---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 06/19/07: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:06 AM - Re: Regulator trouble? Probable resolution (Ed) 2. 12:46 AM - Loadmeter vs Battery Ammeter? (Deems Davis) 3. 07:17 AM - Re: Loadmeter vs Battery Ammeter? (Robert L. Nuckolls, III) 4. 08:16 AM - Fusible Link Connector (Bill Schlatterer) 5. 09:06 AM - VOR/GS Antenna () 6. 09:13 AM - The importance of "good" numbers . . . (Robert L. Nuckolls, III) 7. 09:35 AM - Re: VOR/GS Antenna (Richard Dudley) 8. 10:06 AM - Re: Fusible Link Connector (Robert L. Nuckolls, III) 9. 10:13 AM - Re: Low Voltage plus Alt Loadmeter (Deems Davis) 10. 10:52 AM - Re: VOR/GS Antenna (earl_schroeder@juno.com) 11. 03:37 PM - Re: VOR/GS Antenna (Robert Feldtman) 12. 05:25 PM - Re: VOR/GS Antenna (BobsV35B@aol.com) 13. 11:13 PM - RTV sealants (Harold Kovac) ________________________________ Message 1 _____________________________________ Time: 12:06:23 AM PST US From: Ed Subject: Re: AeroElectric-List: Regulator trouble? Probable resolution I've been e-mailing with Tim over at B and C (very helpful guy) and here's what I just sent him: Howdy Tim, I checked it out using your troubleshooting guide. Results: Resistance from batt neg to pin 7 0.0 - 0.1 ohms batt to engine case 0.0 - 0.1 ohms Buss volts 12.42 volts Pin 3 12.33 - 12.40 v (several measurements) Pin 6 12.07 v Pin 4 11.02 v Field terminal 10.86 v B lead 12.42 v Everything seemed pretty nominal until I was trying to get a probe into the field connector on the alternator where I noticed the field wire looking a little frayed. A very small tug removed it entirely. The wires had no support for the insulation, just the crimp on the wire itself which is where it broke. My theory: The connection would intermittently not conduct too well and the output voltage on the B lead would drop. The regulator would respond by pushing the field voltage up and when the connection got better again, the alternator output voltage would surge in response to the high field voltage and trip the OVM. Logical? I put some heat shrink on the wires to give them some support and reassembled. Started but not yet flown. I expect that the problem is solved. Time will tell. If inflight voltage stabilizes at less than 14.4, I guess I'll have to crawl under the panel and reset it. What's the ideal voltage for charging an RG battery? Thanks for help. Ed Holyoke Thanks for all the advice. If it misbehaves again, I'll let y'all know. Robert L. Nuckolls, III wrote: > > > At 12:18 PM 6/18/2007 -0400, you wrote: > >> >> I have a slightly different take on this as it seems there might >> already be some clues here. >> >> Shouldn't the field voltage go above 8 volts when the alternator is >> loaded on the ground. If it is putting out less that 14.4 volts at >> low rpm - why isn't the field voltage up around 12 or 13? High >> resistance somewhere in the field? > > > The voltage will go that high only if one approaches the alternator's > maximum available output current for that RPM. In this case, he cites > a 17A load and ramp idle RPM. > >> Next I'd want to know why 14.7 volts while taxiing in. Is the >> regulator voltage going up when it is hot? Does it not throttle back >> far enough under light load? Is there a connection that is high >> resistance when hot such that the regulator is sensing 14.4 but >> putting out 14.7 upstream where the voltmeter is located? Or is it an >> inaccurate voltmeter? > > > There's a ton of variables which can stack up to push the setpoint > around a bit . . . what we're interested in finding is an instability > that accounts for the nuisance trip of an OV protection system set to > operate at 16.2 volts or so. > > >> If the connections have already been checked, I'd be tempted to >> temporarilly wire in a cheap regulator and see what happens. > > > A cheap regulator wouldn't have the ov protection built in. It > WOULD be a useful experiment to temporarily wire in a substitute > regulator and a separate OV sensor. I think I've got some hardware > laying around we can send him if we don't see something really > profound . . . or he's unable to observe a field and bus voltage > surge associated with the nuisance trip. > > Bob . . . > > ________________________________ Message 2 _____________________________________ Time: 12:46:38 AM PST US From: Deems Davis Subject: AeroElectric-List: Loadmeter vs Battery Ammeter? Warning this question is posed by an electron nerd.... I'm planning the installation of probes & sensors for a Z14 architecture. The Z-14 Figures in the 'Connection' seem to depict the shunts placed for use as 'loadmeters' i.e. they are placed on the Alternator B lead (which will measure Alt charging only). In reviewing Bob's notes. He favors a Battery Ammeter, the rationale seems to be that it measures both charging and discharging of the battery/s. This seems desirable to me. However, I'm stumped as to where to locate the Shunts in the Z-14 so as to be able to connect Battery ammeters. How about some help? Deems Davis ________________________________ Message 3 _____________________________________ Time: 07:17:49 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Loadmeter vs Battery Ammeter? At 12:41 AM 6/19/2007 -0700, you wrote: > >Warning this question is posed by an electron nerd.... > >I'm planning the installation of probes & sensors for a Z14 architecture. >The Z-14 Figures in the 'Connection' seem to depict the shunts placed for >use as 'loadmeters' i.e. they are placed on the Alternator B lead (which >will measure Alt charging only). In reviewing Bob's notes. He favors a >Battery Ammeter, the rationale seems to be that it measures both charging >and discharging of the battery/s. This seems desirable to me. The Z-figures represent the latest thinking with respect to the optimal solutions. The chapter on electrical instrumentation was written a long time ago and will be updated at revision 12. If you have only one electrical system monitor, it should be a low voltage warning light. If you add anything on top of that, I'd recommend an expanded scale voltmeter on the e-bus and/or alternator loadmeter(s) . . . but both of those are only small peeks at a variety of test points you'll need to look at for diagnosis. Ammeters and voltmeters are poor monitoring tools. And as diagnostic tools, they are only a part of what's necessary for troubleshooting. >However, I'm stumped as to where to locate the Shunts in the Z-14 so as to >be able to connect Battery ammeters. What kind of panel displays are you considering? If they're steam-gages, then they'll likely use shunts but if they're electronic displays, they'll most likely come with hall-effect sensors. Hall sensors can be place ANYWHERE in the system that you think is most useful to you for knowing how many electrons per second are passing that point . . . however, adding shunts in series with the battery as suggested in Chapter 7 is based on wobbly logic and poor practice. However, a hall-sensor can certainly be placed on a battery lead if you so choose. A caveat on battery lead hall-sensors. When the starter hits the battery with an inrush current of as much as 1000 amps, the magnetic forces impressed upon the hall sensor are, shall we say, significant. The hall sensor MUST (by certain pesky laws of physics) be fitted with a core material that serves to restrain the field flux around the wire and supply a proportional sample of that field to the hall device. EVERY magnetic material has a retentivity value . . . a measure of permanent "set" that the core material will take on when excited by an extra-ordinary force. Depending on the materials used in your hall sensor, the act of starting the engine can cause a small but significant semi-permanent "set" of the field flux in the core. This will manifest itself as what is known as "offset" . . . a fixed error value that shows up most strongly when the stimulus to be measured is zero . . . the indicator reads something other than zero due to the core's retentivity and influence of the starter inrush current. Based on this expanded thinking, recommendations for ammeter locations were revised to what you have in your hands today. Without knowing more about the specifics of any hall-sensor that may be supplied to you, I cannot recommend that they be used as battery ammeters EXCEPT where you avoid running starter current through the conductors. This means backtracking to the architecture common in 1965 C-172. The best I know how to do at the moment suggests that active notification of low volts is #1. A voltmeter on the e-bus (gas gage for battery during alternator out operations) is #2. Items 3 and higher have little or no significance in the OPERATION of your airplane . . . so sprinkle sample and display items about your electrical system as you see fit and you budget allows. Just understand that items 3 and higher offer no useful functions in flight and there won't be enough of them to do a detailed troubleshooting study on the ground. Bob . . . ________________________________ Message 4 _____________________________________ Time: 08:16:18 AM PST US From: "Bill Schlatterer" Subject: AeroElectric-List: Fusible Link Connector Is there any reason that you shouldn't use a soldered connection instead of an inline connector in a fusible link? Would the solder go before the wires unlike the solid inline connector? It would just make it a little cleaner looking. Thanks Bill S 7a Z13/8/30/32 ________________________________ Message 5 _____________________________________ Time: 09:06:50 AM PST US From: Subject: AeroElectric-List: VOR/GS Antenna Can anyone explain why some VOR "cat whisker" antennas are mounted with the open end of the 'V' facing forward and some facing aft? Is there a difference in reception quality and/or drag characteristics? Secondly, is the polyester lamination over the steel for improved precipitation static protection worth an extra $60? Thanks for any answers posted. TPackard --- http://USFamily.Net/dialup.html - $8.25/mo! -- http://www.usfamily.net/dsl.html - $19.99/mo! --- ________________________________ Message 6 _____________________________________ Time: 09:13:01 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: The importance of "good" numbers . . . I've often cited a simple-idea proffered by one Lord Kelvin http://www-groups.dcs.st-and.ac.uk/~history/Printonly/Thomson.html of whom it might be said, "Was obsessed with the ideas behind accurate measurement." One of my favorite Kelvin quotes: "I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind. It may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be." - Lord Kelvin We all have at least a rudimentary appreciation for the value of having accurate numbers to describe the function of our aircraft. One can easily deduce the potential for expense and/or hazard if an airspeed indicator is badly out of calibration . . . or perhaps an altimeter, a gyro, etc. In many cases, the gathering and consideration of poor numbers can have an incomprehensible effect on the lives and fortunes of millions. This is especially true when pseudo-scientists come to the attention of legislators and craft law based on poor interpretation of poor numbers. With these thoughts in mind, consider the facts and ideas presented at: http://www.norcalblogs.com/watts/weather_stations/ There are folks belabored of the assumption that data from these weather stations (and no doubt MANY more like them) is accurate to within a tenth of a degree. What do you think? Something to arm yourself with should you have a chance to speak to your own representatives who may be inclined to bring the force of law down upon your future and that of your children. Bob . . . ---------------------------------------- ( "Physics is like sex: sure, it may ) ( give some practical results, but ) ( that's not why we do it." ) ( ) ( Richard P. Feynman ) ---------------------------------------- ________________________________ Message 7 _____________________________________ Time: 09:35:48 AM PST US From: Richard Dudley Subject: Re: AeroElectric-List: VOR/GS Antenna TPackard, I have been told that the orientation is a matter of preference though the reception pattern ahead is slightly better with the tips pointing forward. I think many prefer the appearance with the tips pointing aft. (looks more aerodynamic:) Richard Dudley -6A flying (with tips pointing aft) jtpackard@usfamily.net wrote: > > Can anyone explain why some VOR "cat whisker" antennas are mounted > with the open end of the 'V' facing forward and some facing aft? Is > there a difference in reception quality and/or drag characteristics? > Secondly, is the polyester lamination over the steel for improved > precipitation static protection worth an extra $60? Thanks for any > answers posted. > TPackard > > > --- http://USFamily.Net/dialup.html - $8.25/mo! -- > http://www.usfamily.net/dsl.html - $19.99/mo! --- > > ________________________________ Message 8 _____________________________________ Time: 10:06:02 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Fusible Link Connector At 10:14 AM 6/19/2007 -0500, you wrote: >Is there any reason that you shouldn't use a soldered connection instead >of an inline connector in a fusible link? Would the solder go before the >wires unlike the solid inline connector? It would just make it a little >cleaner looking. Food for thought. I think I'd want to test this. You wouldn't want the joint to melt and then become an intermittent connection with a potential for a "soft fault" energy dump. You can test this. Make up some assemblies and then use them to fault a car battery. See where the circuit opens first. Bob . . . ________________________________ Message 9 _____________________________________ Time: 10:13:29 AM PST US From: Deems Davis Subject: Re: AeroElectric-List: Low Voltage plus Alt Loadmeter THANK YOU sooo much for responding and for the additional information, I've replied where appropriate below and asked an additional question for some clarification. Robert L. Nuckolls, III wrote: > > > At 12:41 AM 6/19/2007 -0700, you wrote: > >> >> >> Warning this question is posed by an electron nerd.... >> >> I'm planning the installation of probes & sensors for a Z14 >> architecture. The Z-14 Figures in the 'Connection' seem to depict the >> shunts placed for use as 'loadmeters' i.e. they are placed on the >> Alternator B lead (which will measure Alt charging only). In >> reviewing Bob's notes. He favors a Battery Ammeter, the rationale >> seems to be that it measures both charging and discharging of the >> battery/s. This seems desirable to me. > > > The Z-figures represent the latest thinking with respect > to the optimal solutions. The chapter on electrical instrumentation > was written a long time ago and will be updated at revision 12. If > you have > only one electrical system monitor, it should be a low voltage > warning light. I have the LR-3's from B&C which drive/include Low Voltage indicators. > If you add anything on top of that, I'd recommend > an expanded scale voltmeter on the e-bus and/or alternator > loadmeter(s) . . . but both of those are only small peeks at a variety > of test points you'll need to look at for diagnosis. Ammeters > and voltmeters are poor monitoring tools. And as diagnostic > tools, they are only a part of what's necessary for troubleshooting. > >> However, I'm stumped as to where to locate the Shunts in the Z-14 so >> as to be able to connect Battery ammeters. > > What kind of panel displays are you considering? I have dual glass panels (EFIS) w a glass back-up. The Engine Interface unit is a JPI product (black box) which captures information from probes and sensors, it relies on Shunts for AMP meter input. The information from the EIU black box is interpreted and displayed on graphic indicators on a display page with the EFIS units. > If they're > steam-gages, then they'll likely use shunts but if they're > electronic displays, they'll most likely come with hall-effect > sensors. Hall sensors can be place ANYWHERE in the system that > you think is most useful to you for knowing how many electrons > per second are passing that point . . . however, adding shunts > in series with the battery as suggested in Chapter 7 is based > on wobbly logic and poor practice. However, a hall-sensor can > certainly be placed on a battery lead if you so choose. > > A caveat on battery lead hall-sensors. When the starter hits the > battery with an inrush current of as much as 1000 amps, the magnetic > forces impressed upon the hall sensor are, shall we say, significant. > The hall sensor MUST (by certain pesky laws of physics) be fitted > with a core material that serves to restrain the field flux around > the wire and supply a proportional sample of that field to the > hall device. EVERY magnetic material has a retentivity value . . . > a measure of permanent "set" that the core material will take > on when excited by an extra-ordinary force. > > Depending on the materials used in your hall sensor, the act > of starting the engine can cause a small but significant > semi-permanent "set" of the field flux in the core. This > will manifest itself as what is known as "offset" . . . > a fixed error value that shows up most strongly when > the stimulus to be measured is zero . . . the indicator > reads something other than zero due to the core's > retentivity and influence of the starter inrush current. > > Based on this expanded thinking, recommendations for ammeter > locations were revised to what you have in your hands today. OK, so I've got the low voltage indicators, and If I go ahead and install the shunts per the Z-14 to supply Alternator loadmeters, I'm not sure I understand how to interpret the information that I receive from the Alternator loadmeters. What would this information be telling me? If I understand it correctly (?) it would display the current that is being output from the Alternator, correct? But if I understand correctly it doesn't tell me that the battery is charging, (Is this what you mean when you say that items 3 and higher have little or no significance in Operations? can you illuminate? > Without knowing more about the specifics of any hall-sensor > that may be supplied to you, I cannot recommend that they > be used as battery ammeters EXCEPT where you avoid running > starter current through the conductors. This means backtracking > to the architecture common in 1965 C-172. > > The best I know how to do at the moment suggests that active > notification of low volts is #1. A voltmeter on the e-bus > (gas gage for battery during alternator out operations) is > #2. Items 3 and higher have little or no significance in > the OPERATION of your airplane . . . so sprinkle sample > and display items about your electrical system as you see > fit and you budget allows. Just understand that items 3 > and higher offer no useful functions in flight and there > won't be enough of them to do a detailed troubleshooting > study on the ground. > Trying to become less of an electron nerd Deems Davis RV-10 http://deemsrv10.com/ ________________________________ Message 10 ____________________________________ Time: 10:52:41 AM PST US From: "earl_schroeder@juno.com" Subject: Re: AeroElectric-List: VOR/GS Antenna I heard once that the forward facing whiskers were to protect the eyes of the public [and unaware pilots]... Can anyone explain why some VOR "cat whisker" antennas are mounted with the open end of the 'V' facing forward and some facing aft? Is there a difference in reception quality and/or drag characteristics? ________________________________ Message 11 ____________________________________ Time: 03:37:59 PM PST US From: "Robert Feldtman" Subject: Re: AeroElectric-List: VOR/GS Antenna shouldnt matter - precip/icing might be an issue/ appearance probably drives it. main thing is it should be horizontally polarized while the comm antennas should be vertically polarized bobf W5RF On 6/19/07, jtpackard@usfamily.net wrote: > > > Can anyone explain why some VOR "cat whisker" antennas are mounted with > the > open end of the 'V' facing forward and some facing aft? Is there a > difference in reception quality and/or drag characteristics? Secondly, is > the polyester lamination over the steel for improved precipitation static > protection worth an extra $60? Thanks for any answers posted. > TPackard > > > --- http://USFamily.Net/dialup.html - $8.25/mo! -- > http://www.usfamily.net/dsl.html - $19.99/mo! --- > > ________________________________ Message 12 ____________________________________ Time: 05:25:24 PM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: VOR/GS Antenna Good Evening bobf and TPackard, May I suggest that consideration be given to using blade antennas? I have installed several sets with excellent results. They are relatively low drag, handle precipitation well, have no issues with ice and nobody has ever gotten an eye poked out by running into one. While reception strength and pattern are not very important with modern radios, the blades do provide excellently balanced reception throughout the operating range. I generally have fed two VHF navigation receivers and two glide slope receivers from one set of blades. All in all, very happy with the results. Happy Skies, Old Bob AKA Bob Siegfried Ancient Aviator Stearman N3977A Brookeridge Air Park LL22 Downers Grove, IL 60516 630 985-8503 In a message dated 6/19/2007 5:41:02 P.M. Central Daylight Time, bobf@feldtman.com writes: shouldnt matter - precip/icing might be an issue/ appearance probably drives it. main thing is it should be horizontally polarized while the comm antennas should be vertically polarized bobf W5RF On 6/19/07, _jtpackard@usfamily.net_ (mailto:jtpackard@usfamily.net) <_jtpackard@usfamily.net_ (mailto:jtpackard@usfamily.net) > wrote: --> AeroElectric-List message posted by: <_jtpackard@usfamily.net _ (mailto:jtpackard@usfamily.net) > Can anyone explain why some VOR "cat whisker" antennas are mounted with the open end of the 'V' facing forward and some facing aft? Is there a difference in reception quality and/or drag characteristics? Secondly, is the polyester lamination over the steel for improved precipitation static protection worth an extra $60? Thanks for any answers posted. TPackard ************************************** See what's free at http://www.aol.com. ________________________________ Message 13 ____________________________________ Time: 11:13:55 PM PST US From: "Harold Kovac" Subject: AeroElectric-List: RTV sealants As far as sealants are concerned, wouldn't shoe goo, Plumbers Goop or RV Goop from eclectic products work as well? I remember Bob talking about Shoe Goo and some other similar products. These I believe are all from eclecti products in LA. I purchased mine at Home Depot...seem to work well. Harold ----- Original Message ----- From: "bob mackey" Sent: Monday, June 18, 2007 9:51 PM Subject: AeroElectric-List: RTV sealants > > There were several recent recommendations for the use of > RTV (room temperature vulcanizing) elastic sealants. > Before putting this stuff near your airframe or avionics, > you should know that there are many different types of RTV, > and most of them are somewhat corrosive as a result of the > acetic-acid curing chemistry (smells like vinegar). > > For mounting antennas to aluminum airframes, consider using an > alcohol-cure RTV such as clear or gray Dow Corning 3145, white > General Electric RTV 162 or gray high strength RTV 167, or clear > Loctite 5140. > > These alcohol-cure RTVs are more expensive. > Instead of a buck or three, McMaster sells the GE 162 for $12.66 > per 2.8 oz tube. > http://www.mcmaster.com (part number 74935A65, page 3305) > The Dow 3145 is quite a bit more expensive than that. > > references: > http://www.logwell.com/tech/servtips/RTV.html > http://www.mgchemicals.com/downloads/appguide/appguide0205-1.pdf > http://www.mgchemicals.com/products/silicones/cureguide-1part.html > ... and of course Google... > > > ------------------------------------------------------------------------------------- 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.