Today's Message Index:
----------------------
1. 07:47 AM - Re: Plane Power's Friendly Warning Light (Robert L. Nuckolls, III)
2. 08:00 AM - Critique please Bob and other learned members (John Cleary)
3. 12:50 PM - Re: Plane Power's Friendly Warning Light (Corrected Link) (Robert L. Nuckolls, III)
4. 05:40 PM - Re: "Coat Hanger" antenna ()
5. 07:22 PM - Request for Bob N. (nauga@brick.net)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Plane Power's Friendly Warning Light |
At 09:46 PM 3/10/2008 -0700, you wrote:
>B&C's flashing warning light is pretty annoying, so I was glad to see
>Plane Power's light is a steady, happy glow.
If I recall correctly, the Plane Power warning
light drives from the alternator fail output of
the built-in regulator. While certainly better than
no light, it's not an independent monitor of
alternator/regulator performance.
You might consider a separate LV Warning
system that flashes the light.
>
>Trouble is, it turns out, that the annoying flash is pretty handy when you
>really need to see it...no equipment failures to report, just didn't use
>the checklist...twice >:-(
Yup, when we crafted that system the flash rate
was set at approx 3 flashes per second. Supposedly
this is the rate most 'irritating', i.e. attention
getting for cockpit warning lamps.
Bill also supplied a 6v lamp for the 14V regulators
to increase intensity of the lamp for sunlight viewability.
>
>So, does anyone have a suggestion as to how to wire a flasher into the PP
>light? Can I just use a simple automotive flasher, or do I need something
>designed for less current? I want a fairly high (annoying) flash rate.
The simplest method for adding flashing to
an existing lamp circuit is by means of a "two-wire
lamp flasher". There are a number of variations
on the theme. One such circuit is illustrated here:
http://www.aeroelectric.com/Pictures/Schematics/Lamp_Flasher_1.pdf
This circuit should be assembled with a C-Mos
version of the ubiquitous 555 timer. In this
case, the Intersil ICM7555 is called out.
This flasher will deliver a symmetrical ON-OFF
flash pattern at approx 3Hz.
An alternative is shown at:
http://www.aeroelectric.com/Pictures/Schematics/Lamp_Flasher_2.pdf
This is built from more generic discrete parts
and can probably be made to do what you want to
accomplish although its not likely to be a
symmetrical pattern.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Critique please Bob and other learned members |
Bob,
First, thank you for your outstanding contribution to the OBAM
community,
especially for the AeroElectric Connection, this email list, and the
sample
wire book which we have used to craft our design. We are building an all
electric panel, IFR RV-10, and in the development of our thoughts and
knowledge about and around our electrical design, your input, and that
of
the other learned people on this email list, have been invaluable. You
have
all helped us move from a position of zero knowledge to a position where
we
now have some idea of what questions to ask.
We struggled around Z-14, Z-13/8 and finally Z-12 to settle on our
current
design, and we would welcome comments from you and others on any aspect
of
our design, but especially on the specific question areas noted below.
Our mission is cross country flight with IFR capability, mostly with two
POB
and the ability to take large amounts of luggage as we tour Australia.
We concluded that the alternator was the unit with the highest
probability
of failure in service and decided early on that we would go with 2
alternators.
We have calculated that we have added about 55 lb to the basic VANs
design
empty weight, primarily in the panel, console, overhead console, second
alternator and second battery. We have elected to maintain design gross
weight which limits baggage in the baggage compartment to 45lb
95% of the time my wife and I will fly in the front seats. We are both
light
by VANs standards, and that combination plus the added weight indicated
a
need to move some weight forward. We have decided to go with 2 PC680
batteries instead of the standard battery, and the W & B works out
theoretically perfect with the second battery relocated forward in the
centre console. The console battery, power buss and power switches are
all
co-located in the centre console with a spark isolation barrier between
the
electrical switches and the fuel system.
This is a long introduction, but necessary I think for you to understand
why
we have gone the way we have.
We began by trying to fit Z14 to our perceived needs, then Z13/8. The
electrical load analysis shows that in IFR conditions with the pitot
heater
on, we will draw about 17 amps continuous on the power circuit and also
on
the combined endurance and avionics circuits. The max/intermittent draw
on
each circuit is about 37 amps. We weren=92t happy with either of these
being
loaded onto the 20 amp system as part of normal operations, especially
if
that system was to be our endurance circuit. Z14 and Z13/8 also both
required that we run an extra fat wire back to one of the batteries.
Our decision finally was that we should concentrate on designing the
system
for robust normal operations with the minimum parts count for
reliability,
weight and cost reasons, and make the back up systems as simple as
possible.
We decided to go with a modified Z12 design because it keeps the noisy
wires
firewall forward and away from the panel, it uses one less contactor to
use
both batteries to crank the engine, the day to day loads are left with
the
larger alternator, and there is one less fat wire needed when the
batteries
are down the back. Normal operations will be to run with both battery
contactors energised, the main alt on, the endurance and avionics busses
fed
from the main buss, and the aux alt resting on standby.
Failure modes would be treated as follows:-
Main alt failure - turn off main alt, turn on aux alt and
adjust
loads to suit
Much less likely failures:-
Main battery contactor fails closed in flight ' no action
needed
till landed
Main battery contactor fails open in flight ' The alternator
load
is balanced by the aux battery which needs to be always on in flight.
The
main battery relay can be opened to bring the main battery back on line
Aux battery contactor fails closed in flight ' no action
needed
till landed
Aux battery contactor fails open in flight ' No action
necessary,
but aux relay can be opened if desired
Both alts fail ' Open main or aux battery relay to run min
endurance load approx 3.5A. Close main and aux batt contactors to
conserve
power for landing phase
Fuse link between power buss and endurance buss blows ' Open
main
or aux batt relay to feed endurance and avionics busses
Alternators:- We plan to go with the Plane Power 60A alternator for the
main
alt, primarily because of its inherent simplicity from an installation
and
operations perspective. We plan to leave the aux alt turned off unless
the
main alt fails, which means it should rarely get used. The SD 8 seems
perfectly designed for this task and there is about a 3 lb penalty with
the
SD 20, but the SD 20 will give better peace of mind should the main alt
fail
in IMC. So, we plan to go with the SD-20 subject to your critique, and
this
leads us to our first question:- Is it OK to leave the SD 20 installed
but
not running? Will this cause any problems with the SD 20? Are the
generic
ford regulator and OVM adequate and appropriate to this task with the SD
20?
Power supply to the alternator fields:- Do you have any concerns with
the
alt fields supplied as depicted ' ie main alt field via 22AWG fuseable
link
through 18AWG wire to the 5A CB, then 20AWG to switch and the main alt
field. Does it matter which side of the switch the CB goes in this case?
Would a 5A SCB be better?
Ground system:- We plan to use your forest of tabs either side of the
firewall for everything on the panel and firewall forward, with the
engine
crankcase grounded to the through firewall stud. We have nominated local
grounds for items such as landing lights, pitot heater, etc. We think we
should ground both batteries locally. Is this correct, or should we
handle
battery grounds some other way with this design?
Fuse tray:- Are there any risks in placing the endurance buss, avionics
buss, regulator and OVM in close proximity to each other on a hinged
fuse
tray under the panel? Is there a preferred way to connect the two busses
together when in such close proximity?
We currently plan not to fit the diode between the main buss and the
endurance buss because the SD 20 gives us the time needed to
systematically
reduce loads as needed should the main alt fail. Do we create any
problems
for ourselves not having an isolation relay or diode between the main
buss
and the endurance buss?
Bob, in appendix Z you comment that the ACS-OFF-L-R-BOTH-START keyswitch
is
not suitable for electronic ignition. I have also read somewhere that if
you
use this switch with an electronic ignition you disconnect the ground at
the
back of the switch. We are confused on this matter, so would you please
explain whether you can use this switch or not with a future electronic
ignition, and what you have to do to make it work properly? If it
can=92t be
used, would you please explain what problem it causes? Do the same
issues
apply with the potential future installation of a Pmag?
Bob and others, we thank you for the time you take to look at our
design,
which is a works in progress. We will value any comments you care to
make.
John and Jenny Cleary and Peter Bowman,
Australia
Canopy and doors 90% done and 90% to go
Trying to finalise the wiring plan so we can drill the holes and fit the
cable attachments prior to painting inside
Checked by AVG.
10/03/2008
11:07 AM
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Plane Power's Friendly Warning Light (Corrected |
Link)
At 08:42 AM 3/11/2008 -0600, you wrote:
<nuckolls.bob@cox.net>
At 09:46 PM 3/10/2008 -0700, you wrote:
B&C's flashing warning light is pretty annoying, so I was glad to see Plane
Power's light is a steady, happy glow.
If I recall correctly, the Plane Power warning
light drives from the alternator fail output of
the built-in regulator. While certainly better than
no light, it's not an independent monitor of
alternator/regulator performance.
You might consider a separate LV Warning
system that flashes the light.
Trouble is, it turns out, that the annoying flash is pretty handy when you
really need to see it...no equipment failures to report, just didn't use
the checklist...twice >:-(
Yup, when we crafted that system the flash rate
was set at approx 3 flashes per second. Supposedly
this is the rate most 'irritating', i.e. attention
getting for cockpit warning lamps.
Bill also supplied a 6v lamp for the 14V regulators
to increase intensity of the lamp for sunlight viewability.
So, does anyone have a suggestion as to how to wire a flasher into the PP
light? Can I just use a simple automotive flasher, or do I need something
designed for less current? I want a fairly high (annoying) flash rate.
The simplest method for adding flashing to
an existing lamp circuit is by means of a "two-wire
lamp flasher". There are a number of variations
on the theme. One such circuit is illustrated here:
http://www.aeroelectric.com/Pictures/Schematics/Lamp_Flasher_1.pdf
This circuit should be assembled with a C-Mos
version of the ubiquitous 555 timer. In this
case, the Intersil ICM7555 is called out.
This flasher will deliver a symmetrical ON-OFF
flash pattern at approx 3Hz.
An alternative is shown at:
http://www.aeroelectric.com/Pictures/Schematics/Lamp_Flasher_2.jpg
(was .pdf)
This is built from more generic discrete parts
and can probably be made to do what you want to
accomplish although its not likely to be a
symmetrical pattern.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: "Coat Hanger" antenna |
>From: "Robert L. Nuckolls, III" <nuckolls.bob@cox.net>
>Subject: Re: "Coat Hanger" antenna
>>At 07:59 AM 3/8/2008 -0800, you wrote:
>>No offense to Ernest or Bob, the old coat hanger
>>antennas that you terminated the coax with crimp on
>>lugs has not been used in production airplanes since
>>the 50's or early 60's.
>>
>>Coat hanger antenna
>><http://www.aircraftspruce.com/catalog/avpages/av534.php">http://www.aircraftspruce.com/catalog/avpages/av534.php>http://www.aircraftspruce.com/catalog/avpages/av534.php
>>
>>What Eric says about "EM field energy", which I recall
>>bits from physics and armature radio, the coax,
>>BNC connector is way more efficient. That inch of
>>exposed shield/core & important lost insulation does
>>count. The "coat hanger antenna connections are
>>subject to corrosion and fatigue way more than a BNC
>>connector. Just my opinion.
>But without quantification. The advantages of the
>modern antennas are mainly mechanical. They don't
>twist in the insulator. In high-dollar models there
>are p-static immunities due to the DC grounded
>fabrication . . . and they look sexier and have lower
>maintenance costs.
Bob its more than sexy it is indeed that last inch of exposed
dielectric, often close to some conductive material, even
in a composite plane (don't they need a ground plane for a 1/4
wave dipole?) that is the issue, at least to me.
>>No one is seriously using the coat hanger wire antenna
>>on new OEM aircraft any more.
>for the reasons stated plus some others but
>none related to observable performance.
Bob I have to take your word for it. However in my experience
I have seen these antennas SRW go up and up and up with time
because of dissimilar metal corrosion and bad crimps. Like I
said most pilots only demand short range line-O-sight
communication, not DX comm. The term observable
performance should include maintenance and durability in
my humble opinion.
>>"Testimonials" that they work in the plane or bench are
>>great, but unless you do a test on the airframe in an
>>antenna test chamber (EMF / RF anechoic chamber),
>>we are guessing. Besides performance there is the
>>reliability of the installation.
>>
>>Just from an installation standpoint, spend the $124
>>for the real antenna and leave the $50 coat hanger
>>antenna for the closet. Antenna energy, non-ionizing
>>radiation is EMF energy at high frequencies. It needs
>>"ducting" to be most effective.
>>
>>???? don't know what this "ducting" stuff is.
Well Wikipedia to the rescue:
http://en.wikipedia.org/wiki/Coaxial_cable
I use the word "ducting" in an informal way to describe how
a coaxial cable propagates elect mag wave energy.
"Coaxial lines solve this problem by confining the
electromagnetic wave to the area inside the cable,
between the center conductor and the shield. The
transmission of energy in the line occurs totally through
the dielectric inside the cable between the conductors."
"ducting" - was a casual my way of describing how coaxial
propagates EMW. Where open wire transmission lines, like
you have that inch before the "coat hanger" antenna, two
parallel wires, have the property where the electromagnetic
wave propagating down the line, extends into the space
surrounding it, an undesirable characteristic. You say the
loss is small? OK I guess, sure but every little bit helps
or hurts. The fact is radios are so good with filters and
excellent sensitivity and stability, a less than optimal
antenna can be some what tollerated.
>>Does the "strip-it crimp-it" antenna connection work?
>>Yes it "works", but gosh ughaaa, ugly.
>>
>>We're talking about 5-8 watts of energy and communications
>>of 5 to 50 mile, line of sight, listening for even more powerful
>>transmitters, usually without obstacles. We can get away
>>with a weak antenna.
>"Weak" is un-quantified. However, just like concerns about
>"iron poor blood" it may help sell alternative antennas.
True it is unqualified, but we could get into dB or signal strength,
but all I am saying is in Aviation we are talking about strong
signals at short distances, most of the time, period. However if
you want real long range communications at distance than it
does matter. Yes "matter" is an unqualified term as well.
>>The coat hanger works, but its not ideal. We have better
>>ways. If I was restoring a classic Beech or something, yea
>>I'd keep the coat hanger antenna. Other wise coat hangers
>>are for the closet (pun intended).
>>
>>$110-$150 for newer antenna design
>><http://www.aircraftspruce.com/catalog/avpages/av17.php">http://www.aircraftspruce.com/catalog/avpages/av17.php>http://www.aircraftspruce.com/catalog/avpages/av17.php
>>
>>PS: Some have experienced RFI with unshielded antenna
>>connections thru gauges and avionics.
>Now this IS a potential effect because the little
>chunk of antenna inside the aircraft is indeed a
>radiator.
So true Bob.
>However, in the age of plastic airplanes (both experimental
>and T/C) and reasonable adherence to DO-160 radiated
>and conducted susceptibility issues, potential victims
>are not going to go T/U due to the small increase in
>energy at the panel due to errant radiation. Field
>strengths for your VHF comm. while transmitting are really
>strong in the cockpit (tens of volts per meter) even
>with idealized antenna installations.
>
>Bottom line is that we're fabricating OBAM aircraft.
>Yes, there are sexier, more convenient and probably
>more 'efficient' antennas to be considered over the
>stone-simple, rod and feed-thru insulator antennas
>that were quite popular 40 years ago. It all comes
>down to the builder's preferences for trading his/her
>personal expenditure of $time$ versus purchasing
>the product of someone else's $time$ for a more
>sophisticated design.
Well sexier I guess, but cost is only times 2 and when you
have a $1000 or $3000 radio, $60 more is a drop in da bucket.
>Performance risks for going the low-dollar, DIY
>route are low and easily managed.
>
>Bob
Well I guess we disagree with the last part, but I agree
making antennas and testing them is FUN! VHF on a plane
is pretty easy, and I have no problem with a DIY, however
as I said in my opinion, if you are going to buy an antenna,
like most builders, get a $120 antenna with a BNC connector.
My focus is all towards metal planes, composites have more
flexibility to experiment with internal antennas.
A BNC will be more secure & robust. You can have BNC
problems and other issues, but keeping the coaxial cable
intact to the last inch, is not totally trivial.
With a composite plane the connection will be on the "back
side of the ground plane? Right? There will be signal loss and
reflected RF into the airplane, IMHO.
Good discussion. The proof is in the eating of the pudding.
Fly a plane with both antennas and test them against a
ground station for both TX and RX. I think you will see a
difference in one antenna getting a weak incoming signal
and getting out a stronger signal. Of course bent whips
are a compromise. The radiating element should be as
perpendicular to the ground plane as possible but most
pilots like the looks and lower drag of the bent whip for a
little more SRW. Also the "Blade" high speed antennas
have "wider" band width. There are good enough antennas
and better, best antennas. It is definitely esoteric but for
just secure connection the BNC has it over the crimp
and screw exposed twin lead approach, at least in the
VHF band of freq's, in my opinion. Old ways are still
good but there is a reason new methods & connections
where developed. It may take more sensitive lab equip
to notice but I can't believe it makes NO difference, but
than you say you tested it, and I have not. All I can go
by is when trouble shooting poor radio performance on
old planes, the first place I look is at those old corroded
connections on the "coat hanger".
Cheers George
---------------------------------
Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Request for Bob N. |
Bob, I have not been able to reach you through direct e-mail or the message area
of your website (multiple attempts both ways) - can you check on the status
of an order for me?
Dave 'Nauga' Hyde
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|