Today's Message Index:
----------------------
1. 06:00 AM - z-14 common failure point (klehman@albedo.net)
2. 06:54 AM - Coaxial Lengths (David E. Nelson)
3. 07:07 AM - Re: z-14 common failure point (Robert L. Nuckolls, III)
4. 07:15 AM - PS: z-14 common failure point (Robert L. Nuckolls, III)
5. 07:15 AM - Re: Copper Clad Aluminum etc. (Robert L. Nuckolls, III)
6. 07:29 AM - Re: A panel full of displays . . . (flyv35b)
7. 07:31 AM - Re: Endurance Bus (F1Rocket@comcast.net)
8. 08:20 AM - Re: Coaxial Lengths (Dave Morris)
9. 09:09 AM - Ignitions/Starting (BFlood@Sauer-Danfoss.com)
10. 09:38 AM - Re: PS: z-14 common failure point (GMC)
11. 11:53 AM - Re: Ignitions/Starting (Matt Prather)
12. 12:40 PM - Dynon heated AOA pitot now available (Bartrim, Todd)
13. 02:13 PM - Re: Ignitions/Starting (Dan Checkoway)
14. 03:06 PM - Re: Re: Architecure Choices (czechsix@juno.com)
15. 03:06 PM - Re: Ignitions/Starting (Sam Hoskins)
16. 03:13 PM - Re: Ignitions/Starting (Sam Hoskins)
17. 03:15 PM - Re: A panel full of displays . . . (czechsix@juno.com)
18. 04:26 PM - Re: Ignitions/Starting (Matt Prather)
19. 05:35 PM - Re: Ignitions/Starting (Pat Hatch)
20. 07:35 PM - Re: Ignitions/Starting (Robert L. Nuckolls, III)
21. 07:57 PM - Re: Ignitions/Starting (Sam Hoskins)
22. 09:21 PM - Re: Ignitions/Starting (Dan Checkoway)
23. 09:43 PM - Re: Ignitions/Starting (Terry Watson)
Message 1
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| Subject: | z-14 common failure point |
--> AeroElectric-List message posted by: klehman@albedo.net
The cross-feed relay/contactor in a dual battery and dual alternator
Z-14 architecture is a common point of failure.
With a small non-cranking second battery, the crossfeed could be fused
or protected with fusable links. With two batteries of the same size
that both provide cranking current, that becomes more difficult.
So today's question is - do crossfeed contactors ever fail in such a
manner that one or both feeds short to ground? This question came to
mind after observing a Docap 24059 contactor. The studs penetrate the
metal case through hard plastic grommets that can't have a terribly high
melting point. Now I'm wondering what is inside that could fail and
short to the metal case. The Cole Hersee site also lists a "plasticized"
24117 version although I've not seen it stocked locally and it is
several times the price. Perhaps I'll just insulate the metal contactor
from the metal airframe.
thanks
Ken
Message 2
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--> AeroElectric-List message posted by: "David E. Nelson" <david.nelson@pobox.com>
Hi Bob,
Finished reading through the "Antenna" chapter last night. Back in my pre-teen
days, I used to spend some time with a ham operator that operated in the HF
band. Although I don't remember the equation, I distinctly remember that he'd
measure all his coaxes before cutting and fitting them with connectors. I seem
to recall that his reasoning for this was so that the coax was a multiple of
the wavelength of the carrier freq. Is this of any relevance to our apps?
Thanks,
/\/elson
Austin, TX
RV-7A - Waiting on the wings....
Message 3
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| Subject: | Re: z-14 common failure point |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:57 AM 4/15/2004 -0400, you wrote:
>--> AeroElectric-List message posted by: klehman@albedo.net
>
>The cross-feed relay/contactor in a dual battery and dual alternator
>Z-14 architecture is a common point of failure.
>
>With a small non-cranking second battery, the crossfeed could be fused
>or protected with fusable links. With two batteries of the same size
>that both provide cranking current, that becomes more difficult.
>
>So today's question is - do crossfeed contactors ever fail in such a
>manner that one or both feeds short to ground? This question came to
>mind after observing a Docap 24059 contactor. The studs penetrate the
>metal case through hard plastic grommets that can't have a terribly high
>melting point. Now I'm wondering what is inside that could fail and
>short to the metal case. The Cole Hersee site also lists a "plasticized"
>24117 version although I've not seen it stocked locally and it is
>several times the price. Perhaps I'll just insulate the metal contactor
>from the metal airframe.
There's no component I'm aware of that has a failure rate of
zero. There are many components with failure rates that are
exceedingly small . . . in the same neighborhood as that of
prop bolts and wing struts.
I'm involved in an investigation of fault-to-ground failure
in a solid state contactor that caused a fire . . . fortunately
on the ground. One might sit right up in their chair with the
wide-eyed stare and declare that this event warrants some
rapid response and real "solutions" . . .
However, looking at the history of this part (25+ years of
service, 4 devices per airplane, fleet size in the upper
hundreds, and what must be millions of flight hours with
no similar failures) I do not at present perceive a
need for such action. The investigation is incomplete but
preliminary studies suggest that inattention to assembly
procedures is the triggering event . . . not gross failure
of any components.
Now, do electro-mechanical contactors fail, you betcha.
See:
http://www.aeroelectric.com/Pictures/6041_Contactor.jpg
and
http://www.aeroelectric.com/Pictures/6041_Contactor_Failure.jpg
This is a $high$ contactor used to control loads of well
over 100A with LONG duty cycles. Contact aging increases
resistance which in turn increases heat which increases
resistance and the end is inevitable.
Is the Z-14 crossfeed contactor at risk? It carries a
PORTION of cranking current for a few seconds at the
beginning of each flight. Its normal operating condition
for 99.9% of flight operations is OFF. With B&C hardware
for alternators, it's unlikely that the crossfeed contactor
will ever be called upon to carry out a primary assigned
duty as mitigator of alternator failure over the lifetime
of the airplane. Even if it DOES get a call-to-service,
it will carry loads at a small fraction of it's rated
service and only for perhaps an hour or two until
landing.
Given the VERY low stress and duty cycle on this contactor,
I'll suggest that there are many, many things in your
system much more likely to fail than this contactor.
Further, given that the continuous duty operating loads
are so small, it's extremely unlikely that it will fail
in an overheat mode that produces faults to ground due
to insulator failure. Now, is the risk of what you've
suggested zero? Nope . . . but I wouldn't loose any sleep
over this one.
Bob . . .
Message 4
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| Subject: | PS: z-14 common failure point |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
It just occurred to me that this style contactor has been
used on SE certified aircraft for about 60 years as a battery
contactor. This offers a tens-of-millions flight-hours experience-
base. I've seen a lot of these contactors fail . . . haven't
seen any catch fire or fault to ground. This same style contactor
is used as battery contactor in OBAM aircraft as well. We're
continuing to pile up millions of flight hours history on
this part in a CONTINUOUS duty application at substantial
current values. If there are valid concerns for the failure mode
hypothesized then it's going to happen at the battery long before
it happens at the crossfeed contactor.
Bob . . .
Message 5
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| Subject: | Copper Clad Aluminum etc. |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>
>With the greatest respect, how can a connection
>between two dissimilar metals not eventually fail?
At 10:32 AM 4/13/2004 -0700, you wrote:
>--> AeroElectric-List message posted by: "Rob Housman" <RobH@hyperion-ef.com>
>
>It's really quite simple. Thermal expansion and contraction of a wire
>within a crimped connection is not sufficient to exceed the elastic limit of
>the surrounding metal (meaning that there is no permanent deformation).
>Because there is no permanent change in size of the metal surrounding the
>wire the connection between the two remains air tight at all times. The
>same applies to the copper cladding over aluminum.
Rob, thank you for the illumination of "simple ideas" that support
the premise of permanency of gas-tight crimps on aluminum. I hadn't
considered the dynamics necessary to open a gap the terminal's grip.
Bob . . .
Message 6
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| Subject: | Re: A panel full of displays . . . |
--> AeroElectric-List message posted by: "flyv35b" <flyv35b@ashcreekwireless.com>
> With all due respect...... how many of us have a had a battery failure?
I
> cannot believe that some of you intend medium to hard IFR with some of our
> homebuilts. First consider empennage, wing and prop anti icing equipment
> first.... Then I'll believe you need all the rest of the equipment.
>
> One battery will due if it is the proper quality.....
I agree. I've been flying for 40 years and owned probably 20 planes during
that time and have never had a battery failure or even heard of one (I am
A&P/IA). And most of the time the battery gives plenty of warning that it
is about to fail or already has per Bob's definition. I see a battery
failure risk as being almost totally negligible in comparison to other IFR
flying risks.
Cliff
----- Original Message -----
From: "Dale Martin" <niceez@cableone.net>
Subject: Re: AeroElectric-List: A panel full of displays . . .
> --> AeroElectric-List message posted by: "Dale Martin"
<niceez@cableone.net>
>
> With all due respect...... how many of us have a had a battery failure?
I
> cannot believe that some of you intend medium to hard IFR with some of our
> homebuilts. First consider empennage, wing and prop anti icing equipment
> first.... Then I'll believe you need all the rest of the equipment.
>
> One battery will due if it is the proper quality.....
>
> Just my opinion,
>
> Dale Martin
> Lewiston, ID
> LEZ-235
>
>
> ----- Original Message -----
> From: <czechsix@juno.com>
> To: <aeroelectric-list@matronics.com>
> Subject: Re: AeroElectric-List: A panel full of displays . . .
>
>
> > --> AeroElectric-List message posted by: czechsix@juno.com
> >
> >
> > Walter,
> >
> > The main thing I'd consider is that your single battery is a single
point
> failure for the whole system. I had planned to go the same route as you
and
> ended up settling on dual battery, single alternator. This gives up the
> advantage of having unlimited juice in case of alternator failure, but is
> more robust from the perspective of keeping the essentials going. It's
also
> cheaper than the SD-8, doesn't extract any engine power, and in my case is
> even a bit lighter since my aux battery is small. If you wanted to keep
the
> benefits that the SD-8 offers, but want to eliminate the chances (however
> small) of losing everything due to battery (or battery lead) failure, I'd
> add at least a small aux battery that can be isolated from the main
battery,
> such that you have the SD-8 tied to the aux, and the main alternator tied
to
> the main battery. Then you have true full redundancy and can fly hard IFR
> with no limitations imposed by any single failure.
> >
> > Just my humble .02
> >
> > --Mark Navratil
> > Cedar Rapids, Iowa
> > RV-8A N2D fwf stuff these days...
> >
> > --------------------------------------------
> >
> > From: Walter Tondu <walter@tondu.com>
> > Subject: Re: AeroElectric-List: A panel full of displays . . .
> >
> > <snip>
> >
> > Since this is an all-electric airplane I plan on two alternators
> > and a single battery with Battery, Essential and Primary buses.
> >
> > <snip>
> >
> > I hate to ask this, but because this is a forum of intelligent
> > people, here goes;
> >
> > Can you make a case where this would not work? And if so
> > what would you change.
> >
> > (Go easy on me, please)
> > --
> > Walter Tondu
> > http://www.tondu.com/rv7
> >
> >
>
>
Message 7
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| Subject: | Re: Endurance Bus |
--> AeroElectric-List message posted by: F1Rocket@comcast.net
Thanks to everyone who answered my questions. I realized after I'd built my switch
panels that even though I had three independent gyro systems in my panel,
I had designed in a single point of failure for all of them. I had concentrated
too much on the endurance bus from the persective of reducing load during
alternator failure and missed the valuable benefit of it providing an alternate
feed path from the battery to my filght instruments. I reasoned away the need
for the endurance bus because I have dual alternators
As designed today, a battery contactor or master switch failure would have rendered
my EFIS, A/P, and electric AH all useless because I left off the endurance
bus. Now, I plan to move all my radios/gyros to the endurance bus and I will
add a switch to my panel to power it. That switch will also serve to power
the radios only before start-up for clearance/ATIS/weather etc. My endurance
bus is "really" an avionics bus, but I promise not to call it that.
Randy
F1 Rocket (RV-6 and Long-EZ using Bob's methods)
http://f1rocket.home.comcast.net/
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <bob.nuckolls@cox.net>
>
> At 05:41 PM 4/14/2004 -0500, you wrote:
> >--> AeroElectric-List message posted by: "Randy Pflanzer"
> ><f1rocket@comcast.net>
> >
> >Using Bob's current wiring diagrams, is it okay to have both the master
> >switch and endurance bus switch on at the same time? I assume the diode
> >between the two buses keeps things from shorting out. Is there any
> >long-term consequence to running with both switches on all the time? It
> >doesn't appear so to me, but I'm not always very good at keeping all the
> >smoke inside the wires.
>
> Nope, you can run with the e-bus alternate feed switch on all the time
> and it doesn't hurt anything. Be sure to turn it off with all other
> switches at shutdown.
>
> Bob . . .
>
>
>
>
>
>
Message 8
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| Subject: | Re: Coaxial Lengths |
--> AeroElectric-List message posted by: Dave Morris <dave@davemorris.com>
Your friend was either a novice or was building special antennas. The only
reason to measure coax is if you're using the coax as an impedance matching
section. Other than that, one of the key benefits of coax versus open
feedline is that you can cut it to any length to wrap around
obstacles. The higher you go in frequency, the higher the losses for
longer pieces, so don't coil up 100 feet of coax if 10 feet will do,
because it will degrade the signal. Other than that, length is of no
importance.
Dave Morris
N5UP
At 08:09 AM 4/15/2004 -0500, you wrote:
>--> AeroElectric-List message posted by: "David E. Nelson"
><david.nelson@pobox.com>
>
>
>Hi Bob,
>
>Finished reading through the "Antenna" chapter last night. Back in my
>pre-teen
>days, I used to spend some time with a ham operator that operated in the HF
>band. Although I don't remember the equation, I distinctly remember that he'd
>measure all his coaxes before cutting and fitting them with connectors. I
>seem
>to recall that his reasoning for this was so that the coax was a multiple of
>the wavelength of the carrier freq. Is this of any relevance to our apps?
>
>Thanks,
> /\/elson
> Austin, TX
> RV-7A - Waiting on the wings....
>
>
Dave Morris
Message 9
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| Subject: | Ignitions/Starting |
04/15/2004 11:09:28 AM
--> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com
To all of you with 1 electronic ignition and one mag - I am assuming the
remaining mag does not have an impulse coupling. So your starting procedure
would be to turn on both the mag and electronic ignition and then start? or
just use the electronic ignition for start? Which leads to my next
question... how do you handle the key switch? Does it just lock out the
starter or do you also disable the electronic ignition to prevent hand
propping (if possible) or is there some type of special switch being used
to switch off both the mag and electronic ignition? I am planning to have
normal switches for the ignitions but a simple key switch for security. So
my best idea yet is to have a key switch to lock out the electronic
ignition and starter and then separate switches for mag/electronic/start.
Essentially the mag could be made hot with only the switch, but then the
plane would be hard to start without the impulse coupling.
Am I on the right track here? What have you done - Why?
Thanks,
Bryan
Message 10
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| Subject: | PS: z-14 common failure point |
--> AeroElectric-List message posted by: "GMC" <gmcnutt@uniserve.com>
Hi Bob
You state that you have "seen a lot of these contactors fail" -
I am assuming that the normal battery contactor failure modes would be (1)
fail to close when turned on, (2) fail to open when turned off, (3) poor
conductivity due pitting of contacts (hard starting) - none of which would
cause a problem in flight.
Are there other battery contactor failure modes (such as drop out) that you
have seen that actually did cause a problem in flight, and if so what are
they??
Thanks,
George in Langley
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
It just occurred to me that this style contactor has been
used on SE certified aircraft for about 60 years as a battery
contactor. This offers a tens-of-millions flight-hours experience-
base. I've seen a lot of these contactors fail . . . haven't
seen any catch fire or fault to ground. This same style contactor
is used as battery contactor in OBAM aircraft as well. We're
continuing to pile up millions of flight hours history on
this part in a CONTINUOUS duty application at substantial
current values. If there are valid concerns for the failure mode
hypothesized then it's going to happen at the battery long before
it happens at the crossfeed contactor.
Bob . . .
_
Message 11
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| Subject: | Re: Ignitions/Starting |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Hi Bryan,
Embedded comments...
> --> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com
>
>
> To all of you with 1 electronic ignition and one mag - I am assuming the
> remaining mag does not have an impulse coupling.
Magnetos without impulse coupling (or some other method to retard the
spark timing) are not suitable for starting.
> So your starting
> procedure would be to turn on both the mag and electronic ignition and
> then start? or just use the electronic ignition for start?
Both of the mags on my O-200 had impulse couplings... So, I used to turn
both of them on when starting. Not unusual. Now, with one electronic
ignition,
I still turn both systems on, as they both properly retard the spark
timing for
starting.
> Which leads
> to my next question... how do you handle the key switch?
No key switch. Removed. Using 2 toggle switches.
> Does it just
> lock out the starter or do you also disable the electronic ignition to
> prevent hand propping (if possible)
My airplane doesn't have a starter. Hand propping is the only way to make
it go. Being able to hand prop might be useful, even on airplanes with
starters.
> or is there some type of special
> switch being used to switch off both the mag and electronic ignition?
The p-lead on magnetos needs to be disconnected to run, and shorted to not
run. Most electronic ignition systems require the oposite conditions, ie
they
need to have 12V connected in order to run. I believe Klaus offers an option
on some of his systems to be able to work with a normal magneto key switch,
though he recommends using toggle switches instead.
> I
> am planning to have normal switches for the ignitions but a simple key
> switch for security.
Secure from what? Accidental starter engagement or from theft? I don't
think a normal key switch provides any protection from either problem. I
suppose that a key switch might discourage a joy rider, but I think that's
about it.
> So my best idea yet is to have a key switch to lock
> out the electronic ignition and starter and then separate switches for
> mag/electronic/start. Essentially the mag could be made hot with only
> the switch, but then the plane would be hard to start without the
> impulse coupling.
The only way I can think to wire up what you are talking about involves
essentially two electrical disconnects for engine ignition. I don't think I
would choose to sacrifice in flight reliability to gain on the ground
security.
For security, as someone (Bob?) suggests, get one of those heavy
padded chains with a high quality padlock, and figure-eight it around the
propellor.
>
> Am I on the right track here? What have you done - Why?
>
> Thanks,
>
> Bryan
>
Regards,
Matt-
N34RD
Message 12
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"'aeroelectric-list@matronics.com'" <aeroelectric-list@matronics.com>
| Subject: | Dynon heated AOA pitot now available |
--> AeroElectric-List message posted by: "Bartrim, Todd" <sbartrim@mail.canfor.ca>
this week for the heated AOA pitot and plans to begin shipping next week.
I've ordered mine. I also currently have the PSS AOA system
installed so I can do some direct comparisons.
S. Todd Bartrim
Turbo 13B
RX-9endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm
"Imagination is more important than knowledge"
-Albert Einstein
Message 13
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| Subject: | Re: Ignitions/Starting |
--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
On my RV-7 I have one Slick impulse coupled mag and one LightSpeed Plasma
II. From what I understand, the LSE retards to zero (TDC) for starting. So
I use both ignition sources at startup and the thing fires on the first
blade when cold, first few blades when hot & purged.
Whenever starting, I do this (after any required priming is complete):
- master switch on battery only (all 3 buses powered on)
- mag switch on (impulse coupler enables starting)
- Lightspeed switch on (timing retarded to zero for starting)
- engage starter
After it's running I flip the master up to the "both" (battery + alt)
position and check volts/amps. I don't think there would be any harm in
going right to the "both" position before starting, but this method helps
force me to check volts/amps after turning on the alternator (B&C L40).
By the way (off topic), I just want to express more thanks to Bob for all
the help during the construction process and for the excellent book. I
followed your guidelines and have what sure seems to be reliable, noise-free
system. About 35 hours and counting.
Now if you happen to have a trick to make my Airflow Performance
high-pressure fuel pump consume less power, I'm all ears!! 8-)
)_( Dan
RV-7 N714D
http://www.rvproject.com
----- Original Message -----
From: <BFlood@Sauer-Danfoss.com>
Subject: AeroElectric-List: Ignitions/Starting
> --> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com
>
>
> To all of you with 1 electronic ignition and one mag - I am assuming the
> remaining mag does not have an impulse coupling. So your starting
procedure
> would be to turn on both the mag and electronic ignition and then start?
or
> just use the electronic ignition for start? Which leads to my next
> question... how do you handle the key switch? Does it just lock out the
> starter or do you also disable the electronic ignition to prevent hand
> propping (if possible) or is there some type of special switch being used
> to switch off both the mag and electronic ignition? I am planning to have
> normal switches for the ignitions but a simple key switch for security. So
> my best idea yet is to have a key switch to lock out the electronic
> ignition and starter and then separate switches for mag/electronic/start.
> Essentially the mag could be made hot with only the switch, but then the
> plane would be hard to start without the impulse coupling.
>
> Am I on the right track here? What have you done - Why?
>
> Thanks,
>
> Bryan
>
>
Message 14
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| Subject: | Re: Architecure Choices |
--> AeroElectric-List message posted by: czechsix@juno.com
Bob, I was about to reply but saw that someone else already caught it...you just
misread my post.
I agree that the SD-8 is a good system and wasn't trying to make a big deal out
of cost/weight/engine power savings, which are marginal differences. My main
point to the original question was if I saw any potential problems with an IFR
machine that uses dual alternators tied to a single battery. Your own advice
to me when asking the same questions about a year ago was that dual batteries,
single alternator was more RELIABLE especially for dual electronic ignition,
but of course you lose the ability to have unlimited duration that you have
with the dual alternator, single battery system.
--Mark Navratil
Cedar Rapids, Iowa
RV-8A N2D finishing
From: "Richard E. Tasker" <retasker@optonline.net>
Subject: Re: AeroElectric-List: Re: Architecure Choices
--> AeroElectric-List message posted by: "Richard E. Tasker" <retasker@optonline.net>
Uuuh, Bob. You read his post wrong. What he said was:
>>This gives up the advantage of having unlimited juice . . .
>>
>>
Meaning, he is choosing to use batteries and one alternator - resulting
in limited juice.
>
> . . . unlimited? That must be a really BIG battery.
>
Likewise.
Other than that, your comments are right on.
Dick Tasker
Message 15
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| Subject: | Ignitions/Starting |
--> AeroElectric-List message posted by: "Sam Hoskins" <shoskins@mchsi.com>
Matt,
You say you hand-prop your O-200. So do I, and I just installed a LSE
Plasma III. It seems to start hard when the engine is cold. I have high
compression pistons and it doesn't seem to go over the next compression
stroke very easily, unless I open the throttle wider than I like to. It
starts a lot easier if it's hot.
Have you had any experience like this? I thought starting was going to be
easier, but so far that's not the case.
Sam
Quickie Q-200 ~ 1,350 hrs.
http://home.mchsi.com/~shoskins/index.htm
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Matt
Prather
Subject: Re: AeroElectric-List: Ignitions/Starting
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Hi Bryan,
Embedded comments...
> --> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com
>
>
> To all of you with 1 electronic ignition and one mag - I am assuming the
> remaining mag does not have an impulse coupling.
Magnetos without impulse coupling (or some other method to retard the
spark timing) are not suitable for starting.
> So your starting
> procedure would be to turn on both the mag and electronic ignition and
> then start? or just use the electronic ignition for start?
Both of the mags on my O-200 had impulse couplings... So, I used to turn
both of them on when starting. Not unusual. Now, with one electronic
ignition,
I still turn both systems on, as they both properly retard the spark
timing for
starting.
> Which leads
> to my next question... how do you handle the key switch?
No key switch. Removed. Using 2 toggle switches.
> Does it just
> lock out the starter or do you also disable the electronic ignition to
> prevent hand propping (if possible)
My airplane doesn't have a starter. Hand propping is the only way to make
it go. Being able to hand prop might be useful, even on airplanes with
starters.
> or is there some type of special
> switch being used to switch off both the mag and electronic ignition?
The p-lead on magnetos needs to be disconnected to run, and shorted to not
run. Most electronic ignition systems require the oposite conditions, ie
they
need to have 12V connected in order to run. I believe Klaus offers an
option
on some of his systems to be able to work with a normal magneto key switch,
though he recommends using toggle switches instead.
> I
> am planning to have normal switches for the ignitions but a simple key
> switch for security.
Secure from what? Accidental starter engagement or from theft? I don't
think a normal key switch provides any protection from either problem. I
suppose that a key switch might discourage a joy rider, but I think that's
about it.
> So my best idea yet is to have a key switch to lock
> out the electronic ignition and starter and then separate switches for
> mag/electronic/start. Essentially the mag could be made hot with only
> the switch, but then the plane would be hard to start without the
> impulse coupling.
The only way I can think to wire up what you are talking about involves
essentially two electrical disconnects for engine ignition. I don't think I
would choose to sacrifice in flight reliability to gain on the ground
security.
For security, as someone (Bob?) suggests, get one of those heavy
padded chains with a high quality padlock, and figure-eight it around the
propellor.
>
> Am I on the right track here? What have you done - Why?
>
> Thanks,
>
> Bryan
>
Regards,
Matt-
N34RD
Message 16
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| Subject: | Ignitions/Starting |
--> AeroElectric-List message posted by: "Sam Hoskins" <shoskins@mchsi.com>
Bryan
It is imperative that any magneto has either a spark retard device (impulse
coupling, shower o sparks, etc) or is inoperative while starting. You
always want your start timing to be close to 0 deg, TDC. You DON'T want to
have an advanced spark when the engine is turning slowly, during the start
phase.
An advanced spark at slow speeds can cause kickback, which is damaging to
starters.
Sam
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
BFlood@Sauer-Danfoss.com
Subject: AeroElectric-List: Ignitions/Starting
--> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com
To all of you with 1 electronic ignition and one mag - I am assuming the
remaining mag does not have an impulse coupling. So your starting procedure
would be to turn on both the mag and electronic ignition and then start? or
just use the electronic ignition for start? Which leads to my next
question... how do you handle the key switch? Does it just lock out the
starter or do you also disable the electronic ignition to prevent hand
propping (if possible) or is there some type of special switch being used
to switch off both the mag and electronic ignition? I am planning to have
normal switches for the ignitions but a simple key switch for security. So
my best idea yet is to have a key switch to lock out the electronic
ignition and starter and then separate switches for mag/electronic/start.
Essentially the mag could be made hot with only the switch, but then the
plane would be hard to start without the impulse coupling.
Am I on the right track here? What have you done - Why?
Thanks,
Bryan
Message 17
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| Subject: | Re: A panel full of displays . . . |
--> AeroElectric-List message posted by: czechsix@juno.com
Hi Dale,
To answer your question, very few of us have had battery failure. It's pretty
rare, and many people may be comfortable with a single battery in an all-electric
airplane (i.e. dual elec. ignition and IFR panel with no vacuum). Personally,
I'm NOT comfortable with having all that at stake in a single battery. There
have been a few battery failures reported here on this List over the past
few years I've followed it, and several people I've talked to have had it happen
in cars. I'm talking catastrauphic failure, where the lead or post breaks
off, or something happens to the battery itself rendering the whole electrical
system dead. I know, I know...they were probably poorly designed installations
and/or poorly maintained, and if you have a well-designed installation without
stressing the battery leads/terminals, with an RG battery rotated out every
other year, the odds of failure are probably reduced to very slim. But in
my case I decided to go with a small aux battery to k
eep my second ignition alive in the ulikely event that it's needed. Each person
can decide for their airplane and mission what they're comfortable with.
--Mark Navratil
Cedar Rapids, Iowa
RV-8A N2D finishing...
From: "Dale Martin" <niceez@cableone.net>
Subject: Re: AeroElectric-List: A panel full of displays . . .
--> AeroElectric-List message posted by: "Dale Martin" <niceez@cableone.net>
With all due respect...... how many of us have a had a battery failure? I
cannot believe that some of you intend medium to hard IFR with some of our
homebuilts. First consider empennage, wing and prop anti icing equipment
first.... Then I'll believe you need all the rest of the equipment.
One battery will due if it is the proper quality.....
Just my opinion,
Dale Martin
Lewiston, ID
LEZ-235
Message 18
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| Subject: | Ignitions/Starting |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Hi Sam,
I have stock pistons in my O-200. It was pretty easy to start with 2
mags, and
somewhat easier to start with the swapout to an LSE and a mag. Mine is
easier
to start when its cold, but only because it is pretty easy to flood when hot.
Does your carb have an accelerator pump or primer?
The way I start mine when cold is to pump the throttle (not primer
equipped) 2-3
times. Then, with all of the switches off, pull 4 blades through. All
switches on,
and it ALMOST always starts on the first pull.
When hot, the easiest starting is had by shutting down via the ignition
switch, not
the mixture control. When ready to go, switches on, and it usually starts
again
on the first pull. If I shut down via mixture and have to restart, I
usually give it
about a half pump on the throttle, switches hot, and then most of the time
it runs
on the 2nd pull.
I am not sure what I would do different if I had hi compression pistons.
I'll have
to think about that. Does the engine fire once but not make it through to
the next
stroke? Or does it not spark at all? Do you have the prop 'clocked' to a
position
where you can get a good hard flip on it?
Regards,
Matt-
N34RD
> --> AeroElectric-List message posted by: "Sam Hoskins"
> <shoskins@mchsi.com>
>
> Matt,
> You say you hand-prop your O-200. So do I, and I just installed a LSE
> Plasma III. It seems to start hard when the engine is cold. I have
> high compression pistons and it doesn't seem to go over the next
> compression stroke very easily, unless I open the throttle wider than I
> like to. It starts a lot easier if it's hot.
> Have you had any experience like this? I thought starting was going to
> be easier, but so far that's not the case.
> Sam
> Quickie Q-200 ~ 1,350 hrs.
> http://home.mchsi.com/~shoskins/index.htm
>
Message 19
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| Subject: | Re: Ignitions/Starting |
--> AeroElectric-List message posted by: "Pat Hatch" <pat_hatch@msn.com>
Dan, one other reason to stay in the battery-only position prior to start is
that in BOTH you are supplying about 2-3 amps to the alternator field
circuit, which is robbing power from your starter. I think it prolongs the
life of your battery too to not load it down more than neccessary during a
start. On my RV-4 the ammeter happens to be on the battery so you can
actually see the 2-3 amps kick in when going to BOTH on the master switch.
You probably knew this, but it might help someone else who might not.
Pat Hatch
RV-4
RV-6
RV-7 Finishing Kit
Vero Beach, FL
----- Original Message -----
From: "Dan Checkoway" <dan@rvproject.com>
Subject: Re: AeroElectric-List: Ignitions/Starting
> --> AeroElectric-List message posted by: "Dan Checkoway"
<dan@rvproject.com>
>
> On my RV-7 I have one Slick impulse coupled mag and one LightSpeed Plasma
> II. From what I understand, the LSE retards to zero (TDC) for starting.
So
> I use both ignition sources at startup and the thing fires on the first
> blade when cold, first few blades when hot & purged.
>
> Whenever starting, I do this (after any required priming is complete):
>
> - master switch on battery only (all 3 buses powered on)
> - mag switch on (impulse coupler enables starting)
> - Lightspeed switch on (timing retarded to zero for starting)
> - engage starter
>
> After it's running I flip the master up to the "both" (battery + alt)
> position and check volts/amps. I don't think there would be any harm in
> going right to the "both" position before starting, but this method helps
> force me to check volts/amps after turning on the alternator (B&C L40).
>
> By the way (off topic), I just want to express more thanks to Bob for all
> the help during the construction process and for the excellent book. I
> followed your guidelines and have what sure seems to be reliable,
noise-free
> system. About 35 hours and counting.
>
> Now if you happen to have a trick to make my Airflow Performance
> high-pressure fuel pump consume less power, I'm all ears!! 8-)
>
> )_( Dan
> RV-7 N714D
> http://www.rvproject.com
>
> ----- Original Message -----
> From: <BFlood@Sauer-Danfoss.com>
> To: <aeroelectric-list@matronics.com>
> Subject: AeroElectric-List: Ignitions/Starting
>
>
> > --> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com
> >
> >
> > To all of you with 1 electronic ignition and one mag - I am assuming the
> > remaining mag does not have an impulse coupling. So your starting
> procedure
> > would be to turn on both the mag and electronic ignition and then start?
> or
> > just use the electronic ignition for start? Which leads to my next
> > question... how do you handle the key switch? Does it just lock out the
> > starter or do you also disable the electronic ignition to prevent hand
> > propping (if possible) or is there some type of special switch being
used
> > to switch off both the mag and electronic ignition? I am planning to
have
> > normal switches for the ignitions but a simple key switch for security.
So
> > my best idea yet is to have a key switch to lock out the electronic
> > ignition and starter and then separate switches for
mag/electronic/start.
> > Essentially the mag could be made hot with only the switch, but then the
> > plane would be hard to start without the impulse coupling.
> >
> > Am I on the right track here? What have you done - Why?
> >
> > Thanks,
> >
> > Bryan
> >
> >
>
>
Message 20
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| Subject: | Re: Ignitions/Starting |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:35 PM 4/15/2004 -0400, you wrote:
>--> AeroElectric-List message posted by: "Pat Hatch" <pat_hatch@msn.com>
>
>Dan, one other reason to stay in the battery-only position prior to start is
>that in BOTH you are supplying about 2-3 amps to the alternator field
>circuit, which is robbing power from your starter. I think it prolongs the
>life of your battery too to not load it down more than neccessary during a
>start. On my RV-4 the ammeter happens to be on the battery so you can
>actually see the 2-3 amps kick in when going to BOTH on the master switch.
>You probably knew this, but it might help someone else who might not.
This use to be the standard advice on certified ships that
it was good practice to leave the alternator and other things
OFF during cranking to "save the battery". In the grand scheme
of things, adding a few percent more load to a 200+ amp cranking
event doesn't have much influence on battery life. Keeping the
engine tuned and developing techniques that get the fires lit
in a few blades is more beneficial than shaving a few amps
of total loads.
> >
> > Now if you happen to have a trick to make my Airflow Performance
> > high-pressure fuel pump consume less power, I'm all ears!! 8-)
What are the physics of your pump operation? I designed a pump controller
about 20 years ago for a pump that was originally designed to deliver
constant pressure to an engine by means of a relief valve. During
periods of low fuel flow, the relief valve cracked and ported
excess flow back to tank. Simple system but use max power under
all fuel flow conditions. By adding an accumulator/transducer
combination downstream of the pump, power to the pump motor
was throttled to maintain constant pressure at any flow. Result
was very low power consumption at low fuel flows and max power
needed only during full-rich, max throttle climbs.
Cut power consumption by about half for most operations and
increased pump brush life by three or four times.
Bob . . .
Message 21
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| Subject: | Ignitions/Starting |
--> AeroElectric-List message posted by: "Sam Hoskins" <shoskins@mchsi.com>
Matt, I have been hand-propping this aircraft for 15 years, and probably
have as many starts as hours. Probably 1,330+
I have an MA3 carb, plus a primer to the intake spider manifold. Both seem
to do the same. I start mine much like you do, however with the
substitution of the Plasma III starting seems to have gotten harder. It
doesn't like to make it over the compression stroke after I release the
blade. I attribute that to the high compression pistons, but it has gotten
worse with the LSE.
Sam
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Matt
Prather
Subject: RE: AeroElectric-List: Ignitions/Starting
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Hi Sam,
I have stock pistons in my O-200. It was pretty easy to start with 2
mags, and
somewhat easier to start with the swapout to an LSE and a mag. Mine is
easier
to start when its cold, but only because it is pretty easy to flood when
hot.
Does your carb have an accelerator pump or primer?
The way I start mine when cold is to pump the throttle (not primer
equipped) 2-3
times. Then, with all of the switches off, pull 4 blades through. All
switches on,
and it ALMOST always starts on the first pull.
When hot, the easiest starting is had by shutting down via the ignition
switch, not
the mixture control. When ready to go, switches on, and it usually starts
again
on the first pull. If I shut down via mixture and have to restart, I
usually give it
about a half pump on the throttle, switches hot, and then most of the time
it runs
on the 2nd pull.
I am not sure what I would do different if I had hi compression pistons.
I'll have
to think about that. Does the engine fire once but not make it through to
the next
stroke? Or does it not spark at all? Do you have the prop 'clocked' to a
position
where you can get a good hard flip on it?
Regards,
Matt-
N34RD
> --> AeroElectric-List message posted by: "Sam Hoskins"
> <shoskins@mchsi.com>
>
> Matt,
> You say you hand-prop your O-200. So do I, and I just installed a LSE
> Plasma III. It seems to start hard when the engine is cold. I have
> high compression pistons and it doesn't seem to go over the next
> compression stroke very easily, unless I open the throttle wider than I
> like to. It starts a lot easier if it's hot.
> Have you had any experience like this? I thought starting was going to
> be easier, but so far that's not the case.
> Sam
> Quickie Q-200 ~ 1,350 hrs.
> http://home.mchsi.com/~shoskins/index.htm
>
Message 22
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| Subject: | Re: Ignitions/Starting |
--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
> > > Now if you happen to have a trick to make my Airflow Performance
> > > high-pressure fuel pump consume less power, I'm all ears!! 8-)
>
> What are the physics of your pump operation? I designed a pump
controller
> about 20 years ago for a pump that was originally designed to deliver
> constant pressure to an engine by means of a relief valve. During
> periods of low fuel flow, the relief valve cracked and ported
> excess flow back to tank. Simple system but use max power under
> all fuel flow conditions. By adding an accumulator/transducer
> combination downstream of the pump, power to the pump motor
> was throttled to maintain constant pressure at any flow. Result
> was very low power consumption at low fuel flows and max power
> needed only during full-rich, max throttle climbs.
>
> Cut power consumption by about half for most operations and
> increased pump brush life by three or four times.
That sure sounds good to me. I'm not too familiar with the inner workings
of the AFP pump & bypass valve setup, but I have to assume it's roughly the
first setup you described above (constant pump operation at full blast +
relief valve).
I do have a fuel flow transducer downstream of the pump, of course in use &
wired to my ACS2002 monitor. Not sure if that could do double duty, or how
complex the "throttle" circuit would be. I don't have the knowledge or
skills to design something like this on my own, but if you're aware of a
simple, affordable method I'd love to learn about it.
Even if the final answer ends up being that I just live with what I've got,
I'm still interested in finding out about alternatives for fun.
Thanks,
)_( Dan
Message 23
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| Subject: | Ignitions/Starting |
--> AeroElectric-List message posted by: "Terry Watson" <terry@tcwatson.com>
I am quite sure I remember a few months ago we were talking on this list
about the idea that the Airflow Performance fuel pump is actually usually
just a back-up to the engine driven mechanical pump; that unless something
goes wrong with the engine driven pump, the Airflow Performance pump is
turned on during takeoff and landing only as a safety precaution in case the
mechanical pump fails during those critical times. I think Eric had or
offered to design a fuel pump switch that would only turn the boost pump on
if the fuel pressure dropped, or if the switch was put in the on regardless
position. In other words, it would always be ready to turn on if needed but
would not normally be running during takeoff and landing unless the pilot
chose the override position.
So, it would seem the best way to make the pump consume less power would be
to use a switch like Eric suggested, leaving the pump off unless it was
actually needed to create the needed fuel pressure. Do I remember this
right?
Terry
--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
> > > Now if you happen to have a trick to make my Airflow Performance
> > > high-pressure fuel pump consume less power, I'm all ears!! 8-)
>
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