---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 06/19/12: 15 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:16 AM - Re: AeroElectric-List Digest: 8 Msgs - 06/18/12 (Franz Fux) 2. 03:55 AM - Re: Generator suppressor (Robert L. Nuckolls, III) 3. 04:01 AM - Re: SL-40 (Robert L. Nuckolls, III) 4. 04:21 AM - Re: Generator suppressor (Jay Hyde) 5. 07:39 AM - Re: Generator suppressor (Robert L. Nuckolls, III) 6. 07:43 AM - Re: Viking Schematic (Robert L. Nuckolls, III) 7. 07:55 AM - Re: Hall Effect rpm sensor (Robert L. Nuckolls, III) 8. 08:33 AM - Re: Hall Effect rpm sensor (Mike Welch) 9. 09:26 AM - Re: Generator suppressor (Jay Hyde) 10. 10:24 AM - Re: Viking Schematic (user9253) 11. 12:52 PM - Re: OBS resolver signals (David Josephson) 12. 01:12 PM - Antenna length (Rob Henderson) 13. 02:21 PM - Re: Antenna length (Peter Pengilly) 14. 04:55 PM - Re: Antenna length (John MacCallum) 15. 07:17 PM - Re: Antenna length (DeWitt (Dee) Whittington) ________________________________ Message 1 _____________________________________ Time: 12:16:36 AM PST US From: "Franz Fux" Subject: AeroElectric-List: Re: AeroElectric-List Digest: 8 Msgs - 06/18/12 only intermittent access to e-mail until June 19th, in an urgent matter contact info@lastfrontierheli.com ________________________________ Message 2 _____________________________________ Time: 03:55:45 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Generator suppressor >, but I am not sure of what values of inductance and capacitance to >use- does anyone have these values squirreled away somewhere so that >I can make a new suppressor? Not sure what these would be. I'd leave them off until you find that they are necessary. Most generator noises were antagonistic to ADF and low frequency nav services. You probably don't need them now. Bob . . . ________________________________ Message 3 _____________________________________ Time: 04:01:20 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: SL-40 At 08:22 AM 6/18/2012, you wrote: Bob, A good thought, but the first fuse blew as I was doing that very thing (running with the alternate feed switch closed). So for the last 12 hours or so, I have run with the alternate switch off. Just strange that it took 12 hours to pop again. Like one of the guys suggested, when I do my tests I might find the radio draw is dancing around the 5A limit...so over time it would probably eat away at the fuse until it fails. I guess the easy fix could be to throw the 7.5 A in there, but it still bothers me that the radio specs indicate the high end draw at tx should be 3.5A (going from memory here) or close to that. I am off to the field now and hope to gather some useable information today. Just hope I don't blow a fuse out there...should get up to about 110 in Phoenix today. As I mentioned before, fuses should be 'de-rated' about 25%, 50% doesn't hurt a thing. If your radio is drawing that much current, there has to be a reason. What are your bus voltage measurements showing? Bob . . . ________________________________ Message 4 _____________________________________ Time: 04:21:39 AM PST US From: "Jay Hyde" Subject: RE: AeroElectric-List: Generator suppressor Thanks Bob, I was thinking along the same lines. It seems to me that these are simply a broad spectrum smoothing filter. I think that I will test run the generator on my lathe and have a look at the output on a scope to see if it looks too rough- a mass produced line filter may just do the job if any smoothing is required. Jay -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: 19 June 2012 12:54 PM Subject: Re: AeroElectric-List: Generator suppressor --> >, but I am not sure of what values of inductance and capacitance to >use- does anyone have these values squirreled away somewhere so that I >can make a new suppressor? Not sure what these would be. I'd leave them off until you find that they are necessary. Most generator noises were antagonistic to ADF and low frequency nav services. You probably don't need them now. Bob . . . ________________________________ Message 5 _____________________________________ Time: 07:39:25 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Generator suppressor At 06:20 AM 6/19/2012, you wrote: > >Thanks Bob, > >I was thinking along the same lines. It seems to me that these are simply a >broad spectrum smoothing filter. I think that I will test run the generator >on my lathe and have a look at the output on a scope to see if it looks too >rough- a mass produced line filter may just do the job if any smoothing is >required. > >Jay That's probably more trouble than it's worth. Generators produce a lot of trash. A 'scope picture is almost never informative. A spectrum analyzer would give you a notion of potential EMC problems but know that DO-160 calls for 'qualified' devices to shrug off up to 1.5 volts pk-pk over 1 to 5 kHz http://tinyurl.com/78kwfk8 and lesser amounts above and below. A 'scope picture of this is pretty spectacular. Alternators are less 'spikey' but still offer considerable ripple voltage. Any filters you might need would go to issues in the RF spectrum http://tinyurl.com/7wrhxbg and cannot be observed in a time domain display. Bob . . . ________________________________ Message 6 _____________________________________ Time: 07:43:10 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Viking Schematic At 04:34 PM 6/17/2012, you wrote: I am helping a friend with a schematic for his Viking powered airplane. See the attached pdf. Is it safe to eliminate the Schottky diode in the lower left corner? I want to remove the diode because it is one more failure point and I do not know if it can handle the full load of the main bus, perhaps as much as 25 or 30 amps. The concern is a short in the alternator or starter circuit (Or is this a remote possibility?) with no way to isolate it without stopping the electrically dependent engine. Thanks for any advice. Joe -------- Joe Gores The rationale for this design is not clear just from the schematic. It appears to borrow nothing from the design philosophies for failure tolerance offered in the Z-figures. I'd have to know more about why it was all wired this way. What are the current demands for the two ignition systems? Bob . . . ________________________________ Message 7 _____________________________________ Time: 07:55:52 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Hall Effect rpm sensor At 05:21 PM 6/18/2012, you wrote: >List guys, > > Can someone direct me to "complete rpm sensor circuit", including > either a digital or analog gauge >that would go along with it? > > I have need of something that will display visually a rotating > motor's shaft. A Hall Effect circuit >would be fine, but I'm open to anyone's suggestion if they have a >better idea how to monitor rpms >of a motor. FYI, the motors will turn at a relatively slow 200-250 >rpm (if that matters). > > If you know of a specific gauge, or LCD display, that could read > these rpms, I'd appreciate that, too. > >Thanks in advance, >Mike Welch What is the rpm range of interest? Is the instrument to be permanently mounted or is it a 'test' or 'setup' environment that could use a hand-held? See: http://tinyurl.com/77ulekb http://tinyurl.com/77lw4bs If you need a permanent, panel mounted instrument, you could use something like this http://tinyurl.com/7nxrh4w but you'd need to build a sensor and some interface electronics. As long as you're building stuff, the data can be displayed on a small, analog instrument where a customized scale sized to your task is pretty easy. https://matronics.com/aeroelectric/Catalog/Loadmeter.jpg Bob . . . ________________________________ Message 8 _____________________________________ Time: 08:33:48 AM PST US From: Mike Welch Subject: RE: AeroElectric-List: Hall Effect rpm sensor Bob=2C Thank you for replying! Here are some of the parameters: 1) motor shafts are anticipated to rotate between 0-300 rpm2) the tach-di splays need to be remotely=2C and permanently mounted (in a console)(I real ly like that digital tach you suggested!!)3) the 'precise' motor rpms do n ot have to be "highly accurate"=2C but they do need to be consistant.(in ot her words=2C if the shaft is actually spinning at 307 rpms=2C and the gauge says "320"=2C that's fine=2C as long as each time it is consistantly off t he same amount!) I did find a very nice electronics package that was close to what I'm loo king for=2C but it had a couple of glitches. First glitch was the rpm rang e it measured=2C which was way too high=2C and the second glitch was the tw o 7 segment displays=2C when I would prefer an actual tachometer like the o ne you suggested. See:http://www.eio.com/p-23310-velleman-k2625-digital-ta chometer.aspx Thanks for your help=2C Bob=2CMike ________________________________ Message 9 _____________________________________ Time: 09:26:59 AM PST US From: "Jay Hyde" Subject: RE: AeroElectric-List: Generator suppressor Sigh... its never simple :-) -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: 19 June 2012 04:38 PM Subject: RE: AeroElectric-List: Generator suppressor --> At 06:20 AM 6/19/2012, you wrote: >--> > >Thanks Bob, > >I was thinking along the same lines. It seems to me that these are >simply a broad spectrum smoothing filter. I think that I will test run >the generator on my lathe and have a look at the output on a scope to >see if it looks too >rough- a mass produced line filter may just do the job if any smoothing >is required. > >Jay That's probably more trouble than it's worth. Generators produce a lot of trash. A 'scope picture is almost never informative. A spectrum analyzer would give you a notion of potential EMC problems but know that DO-160 calls for 'qualified' devices to shrug off up to 1.5 volts pk-pk over 1 to 5 kHz http://tinyurl.com/78kwfk8 and lesser amounts above and below. A 'scope picture of this is pretty spectacular. Alternators are less 'spikey' but still offer considerable ripple voltage. Any filters you might need would go to issues in the RF spectrum http://tinyurl.com/7wrhxbg and cannot be observed in a time domain display. Bob . . . ________________________________ Message 10 ____________________________________ Time: 10:24:37 AM PST US Subject: AeroElectric-List: Re: Viking Schematic From: "user9253" Bob, My friend is building an RV-12 with an automotive engine, the Viking, which is fuel injected and electrically dependent. The power requirements for the ECU are not known but Viking uses 15 amp fuses. http://www.vikingaircraftengines.com/Wiring%20page.html I do not like the electrical drawing on the Viking website because there are several possible points of failure all in series and supplying power to the engine through only one wire. I suggested to my friend that he use one of your drawings but he said they were too complicated. I tried to simplify by removing the E-Bus and E-Bus diode, while still having a redundant power source for the ignition and fuel pumps without having always hot wires pass through the firewall. The ignition and fuel pumps are located on the opposite side (aft) of the firewall from the engine. If the Alternate Feed Switch is turned on, the engine start circuit is disabled. This will prevent starting current from flowing through the Alternate Feed Relay and damaging its contacts. It is intended that the Alternate Feed Switch be turned on after starting and left on for the remainder of the flight. My friend prefers circuit breakers even though I recommended fuses. He also wants to keep weight down by not having a starter contactor. The Main Bus receives power at each end of the bus. If one connection should fail, the other will still provide power to the bus. The engine should keep running with power coming from only the Alternate Feed Relay or only from Master Contactor or only from the Alternator. The Viking ECU has two independent (almost) units in one enclosure, although it only has one wire supplying power. There is no pin-out available for the ECU 37-Pin D-Sub. The only information comes from the Viking website. The ECU has a SELECT wire that enables one of the two units, depending on whether the voltage on that wire is high or low. At least that is what I deduced from the scant information on the Viking website. The major difference between your excellent drawings and my schematic is that I have eliminated the E-Bus diode and replaced it with part of the Alternate Feed switch to prevent starting current from flowing though the Alternate Feed Relay contacts. Now, without that E-Bus diode, I am having second thoughts about possible reverse current due to faults in the starter or alternator circuit. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=376092#376092 ________________________________ Message 11 ____________________________________ Time: 12:52:21 PM PST US From: David Josephson Subject: AeroElectric-List: Re: OBS resolver signals On 6/17/12 11:56 PM, AeroElectric-List Digest Server wrote: > Can anyone explain or point me at any documentation that explains the OBS > resolver signals for setting the course on a NAV set, e.g. a King 165. > > What I know is the the NAV set produces a rounded off square wave at either > 30HZ or 300HZ. The OBS knob then returns two signals representing the sine > and the cosine of the position. So for example sine of 90 degrees is 1 and > cos is zero, sine of 270 degrees is -1 and cos is still 0 > > What I don't know is whether the returning signals go negative (the older > CDIs use transformer technology so could easily produce negative voltage) or > whether they are referenced to the mid point of the excitation signal and > whether the excitation signal itself goes negative or it just varies between > 0 and the reference voltage. If you want to interface with a KX165 you might look at the schematic of that unit, but the nav radios I'm familiar with (just checked a couple of older King and Radair schematics) are all capacitor-coupled so the signal should stay positive with respect to the audio reference ground. Some CDIs may have a transformer input to prevent ground loops -- the return side of the transformer would be run back to the nav radio audio reference ground rather than through the airframe. A VOR station transmits a reference subcarrier at 9.96 kHz, frequency modulated with a 30 Hz tone, and amplitude modulation, also of a 30 Hz tone. The phase angle between the 30 Hz frequency modulation of the subcarrier, and the 30 Hz amplitude modulation of the main carrier, corresponds to the angle between north and the direction from the station to you. The audio input from the nav receiver contains both the 30 Hz AM tone and the 9960 Hz subcarrier with its FM reference modulation. The CDI or VOR converter demodulates the 9960 Hz carrier so you now have two 30 Hz tones. The resolver introduces a known phase shift in the reference; when you turn the OBS knob, you change the amount of phase shift. The VOR needle is driven by a phase comparator that measures the phase difference between the 30 Hz variable signal and the demodulated and phase-shifted 30 Hz reference signal. When the needle centers, the phase shift is zero because the resolver has introduced a phase shift equal to the phase difference between the two 30 Hz signals. Localizer is a different signal entirely but sent on the same wire; there are two tones, 90 and 150 Hz, and the needle reflects the ratio between the amplitude of the two tones. When you are on the centerline of the localizer, you're receiving equal signals from the two sets of antennas on either side of the centerline, one of which is transmitting with 90 Hz modulation and the other with 150 Hz. ________________________________ Message 12 ____________________________________ Time: 01:12:09 PM PST US From: "Rob Henderson" Subject: AeroElectric-List: Antenna length Hi all I would like to make a couple of antennas for my Glastar. Does anyone know what the length is for dipole, or any reason not to "role my own". Transponder: Comm: Nav: Marker: Glide Slope: UAT: I will be using Garmin GTX327 SL30 GMA340 Navworxs ADSB Thanks in advance for all advice -Rob Henderson ________________________________ Message 13 ____________________________________ Time: 02:21:41 PM PST US From: Peter Pengilly Subject: Re: AeroElectric-List: Antenna length It is straight forward to figure out the length required from the frequency of the signal, velocity = frequency x wave length so wave length = vel/freq Using SI units (coz its just easier than imperial) Velocity = 3 x 10^8 m/s Freq = 118 to 137 MHz (so centre freq is 126.5 x 10^6 Hz) So wave length = 3/1.265 m = 2.37m ( about 93 inches) Most dipoles are half wave, a lot of aircraft antennas are quarter wave. Wikipedia (or the Aeroelectric connection) can probably explain better than me - less change of remembering the basic physics wrong! Peter On 19/06/2012 21:11, Rob Henderson wrote: > > Hi all > > I would like to make a couple of antennas for my Glastar. > > Does anyone know what the length is for dipole, or any reason not to > "role my own". > > Transponder: > > Comm: > > Nav: > > Marker: > > Glide Slope: > > UAT: > > I will be using Garmin > > GTX327 > > SL30 > > GMA340 > > Navworxs ADSB > > Thanks in advance for all advice > > -Rob Henderson > > * > > > * ________________________________ Message 14 ____________________________________ Time: 04:55:08 PM PST US From: "John MacCallum" Subject: RE: AeroElectric-List: Antenna length A rough rule of thumb for a free space dipole is:- 299.8/126.5=2.3669m (speed of light divided by the Frequency) 2.3669 * 0.97=2.2989m (Adjusted for the end effect) 2.2989/2=1.1494m (divide by 2 to make a half wave dipole) 1.1494m / 0.0254 (because the US still has not converted to metric) (Couldn=92t resist that one ) 45.25 inches (but make it slightly longer maybe 45.5 inches so you can adjust it by trimming equally on both sides) Cut this in two to make the two halves of the dipole and keep the feed points reasonably close together, Say around =BD an inch, then check with an SWR meter. (If the lowest SWR is below 126.5 mhz then the antenna is trimmed slightly on both ends by say 1/16=94 a time) And the SWR rechecked. If you want to make a qtr wave antenna like the Comant Antennas you see on a lot of Aircraft then make the Antenna about 22.8 inches long and Once again trim for desired SWR spread with an SWR meter. Just remember not to try a use a Dipole inside a Carbon fibre structure since the Carbon fibre is conducive. In the end even though I have made many antennas over the years I decided to buy Comant Antennas for my RV10. Cheers John MacCallum VK2 -GCN Builder #41016 VH-DUU From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Peter Pengilly Sent: Wednesday, 20 June 2012 7:20 AM Subject: Re: AeroElectric-List: Antenna length It is straight forward to figure out the length required from the frequency of the signal, velocity = frequency x wave length so wave length = vel/freq Using SI units (coz its just easier than imperial) Velocity = 3 x 10^8 m/s Freq = 118 to 137 MHz (so centre freq is 126.5 x 10^6 Hz) So wave length = 3/1.265 m = 2.37m ( about 93 inches) Most dipoles are half wave, a lot of aircraft antennas are quarter wave. Wikipedia (or the Aeroelectric connection) can probably explain better than me - less change of remembering the basic physics wrong! Peter On 19/06/2012 21:11, Rob Henderson wrote: Hi all I would like to make a couple of antennas for my Glastar. Does anyone know what the length is for dipole, or any reason not to =93role my own=94. Transponder: Comm: Nav: Marker: Glide Slope: UAT: I will be using Garmin GTX327 SL30 GMA340 Navworxs ADSB Thanks in advance for all advice -Rob Henderson ________________________________ Message 15 ____________________________________ Time: 07:17:56 PM PST US Subject: Re: AeroElectric-List: Antenna length From: "DeWitt (Dee) Whittington" Rob, You should already have Comm I inside your vertical. For our Sportsman we bought the very economical Bob Archer antennas for our Comm II, transponder, and marker beacon. When we checked the two Comm antennas for SWR they measured 1.1 which as far as I know is excellent. The glideslope antenna is the 5T from Advanced Aircraft Electronics, Inc. http://www.advancedaircraft.com/, in Alberqurgue which we mounted crossways just behind Bulkhead A. Our ADS-B antenna came from: Delta Pop Aviation 978 MHz ADS-B *Antenna* Dee Whittington On Tue, Jun 19, 2012 at 4:11 PM, Rob Henderson wrot e: > Hi all**** > > I would like to make a couple of antennas for my Glastar.**** > > Does anyone know what the length is for dipole, or any reason not to =93r ole > my own=94.**** > > ** ** > > Transponder:**** > > Comm:**** > > Nav:**** > > Marker:**** > > Glide Slope:**** > > UAT:**** > > ** ** > > I will be using Garmin**** > > GTX327**** > > SL30**** > > GMA340**** > > Navworxs ADSB**** > > Thanks in advance for all advice**** > > -Rob Henderson**** > > * > =========== =========== =========== =========== > * > > -- DeWitt Whittington www.VirginiaFlyIn.org Building Glasair Sportsman with 3 partners ------------------------------------------------------------------------------------- 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.