---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 05/14/03: 52 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:21 AM - Re: Re: AutoPilot Disconnect Brain Teaser - 05/12/03 (M.J. Gregory) 2. 04:32 AM - Noise () 3. 04:40 AM - Re: OV circuit breaker tripping (Cy Galley) 4. 05:44 AM - Re: Dual electronic ignition - revisited again (John Schroeder) 5. 06:19 AM - non-Microprocessor based Fuel Gauge Linearizer (Eric M. Jones) 6. 06:37 AM - Re: AutoPilot Disconnect Brain Teaser - (Eric M. Jones) 7. 06:52 AM - Cheap blind encoder. (Ian Scott) 8. 07:06 AM - Re: Noise (Robert L. Nuckolls, III) 9. 07:15 AM - Re: non-Microprocessor based Fuel Gauge (Robert L. Nuckolls, III) 10. 07:17 AM - Re: Re: AutoPilot Disconnect Brain Teaser - (Robert L. Nuckolls, III) 11. 07:19 AM - Radio Noise Redux (William Yamokoski) 12. 07:52 AM - Diode failures and "Reliable Systems" [ was Re: Radio Noise Redux] (David Carter) 13. 07:58 AM - Re: Dual electronic ignition - revisited (Robert L. Nuckolls, III) 14. 08:07 AM - Re: 100 % Solution (diode-fed supportbatt-was Avionics bus) (Eric M. Jones) 15. 08:41 AM - Interference (PTACKABURY@aol.com) 16. 08:51 AM - Re: Dual electronic ignition - revisited again (Jim Pack) 17. 09:02 AM - SD-8 Alternator Questions (Phil Birkelbach) 18. 09:14 AM - Re: Dual electronic ignition - revisited (Robert L. Nuckolls, III) 19. 09:14 AM - Re: Dual electronic ignition - revisited again (Geoff Evans) 20. 09:29 AM - Re: non-Microprocessor based Fuel Gauge Linearizer (Jerzy Krasinski) 21. 09:35 AM - Re: Re: AutoPilot Disconnect Brain Teaser - (Rob Housman) 22. 09:38 AM - Re: AutoPilot Disconnect Brain Teaser - (Eric M. Jones) 23. 10:45 AM - non-Microprocessor based Fuel Gauge Linearizer (Eric M. Jones) 24. 10:51 AM - Static when Refuelling re Braid (Fergus Kyle) 25. 11:18 AM - Re: Diode failures and "Reliable Systems" (Robert L. Nuckolls, III) 26. 11:28 AM - Re: SD-8 Alternator Questions (Robert L. Nuckolls, III) 27. 11:32 AM - Re: Cheap blind encoder. (Robert L. Nuckolls, III) 28. 11:50 AM - Wig wag (Bob Kuc) 29. 12:24 PM - Re: Cheap blind encoder. (DHPHKH@aol.com) 30. 12:32 PM - Re: Re: Flap system failure modes (Was circuit protection issues) (Gilles.Thesee) 31. 01:11 PM - Re: OV circuit breaker tripping (John Karnes) 32. 01:32 PM - Re: SD-8 Alternator Questions (Phil Birkelbach) 33. 02:21 PM - Re: Flap system failure modes (Was circuit protection issues) (Robert L. Nuckolls, III) 34. 02:24 PM - Re: Wig wag (Robert L. Nuckolls, III) 35. 02:53 PM - Re: Wig wag (Bob Kuc) 36. 04:16 PM - Re: Cheap blind encoder. (Greg Young) 37. 04:26 PM - Re: Static when Refuelling re Braid (Kent Ashton) 38. 04:31 PM - Re: Wig wag (Robert L. Nuckolls, III) 39. 04:44 PM - Re: SD-8 Alternator Questions (Robert L. Nuckolls, III) 40. 05:08 PM - Re: SD-8 Alternator Questions (Rob Housman) 41. 05:21 PM - Re: Static when Refuelling re Braid (Charlie & Tupper England) 42. 06:23 PM - Re: Avogadro's Number (Robert L. Nuckolls, III) 43. 06:51 PM - encoder wiring (Dave Ford) 44. 07:02 PM - Re: encoder wiring (BobsV35B@aol.com) 45. 07:34 PM - Re: Re: Avogadro's Number (Don Boardman) 46. 07:42 PM - Re: Re: Avogadro's Number (Rob Housman) 47. 08:48 PM - Re: OV circuit breaker tripping (Robert L. Nuckolls, III) 48. 09:25 PM - Re: Cheap blind encoder. (Robert L. Nuckolls, III) 49. 09:27 PM - Re: encoder wiring (Robert L. Nuckolls, III) 50. 10:05 PM - Re: non-Microprocessor based Fuel Gauge (Robert L. Nuckolls, III) 51. 10:14 PM - Re: AutoPilot Disconnect (Robert L. Nuckolls, III) 52. 10:47 PM - Re: non-Microprocessor based Fuel Gauge Linearizer (John Rourke) ________________________________ Message 1 _____________________________________ Time: 03:21:58 AM PST US From: "M.J. Gregory" Subject: RE: AeroElectric-List: Re: AutoPilot Disconnect Brain Teaser - 05/12/03 --> AeroElectric-List message posted by: "M.J. Gregory" Bob I was waiting for you to shake the cube and let all those one billion balls settle so that you could add some more. I understand that stacking balls pyramid-style can fill some 74 percent of the volume. This compares with the 52.3 percent you have by stacking them in one-million-ball layers. The ratio of these figures is approximately sq root 2, but I don't know if this is the mathematically precise relationship. I therefore calculate that you should be able to get some 1,410,000,000 balls into your cube, increasing their surface area to 4,430 sq in. While there would be only a very little direct see-through area round the sides with this arrangement, I shall leave it to others to calculate the reduction in cross sectional area for your liquid flowing through from one face to another. I suspect it would again be a factor of approximately sq root 2. Happy calculations. Mike m.j.gregory@cranfield.ac.uk --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 03:10 PM 5/13/2003 -0500, you wrote: >--> AeroElectric-List message posted by: "Phil Birkelbach" > > > > Take an array of steel balls 0.001" in diameter > > and stack them into 1 cubic inch of volume. How > > many balls does it take to fill the cube? What > > is the total surface area of all balls contained > > in the cube? What is the open (see-through) area > > of the space between the balls for any liquid > > that passes into one face and out the opposite face? > > > > Bob . . . > > >You'll need 1,000 3 steel balls or... > >1,000,000,000 balls > >The surface area of a sphere is... 4*pi*r 2 > >So the area of one ball... 3.141592E-6 sq in >So the area of a billion balls... 3,141.5 sq in or 21.8166 sq ft >which is about 2/3 the area of a piece of plywood. That's the part that really surprises folks . . . that a 1" cube could have that much surface area contained within. >Now for the second part the wetted area... > >It would be 1 sq in - the area of a million circles... > >area of a circle = pi * r 2 > >Area of a 0.001" diameter circle = 7.85398E-7 sq in >Area of a million of them would be... 0.785398 sq in >so the see through area would be... 0.214602 sq in yup . . . >Of course this all assumes that we stack the balls in a rectangular pattern >1,000 balls to an edge, and the 1 cubic inch volume is a 1" x 1" x 1" cube, >if it is anything more sinister than that then I don't have time to look it >up. :-) yeah, getting all those balls to set in there un-nested takes some REAL patience. Bob . . . ________________________________ Message 2 _____________________________________ Time: 04:32:46 AM PST US From: Subject: AeroElectric-List: Noise --> AeroElectric-List message posted by: Slightly off topic, but if analogies exist for noise in aircraft, perhaps the answer will be instructive nonetheless. I am finishing a new room in my house where I want to run a cable connection for a cable modem. The preferred route runs the cable wire along a 240 volt circuit for an air conditioner/heat pump unit. Is there any issue with the 240 volt wire creating interference in the cable line? Thanks, Dan ________________________________ Message 3 _____________________________________ Time: 04:40:58 AM PST US From: "Cy Galley" Subject: Re: AeroElectric-List: OV circuit breaker tripping --> AeroElectric-List message posted by: "Cy Galley" How about high temps melting or softening some wire insulation so it the wire is rubbing some metal. I would check down stream from the CB with an ohm meter. Cy Galley - Bellanca Champion Club Newsletter Editor & EAA TC www.bellanca-championclub.com Actively supporting Aeroncas ----- Original Message ----- From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: OV circuit breaker tripping > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > At 09:10 PM 5/13/2003 -0700, you wrote: > >--> AeroElectric-List message posted by: "John Karnes" > > > > > >Sounds like a dead short. > > > >It would pull down the voltage and the excess amperage would trip the > > > >breaker. > > > > > > I agree . . . check to make sure your diode on > > > the b-lead contactor isn't hooked up backwards > > > or shorted. > > > >How do I check to see if the diode is shorted? I know it's not backwards as > >I haven't changed it and it was working fine before. > > Use your ohmmeter to check the resistance across the diode. > If it (or something else on the line is shorted) it will > read very low (less than 1 ohm) no matter which way you > attach the leads. > > > Could the high heat in > >the engine compartment have caused this? (I'm talking HIGH heat!) > > Not likely. > > Bob . . . > > -------------------------------------------- > ( Knowing about a thing is different than ) > ( understanding it. One can know a lot ) > ( and still understand nothing. ) > ( C.F. Kettering ) > -------------------------------------------- > > ________________________________ Message 4 _____________________________________ Time: 05:44:19 AM PST US Subject: Re: AeroElectric-List: Dual electronic ignition - revisited again From: John Schroeder --> AeroElectric-List message posted by: John Schroeder Geoff - IMHO, look at the Z-14 with two 17 AH batteries. No question as to suitability for dual electronic ignition systems. > I'm trying to avoid the added weight of two full-size batteries, and I > really > like the idea of having the SD-8 as a backup alternator instead. I'm also > trying to avoid the complexity of having a backup battery just for half > of a > dual ignition system -- if that's even a logical position to take. > > Can you put an end to the ambiguity (read: my confusion) one and for all? > > Thanks much! > -Geoff > ________________________________ Message 5 _____________________________________ Time: 06:19:23 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: non-Microprocessor based Fuel Gauge Linearizer --> AeroElectric-List message posted by: "Eric M. Jones" There has been some discussion of this, and I have not gotten very far on my plans to build one. Since I have no shortage of stuff to make (Hey Bob, Re: Other Life, just use you wife's washing machine for the 30G centrifuge. The spin cycle should do 30Gs and you won't hit anybody when the thing comes apart. Paint it gray, stick a NASA label over the Kenmore label, and you're all set! Total cost--Old Washer, Paint, Logo....let's see.). Here's the non-microprocessor plan for the linearizer: (As they say in school, the exercise is left up to the reader). 1) Know the true final volume of the tank. 1) Assume the graph of Fuel Volume (Y) and Fuel Gauge Reading (x) is everywhere a negative slope. (Not necessarily true in all cases, but then it's hopeless.) Draw yourself a sample graph. It looks like a downhill ski run. Remember--all negative slopes! 2) Let's assume that a four-segment straight-line approximation is adequate for the job, divide up the X-axis into four parts and using the intersections of the divisions with the downhill ski run, connect the dots to make four line segments. 3)---A small pause here---The purpose of the four line segments is to model the ski-run curve of declining fuel volume versus fuel gauge reading (note that the linearity of the sender AND the panel meter can be included as one variable). The SLOPE (deltaX/deltaY) of these segments is going to be the voltage amplification of four teeny little op amps that will read these parts of the curve. It is useful to note that the way the x-axis is divided up should reflect the geometry of the tank and the linearity of the gauge and sender. That is, in a smoothly arcing curve, maybe simply quartering the x-axis is fine, but when the reading error is mostly in one place, the line segments that model it should be concentrated there. This make the job simpler, but you can make this basic technique as complicated as you want. 4) Now having the four teeny little op amps (Quad Op Amp LM324), you add four teeny little adjustment pots to set the slopes (gains), and a quad comparator LM339 to tell the output which one of the Op Amps is valid. There are some other parts in this mix--- --An I-V converter chip for the input and a V-I converter chip for the output. Is there a way to avoid this? --A good averaging anti-slosh filter on the input. Easy... --Low fuel setpoint alarm? Now if someone wants to work on this. The total BOM should be less than $20. The entire assembly in surface mount will be 1" X 1.5" X 3/8", it will weight <1 ounce, it will operate up to 30 VDC. Here's my offer: If someone wants to build this on a proto board, design the schematic, and do some work on it--I will build her two samples of the real thing in surface mount. The reality of the internet is that we can design things with world-wide brains and resources in a cooperative venture. Let's get together on this! Regards, Eric M. Jones "When dealing with the enemy, it helps if he thinks you're a little bit crazy." --Gen. Curtis LeMay ________________________________ Message 6 _____________________________________ Time: 06:37:54 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Re: AutoPilot Disconnect Brain Teaser - --> AeroElectric-List message posted by: "Eric M. Jones" The packing fraction for face-centered cubic packing is rho0.7405. Adjust results accordingly. Eric ________________________________ Message 7 _____________________________________ Time: 06:52:52 AM PST US From: "Ian Scott" Subject: AeroElectric-List: Cheap blind encoder. --> AeroElectric-List message posted by: "Ian Scott" HI All, I a getting a Micro air transponder, and was wondering what I should do for encoder and antenna, in a glass plane Ian ________________________________ Message 8 _____________________________________ Time: 07:06:16 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Noise --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 07:31 AM 5/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: > >Slightly off topic, but if analogies exist for noise in aircraft, perhaps >the answer will be instructive nonetheless. I am finishing a new room in >my house where I want to run a cable connection for a cable modem. The >preferred route runs the cable wire along a 240 volt circuit for an air >conditioner/heat pump unit. Is there any issue with the 240 volt wire >creating interference in the cable line? > >Thanks, >Dan No, "noises" from the power wiring in a house are relatively low frequency (60 hz and harmonics plus noises generated by appliances) while your cable modem works at hundreds of megahertz inbound traffic and tens of megahertz outbound. Further, house wiring is carried on parallel pairs . . . for every electron going one way there is a companion headed the other way in close proximity . . . net result is that magnetic fields (strongest noise coupling mode) cancel each other. Bob . . . -------------------------------------------- ( Knowing about a thing is different than ) ( understanding it. One can know a lot ) ( and still understand nothing. ) ( C.F. Kettering ) -------------------------------------------- ________________________________ Message 9 _____________________________________ Time: 07:15:54 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: non-Microprocessor based Fuel Gauge Linearizer --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:21 AM 5/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > >There has been some discussion of this, and I have not gotten very far on >my plans to build one. Since I have no shortage of stuff to make (Hey Bob, >Re: Other Life, just use you wife's washing machine for the 30G >centrifuge. The spin cycle should do 30Gs and you won't hit anybody when >the thing comes apart. Paint it gray, stick a NASA label over the Kenmore >label, and you're all set! Total cost--Old Washer, Paint, Logo....let's see.). > >Here's the non-microprocessor plan for the linearizer: (As they say in >school, the exercise is left up to the reader). >1) Know the true final volume of the tank. >1) Assume the graph of Fuel Volume (Y) and Fuel Gauge Reading (x) is >everywhere a negative slope. (Not necessarily true in all cases, but then >it's hopeless.) Draw yourself a sample graph. It looks like a downhill ski >run. Remember--all negative slopes! >2) Let's assume that a four-segment straight-line approximation is >adequate for the job, divide up the X-axis into four parts and using the >intersections of the divisions with the downhill ski run, connect the dots >to make four line segments. >3)---A small pause here---The purpose of the four line segments is to >model the ski-run curve of declining fuel volume versus fuel gauge reading >(note that the linearity of the sender AND the panel meter can be included >as one variable). The SLOPE (deltaX/deltaY) of these segments is going to >be the voltage amplification of four teeny little op amps that will read >these parts of the curve. It is useful to note that the way the x-axis is >divided up should reflect the geometry of the tank and the linearity of >the gauge and sender. That is, in a smoothly arcing curve, maybe simply >quartering the x-axis is fine, but when the reading error is mostly in one >place, the line segments that model it should be concentrated there. This >make the job simpler, but you can make this basic technique as complicated >as you want. >4) Now having the four teeny little op amps (Quad Op Amp LM324), you add >four teeny little adjustment pots to set the slopes (gains), and a quad >comparator LM339 to tell the output which one of the Op Amps is valid. >There are some other parts in this mix--- >--An I-V converter chip for the input and a V-I converter chip for the >output. Is there a way to avoid this? >--A good averaging anti-slosh filter on the input. Easy... >--Low fuel setpoint alarm? > >Now if someone wants to work on this. The total BOM should be less than >$20. The entire assembly in surface mount will be 1" X 1.5" X 3/8", it >will weight <1 ounce, it will operate up to 30 VDC. > >Here's my offer: If someone wants to build this on a proto board, design >the schematic, and do some work on it--I will build her two samples of the >real thing in surface mount. The reality of the internet is that we can >design things with world-wide brains and resources in a cooperative >venture. Let's get together on this! I've built multi-slope analog systems like this. Did a feel-spring actuator controller for some model of a Cessna way back when that needed to adjust compression on a spring cartridge based on IAS and a second order transfer function. I think we did it with three op amps (two breaks in the curve). That was the best we COULD do then, can't recommend it today. There are microcontrollers for under $5 with built in D/A and enough memory to hold program and scratch pad for this kind of task. The HARDest part is building a user i/o interface so that the end user can plug in a laptop and adjust the lookup table to fit his airplane. If there are enough folks really interested in this, I have some byte-wienies out at RAC that could make this play in software. The board layouts are rudimentary. Bob . . . >Regards, >Eric M. Jones > >"When dealing with the enemy, it helps if he thinks you're a little bit >crazy." >--Gen. Curtis LeMay > > Bob . . . -------------------------------------------- ( Knowing about a thing is different than ) ( understanding it. One can know a lot ) ( and still understand nothing. ) ( C.F. Kettering ) -------------------------------------------- ________________________________ Message 10 ____________________________________ Time: 07:17:40 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: AutoPilot Disconnect Brain Teaser - --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:38 AM 5/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > >The packing fraction for face-centered cubic packing is rho0.7405. Adjust >results accordingly. > >Eric You threw me a new one there Eric. Care to describe "packing fraction" in 25 words or less? ;-) Bob . . . -------------------------------------------- ( Knowing about a thing is different than ) ( understanding it. One can know a lot ) ( and still understand nothing. ) ( C.F. Kettering ) -------------------------------------------- ________________________________ Message 11 ____________________________________ Time: 07:19:42 AM PST US From: "William Yamokoski" Subject: AeroElectric-List: Radio Noise Redux --> AeroElectric-List message posted by: "William Yamokoski" Hi Folks, I've made a bit of progress on the noises I was hearing in my headsets. My main problem continues to be on the transmission side...sometimes fine, sometimes unintelligable. The intermittent nature of the beast is the most frustrating part. I've never been able to hear what people are reporting, but i think I've been able to duplicate what they tell me they hear. The MicroAir is powered from the essential bus, which in turn gets its power from the main bus via a diode as per Bob's drawings. With engine off, main contactors on, pushing the PTT results in a normal feedback in the headsets. When I start adding to the current load (e.g., Naviad, GPS, transponder) things get a little dicey. I start hearing terrible noises in the headset, but only very intermittently. When I then turn on one of the big current loads like the pitot heat or strobes, pushing the PTT switch switch gives me continuous loud growling sounds....voice can barely be made out. At this point the Grand Rapids EIS is showing 11.9 v or thereabouts. This at least seems logical. The radio doesn't get enough electrons, I guess, to tranmit properly. The problem is, why might this be happening with the engine on in flight? Yesterday in flight someone reported my transmission as unreadble, with loud background noise. At that time the EIS read 14.5 v. Twenty minutes earlier I got a report that my transmission was clear, with a small amount of background static. Could there be a problem with the diode? I'm not sure if they fail in an all-or-nothing way or if you can see a "partial." failure. I've used Bob's idea of hooking two 6 volt batteries together to power the radio separately from the busses. That helped me in isolating some of the the odd noises I was getting in the headset. However, I've never used those batteries to power the radio in flight. It seems like it would be easy enough to test-out this diode theory...just by-pass the thing and power the essential bus with a simple wire from the main bus for a while. But am I barking up the wrong tree here? Another Glastar/Subaru owner has replaced his diode due to a failure. Any thoughts appreciated. Thanks Bill Yamokoski ________________________________ Message 12 ____________________________________ Time: 07:52:02 AM PST US From: "David Carter" Subject: Diode failures and "Reliable Systems" [ was Re: AeroElectric-List: Radio Noise Redux] --> AeroElectric-List message posted by: "David Carter" ----- Original Message ----- From: "William Yamokoski" Subject: AeroElectric-List: Radio Noise Redux > --> AeroElectric-List message posted by: "William Yamokoski" > > Hi Folks, The MicroAir is powered from the essential bus, which in turn gets its power from the main bus via a diode as per Bob's drawings. > Could there be a problem with the diode? I'm not sure if they fail in an all-or-nothing way or if you can see a "partial." failure It seems like it would be easy enough to test-out this diode theory...just by-pass the thing and power the essential bus with a simple wire from the main bus for a while. But am I barking up the wrong tree here? Another Glastar/Subaru owner has replaced his diode due to a failure. Any thoughts appreciated. > Thanks > Bill Yamokoski Diodes. . . . . I get a little excited when I hear stories of diodes failing. I've quoted the relevant parts above. Now, my anecdote, prior to asking a ques: Anecdote: While Avionics Officer for an A-7D unit, one of the Big Eight test stations (each of the eight costing about $1 million each) suffered a diode "short" on a circuit card. This simple 2 cent piece failed - resulting in high current flow in that circuit, which was not protected - designers didn't consider the diode failure mechanism. Well, the high current cascaded throughout the test station and resulted in something like a lightning strike on the entire test station. We spent months and LOTS of unit funds repairing that test station. Now, I'm in the role of home builder-designer of my RV-6 electrical system. And we've been talking many months about an Endurance Bus, with a diode allowing power to flow to the E-bus from the main bus, and to prevent battery drain from the E-bus to the main bus when main bus is shut down for alternator failure. A diode. I'll bet those who work in this field have other stories about diode failures. Are there some diodes that are better (more durable, longer lasting) than other diodes? What level of "diode spec" ought to be sufficient to avoid "typical" diode failures? Is "bigger" better? What are diodes most sensitive to? (that would cause them to fail) If I can't "rely" on the diode between Main & E busses, then I might consider "adding parts count" to detect failure of this critter; or special pilot operating procedures to use voltmeter wired to specific, switch selectable places, with opening and closing of e-bus switch or other means of verifying, on every flight, that the diode is function correctly. (Do I smell my own paranoia oozing out?) David Carter ________________________________ Message 13 ____________________________________ Time: 07:58:54 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Dual electronic ignition - revisited again --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:55 PM 5/13/2003 -0700, you wrote: >--> AeroElectric-List message posted by: Geoff Evans > > >Hi Bob. > >I thought I was all squared away after our message exchange of a few months >ago, but some recent postings of yours on the list have rekindled my >confusion. > >Our prior conversations were about using the Z-13 architecture for dual >electronic ignitions, and whether the Z-13 system was any more likely to >result in an electrically-caused engine failure (with dual electronic >ignitions) than a something like a Z-11 system with an aux battery. At the >time, I was confused by some prior postings and some seemingly conflicting >language in your book. > >"We at Aeroelectric Connection do not advocate using the Z-13 architecture >for an aircraft with dual electronic ignitions. We prefer dual batteries >instead." > >or... > >"We at the Aeroelectric Connection believe that the Z-13 architecture does >not have any greater chance of total electrical failure than a Z-11 system >with an aux battery. In fact, we think it's a better option, and it's >perfectly viable for use with dual electronic ignitions." Let's review some simple-ideas which you need to ponder to answer the question for yourself: (1) If a system has but one battery and no alternators proven to be stand-alone providers of electrical energy then there IS risk of loosing the whole system should the one battery become unavailable. (2) If you have an electrically dependent engine with stand-alone backups (like dual ignition) then to preserve as much of the independent qualities of the dual systems, then two power sources capable of operation independent of each other are indicated. (3) If one of those power sources cannot be an alternator, the two batteries are indicated. (4) Obviously, if one of the batteries is tasked only with supporting one ignition system, then it's capacity could be sized to some value that supports ignition for duration of fuel aboard. (5) If a second, small battery is part of your planning, it need not be tied to the system with a heavy contactor. The original Aux Battery Management Module article spoke of an "Ignition" Battery Management Module and suggested a hefty power relay making connection with the main bus to keep a small battery charged. This relay was NOT closed during cranking to assist the main battery in getting the engine started. (6) If the light weight and low cost of the SD-8 as a second engine drive power source is attractive to you then there's no reason why you couldn't take advantage of it using Figure Z-13 but it has little relevance to the reliability considerations for the dual electronic ignitions. It would be handy if it worked when the main alternator quits but it's not NECESSARY for comfortable completion of flight and would assure power to at least one ignition in the face of multiple failures (very unlikely). (7) You might consider a Z-13 system with the aux battery connected so as to parallel with the main battery for normal ops and battery charging. If the aux battery management module is attractive to you, I might drive it from the e-bus so that during main alternator out operations, it would allow the second battery to stay connected to the main battery only if the SD-8 were working and not overloaded because too much stuff is turned on. (8) Now, likelihood of finding yourself without enough engine driven power to keep necessary goodies running is on same order as wing or propeller falling off. Even if you loose the battery contactor or wiring to the main battery, you've still got a small battery that would stabilize the SD-8 for unlimited endurance operations from the e-bus. Now, sort through these ideas and see if you have any disagreement or question as to their validity. Once the suite of ideas is validated, do you see a way to assemble them into a solution suited to your needs? >If you'd rather not make either of those statements (for liability reasons, >or whatever), I totally understand. I'm just trying to get a feel for your >opinion on the matter. Would you personally have any problem getting in an >airplane that uses the Z-13 architecture with dual electronic ignitions? Liability? Let's not make this a decision based on anyone's opinion but your own. The whole universe runs on physics and each basic fact of physics is stone simple . . . a simple-idea. The task is for you to sort through a basket of simple-ideas and make a considered decision based on your own understanding . . . not upon anyone else's opinion. >I'm trying to avoid the added weight of two full-size batteries, and I really >like the idea of having the SD-8 as a backup alternator instead. I'm also >trying to avoid the complexity of having a backup battery just for half of a >dual ignition system -- if that's even a logical position to take. > >Can you put an end to the ambiguity (read: my confusion) one and for all? I can't "put an end" to it, that's not part of my magic wand's bag of tricks. I can put out some simple-ideas for you or anyone else to critique, correct or amplify so that you and others can gather them into a system that offers the comfort of understanding and the utility of system reliability. So, given what's been outlined above, I encourage further discussion to see if those things can satisfy your needs. This is the first time I've considered the architecture described in (7) . . . does anyone have something to contribute there? Bob . . . ________________________________ Message 14 ____________________________________ Time: 08:07:54 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Re: 100 % Solution (diode-fed supportbatt-was Avionics bus) --> AeroElectric-List message posted by: "Eric M. Jones" What Bob says about Mallory (and other) supercaps seems to be true. I looked at putting some supercaps near the starter, but the technology has fallen out of favor for the reasons Bob mentions. For situation where the rate of charging or discharging is important, they still have some use. I do wonder--In a power-limited situation, would it make sense to have greater energy available for the first couple seconds of radio transmission or reception? Would the availability of 15 Volts in the first second extend the low voltage operation? I think this seems reasonable. For anyone interested in battery power, the advances in Lithium-Ion makes the use of anything else questionable, especially if you don't need to fly for a while. Batteries are heavy and Lithium-Ion is CERTAINLY going to supplant everything else, even the much vaunted micro-fuelcells have fallen behind the curve. Li-Ion advantages-- Li-Ion cells weigh around half that of a NiCd or NiMH cell of the same capacity. In addition Li-Ion cells are 40 to 50% volumetrically smaller than NiCd cells, and 20-30% smaller than NiMH cells.The average voltage of a Li-Ion cell (3.6-3.7V) is equivalent to three NiCd or NiMH cells (each 1.2V). Li-Ion cells can typically be discharged at rates up to 1.5C continuous. Very safe environmentally. No Lithium metal, other electrode is carbon. Shapes....any shape and flexible too. When fully charged and fully discharged under normal conditions, the life of a Li-Ion cell is between 300 and 500 cycles (RG batteries are half this). No "memory effect" Fast charge capable, wide operating temperature range, enormous charge retentions, trickle charging is rarely needed. Many batteries are "smart"; that is--they have a computer doing tricks inside of it. Regards Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones@charter.net ________________________________ Message 15 ____________________________________ Time: 08:41:29 AM PST US From: PTACKABURY@aol.com Subject: AeroElectric-List: Interference --> AeroElectric-List message posted by: PTACKABURY@aol.com Bob et al: First background one: I built a LongEZ some 20 years ago and have learned to live with some quirks with the electrical system. For example when I transmit the fuel low lites come on and the Navaid autopilot rolls into a 30 degree bank. I gave up trying to find these uninvited bugs and have learned to enjoy them as part of life's little surprises. Background two: a friend has just completed a beautiful Lancair IVP with a very professional wiring job. When he transmits his SFS fuel indicators go to zero (while using the bottom, externally mounted antenna, not when using the antenna mounted inside the tail). He has been trouble shooting for a few weeks but so far no luck. Now to the point: I am just about ready to string wires and add an external com antenna to my Lancair IV and would like to avoid repeating these interference problems (EMI??). Advice? Does and don'ts? Are these quirks just part of life with a plastic airplane? Are they the result of multiple grounds, insufficient wire shielding, bad antenna installation, com coax too close to other wires, or too few chicken bones tossed during the build process? all help is appreciated--paul ________________________________ Message 16 ____________________________________ Time: 08:51:48 AM PST US From: "Jim Pack" Subject: Re: AeroElectric-List: Dual electronic ignition - revisited again --> AeroElectric-List message posted by: "Jim Pack" With all the talk of a 20 am standby alt & a second battery, why not z14 (dual alt, dual bat)? If it were my plane with dual EI's, I'd want to make sure that at least one was always running (no single point failures in the electrical system will stop the engine). - jim > . . . does anyone have > something to contribute there? > ________________________________ Message 17 ____________________________________ Time: 09:02:46 AM PST US From: "Phil Birkelbach" Subject: AeroElectric-List: SD-8 Alternator Questions --> AeroElectric-List message posted by: "Phil Birkelbach" This recent discussion on dual batteries vs. dual alternators had me thinking about the system that I am planning. I'll be using the "All Electric on a Budget" except with an internally regulated alternator (with OVM and another big contactor), but my question is about the SD-8. I have assumed that the SD-8 is a true permanent magent alternator which means that if you spin it, it will make juice. Is this true? I have heard bits and pieces of debate on this list about the SD-8 requiring power to get started but then the battery can go away after the unit is running and assuming a good filter it will produce decent power. I assume that these concerns are due to the fact that the relay will need some external source of power to get it closed, but once it is closed there is no further need of the battery. I guess I am challenging my own assumptions and want to understand this little alternator a little better. I also read here once that it was not a good idea to start this little alternator during the pre-flight checks because then it will sit there and make power the whole flight and that this was somehow bad for it. I would really like to be able to check this little guy during the pre-taxi check list and would like to better understand what is going on inside it before I plunk down the money. Although my engine will not totaly rely on electrical power my panel does. I'll be blind as the proverbial bat if I lose my electrical system. Oh BTW what was the answer to the water molecule ping pong ball question? I would guess they would be a few inches deep, but I barely passed Chemistry so I can't remember all that mole stuff. Godspeed, Phil Birkelbach - Houston Texas RV-7 N727WB (Reserved) - Fuselage http://www.myrv7.com ________________________________ Message 18 ____________________________________ Time: 09:14:10 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Dual electronic ignition - revisited again --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:51 AM 5/14/2003 -0600, you wrote: >--> AeroElectric-List message posted by: "Jim Pack" > >With all the talk of a 20 am standby alt & a second battery, why not z14 >(dual alt, dual bat)? If it were my plane with dual EI's, I'd want to make >sure that at least one was always running (no single point failures in the >electrical system will stop the engine). > >- jim I think he was talking about the 4# SD-8 as a standby and further interested in downsizing the #2 battery to serve the need of a #2 ignition and then only if BOTH alternators have failed. With two engine driven power sources, the need for e-bus capacity in the main battery goes away. If one can find low capacity batteries with the ability to dump starting current, a Z-13 configured as I described has tremendous potential for weight and volume savings. The biggest gotcha is cost of low capacity batteries that will also crank . . . but again, you can run this battery until it croaks if you have two engine driven power sources. Bob . . . ________________________________ Message 19 ____________________________________ Time: 09:14:58 AM PST US From: Geoff Evans Subject: AeroElectric-List: Re: Dual electronic ignition - revisited again --> AeroElectric-List message posted by: Geoff Evans Bob. Thank you so much for that elegant and concise response. It definitely adds some perspective. Bob wrote: (7) You might consider a Z-13 system with the aux battery connected so as to parallel with the main battery for normal ops and battery charging. If the aux battery management module is attractive to you, I might drive it from the e-bus so that during main alternator out operations, it would allow the second battery to stay connected to the main battery only if the SD-8 were working and not overloaded because too much stuff is turned on. So, given what's been outlined above, I encourage further discussion to see if those things can satisfy your needs. This is the first time I've considered the architecture described in (7) . . . does anyone have something to contribute there? That was going to be my next question... In regard to (7) above, would the small aux battery actually need to be "driven" from the e-bus, or could it be connected to the main battery side of the main battery contactor where the the SD-8 hooks up? It seems to me that if we connected it here, in the unlikely event that the aux battery was deeply discharged, it would prevent high charging currents flowing through the main battery bus and the e-bus. Also, would you recommed the hefty power relay to connect the small aux battery in lieu of the shottky diode that is shown on the drawings that come with the Lighspeed ignition? Personally, I don't know anything about shottky diodes, so I guess this question is more of a request for a "compare and contrast" between a relay connection method and a shottky diode connection method. Thanks again! -Geoff __________________________________ http://search.yahoo.com ________________________________ Message 20 ____________________________________ Time: 09:29:03 AM PST US From: Jerzy Krasinski Subject: Re: AeroElectric-List: non-Microprocessor based Fuel Gauge Linearizer --> AeroElectric-List message posted by: Jerzy Krasinski Eric M. Jones wrote: >.....Now having the four teeny little op amps (Quad Op Amp LM324), you add four teeny little adjustment pots to set the slopes (gains), and a quad comparator LM339 to tell the output which one of the Op Amps is valid..... > >......An I-V converter chip for the input and a V-I converter chip for the output. Is there a way to avoid this?...... > Why would you need these converters? The input and output are voltage signals. An unpleasant feature of this solution is that each segment of the curve has TWO parameters to set. These include the slope and the offset. For a four segment curve one would have to mess around with eight adjusting potentiometers. Any correction of gain or offset in any of the opamps would change alignment of the corresponding curve sector in respect to both neighbouring sectors. That means that if settings for any segment were changed one would have to readjust all other segments, in order to get a curve without kinks at the switching points. And to check if adjustment is done correctly one would have to scan the input over the whole range, and see if there are no output jumps at the op amp change points, and if the slopes are as expected. It can be done but it is rather messy A microcontroller solution has that advantage that one can input separately several slope parameters for the sectors of the curve, or input the data points in a process of adding a gallon to the tank and depressing a button, and leave the whole messy curve generation process to the controller. Jerzy Jerzy ________________________________ Message 21 ____________________________________ Time: 09:35:06 AM PST US From: "Rob Housman" Subject: RE: AeroElectric-List: Re: AutoPilot Disconnect Brain Teaser - --> AeroElectric-List message posted by: "Rob Housman" Better than words is an illustration: http://www.jwave.vt.edu/crcd/farkas/lectures/structure/tsld002.htm. Although this is illustration shows how atoms are arranged in a crystalline lattice it is the same concept as solid spheres being closely packed. In FCC each of the six sides of the cube contains 1/2 of a sphere for a total of three, and the eight corners contribute eight eighths of a sphere for another whole one. Calculate the volume occupied by the four spheres and compare it to the volume of the cube and you get the 74.05% number. Best regards, Rob Housman Europa XS Tri-Gear A070 Airfarame complete Irvine, CA -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert L. Nuckolls, III Subject: Re: AeroElectric-List: Re: AutoPilot Disconnect Brain Teaser - --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:38 AM 5/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > >The packing fraction for face-centered cubic packing is rho0.7405. Adjust >results accordingly. > >Eric You threw me a new one there Eric. Care to describe "packing fraction" in 25 words or less? ;-) Bob . . . -------------------------------------------- ( Knowing about a thing is different than ) ( understanding it. One can know a lot ) ( and still understand nothing. ) ( C.F. Kettering ) -------------------------------------------- ________________________________ Message 22 ____________________________________ Time: 09:38:58 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Re: AutoPilot Disconnect Brain Teaser - --> AeroElectric-List message posted by: "Eric M. Jones" >At 09:38 AM 5/14/2003 -0400, you wrote: >>--> AeroElectric-List message posted by: "Eric M. Jones" >> >>The packing fraction for face-centered cubic packing is rho0.7405. Adjust >>results accordingly. >> >>Eric >You threw me a new one there Eric. Care to describe "packing fraction" >in 25 words or less? ;-) >Bob . . . Sure: Well, If you put a bunch of balls in a box, they achieve a packing that is better than all-lined-up in straight rows and columns. (25 words.) There are an infinite number of way to do this, but pure hexagonal packing is best (hard to prove but easy to measure). When the cubic constraint is applied, a face-centered cubic packing is most efficient (arranged like a diamond's carbon atoms). Illustrative brain teaser-- A cubic box holds a bowling ball. The bowling ball is removed, melted down into very tiny spheres and the tiny balls poured back into the box. To what level is the box filled ? Answer--That's easy! 74.05 percent of the original volume. Any "thought experiment" that arranges balls in purely cubic rows and column misses the fact that the true number is 1/rho (where rho is the packing fraction) times the rows-and-columns-result. Thus there are (1 / 0.7405) X 1 X 10 9 balls in the 1" cube. Regards, Eric M. Jones ________________________________ Message 23 ____________________________________ Time: 10:45:18 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: non-Microprocessor based Fuel Gauge Linearizer --> AeroElectric-List message posted by: "Eric M. Jones" Jerzy--Of course you are right. I was hoping this detail would fall into place, since there are some issues yet to be resolved. Bob and Jerzy and others. You would be right to guess I am more comfortable with op amps than with microprocessors. I returned to using discrete chips after receiving the source code for a device of similar complexity....and it is 25 pages of assembler. The notion that using a microprocessor instead of a couple of chips should best be argued upon the completion of parallel projects. Believe me, I am wholeheartedly a microprocessor fan, but not in this design. Besides....analog input, analog output, and don't a few op amps and comparators make an analog "computer"? Regards, Eric M. Jones "The natural progress of things is for liberty to yield and government to gain ground." -- Thomas Jefferson ________________________________ Message 24 ____________________________________ Time: 10:51:23 AM PST US From: "Fergus Kyle" Subject: AeroElectric-List: Static when Refuelling re Braid --> AeroElectric-List message posted by: "Fergus Kyle" " Any help is kindly > appreciated, but I did buy the tinned copper braid today, and > after reading your message I don't know what to do with it. > > Reg > Tony Renshaw That would be braid dangling inside the tank, wired to electrical ground? It won't do anything during refueling to suppress static charges, since fuel is essentially nonconductive. Fred F" This byplay brings to mind the accident report of the glider over S England hit by lightning well clear of cloud. Basically it blew up. Admittedly, the strike was a big one electrically, but the composition glider came to bits because the bolt fllowed the control rods from aileron to cockpit (sound familiar?), burnt the instructor's jacket collar and blew both occupants into the air. The craft came down in bits and the boys in 'chutes - but the message was 'you don't need fuel to blow it to bits, but you might need a 'chute". I've got a printed version of the report here somewhere. Ferg ________________________________ Message 25 ____________________________________ Time: 11:18:51 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Diode failures and "Reliable Systems" --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" >Diodes. . . . . I get a little excited when I hear stories of diodes >failing. > >I've quoted the relevant parts above. > >Now, my anecdote, prior to asking a ques: Anecdote: While Avionics Officer >for an A-7D unit, one of the Big Eight test stations (each of the eight >costing about $1 million each) suffered a diode "short" on a circuit card. >This simple 2 cent piece failed - resulting in high current flow in that >circuit, which was not protected - designers didn't consider the diode >failure mechanism. Well, the high current cascaded throughout the test >station and resulted in something like a lightning strike on the entire test >station. We spent months and LOTS of unit funds repairing that test >station. > >Now, I'm in the role of home builder-designer of my RV-6 electrical system. >And we've been talking many months about an Endurance Bus, with a diode >allowing power to flow to the E-bus from the main bus, and to prevent >battery drain from the E-bus to the main bus when main bus is shut down for >alternator failure. > >A diode. > >I'll bet those who work in this field have other stories about diode >failures. > >Are there some diodes that are better (more durable, longer lasting) than >other diodes? > >What level of "diode spec" ought to be sufficient to avoid "typical" diode >failures? Is "bigger" better? > >What are diodes most sensitive to? (that would cause them to fail) > >If I can't "rely" on the diode between Main & E busses, then I might >consider "adding parts count" to detect failure of this critter; or special >pilot operating procedures to use voltmeter wired to specific, switch >selectable places, with opening and closing of e-bus switch or other means >of verifying, on every flight, that the diode is function correctly. (Do I >smell my own paranoia oozing out?) > >David Carter It's always useful to critique anecdotal data if only to discover that there is no useful data contained therein. Looking at the above I would offer the following observations and perhaps folks out there can cite others: We've all heard about the nation that was lost for want of a nail in a horseshoe . . . a classic analogy of cascaded failures. There is always potential and even probability that one failure will propagate to the destruction of other components of a system. If any single failure can take the system down, our consideration as flight-system designers is to build firewalls between the failed system and the rest of the aircraft. For most instances, a fuse or circuit breaker is all that's needed to prevent the worst kind of failure in any one system from having a deleterious effect on other systems. As soon as you run a wire from one system to another, then a degree of interdependency has been created that must be considered in your failure mode effects analysis. For example: if the GPS receiver goes down, will my wing-leveler retain any degree of usefulness as an aid to operating this airplane . . . or does it become useless too? So, what can we learn about a 2-cent diode that caused so much grief in the anecdote cited above: We don't know the details of how this "nail" failure propagated across the host system or ancillary systems . . . but if the cost to fix included months of repair time and lost-of-use time, it's reasonable to conclude that damage was extensive. It raises a further question about whether or not the design flaw was corrected to make it more tolerant of such failures . . . or were the failed systems simply repaired leaving a potential for the same failure to happen again? Given that the anecdote cites a diode as the first event in this cascade failure, is this a rational reason for extra-ordinary attention to the use of diodes in our little airplanes? Further, is there anything to suggest that other components are not equally deserving of similar attention. It's conceivable that the very same story could be repeated with the phrase "2-cent resistor" substituted for "2-cent diode." When we design systems for Part 25 and higher duty service, were obligated by decree to consider MULTIPLE failures weighed with each other in reliability analysis . . . presumably to demonstrate that in spite of any two failures, our design is is robust enough to run 1,000,000 hours failure free . . . any skeptics out there? Sooo . . . rather than wrap ourselves around the axles of reliability studies that take lots of research, time and probably don't mean much anyhow, the OBAM community has deduced that it's easier to ASSUME that parts of our system are going to fail and that the goal is to configure for failure tolerance as opposed to failure proof. Something akin to breeding war horses that fight well on three legs. Yup, that diode between the main-bus and e-bus is NOT IMMUNE FROM FAILURE. In what ways can it fail? (OPEN or SHORT). How do we know it has failed (E-BUS STUFF GOES DARK for open and (E-BUS ALT FEED TEST IN PREFLIGHT POWERS THE MAIN BUS - for shorted). What are the consequences of either failure mode? (IF SHORTED WHILE AIRBORNE - probably not noticed . . . but we'll catch it at next preflight) (IF OPEN WHILE AIRBORNE - e-bus goodies go dark and we have to close the alternate feedpath switch for continued operation). Okay, assuming you can deduce no errors of reasoning in the analysis above, how does this affect your concerns about diode reliability in this particular case? If failure concerns are adequately addressed we can turn our attention to reducing likelihood of failure as a sort of icing-on-the-cake . . . i.e. were not trying to improve reliability with an eye on flight comfort but more as a reduced maintenance issue. The smallest diode array that comes in the package I suggest is rated at 25A . . . you can buy these rectifier arrays in ratings up to 35A. Sooo . . . unless you have everything but the kitchen sink powered from the e-bus, our diode is very adequately de-rated. The lowest voltage offered by any diode manufacturer is 50V . . . plenty of headroom for our 14V application. These critters have a voltage drop so they dissipate heat. Can't hang 'em out in the air . . . so bolt it down to a metallic surface. Wrap-up: We've made a considered selection of the component and its installation with a eye toward robustness. Further, we've deduced that failure of the component is no more than a nuisance. Going back to the 2-cent diode bringing down $millions$ worth of equipment. How is this anecdote relevant to how a $5 diode is bolted to your airplane? Bob . . . ________________________________ Message 26 ____________________________________ Time: 11:28:33 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: SD-8 Alternator Questions --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:02 AM 5/14/2003 -0500, you wrote: >--> AeroElectric-List message posted by: "Phil Birkelbach" > > >This recent discussion on dual batteries vs. dual alternators had me >thinking about the system that I am planning. I'll be using the "All >Electric on a Budget" except with an internally regulated alternator (with >OVM and another big contactor), but my question is about the SD-8. I have >assumed that the SD-8 is a true permanent magent alternator which means that >if you spin it, it will make juice. Is this true? yes . . . but it's regulator senses the bus-side . . . >I have heard bits and pieces of debate on this list about the SD-8 requiring >power to get started but then the battery can go away after the unit is >running and assuming a good filter it will produce decent power. I assume >that these concerns are due to the fact that the relay will need some >external source of power to get it closed, but once it is closed there is no >further need of the battery. I guess I am challenging my own assumptions >and want to understand this little alternator a little better. . . . and doesn't bring the SD-8 on line unless there is a battery present. >I also read here once that it was not a good idea to start this little >alternator during the pre-flight checks because then it will sit there and >make power the whole flight and that this was somehow bad for it. I would >really like to be able to check this little guy during the pre-taxi check >list and would like to better understand what is going on inside it before I >plunk down the money. Not true . . . test it and run it any way you like. >Although my engine will not totaly rely on electrical power my panel does. >I'll be blind as the proverbial bat if I lose my electrical system. > >Oh BTW what was the answer to the water molecule ping pong ball question? I >would guess they would be a few inches deep, but I barely passed Chemistry >so I can't remember all that mole stuff. I purposely left out one piece of data to see if anyone remembered their chemistry. There is a physical constant called Avagadro's number (Na = 6.022 times ten to the 23rd power) that defines the number of molecules in a gram-mole of a substance. For example, oxygen molecules have an atomic mass of 32. Therefore, an Avagadro's number of oxygen molecules will have a mass of 32g. H20 has an atomic mass of 16+1+1 or 18. So, an Avagadro's number of water molecules is 18g. 1 cc of water is 1 gram so the cc of water has 1/18th of an Avagadro's number of water molecules. The rest is setting up the calculations to figure out the total volume this number of ping-pong balls (Stacked in planar rows - not nested) and dividing that volume by the surface area of the US . . . give it a try. Trust me, you'll be amazed by the number. Bob . . . ________________________________ Message 27 ____________________________________ Time: 11:32:17 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Cheap blind encoder. --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:52 PM 5/14/2003 +1000, you wrote: >--> AeroElectric-List message posted by: "Ian Scott" > > >HI All, > >I a getting a Micro air transponder, and was wondering what I should do >for encoder and antenna, in a glass plane Look at the ACK model A-30. The street price on these is about $175. Don't know of anything less expensive. Bob . . . ________________________________ Message 28 ____________________________________ Time: 11:50:39 AM PST US From: "Bob Kuc" Subject: AeroElectric-List: Wig wag --> AeroElectric-List message posted by: "Bob Kuc" Bob ... Did you ever receive my Wig Wag package for you to check? It has been a few weeks. Thanks Bob K ________________________________ Message 29 ____________________________________ Time: 12:24:10 PM PST US From: DHPHKH@aol.com Subject: Re: AeroElectric-List: Cheap blind encoder. --> AeroElectric-List message posted by: DHPHKH@aol.com Companion encoder question: Panel will have a transponder and a GNS430. Both require input from an encoder. Can the two units be paralleled to the same encoder (two wires from each encoder pin) or does the typical installation have two encoders? Dan ________________________________ Message 30 ____________________________________ Time: 12:32:58 PM PST US From: "Gilles.Thesee" Subject: Re: AeroElectric-List: Re: Flap system failure modes (Was circuit protection issues) --> AeroElectric-List message posted by: "Gilles.Thesee" Bob, Thanks for your help and your advice. > > Okay. I'm not sure you need to have an on-purpose limitation > to the flaps as long as your pilots are aware how to use > them safely. Benefits of flaps happen at touchdown. More > flaps just makes you come down faster and leaves you with > less energy to squander in the flare. If I were a flight > instructor, I'd not let a student use flaps at all until > they were proficient without them. > > In the older C-150's, you could get the best of both > worlds by hanging out no more drag than you can tolerate > at full throttle to arrest your descent. When you're > sure you have the landing made, put out the rest of > the flaps. > That's the way we use them in this country. We intend to use the full flap position only for particular landing conditions. > > > >I guess you and I know too well.... > > Okay, let's see what we can do to make failures as tolerant > as possible. I think I'd simply wire all four motors in > parallel with each other. Treat them as a single motor. > Drive the system through a single, 20A breaker at the bus. > The idea of protecting each motor in any way is scary. You > don't want the system to continue to run in any way if one > motor has decided to mis-behave. > Yes of course. Indeed my intention to wire them in parallel. My question was about the sizing of the fuse and the wires, considering fuses are faster than breakers ("the others" are using a breaker) > My sense is that this little airplane simply cannot need > as much snort as a 20A breaker would suggest. Wire with > 14AWG wire and put a 20A breaker in for now. During flight > testing, let's put an ammeter in and see what the system > REALLY needs.I wouldn't be surprised to see that we can > drop the breaker size down to 15 or even 10 amps. An > RV actuator runs at under 5A. Will do. You don't need to size the > breaker for inrush currents. Is it the same for fuses ? I'm using fuseblocks, and the only breaker on board is for the alterrnator OV protection. Or do I need to use a breaker for the flaps ? > > If one wanted to reduce the hazards of single motor > failure, we could design some fancy circuitry to sense > abnormal operation and shut the whole system down > when it was detected. > > Single point protection combined with judicious use > of flaps in approach-to-landing should let you make the > best of a rather un-thoughtful design. This wouldn't be > the only airplane flying around with idiosyncrasies > capable of embarrassing you or driving your pucker > factor up. Take a checkout in a Tri-Pacer or a AA-1 > Yankee and have the check pilot show you how easy it > is to get tense in these airplanes. They ain't your > grandfather's C-172. > > If this system has a satisfactory history . . . meaning > that gear-boxes aren't shelling out and motors are > hanging in there, then you're not facing gross design > limits or high rates of infant mortality. This suggests > that until a motor or gearbox reaches wear-out, > you won't have to shoulder duties as a failure modes > test-pilot soon. Maybe this won't happen until after you've > sold the airplane. > Let's hope so ! Thank you, Gilles ________________________________ Message 31 ____________________________________ Time: 01:11:12 PM PST US From: "John Karnes" Subject: Re: AeroElectric-List: OV circuit breaker tripping --> AeroElectric-List message posted by: "John Karnes" Bob and Cy- Today I bypassed the B-load contactor and went directly to the starter contactor from the alternator. I got about 14 volts without any circuit breaker tripping. My problems appear to be centered around the B-load contactor. The diode was about 100 ohms, so I don't think that is the problem. Maybe the contactor itself or the 80 amp fuse??? John Karnes ________________________________ Message 32 ____________________________________ Time: 01:32:21 PM PST US From: "Phil Birkelbach" Subject: Re: AeroElectric-List: SD-8 Alternator Questions --> AeroElectric-List message posted by: "Phil Birkelbach" > >. . . but it's regulator senses the bus-side . . . > > > . . . and doesn't bring the SD-8 on line unless there > is a battery present. > > > Bob . . . Yep that is the piece that I was missing. I didn't think about the regulator. Why would the regulator be built to inhibit the alternator unless there was bus voltage? I must be missing something because it looks like if the regulator saw zero volts it's 'brain' would tell it to do what it took to bring the volts up to setpoint. Does the "All Electric on a Budget" circuit have a single point of failure in the fat wires coming off of the battery? Not that there is much chance of either of those wires failing, but I am curious. I guess if the battery ground wire came loose then the primary alternator would still yield some volts but how ugly would running the main alternator without the battery be? Godspeed, Phil Birkelbach - Houston Texas RV-7 N727WB (Reserved) - Fuselage http://www.myrv7.com ________________________________ Message 33 ____________________________________ Time: 02:21:36 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Flap system failure modes (Was circuit protection issues) --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > My sense is that this little airplane simply cannot need > > as much snort as a 20A breaker would suggest. Wire with > > 14AWG wire and put a 20A breaker in for now. During flight > > testing, let's put an ammeter in and see what the system > > REALLY needs.I wouldn't be surprised to see that we can > > drop the breaker size down to 15 or even 10 amps. An > > RV actuator runs at under 5A. > >Will do. > >You don't need to size the > > breaker for inrush currents. > >Is it the same for fuses ? I'm using fuseblocks, and the only breaker on >board is for the alterrnator OV protection. Or do I need to use a breaker >for the flaps ? Hmmmm . . . Without specific measurements on your group of 4 motors, I'm reluctant to offer an opinion. With the right gear ratio, ONE of those motors will run the flaps. In fact, the actuator popular with RV builders uses a ball-screw that is so efficient that a motor about the same size runs the flaps with very little current compared to ANYTHING with worm or acme drive components. Problem is that inrush is 4x that of a single motor. They're small motors and will accelerate right smartly but the inrush IS going to be higher even if it is relatively short. Let's go the 20A fuse. This will be easy to test before you fly. Run flaps to mid position. Then do a series of flap drive operations for just a second or so each direction. Delay long enough between pulses to let the motors come to a stop. If the fuse stays in place with a couple dozen short term reversals over a period of a minute or so, then it's going to be okay with respect to in-flight operations. Once the ground test is complete, we can go after the flight data to see if we have a justification for scaling the fuse to any lower value. Bob . . . ________________________________ Message 34 ____________________________________ Time: 02:24:19 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Wig wag --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 02:49 PM 5/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Bob Kuc" > >Bob ... > >Did you ever receive my Wig Wag package for you to check? It has been a >few weeks. > >Thanks > >Bob K Yes. I can wasn't able to get your assembly to mis-behave. Poked around on it a bit but no change. It's still on the bench. I'd like to keep it here for further investigation. I'm sending you one I built that's about 1/6th the size and potted for ruggedness. It's the prototype for an article on w/w module I started a few months ago before I found the electronically driven relays. The new module and your original relays will go out this evening. Bob . . . ________________________________ Message 35 ____________________________________ Time: 02:53:55 PM PST US From: "Bob Kuc" Subject: Re: AeroElectric-List: Wig wag --> AeroElectric-List message posted by: "Bob Kuc" Thanks Bob, Onething that I did notice after I sent this out was that I was only supply 10 Volts throught it. Since I am still building and not engine yet, I am stuck at battery power. However, my batery is perty weak, Maybe the low volts is through more amps through there and causin the mis-behaving. Bob ----- Original Message ----- From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Wig wag > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > At 02:49 PM 5/14/2003 -0400, you wrote: > >--> AeroElectric-List message posted by: "Bob Kuc" > > > >Bob ... > > > >Did you ever receive my Wig Wag package for you to check? It has been a > >few weeks. > > > >Thanks > > > >Bob K > > Yes. I can wasn't able to get your assembly to mis-behave. > Poked around on it a bit but no change. It's still on the > bench. I'd like to keep it here for further investigation. > I'm sending you one I built that's about 1/6th the size > and potted for ruggedness. It's the prototype for an article > on w/w module I started a few months ago before I found the > electronically driven relays. > > The new module and your original relays will go out this > evening. > > Bob . . . > > ________________________________ Message 36 ____________________________________ Time: 04:16:47 PM PST US From: "Greg Young" Subject: RE: AeroElectric-List: Cheap blind encoder. --> AeroElectric-List message posted by: "Greg Young" What inputs does your transponder and GNS430 accept, Gray code, serial or both? I just installed UPS gear in my Navion and the SL70 transponder will accept either Gray code or serial encoder input and output a serial signal to the GX60 GPS/Com (it only accepts serial). That let me use my existing (and cheap) Ameriking AK-350 encoder instead of an expensive serial encoder or serial converter and still have the altitude input needed for IFR approval. I suspect Garmin may have similar capability. It's an option to explore. Regards, Greg Young - Houston (DWH) RV-6 N6GY ...project Phoenix Navion N5221K - just an XXL RV-6A > --> AeroElectric-List message posted by: DHPHKH@aol.com > > Companion encoder question: Panel will have a transponder and > a GNS430. Both require input from an encoder. Can the two > units be paralleled to the same encoder (two wires from each > encoder pin) or does the typical installation have two encoders? > > Dan > ________________________________ Message 37 ____________________________________ Time: 04:26:50 PM PST US From: Kent Ashton Subject: Re: AeroElectric-List: Static when Refuelling re Braid --> AeroElectric-List message posted by: Kent Ashton > > >" Any help is kindly > appreciated, but I did buy the tinned copper braid today, and > > after reading your message I don't know what to do with it. > > > Reg > > Tony Renshaw > For fiberglass airplanes, If you rivet the braid, or any wire, to the fuel cap ring and bring it down to some central point, like in the cockpit strake area or the external step, you can at least ground the fuel cap to prevent static sparking between the refueling nozzle and the cap ring. Should help some. --Kent A. ________________________________ Message 38 ____________________________________ Time: 04:31:34 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Wig wag --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:52 PM 5/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Bob Kuc" > >Thanks Bob, Onething that I did notice after I sent this out was that I was >only supply 10 Volts throught it. Since I am still building and not engine >yet, I am stuck at battery power. However, my batery is perty weak, Maybe >the low volts is through more amps through there and causin the >mis-behaving. Hmmm . . I'll try that and see what happens. . . . in any case, the other flasher went out a few minutes ago. Bob . . . ________________________________ Message 39 ____________________________________ Time: 04:44:22 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: SD-8 Alternator Questions --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 03:32 PM 5/14/2003 -0500, you wrote: >--> AeroElectric-List message posted by: "Phil Birkelbach" > > > > > >. . . but it's regulator senses the bus-side . . . > > > > > > . . . and doesn't bring the SD-8 on line unless there > > is a battery present. > > > > > > Bob . . . > >Yep that is the piece that I was missing. I didn't think about the >regulator. Why would the regulator be built to inhibit the alternator >unless there was bus voltage? I must be missing something because it looks >like if the regulator saw zero volts it's 'brain' would tell it to do what >it took to bring the volts up to setpoint. That's what they did. It's a purchased regulator Bill gets from some outfit in Kansas City as I recall. Perhaps the rational for the design was to make sure that any time the alternator was delivering useful power, the presence of a battery made sure it was as clean as practical. I've got some ideas about how to get a few more watts out of and SD-8 with a regulator that would provide quite smooth power sans battery. I'll keep that on the back burner as a potential product. >Does the "All Electric on a Budget" circuit have a single point of failure >in the fat wires coming off of the battery? Not that there is much chance >of either of those wires failing, but I am curious. There is that risk. I've never had or seen a wire come loose but a list member broke a post off a 17 a.h. RG battery and reported on it here a few weeks ago. Obviously, the chances are not zero. If it were my airplane, I'd use 4AWG welding wire battery jumpers to get soft, flexible leads. > I guess if the battery >ground wire came loose then the primary alternator would still yield some >volts but how ugly would running the main alternator without the battery be? Hard to quantify. You can certainly run the experiment after the airplane is built and see. If you don't like what you see, you can always add the tiny aux battery to accommodate that condition. Keep in mind that about 100,000 S.E. aircraft are flying around out there now with one altenrator, one battery and the same risk for loss of system due to battery coming unhooked. It's much more likely that you'll get alternator or contactor failure than failure of wires on the battery. So an all-electric- on-a-budget architecture is waaaaayyyyyy more reliable than anything flying around in spam-can-land. Consider too that for most of the way we use our airplanes, TOTAL loss of electrical system can be tolerated. I normally use hand-held GPS to navigate and I carry a hand-held VOR/COM. When I walk up to a rental airplane, there's no practical way for me to assess the condition or history of that ship's electrical system. If I can fly a J-3 somewhere with no electrical system, I can fly an A-36 too. Bob . . . ________________________________ Message 40 ____________________________________ Time: 05:08:31 PM PST US From: "Rob Housman" Subject: RE: AeroElectric-List: SD-8 Alternator Questions --> AeroElectric-List message posted by: "Rob Housman" When I took P. Chem Avagadro's number was 6.0238 X 10 E 23 Best regards, Rob Housman Europa XS Tri-Gear A070 Airfarame complete Irvine, CA -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert L. Nuckolls, III Subject: Re: AeroElectric-List: SD-8 Alternator Questions --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" SNIP I purposely left out one piece of data to see if anyone remembered their chemistry. There is a physical constant called Avagadro's number (Na = 6.022 times ten to the 23rd power) that defines the number of molecules in a gram-mole of a substance. SNIP Bob . . . ________________________________ Message 41 ____________________________________ Time: 05:21:50 PM PST US From: Charlie & Tupper England Subject: Re: AeroElectric-List: Static when Refuelling re Braid --> AeroElectric-List message posted by: Charlie & Tupper England Fergus Kyle wrote: >--> AeroElectric-List message posted by: "Fergus Kyle" > >" Any help is kindly > appreciated, but I did buy the tinned copper braid today, and > > after reading your message I don't know what to do with it. > > > Reg > > Tony Renshaw > >That would be braid dangling inside the tank, wired to electrical ground? It won't do anything during refueling to suppress static charges, since fuel is essentially nonconductive. >Fred F" > snipped I haven't followed this thread, but this caught my eye. The static discharge problem is *caused* by the fact that fuel is basically non conductive. A glass rod is non conductive, but we've all seen the effects after rubbing one through a cat's fur. Either the fuel or the plane can have a static charge. If they are at a different voltage potential, the chance of a spark exists as the nozzle approaches the tank. The fuel can acquire a charge as it moves through a hose, just like the glass rod through fur. If you don't bring the fuel delivery system & the plane to the same voltage potential before beginning the refueling process, you can get a spark. That's why the line boy grounds the truck and grounds the plane before fueling begins. Charlie ________________________________ Message 42 ____________________________________ Time: 06:23:55 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: RE: Avogadro's Number --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:08 PM 5/14/2003 -0700, you wrote: >--> AeroElectric-List message posted by: "Rob Housman" > >When I took P. Chem Avagadro's number was 6.0238 X 10 E 23 > > >Best regards, A check of my 41st edition (1960) edition of the CRC Handbook calls it 6.0247*10E23 . . . and I seem to recall using 6.025*10E23 in class. . . . but a search on the 'net yields 6.022136736*10E23 http://education.jlab.org/glossary/avogrado.html http://www.britannica.com/ebc/article?eu=381538 You know how those guys are. There are folks who can spend a lifetime refining a single idea. Avogadro's idea seems to have moved a tad. Does the value of Na we carved into the gray matter date when we all took chemistry? Bob . . . ________________________________ Message 43 ____________________________________ Time: 06:51:53 PM PST US From: "Dave Ford" Subject: AeroElectric-List: encoder wiring --> AeroElectric-List message posted by: "Dave Ford" I am at the stage of integrating wiring of instruments and have noticed I have three instruments requesting encoded altitude information from the encoder. Can the encoder output be daisy-chained or paralleled to each instrument needing that information? Is isolation required via resistors? Is an altitude encoder capable of its information going to more than one device without loading its output? Dave Ford ________________________________ Message 44 ____________________________________ Time: 07:02:34 PM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: encoder wiring --> AeroElectric-List message posted by: BobsV35B@aol.com In a message dated 5/14/03 8:52:41 PM Central Daylight Time, dford@michweb.net writes: > I am at the stage of integrating wiring of instruments and have noticed I > have three instruments requesting encoded altitude information from the > encoder. Can the encoder output be daisy-chained or paralleled to each > instrument needing that information? Is isolation required via resistors? > Is an altitude encoder capable of its information going to more than one > device without loading its output? > > Dave Ford > Good Evening Dave, I know nothing about wiring problems, but I have been involved with that problem in the past. You can feed them all by using parallel wiring. My recollection is that it takes about eleven wires to each device. Just double up on the pins and take it on to the next device. One caution, there are some transponders that tend to have a back feed interference of some sort. Specifically, the King KT-76 series. For those, it is advisable to put diodes in the input lines to the transponder so that the data can only go into the transponder and not flow back out. Eleven little 1N4001s will do the job just fine. Anything up to 1N4009s is supposedly OK. Maybe one of those who know what is happening will comment further. Happy Skies, Old Bob ________________________________ Message 45 ____________________________________ Time: 07:34:40 PM PST US Subject: Re: AeroElectric-List: RE: Avogadro's Number From: Don Boardman --> AeroElectric-List message posted by: Don Boardman > seem to recall using 6.025*10E23 in class. > . . . but a search on the 'net yields > 6.022136736*10E23 > You know how those guys are. There are folks who can > spend a lifetime refining a single idea. Avogadro's > idea seems to have moved a tad. Does the value > of Na we carved into the gray matter date when we > all took chemistry? > > Bob . . . Tomorrow I will enjoy telling my 33rd. group of chemistry students that Avogadro's number is alive and well on the Internet list serve circuit! I tell them all the time that it is a number they better remember for life, and that if I run into them when they are older I will expect them to rattle it off in style. 5 weeks to retirement. Regards, Don Boardman Murphy Moose #130 M-14PF 400HP, MT-prop, Aerocet 3500 amphibs, AeroElectric Wired, Rome, NY ________________________________ Message 46 ____________________________________ Time: 07:42:12 PM PST US From: "Rob Housman" Subject: RE: AeroElectric-List: RE: Avogadro's Number --> AeroElectric-List message posted by: "Rob Housman" My P. Chem. text shows a copyright date of 1961 (and shows only four decimal places). I knew a lot of the practical stuff I learned is outdated but I thought the basic stuff should have remained constant. Oh well. Best regards, Rob Housman Europa XS Tri-Gear A070 Airfarame complete Irvine, CA -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert L. Nuckolls, III Subject: AeroElectric-List: RE: Avogadro's Number --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:08 PM 5/14/2003 -0700, you wrote: >--> AeroElectric-List message posted by: "Rob Housman" > >When I took P. Chem Avagadro's number was 6.0238 X 10 E 23 > > >Best regards, A check of my 41st edition (1960) edition of the CRC Handbook calls it 6.0247*10E23 . . . and I seem to recall using 6.025*10E23 in class. . . . but a search on the 'net yields 6.022136736*10E23 http://education.jlab.org/glossary/avogrado.html http://www.britannica.com/ebc/article?eu=381538 You know how those guys are. There are folks who can spend a lifetime refining a single idea. Avogadro's idea seems to have moved a tad. Does the value of Na we carved into the gray matter date when we all took chemistry? Bob . . . ________________________________ Message 47 ____________________________________ Time: 08:48:26 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: OV circuit breaker tripping --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:09 PM 5/14/2003 -0700, you wrote: >--> AeroElectric-List message posted by: "John Karnes" > >Bob and Cy- > >Today I bypassed the B-load contactor and went directly to the starter >contactor from the alternator. I got about 14 volts without any circuit >breaker tripping. My problems appear to be centered around the B-load >contactor. The diode was about 100 ohms, so I don't think that is the >problem. Maybe the contactor itself or the 80 amp fuse??? Hmmm . . . perhaps there's a short inside the contactor. I've heard of such things but never seen them. Disconnect all the wires from the small terminals of the contactor and measure the resistance between the two terminals and then from each terminal to the contactor case and tell us what you find. Bob . . . ________________________________ Message 48 ____________________________________ Time: 09:25:25 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Cheap blind encoder. --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 03:23 PM 5/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: DHPHKH@aol.com > >Companion encoder question: Panel will have a transponder and a >GNS430. Both require input from an encoder. Can the two units be >paralleled to the same encoder (two wires from each encoder pin) or does >the typical installation have two encoders? You can drive multiple loads with one encoder but you need an array of diodes to avoid cross-coupled problems between loads. I don't recall now exactly how the diodes are oriented. I searched the net and found some encoder loads (transponders) that claim to have isolation diodes installed. I'll call around and see if an avionics wienie can tell me of the top of his head which way the diodes have to go . . . Opps, just found an overhaul manual for an encoder on the 'net at: http://www.trans-cal.com/7421%20B.pdf on page 2 it speaks of open collector outputs which are active pull down only devices and that the pull-up for logic "hi" is expected to come from the transponder (signal load). This means that isolation diodes would have to be included in the data lines for each device that expects to get altitude data with the cathode facing the encoder. These diodes prevent the data lines from being pulled to ground by a transponder or GPS that is powered down. I've published an exemplar diagram at http://216.55.140.222/temp/Encoder.pdf The neatest way to install this raft of diodes is to lay out a simple etched circuit board with d-sub connector to bring wires onto and off the board. For driving two loads, there's a total 27 wires . . . a single 37-pin D-sub would do it. I've seen some "professional" installations where the diodes were simply butt-sliced into the wire bundles and covered with heat- shrink. I guess some DER signed off on this somewhere. Be sure to check if the devices that need altitude data for built in diodes. If they're already present, then you can simply eliminate the diodes show in the drawing and wire direct. Bob . . . >Dan > > Bob . . . -------------------------------------------- ( Knowing about a thing is different than ) ( understanding it. One can know a lot ) ( and still understand nothing. ) ( C.F. Kettering ) -------------------------------------------- ________________________________ Message 49 ____________________________________ Time: 09:27:13 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: encoder wiring --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:51 PM 5/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Dave Ford" > > I am at the stage of integrating wiring of instruments and have > noticed I have three instruments requesting encoded altitude information > from the encoder. Can the encoder output be daisy-chained or paralleled > to each instrument needing that information? Is isolation required via > resistors? Is an altitude encoder capable of its information going to > more than one device without loading its output? See my earlier on this subject. If your device needing altitude has isolation diodes already installed, it can be simply paralleled with the other devices. Otherwise you need to add them per the example at: http://216.55.140.222/temp/Encoder.pdf Bob . . . ________________________________ Message 50 ____________________________________ Time: 10:05:40 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: non-Microprocessor based Fuel Gauge Linearizer --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:47 PM 5/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > >Jerzy--Of course you are right. I was hoping this detail would fall into >place, since there are some issues yet to be resolved. > >Bob and Jerzy and others. You would be right to guess I am more >comfortable with op amps than with microprocessors. I returned to using >discrete chips after receiving the source code for a device of similar >complexity....and it is 25 pages of assembler. The notion that using a >microprocessor instead of a couple of chips should best be argued upon the >completion of parallel projects. Believe me, I am wholeheartedly a >microprocessor fan, but not in this design. Hmmm . . . I'll bet the code to read an a/d, get the first lookup table values above and below the reading and average them for output to a d/a wouldn't fill one page. >Besides....analog input, analog output, and don't a few op amps and >comparators make an analog "computer"? There are some single chip processors with an a/d and d/a built in that would do this. Check out the PIC12F675 data sheet at http://www.microchip.com/download/lit/pline/picmicro/families/12f6xx/41190c.pdf and application tips at: http://www.microchip.com/download/lit/pline/picmicro/families/12f6xx/40040b.pdf This device sells for under $3 from Digikey and will do about everything you need to do in one chip . . . in fact, it might be possible to do a DUAL linearizer in the same chip so that both tanks can be calibrated on one assembly. You can talk to the a/d directly from the tank sender driven by a constant current source. A relatively simple routine to drive a fet with a variable duty-cycle would provide for analog i/o to drive the standard gage that comes with the senders. The hardest part would be to write the program to go into a laptop for consumers to talk to the chip and modify its lookup table. Visual Basic would probably help with a user-friendly windows-like interface. I'm finding it increasingly difficult to justify even simple projects in analog and/or discrete logic parts any more. The chips are just too cheap and getting more powerful all the time. Bob . . . ________________________________ Message 51 ____________________________________ Time: 10:14:30 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: AutoPilot Disconnect --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:08 AM 5/13/2003 -0700, you wrote: >--> AeroElectric-List message posted by: John Loram > >This analysis makes some simplifying assumptions; most importantly that the >switch and relay contacts have zero resistance, and that the only non-purely >resistive component is the relay coil. The calculation of the effect of >these tertiary elements are left to the student.... ;-) > > > >(is there a prize????) ;-) -john- > > Sure, after you finish the test . . . > > Bob . . . You got it. Do you have a copy of the CD we sell? Bob . . . ________________________________ Message 52 ____________________________________ Time: 10:47:18 PM PST US From: John Rourke Subject: Re: AeroElectric-List: non-Microprocessor based Fuel Gauge Linearizer --> AeroElectric-List message posted by: John Rourke No need for a laptop... just a switch to put it in calibrate mode, and a serial EEPROM... and some PICs even contain those I think. Switch to "calibrate" mode, have it light each bar of a bar-mode display sequentially, then add the desired amount of fuel to be represrented by that display element, and push a button to "capture" that A/D value - let it build it's own lookup table. Hmmm, maybe I'll make one. -John R. Robert L. Nuckolls, III wrote: >--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > >At 01:47 PM 5/14/2003 -0400, you wrote: > > >>--> AeroElectric-List message posted by: "Eric M. Jones" >> >>Jerzy--Of course you are right. I was hoping this detail would fall into >>place, since there are some issues yet to be resolved. >> >>Bob and Jerzy and others. You would be right to guess I am more >>comfortable with op amps than with microprocessors. I returned to using >>discrete chips after receiving the source code for a device of similar >>complexity....and it is 25 pages of assembler. The notion that using a >>microprocessor instead of a couple of chips should best be argued upon the >>completion of parallel projects. Believe me, I am wholeheartedly a >>microprocessor fan, but not in this design. >> >> > > Hmmm . . . I'll bet the code to read an a/d, get the first > lookup table values above and below the reading and average > them for output to a d/a wouldn't fill one page. > > > > >>Besides....analog input, analog output, and don't a few op amps and >>comparators make an analog "computer"? >> >> > > > There are some single chip processors with an a/d and > d/a built in that would do this. Check out the PIC12F675 > data sheet at > http://www.microchip.com/download/lit/pline/picmicro/families/12f6xx/41190c.pdf > > and application tips at: > > http://www.microchip.com/download/lit/pline/picmicro/families/12f6xx/40040b.pdf > > This device sells for under $3 from Digikey and will do about > everything you need to do in one chip . . . in fact, it > might be possible to do a DUAL linearizer in the same chip > so that both tanks can be calibrated on one assembly. > You can talk to the a/d directly from the tank sender > driven by a constant current source. A relatively simple > routine to drive a fet with a variable duty-cycle would > provide for analog i/o to drive the standard gage that > comes with the senders. > > The hardest part would be to write the program to go into > a laptop for consumers to talk to the chip and modify its > lookup table. Visual Basic would probably help with a > user-friendly windows-like interface. > > I'm finding it increasingly difficult to justify even > simple projects in analog and/or discrete logic parts > any more. The chips are just too cheap and getting > more powerful all the time. > > Bob . . . > > > >