---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 03/11/08: 5 ---------------------------------------------------------- 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 _____________________________________ Time: 07:47:08 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: 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 _____________________________________ Time: 08:00:14 AM PST US From: "John Cleary" Subject: AeroElectric-List: 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 _____________________________________ Time: 12:50:53 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Plane Power's Friendly Warning Light (Corrected Link) At 08:42 AM 3/11/2008 -0600, you wrote: 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 _____________________________________ Time: 05:40:30 PM PST US From: Subject: AeroElectric-List: Re: "Coat Hanger" antenna >From: "Robert L. Nuckolls, III" >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 >> >>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 >> >>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 _____________________________________ Time: 07:22:39 PM PST US From: "nauga@brick.net" Subject: AeroElectric-List: 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 ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.