---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 03/18/06: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:19 AM - Re: Wire Gauge? (Eric M. Jones) 2. 07:50 AM - Re: Capacitor with solder on connectors? (Robert L. Nuckolls, III) 3. 08:17 AM - Re: Capacitor with solder on connectors? (J. Mcculley) 4. 09:05 AM - Re: Capacitor with solder on connectors? (Robert L. Nuckolls, III) 5. 09:46 AM - Re: Z-19 questions (Robert L. Nuckolls, III) 6. 09:48 AM - Re: Z-19 questions (Expanded) (Robert L. Nuckolls, III) 7. 10:22 AM - Headset and Mic Connections (SMITHBKN@aol.com) 8. 11:16 AM - Re: Z-19 questions (John Burnaby) 9. 01:39 PM - KN-73 and KX-125 (Jeff Bertsch) 10. 05:09 PM - Re: Re: Z-19 questions (Ken) 11. 09:17 PM - Re: Z-19 questions (John Burnaby) 12. 09:17 PM - Re: Re: Z-19 questions (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 07:19:39 AM PST US Subject: AeroElectric-List: Re: Wire Gauge? From: "Eric M. Jones" --> AeroElectric-List message posted by: "Eric M. Jones" Just a note that I still sell a lot of #4 and #2 Copper Clad Aluminum wire to builders. A free sample on email request. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones@charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=22479#22479 ________________________________ Message 2 _____________________________________ Time: 07:50:30 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Capacitor with solder on connectors? --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:53 AM 3/18/2006 +0000, you wrote: >--> AeroElectric-List message posted by: > >My partner purchased a 22,000 mF computer grade capacitor with a 35 volt >rating and 105C temperature rating for our Rotax 914. > >It has small solder on connectors, it looks like it is intended to be >soldered to a circuit board. In addition the connectors look like they are >tin plated brass, and use an aluminium rivet to fasten the connector to >the inside of the capacitor. > >If I strain relieve wires is this an acceptable capacitor to use? Give it a try. It can't do anything worse than break a terminal off making your system get noisy. You may not even perceive the increase in noise from the cockpit. >My partner figured getting the higher temperature rating of 105C compared >to 85C, and a 35 volt rating over 25V was better. Not a 'bad' thing to do . . . within bounds. Bigger and higher is better and will probably increase reliability. But one would be ill advised to pick a 450v device for a 14v application. We recommend the "computer grade" devices for this application because they're fitted with robust screw terminals much more convenient for installation. Further, this style of capacitor is generally rated for higher ripple currents . . . meaning it runs cooler under high alternator loading. See: http://www.aeroelectric.com/Pictures/Misc/Computer_Grade_Cap.jpg But give the device you have a try. There are no risks for damage to anything due to the capacitor coming unhooked. Depending on how your wiring arrangement lends itself to coming off the capacitor with some soft braided leads . . . make from short pieces of outer jacket of coax. Cover with heat shrink and use PIDG terminals or splices to connect capacitor into the system. Bob . . . < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > ________________________________ Message 3 _____________________________________ Time: 08:17:18 AM PST US From: "J. Mcculley" Subject: Re: AeroElectric-List: Capacitor with solder on connectors? --> AeroElectric-List message posted by: "J. Mcculley" Is it not wise to also put a fuse(or equivalent)protection in series with the capacitor to handle a possible dead short within the capacitor? Jim McCulley Robert L. Nuckolls, III wrote: > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > At 05:53 AM 3/18/2006 +0000, you wrote: > > >>--> AeroElectric-List message posted by: >> >>My partner purchased a 22,000 mF computer grade capacitor with a 35 volt >>rating and 105C temperature rating for our Rotax 914. >> >>It has small solder on connectors, it looks like it is intended to be >>soldered to a circuit board. In addition the connectors look like they are >>tin plated brass, and use an aluminium rivet to fasten the connector to >>the inside of the capacitor. >> >>If I strain relieve wires is this an acceptable capacitor to use? > > > Give it a try. It can't do anything worse than break > a terminal off making your system get noisy. You may > not even perceive the increase in noise from the cockpit. > > > >>My partner figured getting the higher temperature rating of 105C compared >>to 85C, and a 35 volt rating over 25V was better. > > > Not a 'bad' thing to do . . . within bounds. Bigger > and higher is better and will probably increase > reliability. But one would be ill advised to pick > a 450v device for a 14v application. > > We recommend the "computer grade" devices for > this application because they're fitted with robust > screw terminals much more convenient for installation. > Further, this style of capacitor is generally rated > for higher ripple currents . . . meaning it runs cooler > under high alternator loading. See: > > http://www.aeroelectric.com/Pictures/Misc/Computer_Grade_Cap.jpg > > But give the device you have a try. There are no risks > for damage to anything due to the capacitor coming unhooked. > Depending on how your wiring arrangement lends itself to > coming off the capacitor with some soft braided leads . . . > make from short pieces of outer jacket of coax. Cover with > heat shrink and use PIDG terminals or splices to connect > capacitor into the system. > > Bob . . . > > > > < What is so wonderful about scientific truth...is that > > < the authority which determines whether there can be > > < debate or not does not reside in some fraternity of > > < scientists; nor is it divine. The authority rests > > < with experiment. > > < --Lawrence M. Krauss > > > > > > > > > > > > > > ________________________________ Message 4 _____________________________________ Time: 09:05:41 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Capacitor with solder on connectors? --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:15 AM 3/18/2006 -0500, you wrote: >--> AeroElectric-List message posted by: "J. Mcculley" > > >Is it not wise to also put a fuse(or equivalent)protection in series >with the capacitor to handle a possible dead short within the capacitor? It wouldn't hurt. I've not seen it done recently in the type certificated world. Electrolytic capacitors tend to die by loosing their ability to capacitate (there's a word for you) . . . they dry out and simply become more open circuit than anything else. However, if a capacitor is poorly chosen and ripple currents in normal operation exceed the device's ability to withstand the temperature rise, there is a risk of shorting. So, it's not irrational to consider an in-line fuseholder. I suspect that a failing capacitor is more likely to stink and leak at current levels well below dead-short so picking a suitable fuse is problematic and benefits are difficult to gage. Bob . . . ________________________________ Message 5 _____________________________________ Time: 09:46:11 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-19 questions --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:34 AM 3/17/2006 -0800, you wrote: >--> AeroElectric-List message posted by: "John Burnaby" > >1. Why is there a 7A fuse between the main power distribution bus and the >E-bus? The loads on the E bus are all fused. Fuses protect wires. FAA rule of thumb is any wire over 6" is a candidate for protection. 7A fuse and 16AWG wire sizing (as are all other fuses and wires) are subject to adjustment in accordance with appliance choices and bus loadings unique to your airplane. Keep in mind that the z-figures are ARCHITECTURE drawings, they are not instructions on how to wire your airplane. >2. The schematic shows alternate feeds for an ECU and fuel pump. I will >have dual Light speed ignition, dual fuel pumps, and one EFI. To >accomodate this, do I tap into the upstream legs supplying the dual diode >feeds and add another dual diode feed, each, for the 2nd pump and ignition? Stand-alone, dual accessories like ign and fuel pumps get independent protected (fused) supplies through independent switches. Only single, critical accessories like your EFI will benefit from the diode isolated, multiple feed path illustrated. >3. I want to have a dual feed, from Main & Engine batt. buses, w/circuit >breaker to the EFI. Any elegant ideas to do this? Just like Z-19 shows for engine primary switch. Why circuit breakers? >4. The E bus has an alternate feed path off the Main batt bus. Is it >overkill to have a feed path from the Engine batt bus? Depends on how much "killing" you want to do. We generally draw the line at accommodating single failures for any given flight. If you feel better about stacking lots of failures up and devising a means for dealing with all of them, then whatever additional alternate operating schemes you wish to devise are in order. >5. What is the "Auto" function of the Eng/Bat/Auto switch? See http://aeroelectric.com/Catalog/AEC/9005/9005-701B.pdf >6. The fuse for the voltmeter is 1A at the Main Batt bus and 3A at the Eng >Batt bus. Is this a typo or is there a reason for the difference? No reason whatsoever. See item (1) above. Make the fuses/wires match what YOUR airplane needs. Bob . . . < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > ________________________________ Message 6 _____________________________________ Time: 09:48:23 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-19 questions (Expanded) --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" Sorry, I didn't accurately interpret your question (3). For a single device and two power sources, you might consider two single pole switches (1-3) from each battery bus coming together at an isolation diode. It's LIKE that scheme shown in Z-19 for handling single pump and a single ECU through two pole switches. Since you have only one accessory, single pole switches and only one diode array are needed. At 11:34 AM 3/17/2006 -0800, you wrote: >--> AeroElectric-List message posted by: "John Burnaby" > >1. Why is there a 7A fuse between the main power distribution bus and the >E-bus? The loads on the E bus are all fused. Fuses protect wires. FAA rule of thumb is any wire over 6" is a candidate for protection. 7A fuse and 16AWG wire sizing (as are all other fuses and wires) are subject to adjustment in accordance with appliance choices and bus loadings unique to your airplane. Keep in mind that the z-figures are ARCHITECTURE drawings, they are not instructions on how to wire your airplane. >2. The schematic shows alternate feeds for an ECU and fuel pump. I will >have dual Light speed ignition, dual fuel pumps, and one EFI. To >accomodate this, do I tap into the upstream legs supplying the dual diode >feeds and add another dual diode feed, each, for the 2nd pump and ignition? Stand-alone, dual accessories like ign and fuel pumps get independent protected (fused) supplies through independent switches. Only single, critical accessories like your EFI will benefit from the diode isolated, multiple feed path illustrated. >3. I want to have a dual feed, from Main & Engine batt. buses, w/circuit >breaker to the EFI. Any elegant ideas to do this? Just like Z-19 shows for engine primary switch. Why circuit breakers? >4. The E bus has an alternate feed path off the Main batt bus. Is it >overkill to have a feed path from the Engine batt bus? Depends on how much "killing" you want to do. We generally draw the line at accommodating single failures for any given flight. If you feel better about stacking lots of failures up and devising a means for dealing with all of them, then whatever additional alternate operating schemes you wish to devise are in order. >5. What is the "Auto" function of the Eng/Bat/Auto switch? See http://aeroelectric.com/Catalog/AEC/9005/9005-701B.pdf >6. The fuse for the voltmeter is 1A at the Main Batt bus and 3A at the Eng >Batt bus. Is this a typo or is there a reason for the difference? No reason whatsoever. See item (1) above. Make the fuses/wires match what YOUR airplane needs. Bob . . . < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > ________________________________ Message 7 _____________________________________ Time: 10:22:23 AM PST US From: SMITHBKN@aol.com Subject: AeroElectric-List: Headset and Mic Connections --> AeroElectric-List message posted by: SMITHBKN@aol.com I ordered some headset and mic jacks from B&C Specialty. Are the connections to these supposed to be soldered? If so, is there a standard practice used to attach the wire to the solder tabs on the jacks? The solder tabs have a small diameter hole in them. Thanks ________________________________ Message 8 _____________________________________ Time: 11:16:58 AM PST US From: "John Burnaby" Subject: AeroElectric-List: Re: Z-19 questions --> AeroElectric-List message posted by: "John Burnaby" >3. I want to have a dual feed, from Main & Engine batt. buses, w/circuit >breaker to the EFI. Any elegant ideas to do this? Just like Z-19 shows for engine primary switch. Why circuit breakers? Bob, Thanks for your expanded reply on power feed. I'm electing to CB the EFI because I only have one EFI. The manufacturer argues that the MTBF of the EFI unit is so many magnitudes greater than the MTBF of a recip engine, that I should consider a twin before dual EFI's. Also, he argues that the wiring/switching/sensing of dual units becomes the most likely point of failure in the system, ergo why have dual units. So because I will only have one EFI, I thought to myself that if it goes belly up, I would at least like to have the option of cycling a CB to see if it would re-light. I still can't let go of the idea of dual EFI's controlled by an On-Off-On switch. I don't know why the units have to be integrated beyond sharing 4 sensors (throttle, temp, MP, RPM). But the manufacturer could sell me another unit and he's telling me, I don't want to do this. So the CB is buying me a tiny bit of feel-better. John ________________________________ Message 9 _____________________________________ Time: 01:39:50 PM PST US From: Jeff Bertsch Subject: AeroElectric-List: KN-73 and KX-125 --> AeroElectric-List message posted by: Jeff Bertsch Hello all, I adding a KN-73 to provide glideslope for my KX-125, which drives my Century NSD1000 HSI. I have the KX-125 install manual (thanks to a fellow lister), but I need the KN-73 install manual. Does anyone have the KN-73 install manual, or at least the pinout diagram. Thanks! Jeff Bertsch RV-4 --------------------------------- Brings words and photos together (easily) with ________________________________ Message 10 ____________________________________ Time: 05:09:03 PM PST US From: Ken Subject: Re: AeroElectric-List: Re: Z-19 questions --> AeroElectric-List message posted by: Ken John The advice to not make a primary system less reliable by adding backups that could compromise it is good advice. However if you want a second system, an independant second system can certainly be installed that does not have any common failure points or share items with the primary system. Ideally neither system should know that the other exists. For example a backup efi might be a homemade megasquirt unit that shares no sensors, wiring, injectors, etc. with the primary system. The throttle sensor can be eliminated since airplane throttles are opened slowly. The engine temperature sensor could be eliminated because the engine will already be warm if the backup is needed. So a minimum system needs a crank or cam sensor for rpm, a MAP sensor which is onboard the $150. ish megasquirt, an inlet air temp sensor, one or more additional injectors, an independant power source and a separate power switch. I'm sure you already have a second fuel pump. A lot of reliability concerns go away with the ability to just select another system. Ken John Burnaby wrote: >--> AeroElectric-List message posted by: "John Burnaby" > > > >>3. I want to have a dual feed, from Main & Engine batt. buses, w/circuit >>breaker to the EFI. Any elegant ideas to do this? >> >> > > Just like Z-19 shows for engine primary switch. Why circuit breakers? > >Bob, > >Thanks for your expanded reply on power feed. > >I'm electing to CB the EFI because I only have one EFI. The manufacturer argues that the MTBF of the EFI unit is so many magnitudes greater than the MTBF of a recip engine, that I should consider a twin before dual EFI's. Also, he argues that the wiring/switching/sensing of dual units becomes the most likely point of failure in the system, ergo why have dual units. So because I will only have one EFI, I thought to myself that if it goes belly up, I would at least like to have the option of cycling a CB to see if it would re-light. > >I still can't let go of the idea of dual EFI's controlled by an On-Off-On switch. I don't know why the units have to be integrated beyond sharing 4 sensors (throttle, temp, MP, RPM). But the manufacturer could sell me another unit and he's telling me, I don't want to do this. So the CB is buying me a tiny bit of feel-better. > >John > > > > > > > > > ________________________________ Message 11 ____________________________________ Time: 09:17:15 PM PST US From: "John Burnaby" Subject: AeroElectric-List: Re: Z-19 questions --> AeroElectric-List message posted by: "John Burnaby" Ken, I'm intrigued. Could one just put a single injector squirting into the intake plenum? What takes the sensor signals and fires it? Just remember, you're talking to an electro-phobe. Thanks, John ________________________________ Message 12 ____________________________________ Time: 09:17:15 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Z-19 questions --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:45 AM 3/18/2006 -0800, you wrote: >--> AeroElectric-List message posted by: "John Burnaby" > > >3. I want to have a dual feed, from Main & Engine batt. buses, w/circuit > >breaker to the EFI. Any elegant ideas to do this? > > Just like Z-19 shows for engine primary switch. Why circuit breakers? > >Bob, > >Thanks for your expanded reply on power feed. > >I'm electing to CB the EFI because I only have one EFI. The manufacturer >argues that the MTBF of the EFI unit is so many magnitudes greater than >the MTBF of a recip engine, that I should consider a twin before dual >EFI's. Also, he argues that the wiring/switching/sensing of dual units >becomes the most likely point of failure in the system, ergo why have dual >units. So because I will only have one EFI, I thought to myself that if it >goes belly up, I would at least like to have the option of cycling a CB to >see if it would re-light. > >I still can't let go of the idea of dual EFI's controlled by an On-Off-On >switch. I don't know why the units have to be integrated beyond sharing 4 >sensors (throttle, temp, MP, RPM). But the manufacturer could sell me >another unit and he's telling me, I don't want to do this. So the CB is >buying me a tiny bit of feel-better. Understand. Consider this: You have no personal control over the EFI and no personal knowledge of its reliability from the engineer's perspective. There are tons of anecdotal evidence of the devices reliablity given that millions are giving good service on road. On the other hand, we know that the VAST majority of engine stoppage leading to accidents is fuel starvation with the majority of those cases falling at the feet of poor fuel management on the part of the pilot. So in considering two major data points that suggest the (1) EFI is as close to golden as modern technology can make it and (2) if the engine does quit, the most likely cause is your screw-up. What are the things over which you do have absolute control? System architecture for starters. Okay, put a dual-feed path isolation diode as close as practical to the EFI's power input feeder. Supply two independent sources of power through independent switching and feeder wires . . . like Z-19 suggests. Now, is there value in having a circuit breaker versus a fuse? The dual power and feeder paths are extremely unlikely to suffer failures on any one flight. If some failure occurs that opens a breaker, it is most likely to be someplace between the bus and the input pin to the isolation diode. Anything downstream of that point is in single-point of failure to the system and we've already decided that those numbers (See 1 above) are sufficiently comforting but will call for Plan-C should the unthinkable happen. What's the value of having breakers on the feeders? If the breaker trips due to a fault between bus and diode that feeder is down and out of service. Resetting the breaker is useless and distracting when you should be shifting to Plan-B where the alternate feed path steps in to save the day. If the fault is downstream of the diode, then your faith in the goodness of the EFI was over stretched and again, the presence of a breaker is useless and distracting. Plan-C is the order of the day - start picking your point of arrival with the earth. Classical breaker installations dictate bus bars at the panel which drives up your system's parts count and increases the numbers of busses just to satisfy a desire for breakers that have no demonstrable value. If a breaker opens, likelihood of getting any system back by resetting a breaker is exceedingly low. It's much better to simply provide a second, independent path. You also have absolute control over fuel management and your earlier description called for dual, independently powered and fed fuel pumps. So as long as you don't have some fitting open up and spill all your fuel, the dual pumps and ignition systems provide as much backup as you're ever going to use. So, odds are still much greater that your engine quits for lack of fuel than from any other cause. Rather than breakers on the EFI lines, I'd vote for active notification of low fuel will have more feel-better value than circuit breakers. Now the odds are stacked much more in your favor and probability numbers for having a bad day are lower than for the vast majority of certified single engine airplanes flying today. Those are good odds indeed. Bob . . .