Today's Message Index:
----------------------
1. 01:18 AM - in-rush limiters (Erich_Weaver@URSCorp.com)
2. 04:06 AM - Re: in-rush limiters (Robert L. Nuckolls, III)
3. 04:14 AM - Re: Is EFIS vulnerable at engine start? (FLYaDIVE@aol.com)
4. 04:15 AM - Re: in-rush limiters (Oops!) (Robert L. Nuckolls, III)
5. 05:03 AM - Re: in-rush limiters (FLYaDIVE@aol.com)
6. 05:23 AM - Paralleled microphone circuits? (Robert L. Nuckolls, III)
7. 05:33 AM - Re: Is EFIS vulnerable at engine start? (gert)
8. 05:43 AM - Re: Dynon D10 AOA Boom (Ernest Christley)
9. 05:50 AM - Re: in-rush limiters (Robert L. Nuckolls, III)
10. 06:39 AM - Static port on Dynon AoA probe (Ernest Christley)
11. 07:15 AM - Lex (glen matejcek)
12. 07:51 AM - Re: Is EFIS vulnerable at engine start? (Greg Campbell)
13. 07:58 AM - Re: Paralleled microphone circuits? (FLYaDIVE@aol.com)
14. 08:20 AM - Re: Is EFIS vulnerable at engine start? (Doug Windhorn)
15. 11:59 AM - downside of manual battery disconnects? (D Wysong)
16. 12:14 PM - Re: GRT Wx Impressions (gyoung)
17. 01:07 PM - Re: Static port on Dynon AoA probe (Brian Lloyd)
18. 01:44 PM - Re: Static port on Dynon AoA probe (Kevin Horton)
19. 02:27 PM - Re: Is EFIS vulnerable at engine start? (Carlos Trigo)
20. 02:43 PM - Re: downside of manual battery disconnects? ()
21. 02:58 PM - Re: Re: Alternator Switching (Kelly McMullen)
22. 03:34 PM - Re: Is EFIS vulnerable at engine start? (Nancy Ghertner)
23. 04:51 PM - Re: in-rush limiters (Hopperdhh@aol.com)
24. 05:21 PM - Re: in-rush limiters (Hopperdhh@aol.com)
25. 08:10 PM - Re: Is EFIS vulnerable at engine start? (glaesers)
Message 1
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Subject: | in-rush limiters |
--> AeroElectric-List message posted by: Erich_Weaver@URSCorp.com
I am considering installing in-rush limiters for my landing lights. Can
in-rush limiters be used effectively in conjunction with a wig-wag flasher?
My understanding is that the in-rush limiters do their job through their
odd property of providing decreasing resistance with increasing heat. That
would imply that they would need time to cool down before being able to do
their job the next time the power is turned on. With the flasher however,
the power is being turned on and off very quickly. On the other hand, the
bulb filament is probably not cooling off a lot either between flashes, so
maybe the in-rush limiters do not need to be effective when the wig-wag is
wigging and wagging.
Did I just answer my own question? If so, can someone recommend an
appropriate in-rush limiter for my 12V, 75W halogen lights
thanks
Erich Weaver
Message 2
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Subject: | Re: in-rush limiters |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 05:06 PM 8/30/2006 -0700, you wrote:
>--> AeroElectric-List message posted by: Erich_Weaver@URSCorp.com
>
>
>I am considering installing in-rush limiters for my landing lights. Can
>in-rush limiters be used effectively in conjunction with a wig-wag flasher?
>
>My understanding is that the in-rush limiters do their job through their
>odd property of providing decreasing resistance with increasing heat. That
>would imply that they would need time to cool down before being able to do
>their job the next time the power is turned on. With the flasher however,
>the power is being turned on and off very quickly. On the other hand, the
>bulb filament is probably not cooling off a lot either between flashes, so
>maybe the in-rush limiters do not need to be effective when the wig-wag is
>wigging and wagging.
>
>Did I just answer my own question? If so, can someone recommend an
>appropriate in-rush limiter for my 12V, 75W halogen lights
The inrush limiters are, as you've already guessed,
slow to respond. They have to cool down for perhaps a minute
or more to be an effective inrush limiter for the next
turn-on event.
At the same time, filaments in lamps . . . especially the
halogens have a cooling time constant so long as to eliminate
the need for current limiting between flashes of a wig-wag system
I did some measurements on the bench a few years ago to
flash an automotive halogen headlamp bulb. The first turn-on
transient was what you would have expected . . . light up
transient from cold start was about a 10x running current.
However, sufficient heat was retained between flashes that
subsequent turn-on events were perhaps 1.2x running current.
Before halogens, the notion of installing inrush limiters
or adding some kind of keepwarm circuit had some appeal. With
the proliferation of the much more rugged halogens, the
old life-enhancing techniques are less useful. The next revision
of the 'Connection's lighting chapter will only mention these
techniques as ideas with historical significance but not
recommended for new design.
Bob . . .
---------------------------------------------------------
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
---------------------------------------------------------
Message 3
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Subject: | Re: Is EFIS vulnerable at engine start? |
--> AeroElectric-List message posted by: FLYaDIVE@aol.com
In a message dated 8/30/06 9:15:25 PM Eastern Daylight Time,
gert.v@sbcglobal.net writes:
> begs the question, what about the current crop of electronic engine
> instruments, ya all keep them off till u engine is running.
> What good are they if u can't have them on during engine start ;-)
> so u wait till the engine is running, switch u electronic instruments on
> to discover u have no oil pressure, oops....somehow i don't think i want
> Blue Mountain to check my oil pressure if i have to have their system
> off during engine start.
=====================
I do not know if Blue Mountain (BMA) has an EIS. What I was mentioning was
the EFIS system. There is also a huge difference between the electronics of an
EFIS or Com radio and a simple sending unit and gage used for fuel quantity,
oil temp & pressure and the like.
Now, Grand Rapids states KEEP THE UNIT ON. So there is a difference in
electrical design between the two or at least their thinking!
Barry
"Chop'd Liver"
"Show them the first time, correct them the second time, kick them the third
time."
Yamashiada
Message 4
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Subject: | Re: in-rush limiters (Oops!) |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 05:06 PM 8/30/2006 -0700, you wrote:
>--> AeroElectric-List message posted by: Erich_Weaver@URSCorp.com
>
>Did I just answer my own question? If so, can someone recommend an
>appropriate in-rush limiter for my 12V, 75W halogen lights
P.S.
If you would like to include an in-rush limiter in your
design, consider the KC003L on
http://dkc3.digikey.com/PDF/T062/1405.pdf
Bob . . .
Message 5
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Subject: | Re: in-rush limiters |
--> AeroElectric-List message posted by: FLYaDIVE@aol.com
In a message dated 8/31/06 4:20:49 AM Eastern Daylight Time,
Erich_Weaver@URSCorp.com writes:
> I am considering installing in-rush limiters for my landing lights. Can
> in-rush limiters be used effectively in conjunction with a wig-wag flasher?
>
> My understanding is that the in-rush limiters do their job through their
> odd property of providing decreasing resistance with increasing heat. That
> would imply that they would need time to cool down before being able to do
> their job the next time the power is turned on. With the flasher however,
> the power is being turned on and off very quickly. On the other hand, the
> bulb filament is probably not cooling off a lot either between flashes, so
> maybe the in-rush limiters do not need to be effective when the wig-wag is
> wigging and wagging.
>
> Did I just answer my own question? If so, can someone recommend an
> appropriate in-rush limiter for my 12V, 75W halogen lights
>
> thanks
>
> Erich Weaver
==================================
Erich:
I am familiar with two types of inrush limiters. Neither of them work off of
heat (I would like to learn more about this heat type).
The simplest "limiter" you can build yourself. It is nothing more than a
coil. The coil can be made around either a dowel or a ferrite slug. The wire
size is chosen to handle the current of the load and the basic size is about
1/2" ID, 1" OD and 2" Long. The type of wire is SOLID single strand and is what
is known as Transformer Wire. After wrapping the wire coils TIGHT you can use
heat shrink tubing over them. If you want to get fancy and I would; before
you heat shrink tube them dip them in varnish. They should be located close to
the load device.
Oh! When choosing the wire size, do NOT go by the Mil-Spec wire size used in
wiring the plane. I would DOUBLE that wire size.
Barry
"Chop'd Liver"
"Show them the first time, correct them the second time, kick them the third
time."
Yamashiada
Message 6
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Subject: | Paralleled microphone circuits? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
>Hi Bob,
>
>I am a homebuilder (Midget Mustang, very small single seat) now doing the
>wiring. My radio stack will contain one comm/nav radio and I plan to
>include a small handheld mounted elsewhere in the cockpit. If needed due
>to a failure of the #1 radio, it will interface to my headphones via your
>isolation amplifier.
>
>My question is, "Can I connect my mike to both radios concurrently. I will
>have seperate PTT switches, so only one radio will transmit. I am not sure
>if the 2nd radio will load the mike too much, or will there be some other
>gotcha out there?
Connecting the mic circuits as you've suggested
offers an unknown probability of success . . .
I would guess not a good one.
A transmitter selector switch is suggested. See:
Figure 18-11 of:
http://aeroelectric.com/articles/Rev11/18Audio_R11.pdf
>I use your website lots. Thanks for all your work in that area.
You're most welcome sir!
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
Message 7
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Subject: | Re: Is EFIS vulnerable at engine start? |
--> AeroElectric-List message posted by: gert <gert.v@sbcglobal.net>
for the record, I am NOT worried about it, but it stands to reason that
many an EIS are build on the same platform as the accompanying EFIS, if
a company recommends to not turn on the EFIS and the EIS is on the same
platform, should it then not follow to have that switched off too?? I
just think it is funny that u want to buy a $$$$ EIS but the mfg
recommends to have it off at a important time.
Yes, i know, u can always add another switch to u stick to switch it on
el-pronto when the engine catches ;-)
Robert L. Nuckolls, III wrote:
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <nuckollsr@cox.net>
>
> At 08:10 PM 8/30/2006 -0500, you wrote:
>
>> --> AeroElectric-List message posted by: gert <gert.v@sbcglobal.net>
>>
>> begs the question, what about the current crop of electronic engine
>> instruments, ya all keep them off till u engine is running.
>> What good are they if u can't have them on during engine start ;-)
>> so u wait till the engine is running, switch u electronic instruments
>> on to discover u have no oil pressure, oops....somehow i don't think
>> i want Blue Mountain to check my oil pressure if i have to have their
>> system off during engine start.
>
> The risks are exceedingly low. I suppose there are
> folks who tell tales of having lost an engine when a pump
> shaft sheared on startup . . . but think about it. Just
> how highly stressed are the oil pump parts? If one is
> really worried about a bullet proof oil pressure indication
> at startup, perhaps a pressure switch and "OIL P WARN" light
> in the annunciator panel is called for.
>
> I wouldn't put engine instrumentation on the e-bus. 99.999% of
> the time, engine instruments show the same things they said
> the last time you looked at them. Loss of some engine functionality
> in addition to loss of alternator on same tank of fuel is exceedingly
> remote. Or, one could install an SD-8 for unlimited endurance on
> an 8 Amp e-bus and flip the instrumentation on from time to time.
>
> Bob . . .
>
>
--
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Message 8
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Subject: | Re: Dynon D10 AOA Boom |
--> AeroElectric-List message posted by: Ernest Christley <echristley@nc.rr.com>
Take a peek at http://www.ch601.org/resources/aoa/aoa.htm
The Dynon AOA function requires calibration, just like this instrument
will need. Ed described how it works. The calibration technique is to
go up and do a few stalls, noting where the gauge is at the stall point.
>
>
>>--> AeroElectric-List message posted by: <rparigor@suffolk.lib.ny.us>
>>
>>I have a Dynon D10A. Would be nice to use the AOA feature. Already have a
>>pitot/static under wing of my Europa.
>>
>>I am thinking a probe high up on the rudder may work and not complicate
>>rigging the wings or hurting anything when wings go on trailer.
>>
>>Dynon sells a boom mount AOA/pitot, part number is 100532-000 but it is 1"
>>in diameter and has a pitot.
>>
>>I am thinking something like a thin wall 5/16" or 1/4" tube, with 1" of
>>the tip turned up, flattened, and plugged up and a hole drilled.
>>
>>Has anyone mounted a AOA on rudder?
>>
>>Know where to buy one?
>>
>>Made one?
>>
>>Thx.
>>Ron Parigoris
>>
>>
>>
>>
>>
--
,|"|"|, Ernest Christley |
----===<{{(oQo)}}>===---- Dyke Delta Builder |
o| d |o http://ernest.isa-geek.org |
Message 9
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Subject: | Re: in-rush limiters |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 08:01 AM 8/31/2006 -0400, you wrote:
>--> AeroElectric-List message posted by: FLYaDIVE@aol.com
>
>In a message dated 8/31/06 4:20:49 AM Eastern Daylight Time,
>Erich_Weaver@URSCorp.com writes:
>
> > I am considering installing in-rush limiters for my landing lights. Can
> > in-rush limiters be used effectively in conjunction with a wig-wag
> flasher?
> >
> > My understanding is that the in-rush limiters do their job through their
> > odd property of providing decreasing resistance with increasing
> heat. That
> > would imply that they would need time to cool down before being able to do
> > their job the next time the power is turned on. With the flasher however,
> > the power is being turned on and off very quickly. On the other hand, the
> > bulb filament is probably not cooling off a lot either between flashes, so
> > maybe the in-rush limiters do not need to be effective when the wig-wag is
> > wigging and wagging.
> >
> > Did I just answer my own question? If so, can someone recommend an
> > appropriate in-rush limiter for my 12V, 75W halogen lights
> >
> > thanks
> >
> > Erich Weaver
>==================================
>Erich:
>
>I am familiar with two types of inrush limiters. Neither of them work off of
>heat (I would like to learn more about this heat type).
See
http://www.gesensing.com/products/resources/datasheets/cl.pdf
>The simplest "limiter" you can build yourself. It is nothing more than a
>coil. The coil can be made around either a dowel or a ferrite slug. The
>wire
>size is chosen to handle the current of the load and the basic size is about
>1/2" ID, 1" OD and 2" Long. The type of wire is SOLID single strand and
>is what
>is known as Transformer Wire. After wrapping the wire coils TIGHT you can
>use
>heat shrink tubing over them. If you want to get fancy and I would; before
>you heat shrink tube them dip them in varnish. They should be located
>close to
>the load device.
Adding inductance in series with a load does have an
effect of softening an inrush current event. However,
the time constant of an inductive circuit is (t=L/R)
and the inductance of a 1" x 2" wood core inductor
with 30T of wire on it is about 10 microhenries. Assuming
one finds a suitable hunk of ferrite and assuming also
a permeability of about 10, the inductance goes up to
about 100 microhenries. Cold closed loop resistance for
a 75 watt lamp circuit will be on the order of 0.3 ohms yielding
a max time constant on the order of .0001/0.3 or about 1/3
millisecond for a ferrite core device. A wood core device
yields about a 1/30 millisecond - rather short compared to the time
constant of a part like the KC003L NTC current limiter that
will be in the neighborhood of 10-100 milliseconds.
An inductive current limiter would be so fast compared to
the inrush time for a lamp filament as to offer little
assistance in mitigating the magnitude of inrush current.
>Oh! When choosing the wire size, do NOT go by the Mil-Spec wire size used in
>wiring the plane. I would DOUBLE that wire size.
Don't understand why. The current ratings for choosing wire
size from charts like those found in AC43-13 or chapter
8 of the 'Connection are already de-rated for 10C temperature
rise. The 6A lamp cited in the original post would not
seriously warm an inductor wound with 22AWG (5A rated) wire.
Bob . . .
Message 10
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Subject: | Static port on Dynon AoA probe |
--> AeroElectric-List message posted by: Ernest Christley <echristley@nc.rr.com>
This only has a cursory connection to electronics in airplanes, but I
still thought it would be the best place to ask.
The Dynon AoA probe doesn't have provisions for a static port. It was
designed with the expectation that the ports would be located on the
sides of the fuselage. That's not such a good location in a Delta. The
only flat space to put a port would be along the turtleback, aft of the
cockpit, which would put them deep inside of the wing's wake. The
readings would be all over the place. The plans location is for the
static probe to be low on the front leading edge, along with the pitot.
I have to build a mounting post for the Dynon probe (again, the
available mounting kits are designed for RVs, and don't match up to the
Delta's curves and angles) which is basically a streamline tube flaring
into the wing. I can see two options:
1) build another tube into the streamlined mounting post pointing forward
2) design ports into the side of the streamlined tube mounting post
The second option would look nicer and be aerodynamically cleaner (for
a sufficiently small value of aerodynamically clean). The question is,
where along the streamline crossection would I put the port in order to
reliably pick up static pressure? Would it be better to have a length
of flat section to put the ports in, and if so, how big would a flat
spot need to be? I'm making this mounting post from composite, so
complex shape isn't an issue.
--
,|"|"|, Ernest Christley |
----===<{{(oQo)}}>===---- Dyke Delta Builder |
o| d |o http://ernest.isa-geek.org |
Message 11
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--> AeroElectric-List message posted by: "glen matejcek" <aerobubba@earthlink.net>
B&B-
>...causing him to abort and go off the end of the runway (I'm sure his
>accelerate/stop distance was more than the runway length). If he had kept
>going on the takeoff he probably would have been able to rotate and get off
>the ground in the 3,500 feet he had. Bad day for all.
As I understand it, the plane did roll off the end of the rwy, became
airborne, and came down a mile off the end of the rwy.
>> He was probably still a little below V1
>But did he reach or pass Vrto?
You're probably thinking of V1.
If memory serves, the 2 rwys at LEX cross at about the highest point on the
field. That point is about mid field for the short rwy. The T/O roll
would climb about six feet to the apex of that rwy, which would decrease
normal accelleration, and then descend nine feet to the other end. In
pre-dawn dark, with light rain, one could not see the other end of either
rwy. One could speculate that once one was far enough down the rwy to see
the far end, and had enough time to go through the 'what the...' process,
there was no way to stop in the rwy remaining. Also, that particular rwy
is restricted to day vmc ops, and there seems to have been only one
controller on duty vs the 2 required by FAA policy. There's no telling
what other factors might be in the error chain.
A very sad day, indeed.
glen matejcek
aerobubba@earthlink.net
Message 12
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Subject: | Re: Is EFIS vulnerable at engine start? |
I don't have a Dynon yet - but based on my experience with the Chelton
Sport:
I would say "yes" you do want a separate power switch (for each screen),
and "no" you don't want it on during engine start (if the voltage causes it
to reboot).
My original design had the EFIS screens fused directly to the E-Bus
as I couldn't see a time when I would ever want to turn them off.
Turning the EFIS screens off is no big deal, but turning the
AHRS off and getting an in-flight restart was a big deal
when I had the Crossbow NAV425.
If I start with just one battery, the EFIS would stay on just fine.
If I cross-connect both batteries for the start, the starter would
spin a little faster, but both EFIS screens would usually reboot.
If the batteries were low - then using both batteries and not having two
EFIS
screens drawing a couple of extra amps each would be a nice option.
The Chelton doesn't have an ON/OFF switch on the EFIS, (or I haven't found
it ;-)
The other place it would be nice is if you're trying to shed some load.
I have two screens, but I can easily get by with one. Turning one off in
flight
wasn't an option before. And those screens DO put out the heat.
And finally - if one of the screens acted up & did something weird,
it would be nice to be able to shut it off to avoid the distraction.
So... for all these reasons, I plan on adding a power switch to each
EFIS screen. My current plan is to continue using fuses,
but add a DPDT ON-OFF-ON switch, possibly with a "guard".
With the guard down, it would be in the "normal ON" position and
connected to a fuse in the E-Bus. In the "center OFF" position
the screen would be off. In the "alternate ON" position with the guard up,
it would be connected to a different fuse directly on the main bus.
This gives me the ability to:
1) reboot just one screen
2) turn off one screen (to save power, heat, etc..)
3) take a "second shot" if the first fuse pops, by switching to the
"alternate ON"
4) gain back the voltage lost through the diode to the E-Bus (the second
fuse goes direclty to Bus1)
IF the battery is ever getting really, really, low - that last 0.4v might
make a difference.
The Chelton "small screens" run considerably warmer than the Dynon.
I've been flying with the Chelton's for over a year and my system is still
evolving.
One other thing I discovered is that my Grand Rapids EIS "fades out" long
before
the other screens stop running in a low voltage situation. It continues to
put out
valid engine data to the Chelton, but you won't be able to see it on the
EIS.
Consider what you would do if you smelled electrical smoke in the cockpit !?
Reaching over and shutting off the master switch might be overkill, or it
could
be your first choice. The airlines teach that once you've made the
situation
"survivable" you should usually stop troubleshooting.
Turning off the master switch in-flight needn't leave you clueless,
so my backup instruments include mechanical gages for:
airspeed, altimeter, VSI, compass, and MP. A battery backed Dynon
wouldn't be bad either!
Greg
Message 13
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Subject: | Re: Paralleled microphone circuits? |
--> AeroElectric-List message posted by: FLYaDIVE@aol.com
>My question is, "Can I connect my mike to both radios concurrently. I will
>have seperate PTT switches, so only one radio will transmit. I am not sure
>if the 2nd radio will load the mike too much, or will there be some other
>gotcha out there?
=========================================
It depends on HOW you hook up the PTT switch.
You do NOT want the MIC to be HOT in a parallel radio circuit. That would
change the MIC matching impedance of both radios.
But, if you switch in and out the MIC lines using a PTT switch that would
work.
In most cases the PTT switch ONLY keys ON the radio and does not switch in
and out the MIC. You may have to go to a small relay ... Point of Failure.
The problem as I see it is ... When you talk to yourself or yell at yourself
(as needed) you will NOT have any sidetone in the headset. Lucky it is a
single seater ;-)
Barry
"Chop'd Liver"
"Show them the first time, correct them the second time, kick them the third
time."
Yamashiada
Message 14
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Subject: | Re: Is EFIS vulnerable at engine start? |
FYI, the Dynon is set to come on when powered (mine is via fuse from the
e-bus). If it were necessary to turn it off for starting (not), a
simple push of the lower left button for 2 secs. turns it off.
Doug Windhorn
----- Original Message -----
From: Greg Campbell
To: aeroelectric-list@matronics.com
Sent: Thursday, 31 August, 2006 7:50
Subject: Re: AeroElectric-List: Is EFIS vulnerable at engine start?
I don't have a Dynon yet - but based on my experience with the Chelton
Sport:
I would say "yes" you do want a separate power switch (for each
screen),
and "no" you don't want it on during engine start (if the voltage
causes it to reboot).
My original design had the EFIS screens fused directly to the E-Bus
as I couldn't see a time when I would ever want to turn them off.
Turning the EFIS screens off is no big deal, but turning the
AHRS off and getting an in-flight restart was a big deal
when I had the Crossbow NAV425.
If I start with just one battery, the EFIS would stay on just fine.
If I cross-connect both batteries for the start, the starter would
spin a little faster, but both EFIS screens would usually reboot.
If the batteries were low - then using both batteries and not having
two EFIS
screens drawing a couple of extra amps each would be a nice option.
The Chelton doesn't have an ON/OFF switch on the EFIS, (or I haven't
found it ;-)
The other place it would be nice is if you're trying to shed some
load.
I have two screens, but I can easily get by with one. Turning one off
in flight
wasn't an option before. And those screens DO put out the heat.
And finally - if one of the screens acted up & did something weird,
it would be nice to be able to shut it off to avoid the distraction.
So... for all these reasons, I plan on adding a power switch to each
EFIS screen. My current plan is to continue using fuses,
but add a DPDT ON-OFF-ON switch, possibly with a "guard".
With the guard down, it would be in the "normal ON" position and
connected to a fuse in the E-Bus. In the "center OFF" position
the screen would be off. In the "alternate ON" position with the
guard up,
it would be connected to a different fuse directly on the main bus.
This gives me the ability to:
1) reboot just one screen
2) turn off one screen (to save power, heat, etc..)
3) take a "second shot" if the first fuse pops, by switching to the
"alternate ON"
4) gain back the voltage lost through the diode to the E-Bus (the
second fuse goes direclty to Bus1)
IF the battery is ever getting really, really, low - that last 0.4v
might make a difference.
The Chelton "small screens" run considerably warmer than the Dynon.
I've been flying with the Chelton's for over a year and my system is
still evolving.
One other thing I discovered is that my Grand Rapids EIS "fades out"
long before
the other screens stop running in a low voltage situation. It
continues to put out
valid engine data to the Chelton, but you won't be able to see it on
the EIS.
Consider what you would do if you smelled electrical smoke in the
cockpit !?
Reaching over and shutting off the master switch might be overkill, or
it could
be your first choice. The airlines teach that once you've made the
situation
"survivable" you should usually stop troubleshooting.
Turning off the master switch in-flight needn't leave you clueless,
so my backup instruments include mechanical gages for:
airspeed, altimeter, VSI, compass, and MP. A battery backed Dynon
wouldn't be bad either!
Greg
Message 15
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Subject: | downside of manual battery disconnects? |
--> AeroElectric-List message posted by: D Wysong <hdwysong@gmail.com>
Does anyone have any experience with the manual battery
disconnects that the hot rod folks use?
Has anyone heard any issues with corrosion or failures or
horror stories floating around about these things?
Are certain brands better than others?
Are any (for whatever reason) more suitable for aircraft use
than others?
Thanks for the insight!
D
Message 16
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Subject: | Re: GRT Wx Impressions |
--> AeroElectric-List message posted by: "gyoung" <gyoung@cs-sol.com>
Has anyone opened up the 396 power (cig lighter) cord to see if there are wires
in it for the data connections? I know I can buy a cord with bare wires that
has the power and serial connections but I'd like to maintain the cig lighter
plug for power. If the wires are in the one I have, I'll splice into them. Any
other alternatives?
Regards,
Greg Young
james(at)berkut13.com wrote:
> Thanks for the report Mike,
>
> Unfortunately, your friend must not have had the Garmin 430 and 396
> connected by the serial data line. The two units, if properly connected,
> will transfer the flight plans requiring only a single data entry in the
> 430. They also connect to the SL-30 radios to pre-select the frequencies as
> the flight progresses.
>
> Of course, if it's not plugged in...it will never work. ;-)
>
> James Redmon
> Berkut #013 N97TX
> http://www.berkut13.com
>
> ---
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=58764#58764
Message 17
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Subject: | Re: Static port on Dynon AoA probe |
--> AeroElectric-List message posted by: Brian Lloyd <brian-av@lloyd.com>
Ernest Christley wrote:
> 1) build another tube into the streamlined mounting post pointing forward
> 2) design ports into the side of the streamlined tube mounting post
If you examine the pitot tube on a Yak-52 or CJ6A you will find that the
static ports are in a ring around the pitot tube about 1" back from the
front. The whole assembly sticks out of the leading edge of the wing by
about 16". It works just peachy and the errors are minimal.
Brian
Message 18
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Subject: | Re: Static port on Dynon AoA probe |
--> AeroElectric-List message posted by: Kevin Horton <khorton01@rogers.com>
On 31 Aug 2006, at 09:38, Ernest Christley wrote:
> --> AeroElectric-List message posted by: Ernest Christley
> <echristley@nc.rr.com>
>
> This only has a cursory connection to electronics in airplanes, but
> I still thought it would be the best place to ask.
> The Dynon AoA probe doesn't have provisions for a static port. It
> was designed with the expectation that the ports would be located
> on the sides of the fuselage. That's not such a good location in a
> Delta. The only flat space to put a port would be along the
> turtleback, aft of the cockpit, which would put them deep inside of
> the wing's wake. The readings would be all over the place. The
> plans location is for the static probe to be low on the front
> leading edge, along with the pitot.
> I have to build a mounting post for the Dynon probe (again, the
> available mounting kits are designed for RVs, and don't match up to
> the Delta's curves and angles) which is basically a streamline tube
> flaring into the wing. I can see two options:
>
> 1) build another tube into the streamlined mounting post pointing
> forward
> 2) design ports into the side of the streamlined tube mounting post
>
> The second option would look nicer and be aerodynamically cleaner
> (for a sufficiently small value of aerodynamically clean). The
> question is, where along the streamline crossection would I put the
> port in order to reliably pick up static pressure? Would it be
> better to have a length of flat section to put the ports in, and if
> so, how big would a flat spot need to be? I'm making this mounting
> post from composite, so complex shape isn't an issue.
There is no reliable way to predict an exact probe profile and
location that will give an acceptable static source. I have been
involved with two projects that tried to chose locations for static
pressure ports. One project, on a type-certificated light aircraft,
used engineering analysis and experience to chose a static port
location. The chosen location had large errors, and the easiest
solution was to launch into a fly, fix, fly approach, using a
modified Piper pitot-static port. They kept on changing the angle on
the bottom of the Piper port until they found an acceptable
compromise. I recall that there were at least four configurations
tested, maybe more.
The other project, on a large business jet, had a much larger
budget. They used computational flow dynamics (CFD) computer
predictions to chose a static port location. The chosen location
produced such large errors at high angle of attack that the indicated
airspeed would stagnate as you approached the stall, then it would
start increasing as you got closer to the stall. It was fixed by
putting a very complicated correction curve in an air data computer.
Bottom line - the best bet is to copy exactly what someone else has
done, assuming they have a successful installation with acceptable
errors. If you start experimenting, the best chance of success is to
get the static port as far ahead of the wing as possible. Any
location near the wing is a recipe for trouble, as the wing's purpose
is to modify the local pressures to create lift, and a static port
needs to see the far-field ambient pressure. If you put a "roll your
own" system near the wing, expect to find large errors. If you enjoy
flight testing, this is a good thing, as it will keep you busy for
months doing fly, fix, fly.
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 19
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Subject: | Re: Is EFIS vulnerable at engine start? |
So... for all these reasons, I plan on adding a power switch to each
EFIS screen. My current plan is to continue using fuses,
but add a DPDT ON-OFF-ON switch, possibly with a "guard".
With the guard down, it would be in the "normal ON" position and
connected to a fuse in the E-Bus. In the "center OFF" position
the screen would be off. In the "alternate ON" position with the
guard up, it would be connected to a different fuse directly on the main
bus.
This gives me the ability to:
1) reboot just one screen
2) turn off one screen (to save power, heat, etc..)
3) take a "second shot" if the first fuse pops, by switching to the
"alternate ON"
4) gain back the voltage lost through the diode to the E-Bus (the
second fuse goes direclty to Bus1)
Greg
I am planning something similar, but some time ago I realized that when
one wants to go from "normal ON" to "alternate ON", or backwards, it is
not possible without rebooting the unit, since you will have to pass by
the central OFF position of the DPDT switch, which will cut power to
unit. How can this be solved?
I looked for a OFF - ON - ON switch but didn't find it. Does it exist?
Carlos
Message 20
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Subject: | Re: downside of manual battery disconnects? |
--> AeroElectric-List message posted by: <chaztuna@adelphia.net>
---- D Wysong <hdwysong@gmail.com> wrote:
> --> AeroElectric-List message posted by: D Wysong <hdwysong@gmail.com>
>
> Does anyone have any experience with the manual battery
> disconnects that the hot rod folks use?
>
> Has anyone heard any issues with corrosion or failures or
> horror stories floating around about these things?
>
> Are certain brands better than others?
>
> Are any (for whatever reason) more suitable for aircraft use
> than others?
>
> Thanks for the insight!
>
> D
D
I would suggest getting a brand name unit. The German made Hella brand is very
good quality. You can find them at your local marine supply store.
Charlie Kuss
Message 21
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Subject: | Re: Alternator Switching |
--> AeroElectric-List message posted by: Kelly McMullen <kellym@aviating.com>
Your 1960 Mooney came with a generator and a single master switch, so
there was no choice but to have the whole bus active during start.
Generators could care less whether the master is on or off. Of course,
it didn't have an avionics master either.
Do Not Archive
Quoting Dave N6030X <N6030X@DaveMorris.com>:
> --> AeroElectric-List message posted by: Dave N6030X <N6030X@DaveMorris.com>
>
> My scratch-built Dragonfly did not come with a POH. And my 1960 Mooney
> POH doesn't tell me what order to switch them on either. I suspect
> most of the people on this list are building experimentals and will be
> WRITING the POH.
>
> Dave
>
> At 09:08 AM 8/30/2006, you wrote:
>> Repeat: FOLLOW THE CHECKLIST AS DESIGNED BY A TEAM
>> OF ENGINEER'S (who have covered all bases) AND IS APPROVED
>> BY THE FAA. If experimental try to follow industry standards, which
>> is: ALT on before start, ALT off after shutdown. Simple.
>
>
Message 22
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Subject: | Re: Is EFIS vulnerable at engine start? |
--> AeroElectric-List message posted by: Nancy Ghertner <nghertner@verizon.net>
On 8/30/06 9:10 PM, "gert" <gert.v@sbcglobal.net> wrote:
> --> AeroElectric-List message posted by: gert <gert.v@sbcglobal.net>
>
> begs the question, what about the current crop of electronic engine
> instruments, ya all keep them off till u engine is running.
> What good are they if u can't have them on during engine start ;-)
> so u wait till the engine is running, switch u electronic instruments on
> to discover u have no oil pressure, oops....somehow i don't think i want
> Blue Mountain to check my oil pressure if i have to have their system
> off during engine start.
>
> A DeMarzo wrote:
>> And I think that I would spring for a $10 switch as just a tiny bit
>> more protection on my $3000 instrument.
>>
>> Spikes Happen
>>
>> Al
>> General Aviation - Pricing People Out Daily
>>
>>
>>
>> On 08/30/2006 7:56:01 AM, Bill Denton (bdenton@bdenton.com
>> <mailto:bdenton@bdenton.com>) wrote:
>>> Dynon disagrees...
>>>
>>> The following exchange came from
>>> Dynon's message board:
>>>
>>> Question: "I've just installed my D10A and as
>>> advised in the instructions wired it through a 2 amp fuse. Since I
>>> didn't order the internal battery, I did not connect the "stay
>> alive" wire and also did not install a separate power switch. The unit
>> comes on when I turn on the master switch without my pressing the unit's
>>> power button. I assume this in normal, but can I have problems with
>> power
>>> spikes during engine start? Should I install a separate power switch in
>>> the Dynon circuit? If not, should I turn off the EFIS before engine
>>> start?"
>>>
>>>
>>> Answer, from Dynon Support:
>>>
>>> "The EFIS is indeed
>>> designed to come alive when power is applied.
>>>
>>> Many customers install the EFIS in exactly the same electrical
>>> configuration you have set up. The unit will not be damaged by having it
>>> on during engine start, but it may reboot if the voltage momentarily
>> drops
>>> below 10V.
>>>
>>> Also, since you did not purchase the internal battery, you may want to
>>> connect the keep alive wire to power the clock when your master
>> switch is
>>> off. Otherwise it will reset after every power
>> *
>>
>>
>> *
You can hook up a back up battery either for the Blue Mountain alone with a
diode in the circuit available on their website, or as I am doing use the
back up battery for the emergency bus to power up the efis before start up.
Lory Ghertner
Message 23
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Subject: | Re: in-rush limiters |
In a message dated 8/31/2006 8:53:53 A.M. Eastern Daylight Time,
nuckollsr@cox.net writes:
Don't understand why. The current ratings for choosing wire
size from charts like those found in AC43-13 or chapter
8 of the 'Connection are already de-rated for 10C temperature
rise. The 6A lamp cited in the original post would not
seriously warm an inductor wound with 22AWG (5A rated) wire.
Bob . . .
Bob,
When wire is wound in a transformer or choke, the density of the power loss
is much greater than even in a bundle of wires. A typical design value is
500 to 1000 circular mils per amp. Solid number 22 wire is 25.3 mils in
diameter and has about 643 circular mils. Therefore it is only rated for about
1
amp when wound in a multi layered coil. Operating a number 22 enamel wire at
5 amps continuously when it is tightly surrounded by more number 22 enamel
wire also carrying 5 amps would cause it to overheat.
Dan Hopper
Retired electrical engineer and transformer nut.
Message 24
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Subject: | Re: in-rush limiters |
Bob,
Sorry, after rereading all the posts on this subject, I made a wrong
assumption in writing the reply below. The reply still is correct, but probably
not
applicable.
Dan
In a message dated 8/31/2006 7:54:57 P.M. Eastern Daylight Time,
Hopperdhh@aol.com writes:
In a message dated 8/31/2006 8:53:53 A.M. Eastern Daylight Time,
nuckollsr@cox.net writes:
Don't understand why. The current ratings for choosing wire
size from charts like those found in AC43-13 or chapter
8 of the 'Connection are already de-rated for 10C temperature
rise. The 6A lamp cited in the original post would not
seriously warm an inductor wound with 22AWG (5A rated) wire.
Bob . . .
Bob,
When wire is wound in a transformer or choke, the density of the power loss
is much greater than even in a bundle of wires. A typical design value is
500 to 1000 circular mils per amp. Solid number 22 wire is 25.3 mils in
diameter and has about 643 circular mils. Therefore it is only rated for about
1
amp when wound in a multi layered coil. Operating a number 22 enamel wire at
5 amps continuously when it is tightly surrounded by more number 22 enamel
wire also carrying 5 amps would cause it to overheat.
Dan Hopper
Retired electrical engineer and transformer nut.
(http://www.matronics.com/Navigator?AeroElectric-List)
(http://www.matronics.com/contribution)
Message 25
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Subject: | Re: Is EFIS vulnerable at engine start? |
--> AeroElectric-List message posted by: "glaesers" <glaesers@wideopenwest.com>
----------------------------------------------------------------------------
----------------------------
I am planning something similar, but some time ago I realized that when
one wants to go from "normal ON" to "alternate ON", or backwards, it is
not possible without rebooting the unit, since you will have to pass by
the central OFF position of the DPDT switch, which will cut power to
unit. How can this be solved?
I looked for a OFF - ON - ON switch but didn't find it. Does it exist?
Carlos
----------------------------------------------------------------------------
---------------------------
The switch you are looking for is the Master Switch that B&C sells (the
S-10 - $19.50).
See:
http://www.bandc.biz/cgi-bin/ez-catalog/cat_display.cgi?11X358218#s700-2-10
This is a double-pole switch, which may be more than you need, but getting a
single pole version will be a $pecial order item from someplace like Digikey
or Mouser or OnlineComponents and probably take a while to get.
Dennis Glaeser
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