---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 10/13/07: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:49 AM - Re: Z-19 and considerations of SYSTEM reliability () 2. 10:08 AM - Re: Ground loop risk? (Robert L. Nuckolls, III) 3. 10:25 AM - Re: Re: Z-19 and considerations of SYSTEM reliability (Robert L. Nuckolls, III) 4. 11:15 AM - Re: Re: Z-19 and considerations of SYSTEM reliability (Robert L. Nuckolls, III) 5. 12:33 PM - Engine sensor ground (vicster_26) 6. 04:31 PM - Re: Z-19 (Robert L. Nuckolls, III) 7. 04:36 PM - Ver 11.1 of the Data CD is uploaded (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 05:49:23 AM PST US From: Subject: AeroElectric-List: RE: Z-19 and considerations of SYSTEM reliability 10/13/2007 Hello Bob, You wrote: " . . . and the pump is already ON for takeoff and landing." Just a reminder that in some aircraft the electrically driven fuel boost pump is not turned on for takeoff or landing. The problem in those aircraft is that with the engine driven fuel pump and the electrically driven fuel boost pump both operating the engine can be drowned in fuel and not operate properly or at all. The function of the electrically driven fuel boost pump in those aircraft is to prime the engine prior to starting the engine and to be turned on in flight in case of failure of the engine driven fuel pump. 'OC' Says: "The best investment we can make is the effort to gather and understand knowledge." -------------------------------------- Time: 06:54:48 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: RE: Z-19 and considerations of SYSTEM reliability ..... snip ............. Our low-wing, TC aircraft have been fitted with boost pumps since day one. 95+ percent of all engine falters in flight have to do with fuel issues. We were taught to hit the pump switch first. Perception, interpretation and reaction took perhaps two seconds. . . . and the pump is already ON for takeoff and landing. So, what is the return on investment of adding an automatic "failover" device in those aircraft? Now, if these engines tend to quit and be hard to get restarted then perhaps some form of automatic, fast reaction system is called for. But if it just falters, windmills and recovers immediately upon return of fuel flow, then perhaps the automatic system is less than elegant. THAT decision is entirely yours . . . I'm only suggesting that you ponder the decision with good data and a goal of arriving at the elegant solution. Bob . . . ________________________________ Message 2 _____________________________________ Time: 10:08:18 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Ground loop risk? At 05:03 PM 10/12/2007 -0400, you wrote: > >I'm feeding my strobes from the 12 volt buss behind the panel. >Is it necessary to run the ground for the strobes back to the panel ground >buss, or can I just run the ground to the battery terminal since I'm in >that vicinity? >I'm trying to save a wire going forward. >Will I risk a ground loop if I have more than one ground termination point? What kind of airplane? If a metal airplane it is perfectly useful to use local grounds for landing lights taxi lights nav lights pitot heaters strobe power supplies landing gear hydraulic pumps etc. These are ALL potential antagonists for loading alternator noise onto the airframe. But taking potential victims to the single point grounds on firewall and/or instrument panel as suggested in Figure Z-15 of: http://aeroelectric.com/articles/Rev11/AppZ_R11K.pdf Bob . . . ________________________________ Message 3 _____________________________________ Time: 10:25:26 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RE: Z-19 and considerations of SYSTEM reliability At 08:48 AM 10/13/2007 -0400, you wrote: > >10/13/2007 > >Hello Bob, You wrote: " . . . and the pump is already ON for takeoff and >landing." > >Just a reminder that in some aircraft the electrically driven fuel boost >pump is not turned on for takeoff or landing. > >The problem in those aircraft is that with the engine driven fuel pump and >the electrically driven fuel boost pump both operating the engine can be >drowned in fuel and not operate properly or at all. > >The function of the electrically driven fuel boost pump in those aircraft >is to prime the engine prior to starting the engine and to be turned on in >flight in case of failure of the engine driven fuel pump. Sure . . . which re-enforces the notion that NOTHING written anywhere by anyone that is not specific to a study of demonstrated test data about a particular design is to be taken as gospel. Every new recipe for success combines simple ideas for the purpose of meeting a design goal. It's up to the writer of specific instructions to explain the rationale for that particular combination of parts and recommend a modus operandi for that system. This is what the 40-hour fly-off is all about. But many builders have put their own flavors onto another builder's recipe. Too many modified recipes have been turned loose on open skies and grinning pilots with undiscovered potential for problems. Its fortunate that reliance on electrical systems issues is Waaaaayyy down the list of things that routinely bend airplanes and kill folks. Fiddling with these recipes generally don't generate much physical risk, only surprise and cost of ownership. But we're talking about powerplants here so the details are worthy of extra attention. Now, may I take you to task my friend for, "The function of an electrically driven fuel boost . . .". The POH for many of the aircraft I fly instructs a pilot to turn the boost pump on for take-offs and landings. Bottom line is that there should be GOOD reasons for doing or not doing a lot of things on our airplanes . . . but the final word needs to come from designers and testers that have, "Been there. Done that." All other assertions are worthy of measured skepticism and further study. >'OC' Says: "The best investment we can make is the effort to gather and >understand knowledge." HEAR, Hear! Bob . . . ________________________________ Message 4 _____________________________________ Time: 11:15:44 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: RE: Z-19 and considerations of SYSTEM reliability At 10:20 AM 10/12/2007 -0500, you wrote: > >Thanks Bob, > >I can't seem to find the email but I think Eggenfellner has decided that a >simple switch on Pump#2 is fine. They were having too much trouble with the >pressure switch for automatic fail-over. > >As a computer geek I find it so hard to resist "automatic techno gadgets"! >Thanks for the detailed exhortation. Yup, a lot of what's being done in new systems design is driven more by what we're capable of doing as opposed to crafting the minimum parts count, highest reliability, lowest cost (i.e. elegant) solution. The drive to add whippy new features is oft offered by folks who have little or poor connection to end users. We see this in the Heavy Iron Aviation all the time. In addition to bureaucratic pressures to do or not do things, decisions about what's attractive to the end user (owners and pilots) tend not to be made with the elegant solution as a design goal. Walter, Dwayne, Ed, Arthur, Bill, Al and Lloyd would be sad to observe the remnants of their legacies. Bob . . . ________________________________ Message 5 _____________________________________ Time: 12:33:35 PM PST US Subject: AeroElectric-List: Engine sensor ground From: "vicster_26" Hello, I understand that in a single point ground system, those sensors that are connected to the engine case should have their ground returned from the instrument to the engine side of the firewall ground. A question here, with some of these new electronic engine analyzers where you have multiple sensors connecting to one instrument via a D-sub connector, how do you resolve the issue of returning the relevant ground back to engine side when the ground is grounded internally in the instrument. In my case, most of the sensors are isolated from the engine except for the Oil Temp which is obviously threaded directly to the engine case. I have a factory built airplane with very basic instrumentation and avionics, in fact it had just one old chunky radio and the avionics master switch is simply a 5amp switch type circuit breaker. Now that I am installing a few more avionics, is there any problems with connecting all of them to this one circuit breaker or perhaps running a bus from this switch/circuit breaker to separate circuit breakers for each avionics? Thanks in advance Vic Read this topic online here: http://forums.matronics.com/viewtopic.php?p=139789#139789 ________________________________ Message 6 _____________________________________ Time: 04:31:32 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-19 At 08:46 PM 10/11/2007 -0400, you wrote: >Bob, > >I have decided on a ULPower 260i engine for my Europa. It has one ECU and >one fuel pump. In my book there is a Z-19 drawing, but I can't find it on >the disk I picked up at your seminar or on your latest download from your >site. Do you suppose that you could email it to me? Thanks > >Vaughn Teegarden >vaughnray@bvunet.net All of the latest drawings are on the website's Page-Per-System library at: http://www.aeroelectric.com/PPS/ACAD_Architecture_Dwgs/ for the AutoCAD .dwg format and . . . http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/ for the .pdf versions. Your heads-up on the CD download is appreciated. I forgot to update it. I've loaded Ver 11.1 up at: http://www.aeroelectric.com/CD Bob . . . ________________________________ Message 7 _____________________________________ Time: 04:36:59 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Ver 11.1 of the Data CD is uploaded I've just uploaded the latest copy of the 'Connection's data CD. Version 11.1 zip file may be accessed at: http://www.aeroelectric.com/CD/AEC_11p1.zip This is about a 400M file. It can take awhile on even some "high speed" systems. Bob . . . ---------------------------------------- ( "Problems are the price of progress. ) ( Don't bring me anything but trouble. ) ( Good news weakens me." ) ( -Charles F. 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