---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 05/05/06: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:04 AM - Re: FW: Alternator Voltage Spikes (Brian Lloyd) 2. 07:04 AM - Use of GPS in lieu of ADF and DME, was: Converting IFR... (BobsV35B@aol.com) 3. 07:14 AM - Re: Alternator Voltage Spikes (Robert L. Nuckolls, III) 4. 07:30 AM - Re: Alternator set point (Robert L. Nuckolls, III) 5. 07:54 AM - Re: Re: Charging system failure (Brian Lloyd) 6. 09:39 AM - Use of GPS......... () 7. 10:03 AM - SAE documentation question (Lloyd, Daniel R.) 8. 11:15 AM - Re: Use of GPS......... (BobsV35B@aol.com) 9. 11:45 AM - Strobe Fuse Blow?? ('Peter Braswell') 10. 12:52 PM - Re: Strobe Fuse Blow?? (Matt Prather) 11. 02:23 PM - Re: SAE documentation question (bikcrzy@aol.com) 12. 05:37 PM - Re: SAE documentation question (Lloyd, Daniel R.) ________________________________ Message 1 _____________________________________ Time: 07:04:00 AM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: FW: Alternator Voltage Spikes --> AeroElectric-List message posted by: Brian Lloyd On May 4, 2006, at 2:49 PM, Rogers, Bob J. wrote: > --> AeroElectric-List message posted by: "Rogers, Bob J." > > > Do you think the assertion below is true(that there are 200 volt > spikes > when starting)? No. Brian Lloyd 361 Catterline Way brian-yak AT lloyd DOT com Folsom, CA 95630 +1.916.367.2131 (voice) +1.270.912.0788 (fax) I fly because it releases my mind from the tyranny of petty things . . . Antoine de Saint-Exupry ________________________________ Message 2 _____________________________________ Time: 07:04:00 AM PST US From: BobsV35B@aol.com Subject: AeroElectric-List: Use of GPS in lieu of ADF and DME, was: Converting IFR... --> AeroElectric-List message posted by: BobsV35B@aol.com Good Morning Richard, Glad to have been of some assistance! You stated: "Now that I've found an expert I have three nuance questions..." I do consider myself an expert on the "In Lieu Of" provisions. For the rest, merely an interested and experienced user. I am happy to provide my current interpretations for the following questions. "#1 If someone has a GX-65 (enroute only) do they still file as /G? Does that create any confusion with ATC if they are asked/vectored for a GPS approach?" That may result in some confusion, but only because the powers that be have changed the rules so often. When /G was first implemented, you had to have full and current approach capability to use it. A few years later, they changed the rules and the AIM now tells us we can file /G if we have enroute and terminal capability. See AIM figure 5-1-2. I believe the GX-65 is approvable for both enroute and terminal operations. Is yours not so approved? Your individual FAA Approved Airplane Flight Manual Supplement could further confuse the issue. More later! "#2 Lets say my IFR GPS database is out of date (most recent updates not yet applied). (a) I understand that I can still use the GPS for enroute navigation (i.e. file and accept "direct") as long as I verify that the relevant data points are still accurate." That is quite likely to be a true statement. AC 20-138 is the document that provides guidance for the approvals. There have been revisions to that document. Consequently, one factor that could apply might be the time frame during which the manufacturer of your set obtained the original approval as well as when your supplement was written. The original guidance was that such language could be used in the approved supplement. Another, and more obtuse complication, is due to the nature of the approval process used. Until very recently, each and every individual installation was done under the FAA inspector's right to do what are called local approvals via a 337. In the fall of 1997, (August I think) the folks at UPSAT received approval of wording such that approaches could be conducted with an "out of date" data card if an adequate verification procedure was used. >From that time on, the "sample" approval that was included with every new UPSAT unit contained that liberalized language. Some folks within the FAA felt that such language should not be allowed and they refused to use it for installations that were performed in their area. A very few individual installers used the UPSAT language in approval applications for sets other than UPSAT ones. The result of all this is that how you use your set is very dependent on the language that is in your individual Flight Manual Supplement and how it is interpreted. Interpretations do vary among various experts in the field and some FAA personnel. "#2(b) I understand that I cannot use it for IFR GPS approaches (until updated)." Possibly true. As stated previously, that is dependent on the language in your supplement and the method that you may use to assure currency of the data on your card. #2 (c) "Would I file /G?" As long as you are legal for enroute and terminal operations according to your individual FAA Approved Flight Manual Supplement, you should file /G. #2(d) "Do you know of the AC/FAR/Aim reference to this scenario?" For the /G question, AIM figure 5-1-2. For the rest, the guidance is in the FAA inspectors interpretations manual and I am not expert in that at all! "#3 Continuation of scenario #2... If I am flying a VOR/DME or LOC/DME or an ILS with a required ADF (for the missed) with a traditional and valid NAV/CDI, can I legally use the out-of date GPS to substitute the DME or ADF if I have verified the accuracy of the relevant GPS data? Do you know of the AC/FAR/Aim reference to this scenario?" Unfortunately, you cannot. That was a slip up in the acceptance of the "In Lieu Of" interpretation process and I am partially responsible for that bad move. It is another long story, but you must have a current data card to use the "In lieu Of " provisions. Check AIM 1-1-19, f, 1, (b), (3) Middle of the paragraph where it says: "The database must be current." On more comment. I have a whole stack of revisions that I have not yet gone through. If something has changed in the AIM in the last couple of months, the references I have given could be in error. Hope this helps! 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 5/5/2006 12:21:40 A.M. Central Standard Time, rtitsworth@mindspring.com writes: Now that I've found an expert I have three nuance questions... #1 If someone has a GX-65 (enroute only) do they still file as /G? Does that create any confusion with ATC if they are asked/vectored for a GPS approach? #2 Lets say my IFR GPS database is out of date (most recent updates not yet applied). I understand that I can still use the GPS for enroute navigation (i.e. file and accept "direct") as long as I verify that the relevant data points are still accurate. I understand that I cannot use it for IFR GPS approaches (until updated). Would I file /G? Do you know of the AC/FAR/Aim reference to this scenario? #3 Continuation of scenario #2... If I am flying a VOR/DME or LOC/DME or an ILS with a required ADF (for the missed) with a traditional and valid NAV/CDI, can I legally use the out-of date GPS to substitute the DME or ADF if I have verified the accuracy of the relevant GPS data? Do you know of the AC/FAR/Aim reference to this scenario? ________________________________ Message 3 _____________________________________ Time: 07:14:59 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Alternator Voltage Spikes --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 04:49 PM 5/4/2006 -0500, you wrote: --> AeroElectric-List message posted by: "Rogers, Bob J." Do you think the assertion below is true (that there are 200 volt spikes when starting)? -----Original Message----- From: Rotary Engine [mailto:rotaryeng@earthlink.net] Sent: Tuesday, May 02, 2006 5:44 PM Subject: Alternator Voltage Spikes Subject: Alternator Voltage Spikes I have been noticing all the comments about voltage spikes during starting/shutdown. One poster mentioned that a battery couldn't put out 200 volts, so I thought I would toss my 2 cents in. I worked for several years as an IC design manager at Texas Instruments in the automotive group where we designed ICs for automotive regulators. I will assure you that charging systems for cars (and airplanes) do indeed put out spikes well over 200 volts when the alternator is rotating very slowly. This voltage can easily cause oxide failure, known as 'punch-through', which shorts VCC and Ground inside the IC. Once that happens, heavy current flows through the IC causing the smoke stored in the IC to escape. ICs don't work once you let the smoke out! :-) To understand how a 12 volt battery/alternator can put out a high voltage, you have to understand that in an inductor (i.e. the windings of the alternator), the voltage across the inductor is equal to L*di/dt, or the Inductance of the winding times the rate of change of the current through the inductor. If you attempt to instantly stop or start the current through an inductor, di/dt will become very large, and the voltage will increase to whatever level necessary to collapse or create the magnetic field around the inductor. BN: The "explanation" is not conducive to understanding. Yes, inductors suddenly cut loose from their energizing sources will indeed present voltages at the open terminals that can be many times higher than the voltage that produced the excitation in the first place. The voltage induced in the inductor is a function of magnetic field collapse only, and the fact that he cites the voltage spike as being a first order causation of creating or collapsing a magnetic field suggests that he is simply parroting stuff he's heard or been told by someone else. When an alternator is turned very slowly, there are points where the windings are open circuited (or routed through high resistance paths) which causes voltages to rise to the level that breaks down the primary protection - around 200 volts. BN: I cannot imagine what is being suggested here. First, "very slowly" is non quantified. If you turn an alternator at speeds below minimum speed for regulation (puts out 12 volts but zero current) the the rectifier diodes are non-conducting, there's no current flowing in the windings to "charge" the inductance, hence no stored energy to be concerned with even if it MIGHT be hazardous. Minimum speed for regulation is on the order of 1000 rpm. See: http://www.aeroelectric.com/Pictures/Alternators/Rotax_Aux_Alternator.gif http://www.aeroelectric.com/Pictures/Alternators/Rotax_PM_Alternator_1.gif and http://www.aeroelectric.com/Pictures/Curves/80A_OutCurve.gif Note that alternator output goes to zero current at about 1000 rpm in all cases. This means that it's ability to deliver energy at system voltage is zero, hence zero current in stator windings. 1000 RPM doesn't strike me as being "very slowly". In an automobile, there is a highly reliable circuit that disconnects the radio bus from the charging bus during start and shut-down to protect equipment from these spikes. BN: Hmmm . . . yes, it's called the ACCESSORY terminal on the starter switch . . . and it's primary purpose is to uload the battery of all things not essential to getting an engine started. This includes radios, blowers, wipers, etc, etc. and has nothing to do with protecting these devices from evil spikes. However, maybe this gives us a calibration on "very slowly" . . . engine cranking is the interval which the alternator sees the most sustained rotation at low RPM and I would expect this to be on the order of perhaps 200 RPM . . . if this is the condition under which the writer expects an alternator to be lying in wait for an unsuspecting integrated circuit to come by . . . well. This is what Cessna attempted to do with some aircraft, but the circuit they used is somewhat crude and potentially unreliable, so people disconnected its output that was supposed to control the avionics power relay, and rewired this relay to be controlled by a simple switch on the panel. BN: I'd like to see what he was talking about here. He doesn't mention which aircraft. I'll have to call my spies and see if they have any idea what's being discussed. Sure, Cessnas have had avionics master switches since the late 60's but to the best of my knowledge, they've always been manually operated just like they are today in our entire fleet of production airplanes. I've been on that "snipe hunt" for decades. I've made serious attempts to catch the elusive start-up spike, identify it's source impedance, magnitude and duration but alas, I have yet to even see one much less quantify it. But I keep looking. Every time I have my 'scope attached to the bus of an airplane, I set up to capture one of the crafty buggers just in case one comes buy . . . but no joy. I'm not saying that transients on the bus do not exist. I am saying that I've never been able to capture a radio-killing spike of any magnitude or source and in particular, transients generated by alternators/starters. We qualify electronics for aviation base on protocols outlined in DO-160 . . . http://aeroelectric.com/articles/Whats_all_this_DO160_Stuff_Anyhow.pdf The aviation industry designs to withstand certain QUANTIFIED excursions of bus voltage. The levels were selected by individuals I don't know and many moons ago. I'd love to interview the writers of DO-160 to discover the rationale behind their selection of test criteria but that's not practical. Having embraced the stress levels cited in DO-160 as good things to observe, my own design career and that of thousands of others has progressed risk-free of any transistor-killing events in the wild. So in general, these old hangar tales about un-quantified, un-qualified, non-demonstrable events should be considered with skepticism no matter what the source. Even in the "enlightened" sector of the industry, data sheets and papers abound wherein authors allude to the existence of killer spikes (mostly written by those selling transient suppression devices). None, I repeat NONE have cited the repeatable experiment by which their assertions are supported. They cite the "potential" for individual components (like window lock solenoids) to store and dump certain energies and then proceed to convince you that it's wise to protect a system from these potentials. This philosophy pre-supposes that anyone who incorporates potential antagonist components in their design are not taking a responsible place in the community and limiting their product's ability to wreak havoc on the rest of the system. The practice sells parts but it's not good science or good engineering. The author of the piece that prompted this thread may indeed have experience as an IC designer but he does not demonstrate an understanding of the systems or design guides for the use of his products in those systems. He tossed in some accurate tid-bits but failed to connect them into a coherent explanation. It's like asserting that the sun is 93,000,000 miles away and the speed of light is 299,000,000 meters/second and therefore, one should be careful of UV exposure on the beach. As Charles Kettering observed, "You can know a great deal about a topic and yet understand nothing." 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 4 _____________________________________ Time: 07:30:02 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Alternator set point --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:58 PM 5/4/2006 -0400, you wrote: >--> AeroElectric-List message posted by: BobsV35B@aol.com > > >Good Afternoon Dave, > >I have set one for 14.2. That was on the advice of the Concorde battery >folks and the manufacturer of the solid state regulator used on the airplane. > >It seems to have worked very well for the last two hundred hours or so that >have been put on the airplane since the installation was made. > >Happy Skies, > >Old Bob Good point. When one considers the physics, practical applications and variables that affect service life of batteries, the set-points selected for aviation charging systems of 14.25/28.5 volts has stood us well for decades. Yes, there are data sheets for EVERY battery where EVERY designer/manufacturer has offered his/her recommendations for squeezing the most life from their particular product. Bottom line is that there are service stresses with far greater influence on the battery's service life than the fine tuning of bus voltage. 14.2 has been used with lead-acid technology batteries since day-one and while setting one to run at 14.6 or higher is recommended by some and not-recommended by others, in the final analysis, it doesn't make a noticeable difference in most cases. I think I wrote some years ago about discovering that the alternator on my GMC Safari was running 15.2 volts! It had been at that voltage for a very long time and I left it alone as an experiment. I was running a 33 a.h. Panasonic RG battery at the time. I still got about three years service from the battery . . . so I have a single data point experiment that suggests that a startlingly high bus voltage did not portend imminent doom for the battery. Higher than 14.2 will RECHARGE a battery faster after start up but is unnecessarily high for bringing a lead-acid battery up to 100% capacity. ALL lead-acid technology batteries will achieve 100% of charge at room temperature at 13.8 volts charging potential. 14.2 is a compromise between long life at float and rate of recharge after the engine starts. Higher than 14.2 pre-biases any form of ov protection device closer to it's trip point and increases the possibility of nuisance trips. Bob . . . ________________________________ Message 5 _____________________________________ Time: 07:54:34 AM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: Re: Charging system failure --> AeroElectric-List message posted by: Brian Lloyd On May 4, 2006, at 2:44 PM, DAVID REEL wrote: > ... > I turned on some loads, my only significant one being the Whelen =20 > strobe > lights. The voltage became unstable, jumping up to 14.6 and back =20 > down to > 14.3. I'm thinking this relates to Bob's remark about the =20 > unstability of > regulators that use the field circuit to sense bus voltage. I =20 > wonder if > anyone can explain the mechanism for this instability. In =20 > particular, I'm > wondering if, as the battery gets a full charge & stops providing a =20= > large > proportion of the load, a varying load such as the strobes could =20 > cause it to > burp up to 16 volts or more occasionally? This regulator seemed to =20= > settle > on 14.8 volts when the battery was fully charged. > > I've just recieved Van's variable voltage regulator & will be =20 > installing > this. Think I'll set it low, maybe 13.8v, to try and eliminate these > crowbar events. Certainly, 14.8 volts seems to start overcharging the > battery almost immediately & is way overkill. Have others used lower > charging voltages successfully? Dave, I hate to say this but I think you are approaching the problem =20 the wrong way. Frankly, getting a variable VR and putting it in is a =20 band-aid and not a real fix. Of course, this is assuming that your =20 original VR is working properly -- you need to test it. Frankly, there is no reason for the voltage to wander around much =20 even as you change loads. The fact that you see a relatively high =20 buss voltage of 14.8V worries me too. Can these two symptoms be =20 related? I think so. They can if the VR is not really sensing bus =20 voltage but rather bus voltage after a drop. Let me address your question about instability and sensing the field =20 current. First, the VR works by increasing alternator field current =20 when it senses a reduction in bus voltage. The logic is simple; if =20 the voltage goes down it is probably because something is drawing =20 more current and therefore we need more output from the alternator. =20 The problem arises because the designers of most VRs figured that, =20 since the VR needed power from the bus in order to drive the field =20 and they needed a wire to the bus to sense the voltage, they could =20 save time, effort, and money by using the same wire to perform both =20 functions. Good idea -- NOT! The problem is, every wire and connection is a resistor. When you put =20= more current through it the voltage across it increases too (ohms =20 law). This "voltage drop" makes the voltage at the end of the wire =20 lower than at the beginning of the wire. Now lets think about our =20 alternator system. The VR senses the voltage between the ground and =20 input (bus) terminals on the VR. It does NOT sense bus voltage but =20 rather the voltage AFTER it has traversed the wiring from bus through =20= the fuse through the breaker and through several intervening =20 connections. Now we put the field current through that wire, =20 typically up to about 3A at high output. That means that the voltage =20 at the input (bus) terminal of the VR is LOWER than the voltage on =20 the bus. The VR doesn't care. It turns on the alternator harder until =20= the voltage comes up to what it wants to see. This increases field =20 current which increases drop which makes the VR sense a lower voltage =20= which increases field current which increases drop which makes the VR =20= sense a lower voltage which increases field current which increases =20 drop which makes the VR sense a lower voltage ... Do you get the picture? This is the instability Bob was referring to. =20= This is called positive feedback and can cause the alternator system =20 to eventually break into oscillation (up and down and up and down and =20= up and down and ...). Now in a properly designed VR there is a separate wire that senses =20 the voltage. This gets connected to the bus and has little or no =20 current flowing through it as it doesn't have all that field current. =20= It can proper sense the bus voltage without any drop and therefore =20 does a MUCH better job of keeping the voltage stable. OK, that is the =20= better way to do it. Now let's work with what you have and see if we can make it good =20 enough. The first thing to do is to eliminate as many drops as =20 possible. That means you need to get rid of any extra and extraneous =20 connections and devices that drop too much voltage. Step 1: LOSE THE FRICKING FUSE That fuse and fuse holder are a serious source of voltage drop when =20 current flows through them. The fuse is a resistor designed to drop =20 current and get hot enough to melt. (So is the breaker but you have =20 to have the breaker.) Add to that the extra connections and the poor =20 connections in the fuse holder to the fuse and you have a serious =20 source of voltage drop. Bad. Bad bad. Bad bad bad. No flight for you! So, task one is to lose the fuse and use an unbroken piece of 18AWG =20 wire from your bus to your field breaker and then an unbroken piece =20 of 18AWG wire from breaker to the input of your VR. That will =20 minimize any "movement" (voltage change) of the VR input terminal =20 when the VR decides to change the field current. OK, so you want some protection for your 18AWG wire between the bus =20 and the breaker. If you must have this (frankly, I wouldn't put it =20 in) use a fusible link that is properly soldered and protected. And you want this lead as close to the positive terminal of the =20 battery as possible. You don't want any more voltage drops to occur =20 between the battery's positive terminal and the input to the VR. This =20= means you want to move the VR input wire as close to the battery's =20 positive terminal as is humanly possible. This probably means putting =20= it right at the battery contactor if possible. (I am trying to =20 eliminate as many drops as possible here folks.) You know that point =20 on the battery contactor where the alternator 'B' lead connects and =20 where your bus distribution wire connects? Yeah, right there. Now you have minimized any drop between the battery and the VR. But there is also another source of change in the voltage sensed by =20 the VR. That is the ground wiring to the VR. Remember that the VR =20 senses the voltage between its input terminal and ground terminal? =20 Well, if your ground terminal can move around (electrically speaking) =20= the VR will change the field current to compensate. If the voltage =20 change sensed by the VR is the result of any voltage drops associated =20= with the ground circuit, you end up with yet another source of =20 instability. This is where the whole single-point-ground concept =20 comes in. We need to make sure that the ground terminal of the VR is =20 electrically as close as it can be to the negative terminal of the =20 battery. Now since you can't actually connect it to the negative =20 terminal of the battery (it would be just too inconvenient), it needs =20= to connect to where the negative terminal of the battery connects to =20 the aircraft ground system. You are using a single point ground, =20 right? If not (more bad on you), you need to connect it to the same =20 bolt where you connect your battery's negative terminal to the airframe. Once you do these things to improve sensing we will know that the VR =20 *can* do its job properly. Put your voltmeter right on the battery =20 terminals. Start the engine and turn on some big loads, e.g. landing =20 light, pitot heat, vacuum tube radios, etc., and run the engine at =20 the lowest RPM that will bring the bus voltage up to normal. (At low =20 RPM the field current is greatest.) Switch the big loads on and off =20 at the same time while watching the voltmeter. It should be at the =20 same voltage whether the loads are on or off. That voltage should be =20 somewhere around 14.2 volts. (Frankly I like an analog expanded-scale =20= meter or oscilloscope for this. If it is, you have solved your =20 problem. If it is not then NOW you can suspect the VR. BTW, it is normal for the meter to twitch right at the moment you =20 switch the loads as the alternator system takes a fraction of a =20 second to respond. Regardless, it should settle right back on the =20 same voltage. So, time to do some homework. Make sure that this part of things are =20 right and then let us know what happens. Brian Lloyd 361 Catterline Way brian-yak AT lloyd DOT com Folsom, CA 95630 +1.916.367.2131 (voice) +1.270.912.0788 (fax) I fly because it releases my mind from the tyranny of petty things . . . =97 Antoine de Saint-Exup=E9ry ________________________________ Message 6 _____________________________________ Time: 09:39:13 AM PST US From: Subject: AeroElectric-List: Use of GPS......... --> AeroElectric-List message posted by: 5/5/2006 Responding to a previous posting by Bo, copied below. Hello Listers, I want to express my appreciation for all who posted on this subject. It has been an exemplary exchange of reasonable and useful opinions and facts. I'd like to throw in some tidbits that may have some value: 1) From NACO one may purchase a CD-ROM that contains a digital navaid file. http://naco.faa.gov/ecomp/ProductDetails.aspx?ProductID=DAICD This CD-ROM provides the lat long location of navaids, including localizers. Be careful when using this data though because the format may be slightly different than that contained in your GPS box. 2) An examination of localizer installations shows that the DME antenna and the localizer antenna are not precisely co located. The DME antenna is usually mounted on the electronic shelter that is a short distance away from the localizer antenna array. 3) When flying an approach, regardless of which kind of approach, keep clearly in mind what distance you are reading on your GPS display. A) Is it to the next fix on the approach sequence as is typical in a published RNAV (GPS) approach? (The runway end itself is usually the final fix in this sequence). B) Is it the "DME" distance to the geographical location of the localizer / DME antennas on a published ILS or localizer approach? In which case the runway end "distance to" reading should appear printed on the approach plate. C) Is it the distance to some navaid such as an ADF, VOR, VORTAC, or compass locater? D) Is it the distance to some named five letter fix located on the field? F) Is it the distance to some named five letter missed approach point? G) Is it the distance to a five letter named fix at the end of the runway? H) Is it the distance to the lat long printed for the field on the approach plate that you have entered into your GPS? You get the idea -- pay close attention to what the distance to number represents. 4) My tendency when flying ILS approaches is to fly the approach using my SL-30 as the primary navigation device feeding my external CDI and use my Garmin GNS 430 as a "big picture" aid and set up the GPS "navigating to" point as desired. This GPS navigating to point is usually either the localizer or the runway end depending upon the approach information available. I feel that this gives me the best combination of precision and big picture. OC Time: 08:17:13 PM PST US From: Kelly McMullen Subject: Re: AeroElectric-List: Use of GPS in lieu of ADF and DME, was: Converting IFR GPS to Terminal --> AeroElectric-List message posted by: Kelly McMullen Bob, I think the only thing that is added is that you have to verify that the DME location is in the database, especially where it is a loc/dme approach where it presumably is at the far end of the runway, at the Loc antenna. I don't know that all of those are in a non-approach GPS data base. Otherwise I agree with everything else you are presenting. Bo ________________________________ Message 7 _____________________________________ Time: 10:03:26 AM PST US Subject: AeroElectric-List: SAE documentation question From: "Lloyd, Daniel R." --> AeroElectric-List message posted by: "Lloyd, Daniel R." Because I am too cheap to buy the standards report ($100 each), I was wondering if anybody knew where I could get a copy of SAE J845 and SAE J595 Any help would be greatly appreciated THX Dan RV10 40269 Do not archive ________________________________ Message 8 _____________________________________ Time: 11:15:54 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: Use of GPS......... --> AeroElectric-List message posted by: BobsV35B@aol.com In a message dated 5/5/2006 11:41:13 A.M. Central Standard Time, bakerocb@cox.net writes: 2) An examination of localizer installations shows that the DME antenna and the localizer antenna are not precisely co located. The DME antenna is usually mounted on the electronic shelter that is a short distance away from the localizer antenna array. 3) When flying an approach, regardless of which kind of approach, keep clearly in mind what distance you are reading on your GPS display. Good Afternoon Jim, That is a very good point. The location of the DME transceiver is shown on the Jepp charts, but I know of no way to determine it's location on a NACO chart other than to do a bit of sleuthing involving various distances listed on the charts. In Minneapolis, the DME transceiver for the approaches to the opposite ends of runways 12R and 30L is located at the glide path intercept point for Rwy 30L. The localizers for both runways are on the same frequency. Obviously, both are not transmitting at the same time! When 12R is in use, the identifier for the localizer and the DME location is listed as IHKZ. When 30L is in use, it is identified as IMSP. In any case, the transceiver does not move! All of the mileages posted on the chart are referenced to that same point. If you have a Garmin or King IFR approved receiver with a current database, you can enter either IHKZ or IMSP and you will get the proper location and distance from the pertinent DME transceiver site. The boss says I have to get on to other things, but I will try to get back with more comments later if anyone is interested. Happy Skies, Old Bob AKA Bob Siegfried Ancient Aviator Stearman N3977A Brookeridge Air Park LL22 Downers Grove, IL 60516 630 985-8503 ________________________________ Message 9 _____________________________________ Time: 11:45:20 AM PST US From: "'Peter Braswell'" Subject: AeroElectric-List: Strobe Fuse Blow?? --> AeroElectric-List message posted by: "'Peter Braswell'" All, I've wired my A/C electrical system almost to the Nuckol's letter in that I've choosen to use fuses instead of breakers. When I turn on my strobes, turn them off and then quickly (one-count, two-count) turn them back on, the fuse blows. If I turn them off, then wait a few minutes (2-5 minutes unscientifically) the fuse does not blow. Operationally this is probably not a huge deal as I'm not sure I'd ever intentially turn on, off, and then on the strobes in a quick fashion but it is a curious problem. Any thoughts? Is there such thing as a slow-blow fuse available for the B&C fuse blocks? Would this solve the problem? Am I missing something? -peter _______________________________________ Peter J. Braswell CTO/CIO Canal Capital LLC 804.934.0300 ext 21 _______________________________________ ________________________________ Message 10 ____________________________________ Time: 12:52:38 PM PST US Subject: Re: AeroElectric-List: Strobe Fuse Blow?? From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" Interesting. What's the wire size, and fuse size? Do you have any current measurements for the strobes (or published current specs)? Maybe the fuse is on the edge of being too small, and so consequently runs fairly hot. When you cycle the power back on without allowing the fuse time to cool, the brief turn-on transient current required to charge the caps in the strobe power supply causes the fuse to get hot enough to blow.. If the wiring is big enough to support the next larger fuse size, you could safely make a substitution there, and probably cure the problem. Regards, Matt- > --> AeroElectric-List message posted by: "'Peter Braswell'" > > > All, > I've wired my A/C electrical system almost to the Nuckol's letter in > that I've choosen to use fuses instead of breakers. > > When I turn on my strobes, turn them off and then quickly (one-count, > two-count) turn them back on, the fuse blows. If I turn them off, then > wait a few minutes (2-5 minutes unscientifically) the fuse does not > blow. > > Operationally this is probably not a huge deal as I'm not sure I'd ever > intentially turn on, off, and then on the strobes in a quick fashion but > it is a curious problem. > > Any thoughts? Is there such thing as a slow-blow fuse available for the > B&C fuse blocks? Would this solve the problem? Am I missing something? > > -peter > > > _______________________________________ > > Peter J. Braswell > CTO/CIO Canal Capital LLC > > 804.934.0300 ext 21 > > _______________________________________ > > ________________________________ Message 11 ____________________________________ Time: 02:23:51 PM PST US From: bikcrzy@aol.com Subject: Re: AeroElectric-List: SAE documentation question --> AeroElectric-List message posted by: bikcrzy@aol.com Dan, Check your mailbox. JR -----Original Message----- From: Lloyd, Daniel R. Sent: Fri, 5 May 2006 12:57:03 -0400 Subject: AeroElectric-List: SAE documentation question --> AeroElectric-List message posted by: "Lloyd, Daniel R." Because I am too cheap to buy the standards report ($100 each), I was wondering if anybody knew where I could get a copy of SAE J845 and SAE J595 Any help would be greatly appreciated THX Dan RV10 40269 Do not archive ________________________________ Message 12 ____________________________________ Time: 05:37:29 PM PST US Subject: RE: AeroElectric-List: SAE documentation question From: "Lloyd, Daniel R." --> AeroElectric-List message posted by: "Lloyd, Daniel R." I really appreciate this, this is exactly the information I needed. If I can ever be of help to anyone on the list, let me know. I am in the IT field, so as a geek I should be able to lend some value? "grin" Dan Do not archive -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of bikcrzy@aol.com Sent: Friday, May 05, 2006 5:17 PM Subject: Re: AeroElectric-List: SAE documentation question --> AeroElectric-List message posted by: bikcrzy@aol.com Dan, Check your mailbox. JR -----Original Message----- From: Lloyd, Daniel R. Sent: Fri, 5 May 2006 12:57:03 -0400 Subject: AeroElectric-List: SAE documentation question --> AeroElectric-List message posted by: "Lloyd, Daniel R." Because I am too cheap to buy the standards report ($100 each), I was wondering if anybody knew where I could get a copy of SAE J845 and SAE J595 Any help would be greatly appreciated THX Dan RV10 40269 Do not archive