the engine stumbles, we KNOW that 99+% of the
time it's from fuel starvation. This means either (1) failure
of some flow control/generation component in the system or
(2) starvation due to mis-placement of fuel controls
and/or empty tank(s).
How long from onset of event does it take for you to
recognize the problem, research the range of causes
and react to them (assuming there's some reaction
that CAN fix it)?
I'll suggest that this is generally a few seconds . . .
certainly less than 10. How much altitude would you loose
in ten seconds?
The autoswitching pump can react only to failure of
normal pump. If you're using electronic pumps like FAWCET,
normal pump failure is close to zero. This failure mode
figures in only a tiny percentage of fuel flow problems.
It has the probability of unwanted behavior unless the
circuit is more complex. All this adds to cost of ownership
and addresses a very rare event.
Bob . . .
Message 10
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| Subject: | Re: Oil Pressure Switch |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:45 AM 8/22/2003 -0400, you wrote:
>--> AeroElectric-List message posted by: KITFOXZ@aol.com
>
>In a message dated 8/21/2003 4:50:22 PM Eastern Standard Time,
>ripsteel@edge.net writes:
>Howdy A-list-
>
>I have the switch from B & C and you'd think this has got to be a
>pretty simple device. However, I am mystified at it's operation.
>Terminals are P S & I (cute). P appears to be common. With no
>pressure, I read anywhere between 120 & 2 to 3+ M ohms from P to S
>(wandering around sometimes on my Fluke 87, sometimes stable at around
>130-140 ohms), then when pressure applied, infinity. P to I acts like
>normal NO connection, switching properly when pressure is applied. I am
>using air- maybe it needs oiling? Or is it defective? Maybe the
>internal processor or kadink muffler is defective, or it needs
>shielding?
These are very simple, but fancy either. If it's the
same switch I used to sell, it's got bare brass contacts
that might deliver strange readings until after exercised
in service.
>Hello Mark,
>
>I was going to reply to you privately but then I thought "Hey, Mark has a
>great sense of humor and would really appreciate this to be shared with
>all!"
>Your pressure switch problem is kind of like the story about the blonde
>who was
>asking the car parts guy for a "lio" cap casket for her shinny new red
>convertible. She was reading the "part number" upside down.
>
>I am betting that oil pressure switch from B & C is a simple dry contact type
>device. The terminals are probably not marked at all and what you are
>reading is "PSI" with a second paper sticker that read: "100 lb.. Max"
>that has
>fallen off. Digital voltmeters tell us much more than we need to know at
>times.
>They are very high input impedance instruments and use a very tiny current to
>check resistance. If all you had at your disposal was a simple test light,
>you would have figured out which contacts are which. 8 )
>
There's another possibility: You may have an earlier switch that
I selected several years ago. I've heard that they have a new
product that is more robust and promises to work better. While
I was selling the switch, I think I had one return in about 4 years
and sold perhaps two dozen switches. Not a high return rate but
not a very big sample either.
Check with B&C and see if you might be more interested in
the later offering.
Bob . . .
Message 11
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| Subject: | Re: Fuel pressure automatic switch? |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Here is my Auto Fuel Pressure Switch ---"Boos'Witch":
Available "soon" as they say. I've got three prototypes, but I just got my oscilloscope
back so it's time to get back to work on this. The internal Mosfet will
drive any electric pump I can find. 15 Amps is not a problem.
http://www.periheliondesign.com/booswitch.pdf
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
Message 12
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| Subject: | Re: Fuel pressure automatic switch? |
--> AeroElectric-List message posted by: "Steve Richard" <steve@oasissolutions.com>
Very interesting device. How would you handle a low boost / high boost
requirement and a momemtary low boost / high boost requirement? My hot
starting method involves a momentary low boost switch.
Regards,
Steve Richard
steve@oasissolutions.com
-----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: Re: Fuel pressure automatic switch?
--> AeroElectric-List message posted by: "Eric M. Jones"
<emjones@charter.net>
Here is my Auto Fuel Pressure Switch ---"Boos'Witch":
Available "soon" as they say. I've got three prototypes, but I just got my
oscilloscope back so it's time to get back to work on this. The internal
Mosfet will drive any electric pump I can find. 15 Amps is not a problem.
http://www.periheliondesign.com/booswitch.pdf
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
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