---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 06/21/07: 8 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:39 AM - Re: Low Voltage plus Alt Loadmeter (Deems Davis) 2. 08:44 AM - Re: Re: MB antennnas (Robert L. Nuckolls, III) 3. 08:44 AM - Re: Low Voltage plus Alt Loadmeter (Robert L. Nuckolls, III) 4. 02:06 PM - FUELGARD/fuel flow unit (Bill Ingram) 5. 02:43 PM - Re: FUELGARD/fuel flow unit (Ron Quillin) 6. 03:01 PM - Question about Aux battery contactor on Z30 (Vernon Smith) 7. 05:44 PM - Re: Question about Aux battery contactor on Z30 (Robert L. Nuckolls, III) 8. 07:54 PM - Re: Question about Aux battery contactor on Z30 (Vernon Smith) ________________________________ Message 1 _____________________________________ Time: 01:39:49 AM PST US From: Deems Davis Subject: Re: AeroElectric-List: Low Voltage plus Alt Loadmeter Thank you, The fog is beginning to lift Deems Robert L. Nuckolls, III wrote: > > > At 10:12 AM 6/19/2007 -0700, you wrote: > >> >> >> 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. >>> >> I have the LR-3's from B&C which drive/include Low Voltage indicators. > > That covers the "essentials" . . . > >>> 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. > > You use the plural version of shunt. Does the system > have more than one input for monitoring a current? Or > is there one input that can be switched to one of mulitple > shunts? > > >> 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? > > IF the bus is being supported at the design set point (i.e. > 13.8 to 14.6 volts with 14.2 being nominal) AND assuming > further that the battery is in good shape and capable of > accepting a charge, then it IS being charged. There is no > value in having a minus-zero-plus indicator (battery ammeter) > to confirm this. > > I'm presuming that you intend to MAINTAIN the battery with > respect to KNOWING that its capacity is sufficient to your > endurance needs, then knowing that the bus voltage is where > it should be is sufficient. > > Alternator loadmeters are generally set up to display percent > of full load. See: > > https://matronics.com/aeroelectric/Catalog/9007-120-1_Loadmeter.jpg > > The instrument is then paired with shunt(s) that are sized > for the capability of the device being monitored. E.g. a > 55A alternator should get a 55A shunt, a 20A alternator is > fitted with a 20A shunt. This allows one to switch a single > instrument to as many devices as you wish and know what > PERCENTAGE of that device's capabilities are in demand > at any given time. > > As to operations . . . if the low volts warning light is > OUT (and the engine monitor confirms the bus at an acceptable > voltage) of what value is it as a pilot to know what ANY > current is? You have designed your system to carry all the > loads required for operation. Knowing what those loads are > at any given moment are incidental to piloting the airplane. > > If the low voltage warning light is ON, of what value is > it to know what any current is? You have designed your > Plan-B operations and KNOW that the battery will support > Plan-B for x number of hours with loads you've already > decided to support. > > My assertion is that every load situation for both normal > and alternator-out operations are known in advance and > knowing a reading only validates your Plan-B design > . . . it adds no value for comfortable completion of flight. > > Once you're on the ground, you're going to find that > you need a LOT more data to interpret the failure and > deduce needs for repair. So unless you're going to install > a LOT of shunts and voltage sample points for the purpose > of diagnosing the failure from the pilot's seat, the > classic choices for instrumentation beyond a low-volts > warning and an e-bus voltmeter are a toss up. > > Bob . . . > > ________________________________ Message 2 _____________________________________ Time: 08:44:40 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: re: MB antennnas At 12:42 PM 6/20/2007 -0700, you wrote: > > >Robert L. Nuckolls, III wrote: > >> I don't need the antenna . . . but if you could >> get me the dimensions I asked about earlier, it >> would be helpful. >> Bob . . . > >Down 6" from the belly and then 88" long. In addition, there is a copper >wire coil about 6" long in the middle of the antenna. Hope this helps. Interesting!!! Let's dissect these figures in the light of what we know about antenna design and performance. A full wavelength at 75 Mhz is 300/75 = 4 meters. A quarter wave antenna would therefore be 1 meter or 39.36 inches. The sled runner I illustrated at http://www.aeroelectric.com/Pictures/Antenna/AV-533.jpg the far end bolts to the airframe and is grounded to the skin at that point. The antenna is supported off the skin by some distance set by the design of the bend at the the "ground" end and duplicated by a non-conducting support post . The feedline for routing antenna energy to the receiver is tapped onto the antenna some distance away from the ground end. In antenna parlance, this is called a "gamma match". The idea is that we know the impedance of the system at the ground end of the antenna is zero ohm. On the free end, it will approach mucho-ohms. Someplace between mucho and zero, we'll find a point that is very close to 50 ohms. Hence, you see the feedline tap fastened to the antenna rod at some distance nearer the ground end but optimized during design and testing to maximize the energy transfer between antenna and feedline. Now, what about this 88" figure? This is longer than 1/2 wavelength. Further, he does not speak to a feedpoint attachment. John, do you know that you have ALL of the antenna as- removed? Is there any evidence that a feedpoint tap was ever installed some distance from the forward end of the antenna? Is the mounting hardware still present for the forward end? Is it all metal . . . or does the collection of components offer an insulated penetration of the belly skin? Pending John's future findings and based on what we know so far, it's my best guess that this antenna feeds from what is usually the "ground end" of the sled-runner illustrated above. Further, we know that antennas offer a useable, relatively low impedance feed-point at the ground end that repeats at odd quarter-wave intervals for overall length. For example, a ham's 1/4-wave vertical antenna optimized for operation at 7.3 MHz offers some opportunity for useful performance on the 21 MHz band where the antenna is nominally 3x 1/4-wave. The antenna John is describing to us may well be a nominally "too long" antenna for 1/4-wave performance and "too short" for 3/4-wave service. However, by inserting a small inductance at some point along the antenna's length, the system can be electrically "loaded" to appear as if it were really 3/4-wave in length when in fact it is much shorter. Amateur radio mobile antennas operate over a range of 3.0 to 30 MHz which would require physical lengths of 25 to 2.5 meters for 1/4 wave performance. Typically these antennas are 3 meters or so in length and fitted in an adjustable "loading coil" for the purpose of optimizing the antenna's performance at any frequency of interest. My guess is that the designer intended this antenna to appear as if it were a 3/4-wave antenna with what I would suppose was an intent to improve performance as a receptor of energy from the ground based marker transmitter. This is a bit mystifying for modern systems because the markers used during approach are quite strong and your distance above them is in hundreds of feet. Now, it may be that this antenna was designed for installation on a larger airplane and used for IFR navigation back in the 30s and 40s when the airways were electronically marked laterally with low frequency A-N radio range stations and your location along any given airway was made known by the occasional electronic milestone called an airway marker. I've not found a description of the US versions of the visual/aural range system that used low frequency ground stations (150-500 Khz) however, in the 50's when we were phasing out our LF VAR systems for VHF VOR systems, the Australians were adapting VHF Localizer and ILS technologies to their own version of the 4-course VARS but with the advantage of being able to fly a needle on the panel instead of having to listen to the aural signature of the AN-range station signal through static crashes of hopefully not to near thunderstorms. Both the US and AUS 4-course range systems used 75 MHz marker transmitters for locating one's position along a route. See page 6 of . . http://www.aeroelectric.com/Reference_Docs/RadioNavigation/VAR_Marker-Beacon_Notes.pdf I believer the US airways marker used to operated the white indicator on the suite of marker lamps and the morse code tone was unique to the marker so you knew which transmitter was talking to your receiver. This functionality was replaced by "inner marker" and "fan markers" on the ILS to some approaches. See: http://en.wikipedia.org/wiki/Marker_beacon Back then receiver performance limitations could be enhanced by an extraordinarily large antenna so that the crew would get reliable indication of having passed a marker that was thousands of feet below and perhaps a mile or two off to one side or the other. The US 4-course, AN Ranges stations and the Australian VAR systems were replaced by early cousins to the VHF Visual Omni Range stations that are still in use today. See http://en.wikipedia.org/wiki/VHF_omnidirectional_range The need for receiving airway markers faded away with the advent of VOR and DME. We may never know for sure but it seems likely that John is in possession of a relic of our radio-navigation yesteryear. Bob . . . ________________________________ Message 3 _____________________________________ Time: 08:44:53 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Low Voltage plus Alt Loadmeter At 01:31 AM 6/21/2007 -0700, you wrote: > >Thank you, The fog is beginning to lift > >Deems Very good . . . that's the mission here on the List. If you need more clarification, don't hesitate to ask. Bob . . . ________________________________ Message 4 _____________________________________ Time: 02:06:32 PM PST US From: "Bill Ingram" Subject: AeroElectric-List: FUELGARD/fuel flow unit I have a Fuelgard fuel flow unit and would like to find out what the pin out is for this unit. Silver inst, model 201B Chili Willy ________________________________ Message 5 _____________________________________ Time: 02:43:45 PM PST US Subject: Re: AeroElectric-List: FUELGARD/fuel flow unit From: Ron Quillin Is it a flowscan 201B sensor/sending unit? Red + Black ground White signal At 14:03 6/21/2007, you wrote: >I have a Fuelgard fuel flow unit and would like to find out what the >pin out is for this unit. Silver inst, model 201B > >Chili Willy > > ________________________________ Message 6 _____________________________________ Time: 03:01:07 PM PST US From: Vernon Smith Subject: AeroElectric-List: Question about Aux battery contactor on Z30 Hi, On drawing Z30 there is a auxiliary battery contactor. If the auxiliary bat tery is not being used for cracking the engine could this contactor be repl aced with a diode similar to the endurance buss diode and still allow charg ing of the aux battery? The reasoning behind this question is it would lowe r the component count and simplify the isolation of the auxiliary battery. Thanks, Vern Smith _________________________________________________________________ Make every IM count. Download Windows Live Messenger and join the i=92m Ini tiative now. It=92s free.-- http://im.live.com/messenger/im/home/?source=TAGWL_June07 ________________________________ Message 7 _____________________________________ Time: 05:44:29 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Question about Aux battery contactor on Z30 At 03:56 PM 6/21/2007 -0600, you wrote: >Hi, > >On drawing Z30 there is a auxiliary battery contactor. If the auxiliary >battery is not being used for cracking the engine could this contactor be >replaced with a diode similar to the endurance buss diode and still allow >charging of the aux battery? The reasoning behind this question is it >would lower the component count and simplify the isolation of the >auxiliary battery. >Thanks, If the aux battery is never intended to drive the bus and only support its battery bus, then (1) a smaller power relay can be used like the S704-1 automotive plastic relay which offers a voltage drop on hte order of tens of millivolts. See: http://tinyurl.com/2sno9m (2) Or you could use a power diode. Silicon junction devices have about .6 volts of drop in the conducting mode See http://www.vishay.com/docs/88612/gbpc12.pdf (3) a schottky device would bring this down to .4 volts. See http://www.vishay.com/docs/93275/9327520c.pdf Folks have found all three techniques useful. Bob . . . ________________________________ Message 8 _____________________________________ Time: 07:54:09 PM PST US From: Vernon Smith Subject: RE: AeroElectric-List: Question about Aux battery contactor on Z30 Bob, Thank you for the quick response and the multiply options. In building an a irplane, so far, the electrical is by far the most intriguing to me. Thanks again, Vern Smith do not archive> Date: Thu, 21 Jun 2007 19:41:52 -0600> To: aeroelectric-lis t@matronics.com> From: nuckollsr@cox.net> Subject: Re: AeroElectric-List: Q uestion about Aux battery contactor on Z30> > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > At 03:56 PM 6/ 21/2007 -0600, you wrote:> > >Hi,> >> >On drawing Z30 there is a auxiliary battery contactor. If the auxiliary > >battery is not being used for cracki ng the engine could this contactor be > >replaced with a diode similar to t he endurance buss diode and still allow > >charging of the aux battery? The reasoning behind this question is it > >would lower the component count an d simplify the isolation of the > >auxiliary battery.> >Thanks,> > If the a ux battery is never intended to drive the bus and> only support its battery bus, then> > (1) a smaller power relay can be used like the S704-1> automo tive plastic relay which offers a voltage drop> on hte order of tens of mil livolts. See:> > http://tinyurl.com/2sno9m> > (2) Or you could use a power diode. Silicon junction> devices have about .6 volts of drop in the conduct ing mode> > See http://www.vishay.com/docs/88612/gbpc12.pdf> > (3) a schott ky device would bring this down to .4 volts.> > See http://www.vishay.com/d ocs/93275/9327520c.pdf> > > Folks have found all three techniques useful.> =====================> > > _________________________________________________________________ Live Earth is coming.- Learn more about the hottest summer event - only o n MSN. http://liveearth.msn.com?source=msntaglineliveearthwlm ------------------------------------------------------------------------------------- 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.