---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 09/05/10: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:44 AM - LED as LV Annunciator (jonlaury) 2. 10:39 AM - Re: LED as LV Annunciator (Robert L. Nuckolls, III) 3. 11:18 AM - IFR in with a JAB3300 + SD8 (Robert L. Nuckolls, III) 4. 01:17 PM - Now, Jeff (Fergus Kyle) 5. 01:17 PM - Re: LED as LV Annunciator (jonlaury) 6. 01:26 PM - Re: Re: LED as LV Annunciator (Robert L. Nuckolls, III) 7. 02:12 PM - Re: Now, Jeff (darnpilot@aol.com) ________________________________ Message 1 _____________________________________ Time: 08:44:22 AM PST US Subject: AeroElectric-List: LED as LV Annunciator From: "jonlaury" I want to use an LED as a LV annunciator. But from the products that AEC lists for driving LED's and what they do, I gather that using LED's over incandescent lamps can cause noise problems. Does using a couple of LED's with the appropriate resistor create noise antagonists? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=311437#311437 ________________________________ Message 2 _____________________________________ Time: 10:39:28 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: LED as LV Annunciator At 10:42 AM 9/5/2010, you wrote: > >I want to use an LED as a LV annunciator. > >But from the products that AEC lists for driving LED's and what they >do, I gather that using LED's over incandescent lamps can cause >noise problems. You must be reading the information published concerning noise issues on POWER SUPPLIES used to excite high intensity arrays of LEDs. Emacs! In this case, it's the electronics that becomes a potential antagonist for sensitive victims. It was a potential cum reality that prompted a re-packaging of the LuxDrive power supplies on a filter board as shown above. >Does using a couple of LED's with the appropriate resistor create >noise antagonists? The LED is probably 10x noisier than other diodes . . . but take that with a grain of salt. Virtually ALL electronic devices passing current generate some noise. But in the case of diodes, resistors and such, the amount of is so tiny as to require special receivers just to go find it . . . the garden variety instrumentation system wont know it's there. So install as many LEDs and companion resistors as needed to meet your design goals. Noise potential has no practical significance. Bob . . . ________________________________ Message 3 _____________________________________ Time: 11:18:11 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: IFR in with a JAB3300 + SD8 At 01:38 AM 9/5/2010, you wrote: Thanks Bob It would only be occasional penetration of cloud for getting in or out not planning to cruise in IMC. My load analysis is cruise about 15 amps but on approach in Imc with lights off (all leds) and pitot on load is about 17 so not much margin with the J3300 alternator (I'm estimating about 6 amps for a dual screen Dynon skyview system ) Just don't want a discharge light on half way through an approach ! Maybe its overkill to go dual Alternators ? Not 'overkill' assuming that the alternators are evaluated for performance while paralleled with each other. What we're discussing is risk reduction. If you're crafting a system where intended use demands high order of reliability for BOTH alternators, it's not clear to me that the Jab 3300 paralleled with an SD8 is a good choice. Pitot heat is not a particularly useful feature on a small airplane. If it's your intent to spend some time in the clouds at temperatures conductive to ice accumulation, then having a pitot heater is "whistling in the dark". Forgive me an anecdotal example: Late in my career as a student, I was wanting to go do some 'real' IFR. One weekend found me at ICT unable to go flying by myself . . . but there was a real cool, 2000 foot layer that looked like a good practice opportunity. After some badgering, my instructor relented. I planed and filed an IFR to Hutchinson some 40 miles N.E. of Wichita. We punched through out of Wichita but the Hutch controller put me down into the clouds for crossing the VOR fix several miles S.W. of Hutch. I eagerly dived in, kept all the needles mostly centered to the VOR, turned out to the marker, crossed the marker, captured the LOC outbound and did the procedure turn. Was really proud of myself for keeping all the needles centered until I broke out. Grinning ear to ear I finished the approach and just as I started the flare to put wheels on the ground, the airplane fell out of sky and plopped down pretty hard. I looked over at the instructor who was smiling. "Taxi in he says, and let's talk". When we got parked, we pile out of the airplane and he showed me what he had been observing while I was busy grinning at the gages. During our 12 or so minutes in the clouds, a thin strip of VERY hard ice was building on the stagnation point of the wing's leading edge. Nothing serious from the standpoint of weight or drag but significant in terms of flying qualities. The airplane didn't have pitot heat so he had been watching for signs of IAS indication to degrade. He was of the opinion that it would also have offered a good teaching moment. He admonished me that I COULD have requested and would have been granted permission to do all the maneuvers to final above the clouds. All that preliminary stuff is just to get you on the beams at ANY appropriate altitude. He also made a good point that just because you don't see stuff on the windshield doesn't mean it isn't on the prop and leading edges. The ice was so hard that I had to put the airplane into a hangar and warm it up. Further, since I reported ice to ground control, I had essentially closed the airport for my departure until at least several more flights arrived behind me without reporting ice. That's ONE way to turn a 2 hour adventure into a 4 hour study in aviation realities. I'm thinking that your dual alternator installation is just fine where the SD-8 is the occasional backup for the main alternator. Your main alternator is rated for 22A intermittent (which you could probably boost to continuous duty with some well considered cooling). If you can give up the pitot heater, then you MAY be home free. Also, go find out how much the the built in alternator and the SD-8 will do for output at RPMs appropriate to approach configurations. Don't guess, go get the numbers. Then modify plan-A, plan-B contingencies to match. Having said all that, it's a really good idea to go do practice approaches in the same configuration you plan to use for real approaches. Bob . . . ________________________________ Message 4 _____________________________________ Time: 01:17:18 PM PST US From: "Fergus Kyle" Subject: AeroElectric-List: Now, Jeff We realise you have a problem on your hands and hasten to attempt some sort of solution BUT your 16 line message took a total of 240 lines of cyber space and display manoeuvring to accomplish it. If four of us answered with ten lines each, using your transcript routine, it would take 1500 lines to scroll through to acquire them. Don't make me come out there! I know. Cheers, Ferg ________________________________ Message 5 _____________________________________ Time: 01:17:29 PM PST US Subject: AeroElectric-List: Re: LED as LV Annunciator From: "jonlaury" Bob, Thank you for that illumination. (I couldn't resist;-) Ohmy God! This is getting revolting! I seem stuck here no matter watt I do. John Do not archive Read this topic online here: http://forums.matronics.com/viewtopic.php?p=311459#311459 ________________________________ Message 6 _____________________________________ Time: 01:26:37 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: LED as LV Annunciator At 03:16 PM 9/5/2010, you wrote: > >Bob, >Thank you for that illumination. (I couldn't resist;-) Ohmy God! >This is getting revolting! I seem stuck here no matter watt I do. Better to be "stuck" in the light as opposed to wandering in the dark. We all started from right where you are now. Bob . . . ________________________________ Message 7 _____________________________________ Time: 02:12:34 PM PST US From: darnpilot@aol.com Subject: Re: AeroElectric-List: Now, Jeff > I'll try to apply the protocol of the day. I'm still learning this list and how it automatically configures replies. 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