AeroElectric-List Digest Archive

Mon 01/19/09


Total Messages Posted: 14



Today's Message Index:
----------------------
 
     1. 01:16 AM - GT-50 G-meter (Martin & Chris)
     2. 05:13 AM - Re: Feedline Radiation in Composite Airplane (h&jeuropa)
     3. 06:50 AM - Static wicks (Jesse Jenks)
     4. 07:31 AM - Re: Static wicks (Harley)
     5. 08:38 AM - Wig Wag system (Jay Hyde)
     6. 08:42 AM - Bridge Rectifier Terminal Identification (Jay Hyde)
     7. 09:23 AM - Re: Static wicks (BobsV35B@aol.com)
     8. 09:33 AM - Re: Bridge Rectifier Terminal Identification (Robert L. Nuckolls, III)
     9. 09:48 AM - Re: Bridge Rectifier Terminal Identification (Sam Hoskins)
    10. 10:10 AM - Re: Wig Wag system (marcausman)
    11. 10:59 AM - Re: Feedline Radiation in Composite Airplane (Robert L. Nuckolls, III)
    12. 08:24 PM - Re: Re: Wig Wag system (Ed Holyoke)
    13. 09:52 PM - Re: Wig Wag system (marcausman)
    14. 10:50 PM - Thoughts on the least evil antenna placements (rparigor@SUFFOLK.LIB.NY.US)
 
 
 


Message 1


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    Time: 01:16:26 AM PST US
    From: Martin & Chris <aerobiz@optusnet.com.au>
    Subject: GT-50 G-meter
    Hi Peter, I have fitted the GT-50 to both my aircraft ( one still under construction) but I find it a very reasonably priced and accurate instrument with a number of usefull functions. I wired it as per the instructions, which means running the 'always on' wire direct to the battery. Never had a problem with the Odyssey PC680 starting the RV-6, but then again, I try and fly at least once a week. If you are worried about battery drain, leave it disconnected till you need it or put a switch in-line. Just means that the clock function will be only accurate twice a day..... Martin in Oz


    Message 2


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    Time: 05:13:45 AM PST US
    Subject: Re: Feedline Radiation in Composite Airplane
    From: "h&amp;jeuropa" <butcher43@att.net>
    Had a similar problem with our Europa. Made a balun similar to the AeroElectric you mentioned. Also tuned the antenna using a Antenna Analyzer. Contact a local ham radio club to see if anyone has an Analyzer. The balun that Bob describes, I found most references say that the the balun stub needs to be an electrical quarter wave, so you have to shorten by the velocity factor of the coax. Balun will probably help a lot. I never could get ferrite beads to do much. I also shielded some items with aluminum foil that is grounded to the aircraft ground point and used shielded cable for wiring. Jim Butcher Europa XS N241BW Read this topic online here: http://forums.matronics.com/viewtopic.php?p=225637#225637


    Message 3


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    Time: 06:50:51 AM PST US
    From: Jesse Jenks <jessejenks@hotmail.com>
    Subject: Static wicks
    I have always wondered why (most) certified airplanes have static wicks=2C but not homebuilts? This makes me want to know what their actual function i s? I was always taught "they dissipate static electricity". Is static reall y that big of an issue=2C and if so=2C do wicks actually make a difference? I'm building an all metal airplane=2C and so far have not given any though t to control surface bonding=2C or static wicks. Thanks. _________________________________________________________________ Windows Live=99: Keep your life in sync. http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_012009


    Message 4


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    Time: 07:31:39 AM PST US
    From: Harley <harley@AgelessWings.com>
    Subject: Re: Static wicks
    They can work to dissipate static if they are attached to a conducting surface. That way, they can bypass whatever is creating the static and insulating the object from a normal ground (like the plastic or rubber tires on a fork lift). But on many homebuilts, the plane is made of non conducting materials (wood and fabric or fiberglass and/or epoxy), and a static wick will only discharge the point that it is attached. A couple of inches away from that point, the charge remains as strong as ever. I had many a discussion with fork lift drivers at Pennwalt when they would attach a static wick to the plastic part of the frame on the truck (it was easier to drill a hole into), and then complain that they still got zapped when they stepped off the truck. For those that really thought they needed it, we would attach the wicks to the metal frame under the truck. But, that often didn't help either, because the wick was often dragging on a non conducting surface (epoxy sealed floors). Also, the line operators used vacuum cleaners to pick up the spilled foot powder...even though they used a so-called static proof hose (it had a grounded wire spiraling along the length of it) they would still get zapped when they put the hose down. The charge was decreased, because of the presence of the wire, but still built up on the hose between the wire coil wraps. In short, you need a continuous conductive path to discharge a static charge. From every area where the charge can build. Harley ------------------------------------------------------------------------ Jesse Jenks wrote: > I have always wondered why (most) certified airplanes have static > wicks, but not homebuilts? This makes me want to know what their > actual function is? I was always taught "they dissipate static > electricity". Is static really that big of an issue, and if so, do > wicks actually make a difference? I'm building an all metal airplane, > and so far have not given any thought to control surface bonding, or > static wicks. > Thanks. > > ------------------------------------------------------------------------ > Windows Live^(TM): Keep your life in sync. Check it out. > <http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_012009> > > * > > > * > ------------------------------------------------------------------------ > > > Agelesswings certifies that no virus is in this incoming message. > Checked by AVG - http://www.avg.com > >


    Message 5


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    Time: 08:38:47 AM PST US
    From: "Jay Hyde" <jay@horriblehyde.com>
    Subject: Wig Wag system
    These sound very interesting, but what is it suppoed to do???!! :-) -- This message has been scanned for viruses and dangerous content by Pinpoint, and is believed to be clean.


    Message 6


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    Time: 08:42:34 AM PST US
    From: "Jay Hyde" <jay@horriblehyde.com>
    Subject: Bridge Rectifier Terminal Identification
    How do you figure out which terminals are which on one of these potted bridge rectifiers? There are 3 tabs oriented the same way and one at 90 deg to the others. my multimeter doesn't help either; I get 500 ohm between the 'ood' tab and two of the others when positively biased and infinite when negatively biased.. Help? -- This message has been scanned for viruses and dangerous content by Pinpoint, and is believed to be clean.


    Message 7


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    Time: 09:23:39 AM PST US
    From: BobsV35B@aol.com
    Subject: Re: Static wicks
    Good Morning Jesse, I have almost no experience in homebuilt aircraft, but I do have several thousand hours in aircraft that were equipped with static wicks and several thousand hours in aircraft with no static wicks applied. My suggestion would be to thoroughly bond all control surfaces, flaps included, but not bother with static wicks unless you note a problem. The static problem was greater in the days of low frequency radio. It was not at all uncommon to lose all communication capability when we were using the HF transmitters and receiving on low frequency. I have encountered precipitation static strong enough to knock out VHF communications for just a very few minutes, but that has never lasted more than four or five minutes. I have also experienced static discharges, but that has always been on aircraft that were equipped with static wicks. There is no doubt that I have flown in much heavier precipitation in static wick equipped airplanes than I have in airplanes that are not so equipped, but I have flown both in some rather severe situations. Wait and see if you have a problem. If you lose VHF navigation capability in a heavy thunderstorm, you may want to add static wicks or you may just decide to stay out of such conditions! In any case, I have never seen a GPS signal affected by any static build up. The only time I would suggest using static wicks is if your only means of navigation is a LORAN. Even then, you don't need it if you stay out of precipitation. Summary? Bonding YES, Static Wicks? NO Happy Skies Old Bob AKA Bob Siegfried Ancient Aviator 628 West 86th Street Downers Grove, IL 60516 630 985-8502 Stearman N3977A Brookeridge Air Park LL22 In a message dated 1/19/2009 8:52:32 A.M. Central Standard Time, jessejenks@hotmail.com writes: I have always wondered why (most) certified airplanes have static wicks, but not homebuilts? This makes me want to know what their actual function is? I was always taught "they dissipate static electricity". Is static really that big of an issue, and if so, do wicks actually make a difference? I'm building an all metal airplane, and so far have not given any thought to control surface bonding, or static wicks. Thanks. **************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! cemailfooterNO62)


    Message 8


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    Time: 09:33:01 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Bridge Rectifier Terminal Identification
    At 10:47 AM 1/19/2009, you wrote: >How do you figure out which terminals are which >on one of these potted bridge rectifiers? There >are 3 tabs oriented the same way and one at 90 >deg to the others=85 my multimeter doesn=92t help >either; I get 500 ohm between the =91ood=92 tab and >two of the others when positively biased and infinite when negatively biased.. > >Help? See: http://aeroelectric.com/Pictures/Misc/s401-25.jpg Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ----------------------------------------


    Message 9


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    Time: 09:48:50 AM PST US
    Subject: Re: Bridge Rectifier Terminal Identification
    From: Sam Hoskins <sam.hoskins@gmail.com>
    B&C shows this: http://www.bandc.biz/Diode_Installation.pdf On Mon, Jan 19, 2009 at 11:31 AM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > At 10:47 AM 1/19/2009, you wrote: > > How do you figure out which terminals are which on one of these potted > bridge rectifiers? There are 3 tabs oriented the same way and one at 90 deg > to the others=85 my multimeter doesn't help either; I get 500 ohm betwee n the > 'ood' tab and two of the others when positively biased and infinite when > negatively biased.. > > Help? > > > See: > > http://aeroelectric.com/Pictures/Misc/s401-25.jpg > > Bob . . . > > ----------------------------------------) > ( . . . a long habit of not thinking ) > ( a thing wrong, gives it a superficial ) > ( appearance of being right . . . ) > ( ) > ( -Thomas Paine 1776- ) > ---------------------------------------- > > > * > =========== =========== =========== =========== > * > >


    Message 10


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    Time: 10:10:10 AM PST US
    Subject: Re: Wig Wag system
    From: "marcausman" <marc@verticalpower.com>
    These flash the landing lights so that you can been more easily while in the air. This is built into the Vertical Power system, or you can buy and wire a separate "black box" to do this. More advanced ones (like Vertical Power) will warm up the lights for a short period of time before flashing, and/or turn off the pulsing automatically on the ground and turn it on automatically in the air. -------- Marc Ausman http://www.verticalpower.com RV-7 IO-390 Flying Read this topic online here: http://forums.matronics.com/viewtopic.php?p=225705#225705


    Message 11


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    Time: 10:59:32 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Feedline Radiation in Composite Airplane
    At 05:48 PM 1/18/2009, you wrote: > >I'm trying to help a builder kill the dragon in the subject line- > >Specifics: Garmin SL-30/40 with RG-400 to dipole on vertical stab >spar immediately in front of rudder, terminated with ring >connectors/screws/nuts. Coax terminated at radio using the supplied >90 deg. Garmin/Apollo fitting and runs with other wiring through >center floor tunnel to rear of plane, passing within about 12" from >pitch servo. Dipole is two aluminum bars, 1/2"x1/16"x20" long for >each element (I know this is a bit short- packaging issues. Optimum >would be about 44" overall length, I believe) > >On com transmission, several systems are affected- Ray Allen trim >LEDs dim, indicated EGT/CHT temps rise (EIS), and most excitingly, >the autopilot (TruTrak) will occasionally re-direct the aircraft if >engaged, usually in a pitch-up of variable amounts depending on >frequency transmitting on. Usually worse at lower com freqs. > >My own research (Wikipedia has a pretty good article on dipole >antennas(ae?) with several balun examples at end of article: >http://en.wikipedia.org/wiki/Dipole_antenna ) indicates the coax is >radiating lots of nasties off the shield, which I assume is making >the mischief. > >Material from the Aeroelectric site ( >http://www.aeroelectric.com/articles/BALUN/Balun_Fabrication.html ) >describes a balun for nav- is this same approach suitable for com? > >We've tried several ferrite ring arrangements, clamped around coax >at various locations, rings near the antenna end etc. Most >effective has been using a "ring", actually a small block that has >two parallel holes through it- the center conductor at the antenna >end is passed through one hole and back through the other in a tight >"U" turn then connected to the element. I suspect this is helping >simply by reducing the overall power output as it warms to the touch >after a few transmissions by absorbing some of the RF energy in the conductor? > >A complicating factor may be that the rudder is attached by a >contiuous stainless steel hinge pin that parallels the antenna >full-length a bit over one inch away from it, but even with this pin >removed, ground testing does not seem to indicate much of a change >in the symptoms. >Perhaps separating the upper and lower half of this pin and >connecting the coax to them as the antenna elements might be a neat experiment? > >Also read >http://www.aeroelectric.com/articles/Morris_Com_Loop_Antenna.pdf and >curious if anyone can comment. This would fit into the tailcone >nicely, but place the antenna loop within about 12-14" of the >magnetometer and pitch servo. > >Any advice/insight/suggestions appreciated! It's not likely that you're suffering from the effects of feedline radiation. Most avionics devices for the TC aircraft side of the house have deep roots in designs optimized for metal aircraft. A conductive airframe offers considerable isolation between potential victims inside the airplane from energies emitted by antennas outside the airplane. With the advent of composite aircraft, our brothers have found it prudent to qualify their products at much higher levels of radiated susceptibility. Virtually every instance in my experience for mitigating a radiated susceptibility symptom involved combinations of reduced radiation (move victim/antenna further apart) or improving on the victim's ability to stand off the more aggressive antagonist. Ferrite beads over a coax are almost useless for de-coupling the shield radiation of a poorly terminated coax. I witnessed a demonstration in the lab wherein a technician first terminated a 50 ohm coax with a 200 ohm load (4:1 swr). You could watch the swept frequency SWR display and witness a small change in presentation when you grabbed the coax with your hand. This happens only if there are components of the feedline energy flowing on the outside of the coax. He added a half dozen donuts to the feedline right at the end. There was no discernable benefit for having added the beads. He then put all beads he had on the coax . . . something over 20 pieces. You you see SOME benefit but it was still not zero. But in any case, the ratio of energy radiated from a poorly matched coax versus radiated from the physical antenna is huge. It's most likely that you're suffering from the effects of sitting inside sphere of strong radio frequence energy. Adding a balun would not hurt anything. http://www.aeroelectric.com/Reference_Docs/Antenna/BALUN_Analysis.pdf http://www.aeroelectric.com/articles/BALUN/Balun_Fabrication.html Note that this balun does NOT use energy carried inside the coax as part of the reactie network. Thus you'll note that dimensions for the 1/4 wave balun element and the antenna element are the same length (open-air 1/4-wave). Shorten the 26" dimensions to 23" for the comm antenna. Then adjust ends of antenna elements for lowest swr in center of range of interest (125 mhz). Now, assuming this does not produce the hoped-for result, you'll need to look at individual victims for ways they can be made more tolerant of the environment in which they're expected to perform. Bob . . .


    Message 12


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    Time: 08:24:11 PM PST US
    From: Ed Holyoke <bicyclop@pacbell.net>
    Subject: Re: Wig Wag system
    I wig wag them on the ground to try and get the attention of all the idiot drivers running around on the taxiways not looking out for airplanes. I definitely don't want to turn 'em off automatically on the ground. Pax, Ed Holyoke marcausman wrote: > > These flash the landing lights so that you can been more easily while in the air. This is built into the Vertical Power system, or you can buy and wire a separate "black box" to do this. > > More advanced ones (like Vertical Power) will warm up the lights for a short period of time before flashing, and/or turn off the pulsing automatically on the ground and turn it on automatically in the air. > > -------- > Marc Ausman > http://www.verticalpower.com > RV-7 IO-390 Flying > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=225705#225705 > > >


    Message 13


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    Time: 09:52:26 PM PST US
    Subject: Re: Wig Wag system
    From: "marcausman" <marc@verticalpower.com>
    Pat, You can always turn off the feature so it will wig-wag all the time if that's what you want. :) Nice thing is it is configurable using menus (to match each builder's needs) rather than hard wired. -------- Marc Ausman http://www.verticalpower.com RV-7 IO-390 Flying Read this topic online here: http://forums.matronics.com/viewtopic.php?p=225820#225820


    Message 14


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    Time: 10:50:55 PM PST US
    Subject: Thoughts on the least evil antenna placements
    From: rparigor@SUFFOLK.LIB.NY.US
    Wondering if I could get opinions on the least evil antenna placements on my Europa XS Monowheel. Have a Bob Archer "E" style com #1antenna in vertical fin for Becker com. The question I have is about placement of my Vertex handheld (panel mounted)nav com antenna. It is an AAE that will be bent in half at 90 degrees so it should work equal as bad on nav as it does on com (AAE said it should work about 70% of proper orientation for each) I have a 121.5 / 246 ELT antenna mounted on floor aft of D panel in baggage bay and will have AAE transponder antenna mounted at least 20" away (aft) of AAE nav com antenna for Becker 250 watt mode C transponder. Now for opinion needed, A or B: A) Mount AAE nav com on starboard side which place it 22" away from ELT antenna (same frequency) but allow the RG400 antenna wire to go forward at 90 degrees for 22", then down at a 45 degree angle for 1 foot, then a 45 degree andforward for a long ways. Thus this routing puts antenna closer to ELT but has a friendlier wire exit. B) Place AAE nav com antenna 28" away from ELT which is 6" further away from ELT compared to A, but exiting wire run is not as friendly: The RG 400 antenna wire can exit at 90 degrees for 22", thengo down at a 45 degree angle for 1 foot, then needs to make a 90 degree angle horizontal for 29" (this will be parallel to the nav half of the antenna about 32" away), than make a 90 degree angle and go forward for a long ways. OK what is the least evil, A or B? Or any ideas welcome on a choice "C" Thanking you in advance Ron Parigoris




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