---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 01/30/13: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:13 PM - Re: Grounding a Super Cub (Peter Pengilly) 2. 01:26 PM - (Bill Settle) 3. 05:03 PM - Re: (Robert L. Nuckolls, III) 4. 06:20 PM - Re: Grounding a Super Cub (Tundra10) 5. 06:41 PM - Re: Re: Grounding a Super Cub (Bill Bradburry) ________________________________ Message 1 _____________________________________ Time: 12:13:48 PM PST US From: Peter Pengilly Subject: Re: AeroElectric-List: Grounding a Super Cub Not trying to cause any trouble here!!! My airplane is a single seat aerobatic One Design - I was very keen to keep weight to a minimum, and I wasn't too concerned about the compass (definitely VFR only). To ensure good starting I decided to 'spend' 2lb on a Sky-tec NL starter - which draws much less current than a permanent magnet type (also achieves better engagement on starter ring, but that may have been a peculiarity of my engine). With a PC680, starter solenoid on top of battery and once length of wire from solenoid to starter so far starting has been good, even in damp, cold weather after several weeks of inactivity. I could have gone with Eric's copper covered aluminium wire, but I had the copper wire to hand ... If I was going to use heavy gauge both ways I would definitely use his Super-CCA wire. Thinking about it I guess my design goals might not be that similar to a Tundra or Super Cub builder! Peter On 30/01/2013 05:17, Robert L. Nuckolls, III wrote: > > > >> I have tube & fabric aircraft with an IO-360 and the battery in the >> back. I have a tab welded on on the engine mount and a tab welded on >> the frame near to the battery both used for earth strap connection. >> What is the down side of putting very short duration starter current >> through the engine mount, and equally through the fuselage frame? > > They're magnetic materials . . . steel . . . > with higher resistance than copper. While > carrying high currents, the steel conductors generate > strong local magnetic fields which do not go > completely away after the current goes to zero. > > Remote battery grounding on aluminum airplanes is > less problematic . . . but many builders still run > starter currents through the engine mount and/or > fire wall sheet . . . for the most part they don't > perceive any problems. Performance degradation is > most likely to present during cold weather cranking. > > So MANY things pile on top of each other in cold > weather that one is unlikely to see much difference > fore wired vs. airframe battery ground. But a combination of > design and preventative maintenance efforts can > add up to a significant difference. Those would > include selection of starter, keeping the battery > well maintained, minimizing joints in the cranking > path, and in extreme conditions, warming the engine > and battery, etc. > >> Why would the (very thin) firewall be any better? > > It's not. I try NEVER to depend on fire wall sheet for anything > other than grounding of light draw accessories like case-ground > regulators, facet fuel pumps, starter contactors, etc. > >> Most people I know have saved the weight of a 2nd heavy gauge wire >> by using the fuselage frame as the ground return. > > Which is what's been done on thousands of airplanes > for 100+ years . . . but I'm aware of no study > that quantifies performance or maintenance issues > for having done so. > > My personal design goals call for a minimum number > of made up joints between battery (-) and crankcase > and avoid using airframe ground for all but the few > outlying appliances depicted in Figure Z-15. The ideal > battery ground is an engine-cranking-sized-wire from > battery(-) to fire wall single-point ground . . . and > a second conductor from single-point ground stud > to the crankcase. > > But if one wishes to embrace another philosophy, > it will probably function. > > > Bob . . . > > ________________________________ Message 2 _____________________________________ Time: 01:26:55 PM PST US From: Bill Settle Bob,=0A =0AI'm trying to figure out my LED Nav lights and I have a couple o f questions: I =0Abought a set of wingtip LED Nav lights from a builder of f of VAF who was =0Aproducing them prior to you offering your LuxDrive filt ers. They came with =0A700mA LuxDrive Power Pucks. After you started offe ring your filters, I bought a =0Acouple of those. They came with 1000mA Po wer Pucks. Can I use the 1000mA =0Amodels or should I reorder 700mA units? =0A=0A =0AWhen I received the filters, it came with a hand written sketch for a wiring =0Adiagram. I have since downloaded a newer schematic from y our website. =0AComparing the two, I see there is a difference in them con cerning pins 2 & 3. =0AOn the original hand written one, both pins are lab eled =9CN/C=9D. I assume this =0Ameans =9CNot Connected. =9D (?) The newer schematic shows pin 2 as 5v ref and pin 3 =0Aas =9CControl Dimming.=9D As I am not considering dimming my Nav lights, I don=99t =0Aneed to connect these, correct?=0A =0AAlso, on b oth drawings, pins 4 & 8 and pins 5 & 9 are common with each other. =0AIs this for one filter to drive two different Nav lights?=0A=0AThanks,=0ABill Settle=0ARV-8 ________________________________ Message 3 _____________________________________ Time: 05:03:40 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: At 03:24 PM 1/30/2013, you wrote: >Bob, > > >I'm trying to figure out my LED Nav lights and I >have a couple of questions: I bought a set of >wingtip LED Nav lights from a builder off of VAF >who was producing them prior to you offering >your LuxDrive filters. They came with 700mA >LuxDrive Power Pucks. After you started >offering your filters, I bought a couple of >those. They came with 1000mA Power Pucks. Were you wanting filter boards only for your 700mA devices? Are they the 3021 series devices with ECB pins? http://tinyurl.com/a4nltlv If so, you can trade your 1000 mA filtered supplies for filters + refund. > Can I use the 1000mA models or should I reorder 700mA units? As shown on the LuxDrive data sheet, you can 'dim' the 3021 series devices by connecting the appropriate resistor between CTRL and REF pins. Emacs! This adjustment sets a new operating current that is lower than the rated current for the device. > > >When I received the filters, it came with a hand >written sketch for a wiring diagram. I have >since downloaded a newer schematic from your >website. Comparing the two, I see there is a >difference in them concerning pins 2 & 3. On >the original hand written one, both pins are >labeled =9CN/C=9D. I assume this means =9CNot >Connected.=9D (?) The newer schematic shows >pin 2 as 5v ref and pin 3 as =9CControl >Dimming.=9D As I am not considering dimming my >Nav lights, I don=99t need to connect these, correct? You can wire a resistor (about 220 ohms I think) between 2 and 3 on the 9-pin connector to set your 1000 mA units to any desired lower current. I now offer bench adjusted power supplies wherein I attach a resistor to the bottom of the board that produces the desired maximum current . . . this lets me stock only one power supply (1000 mA) to service the full range of builder needs. In the future, I'll be re-laying the board to provide a clearance hole to the potentiometer that comes on the "I" devices. >Also, on both drawings, pins 4 & 8 and pins 5 & >9 are common with each other. Is this for one >filter to drive two different Nav lights? If your lamps are two strings of leds in series where each requires 1/2 of total current, then the extra pins enable that connection. Let me know what works for you. Bob . . . ________________________________ Message 4 _____________________________________ Time: 06:20:28 PM PST US Subject: AeroElectric-List: Re: Grounding a Super Cub From: "Tundra10" My friend has some 2AWG available from another project, so he will be using that. However, I tried to do a comparison between 2AWG and 4AWG, based on Bob's discussions of voltage at the starter motor. It seems that battery internal resistance and connection resistance are the most significant factors. I calculated that for his airplane it will cost 2.2 additional pounds to gain 4% more voltage at the starter. For my airplane, with the battery on the firewall, it would cost 0.8 pounds to gain 1.5% more voltage at the starter. I think longer cable runs are required before the lower resistance cable makes a significant difference. A battery with lower internal resistance makes the biggest difference of all. Jeff Page Dream Aircraft Tundra #10 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=393334#393334 ________________________________ Message 5 _____________________________________ Time: 06:41:39 PM PST US From: "Bill Bradburry" Subject: RE: AeroElectric-List: Re: Grounding a Super Cub Tell him to try some of this lightweight wire. http://www.periheliondesign.com/fatwires.htm Bill B -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Tundra10 Sent: Wednesday, January 30, 2013 9:19 PM Subject: AeroElectric-List: Re: Grounding a Super Cub My friend has some 2AWG available from another project, so he will be using that. However, I tried to do a comparison between 2AWG and 4AWG, based on Bob's discussions of voltage at the starter motor. It seems that battery internal resistance and connection resistance are the most significant factors. I calculated that for his airplane it will cost 2.2 additional pounds to gain 4% more voltage at the starter. For my airplane, with the battery on the firewall, it would cost 0.8 pounds to gain 1.5% more voltage at the starter. I think longer cable runs are required before the lower resistance cable makes a significant difference. A battery with lower internal resistance makes the biggest difference of all. Jeff Page Dream Aircraft Tundra #10 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=393334#393334 ------------------------------------------------------------------------------------- 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.