---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 11/19/19: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 0. 06:33 AM - Please Make a Contribution to Support Your Lists... (Matt Dralle) 1. 03:53 PM - Re: YOU BETTER HAVE A PLAN! (Robert L. Nuckolls, III) ________________________________ Message 0 _____________________________________ Time: 06:33:58 AM PST US From: Matt Dralle Subject: AeroElectric-List: Please Make a Contribution to Support Your Lists... Dear Listers, Just a reminder that November is the Annual List Fund Raiser. Please make a Contribution today to support the continued operation and upgrade of these great List services!! Pick up a really nice free gift with your qualifying Contribution too! The Contribution Site is fast and easy: http://www.matronics.com/contribution or by dropping a personal check in the mail to: Matt Dralle / Matronics 581 Jeannie Way Livermore CA 94551-0347 Thank you! Matt Dralle Matronics Email List Administrator ________________________________ Message 1 _____________________________________ Time: 03:53:50 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: YOU BETTER HAVE A PLAN! At 04:23 PM 11/18/2019, you wrote: > >I value SIMPLICITY! > >While Bob & Stein are absolutely correct in the previous discussion >about aircraft electrical architecture, I would like to share my perspective. >Say you actually have an electrical shorting problem and get smoke >in the cockpit - WHADDAYA' DO NOW? > >YOU BETTER HAVE a PLAN! My plan is, one motion, KILL MASTER >SWITCH; turning off all electrical power. And do anything necessary >in order to breath some fresh air, including sticking head outside >window. Often, you only have a very few seconds react and figure >it all out, or.... GAME OVER! While smoke (or any untoward smells) in the cockpit are never a good thing. But the idea that a failing conductor's noxious output risks become an olfactory tsunami cries out for an FMEA. Years ago I did appliance service work from a van that some yahoo had wired in a burglar alarm by twisting wires together. While driving down the road at about 40 mph, the darned wiring shorted out and it was all I could do to get the van stopped and roll out onto the roadway coughing my brains out; completely oblivious to oncoming traffic. I was totally incapacitated in mere seconds due to PVC fumes from melted wiring. The interior of that van had a whole lot more room to disperse fumes than a typical homebuilt airplane or even my 172. I'm pleased that your experience had a happy resolution. But let's do our FMEA thingy as follows: How was the failing wire situated in the vehicle such that an overload of ANY size would produce smoke? The PRIME DIRECTIVE all circuit protective devices is: prevent smoke. >While I am on this subject, please do not wire your airplane with >anything but certified aircraft wire (MIL-W-22759). PVC insulated >crap from the auto store will incapacitate you MUCH sooner. Be >aware that power cables from accessories and devices never meant to >be panel installed in certified aircraft have the same danger. Actually, there is no such thing as 'certified aircraft wire'. There's a very long list of wire types flying in T/C aircraft that are considered flightworthy because they are part of the ship's type certificate. It is perfectly acceptable to repair a vintage aircraft with the same wire that was installed at the factory . . . this is true all the way back to uncle Clyde's C-140A that was wired with cotton over rubber. You used to be able to buy that stuff (people restoring old cars were BIG customers). In the 1960s tens of thousands of s.e. Cessnas were wired with M19868 type BN (Nylon over PVC). You can still buy that stuff. Then about 1980 there were about a dozen variations on 'insulation of the day' used throughout the heavier-than-air industries and yeah, the Wichita crowd came down on the side of Tefzel. But I can assure you, if you 'smoke' a Tefzel wire in your airplane, you're not going to find it any more pleasant than a smoking cotton over rubber wire in your nice ol' C140 or a nylon over PVC in your vintage C172, >As I said, I value simplicity. >What electrical devices do I need to get my airplane safely back on >the ground? Answer: ABSOLUTELY NOTHING! >Can I safely land without flaps or radio or anything else >electrical? Answer: YES - magneto ignition and flying VFR only. >Would I rather be flying a homebuilt Van's RV? Answer: You better >believe it; but I am too darned old now and consider myself very >lucky to keep what I already have (wife included). May I suggest an alternative . . . don't allow any wire a potential to make smoke. I.e. offer proper protection based on artful FMEA. >If you have an electrically dependent airplane.... Good luck with that! >You had better make those systems very robust and completely >isolated from the rest as much as humanly possible. Yup, that's what battery busses are for. >AND, electronic ignition is great and can offer advantages as long >as you retain ONE stock magneto. Don't be fooled by marketeer >nonsense that can kill you. Yeah, I know that I am going to take >some heat from this; especially since all GA is headed toward EFI >and total electrical dependency, but I stand my ground. > >Keep the odds on your side. There are electronic ignitions that come with their own, built in power supplies. There are also ways to architecture buss-powered ignition systems to function independent of each other. It's a decades old technology with a track-record. Bottom line is that the 'better plan' is not difficult to put in place . . . it's been done for over a century with great success. 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.