---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 12/11/16: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:03 AM - Re: Z-12 questions (William Greenley) 2. 10:39 AM - Re: Z-12 questions (user9253) 3. 10:55 AM - Re: Z-12 questions (Robert L. Nuckolls, III) 4. 11:24 AM - On other topics. (Robert L. Nuckolls, III) 5. 08:53 PM - Audio Isolation Amplifier Boards (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:03:58 AM PST US From: William Greenley Subject: Re: AeroElectric-List: Z-12 questions My thinking on the ebus was that the radio has a very small draw when not in use, and the flaps, landing light and fuel pump have zero draw. Having them on the ebus would allow their use for landing in case of master contactor or switch failure, if not for that failure mode, the need for the ebus would be if both alternators fail. Wonder which is more likely. On Sun, Dec 11, 2016 at 1:33 AM, don van santen wrote: > William, > The EBus should be switched with a relay. The avionics switch is not a > good idea as it introduces a single point of failure. I believe that you > might be misunderstanding the EBus concept. It is designed to power only > essential items such as in an electric ac one efis one com and maybe the > pmags. The idea is that you can easily reduce the electrical load such th at > the available fuel is the only determining factor as to when you will nee d > to land. Switching the master off reduces the load to the point that your > standby alternator can power the remaining load till you arrive at your > destination. You could then switch the master back on and hve your entir e > panel for the landing. Fuel pump and flaps are not required for cruise > flight although they do draw any current when switched off, so they are n ot > against the EBus concept. Hope this helps. I have an RV7 with Z12-8 from > day one and it works perfectly as designed. My standby alternator is the > B%C SD8. > > On Sat, Dec 10, 2016 at 9:09 PM, William Greenley > wrote: > >> Building an RV-10 and working on wiring following Z-12 with 60 amp main >> alternator from B & C, and 30A backup alternator also from B&C. Planning on >> using the mythical 6-cyl P-Mags, but in the meantime will be setting up >> shower of sparks as I have that on hand. A couple of questions regarding >> switches. As I look at the endurance bus, I am trying to figure out what is >> an appropriate switch to use, I am looking at putting the GTN 650, a G3X >> display, flap motor, fuel pump, and landing lights on the endurance bus. >> While the 650 can be a large draw, that is only while transmitting, simi lar >> with the fuel pump and flap motor. Lights would only be for a few minute s >> on landing. But in total these could be a large draw for short periods o f >> time, what is an appropriate switch to use for the endurance bus, typica l >> toggle switches I see are rated at no more that 15 =93 20 amps. I really >> don=99t want to use one of the pull switches. >> >> >> >> A similar question for an avionics bus, while I know this is not needed >> to protect the avionics, I have been advised it is a good idea so that >> there is minimal battery drain while starting the plane, after start you >> flip the avionics master to turn on the majority of the avionics. Some >> items like one display, and the engine sensors would be powered on with the >> main battery switch. It seems like this switch could be asked to handle a >> lot of amps, with radio, transponder, etc. What are your thoughts on an >> avionics bus for this reason, and also what is an appropriate switch to use? >> >> Bill Greenley >> >> Build an RV-10 in SW Michigan >> > > ________________________________ Message 2 _____________________________________ Time: 10:39:52 AM PST US Subject: AeroElectric-List: Re: Z-12 questions From: "user9253" Minimizing battery drain during engine cranking is not a valid reason to have an avionics switch. Avionics use very little current compared to the starter motor. A better way to improve starter performance is to use larger wire size. An avionics master switch is an unnecessary failure point. Use an automotive relay located near the battery to power the E-bus. A small panel mounted switch can control the relay. Relays have the advantage of remote control and larger current carrying capacity. Search for relay part number 1432793-1. It is rated for 40 amps, costs less than $5, and has a built-in diode for arc suppression. The diode arrow should point towards positive or else it will self destruct. Here is a link to a circuit that you might consider: https://drive.google.com/file/d/0B7ZTG2VpCuDRSVNVa3JwUmFuMzQ/view?usp=sharing The E-Bus will not draw power from the main battery during engine cranking. The small brownout battery will prevent E-Bus voltage sagging during engine start. Thus avionics will not reboot. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=463838#463838 ________________________________ Message 3 _____________________________________ Time: 10:55:47 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-12 questions At 07:54 AM 12/11/2016, you wrote: >My thinking on the ebus was that the radio has a very small draw >when not in use, and the flaps, landing light and fuel pump have >zero draw. Having them on the ebus would allow their use for landing >in case of master contactor or switch failure, if not for that >failure mode, the need for the ebus would be if both alternators >fail. Wonder which is more likely. Your throwing a lot of rocks into the electro-gearworks . . . First, the E-bus is an ENDURANCE bus originally intended to offer a simple, plan-B approach to MINIMIZING loads on limited energy resources for the en route phase of flight. The idea was that should the ONLY engine driven power source become unavailable, then it's entirely possible and practical to plan for continued, comfortable flight to airport of intended destination (or a similarly friendly one where repair resources are available). In other words, inoculate your system against the 'dark-n-stormy-night' syndrome. As originally proposed, the E-bus would let flyers continue with RUNNING LOADS as small as a few amps with a goal of reaching friendly concrete. Over the years, the E-bus has been badly mutated into a collection of band-aids that go to addressing very unlikely if none existent worries. Worries easily address by consulting gray-beards here on the List and deciding just what devices are must useful for meeting the ENDURANCE mode design goals. Z-12 was the next evolutionary step for replacing a pieces-of-@#$# generator on Bonanzas with an alternator having about 4-5x the output and 100x the service life. . . It was never being suggested as the elegant solution for a clean piece of paper design. I'm not suggesting that it's not going to perform as intended . . . in fact, it's a perfectly satisfactory alternative to the legacy architecture typical of a few hundred thousand spam cans (the vast majority of which will not be center stage in a dark-n-stormy-night story). Emacs! If you're well down the road with Z-12 then I would recommend ditching e-bus, and anything resembling an avionics bus. With a robust second alternator, you will not be energy deprived for the en route phase of flight. Just reduce loads till the alternator loaded light stops flashing. This holds ALL of the battery's contained energy in reserve for descent and approach to landing . . . turn on anything else you want to have (short of the air conditioner). Emacs! Loosing ONE properly selected, installed and maintained alternator is very unlikely. Loosing BOTH alternators is on a par with being hit by an incoming meteor. if Z-12 is good for hundreds of Beech, Piper and Mooney airplanes obsessed over by hoards of folk paid good salaries to WORRY about everything . . . then it's golden in your projct. Bob . . . ________________________________ Message 4 _____________________________________ Time: 11:24:01 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: On other topics. >Building an RV-10 and working on wiring >following Z-12 with 60 amp main alternator from >B & C, and 30A backup alternator also from B&C. >Planning on using the mythical 6-cyl P-Mags, but >in the meantime will be setting up shower of >sparks as I have that on hand. A couple of >questions regarding switches. As I look at the >endurance bus, I am trying to figure out what is >an appropriate switch to use, I am looking at >putting the GTN 650, a G3X display, flap motor, >fuel pump, and landing lights on the endurance >bus. While the 650 can be a large draw, that is >only while transmitting, similar with the fuel >pump and flap motor. Lights would only be for a >few minutes on landing. But in total these could >be a large draw for short periods of time, what >is an appropriate switch to use for the >endurance bus, typical toggle switches I see are >rated at no more that 15 ' 20 amps. I really >don=99t want to use one of the pull switches. See http://tinyurl.com/z22xf8q Laboratory performance ratings for switches are almost totally irrelevant in the single engine light aircraft that sees perhaps 100 flight cycles per year MAX. The Carling toggles offered by B&C and others are suited for any of the RV10's appliance loads. >A similar question for an avionics bus, while I >know this is not needed to protect the avionics, >I have been advised it is a good idea so that >there is minimal battery drain while starting >the plane, after start you flip the avionics >master to turn on the majority of the avionics. . . . old flyer's prophylactic having roots in a time when radios were fitted with vacuum tubes and electro-mechanical power supplies. Also a time when airplanes were cranked with rather soggy, flooded, lead- acid batteries. Emacs! The avionics master (like the Kettering spark system) is a feature we can appreciate for its value at the time . . . but happily discarded when that value diminishes and gets replaced by something better. See http://tinyurl.com/jn6gykz Emacs! Bob . . . ________________________________ Message 5 _____________________________________ Time: 08:53:11 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Audio Isolation Amplifier Boards I've had some requests for the bare etched circuit board called out in the DIY amplifier project featured at http://tinyurl.com/hn28p2q Unfortunately, there is a minimum quantity for fabricating these. If I could sell three more boards at $25 each postage paid, I would be wiling to bring another batch of these in house. This was probably the most successful DIY project on the AeroElectric website. I think we sold about 80 of those boards over the years. I've placed an order for the boards based on requests received to date. The boards are ordered in lots of 6. From the 2 lots just ordered I'll have 4 residual boards available. Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.