---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 07/19/09: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:57 AM - Re: Fuselinks & breakers (Robert L. Nuckolls, III) 2. 10:53 AM - Re: D.A.R question about fuse access (Robert L. Nuckolls, III) 3. 04:09 PM - Re: D.A.R question about fuse access (BobsV35B@aol.com) 4. 07:37 PM - p and retard leads (Jeff Peterson) 5. 08:38 PM - (Robert L. Nuckolls, III) 6. 08:43 PM - Re: p and retard leads (Kelly McMullen) 7. 09:05 PM - Air conditioning stuff for sale (DEAN PSIROPOULOS) ________________________________ Message 1 _____________________________________ Time: 09:57:42 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Fuselinks & breakers At 12:15 PM 7/18/2009, you wrote: >Bob, in several of your Z drawings, you show a fuselink in series >with a breaker. For instance, Z-18. You also have a fuselink and a >breaker separated only by a relay in Z-18RB. > >What is the rationale behind this seemingly redundant layout? Fusible links are not to be confused or even placed in the same class as breakers and the run-o-the-mill plastic fuses. Not all that is offered as a "circuit protective device" has the same design goals. Fuses are VERY FAST acting devices compared to thermal breakers. Fusible links and the ANN/ANL "current limiters" are VERY SLOW compared to the breakers and slower still compared to fuses. In the cases you cited, the protective device upstream of a crowbar ov protection system needs to be pilot re-setable . . . but when combined with remotely mounted fuse blocks, a "extension" of the main bus bar up to the field breaker, the legacy design goals call for some form of protection for the extended bus that drives the one and only breaker. However, it must be MUCH more robust protection than the breaker itself. I.e., feeders protected with ANL limiters or fusible links. Fusible links and current limiters are SPECIAL, robust forms of circuit protection which are NOT interchangeable with fuses and breakers on distribution feeders. They are recommended for use only in situations described in the Z-figures. I had a builder some years ago share his wiring diagram with me concerning some other issues wherein he had scattered a number of fusible links around the system. Your car has one, maybe two fusible links. All other circuit protection is breakers, fuses or polyfuses specifically tailored to the protection task. Before you do anything with links or limiters, let's talk about it here on the list before you do it. Further, the short answer to your question is that the buss extension up to the breakers cited is classically protected by some extra-robust device at the feeder end. Bob . . . --------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) --------------------------------------- ________________________________ Message 2 _____________________________________ Time: 10:53:03 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: D.A.R question about fuse access > >The nice thing about having internal batteries within the EFIS is that >nothing changes while you scurry to either change the fuse or land and >repair - even for the AP. If I couldn't isolate the problem by replacing >the fuse - I'd just land. Kind-o-like the ole' circuit breaker theory - >if it blows once you reset it. If it blows twice, you leave it. But what is the likelihood that replacing a properly sized, popped fuse will restore any system to functionality? If it's anticipated that the wing leveler's services will ever be critical to comfortable termination of flight, then is not as essential as radio navigation or cockpit lighting? Perhaps dual wing levelers are in order? I'd bet that a BIG chunk of the accidents due to poor pilot visibility and/or workload distractions for single-pilot IFR would have been averted electrons had the stick. I'll suggest that most IFR capable airframes would be better outfitted for ventures into poor visibility if there were NO displays on the panel and dual, heading-slaved wing levelers installed. The wing levelers are probably lighter and more reliable than a suite of panel mounted gyros and more capable than pilot's trying to manage an airplane interleaved with other distractions/ duties in the cockpit . . . including the distraction of fiddling with fuses -OR- breakers. Bob . . . --------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) --------------------------------------- ________________________________ Message 3 _____________________________________ Time: 04:09:20 PM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: D.A.R question about fuse access Good Evening Bob, I agree with your evaluation, but back when Mooney tried it, most pilots didn't care for it. You would regularly find the interrupt button taped down thus deactivating the system. I feel certain that some method could be made to work and still be acceptable to the average pilot, but no one has, as yet, figured out that method. Had JFK jr just let his autopilot fly his airplane, we would probably have a light plane pilot high in our government hierarchy by now. 'Tis a quandary indeed! Happy Skies, Old Bob AKA Bob Siegfried LL22 Stearman N3977A In a message dated 7/19/2009 12:53:57 P.M. Central Daylight Time, nuckolls.bob@aeroelectric.com writes: Perhaps dual wing levelers are in order? I'd bet that a BIG chunk of the accidents due to poor pilot visibility and/or workload distractions for single-pilot IFR would have been averted electrons had the stick. I'll suggest that most IFR capable airframes would be better outfitted for ventures into poor visibility if there were NO displays on the panel and dual, heading-slaved wing levelers installed. The wing levelers are probably lighter and more reliable than a suite of panel mounted gyros and more capable than pilot's trying to manage an airplane interleaved with other distractions/ duties in the cockpit . . . including the distraction of fiddling with fuses -OR- breakers. **************Can love help you live longer? Find out now. (http://personals.aol.c om/articles/2009/02/18/longer-lives-through-relationships/?ncid=emlweuslove00000001) ________________________________ Message 4 _____________________________________ Time: 07:37:32 PM PST US Subject: AeroElectric-List: p and retard leads From: Jeff Peterson I have an engine with bendix shower of sparks magnetos. The mags have number S4LN-200 and S4LN-204. I need 2 ea. p-leads and 1 ea. retard lead to hook this up. I dont know whether I need the hex nut or round nut connector, nor where I can get same. -- Jeff Peterson ________________________________ Message 5 _____________________________________ Time: 08:38:29 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: At 06:06 PM 7/19/2009, you wrote: >Good Evening Bob, > >I agree with your evaluation, but back when Mooney tried it, most >pilots didn't care for it. You would regularly find the interrupt >button taped down thus deactivating the system. I feel certain that >some method could be made to work and still be acceptable to the >average pilot, but no one has, as yet, figured out that method. Yeah . . . PC (positive control) by Brittain as I recall. A totally pneumatic wing leveler that operated directly though valves at the back of the turn-coordinator driving "tomato juice can" servos. A truly elegant design for its time. Just found that the system is still offered at: http://www.brittainautopilots.com/ I liked it. You couldn't hurt it by direct over-ride while engaged. No servos to smoke, no clutches to burn, no engagement solenoids to burn out. This was TSO-C3a hardware which tells us how far back that goes. I did a little white paper for Cessna way back when that suggested large diaphragm pneumatic force cartridges operated by pitot/static delta-P and permanently rigged to ailerons. A simple reed valve system driven from a turn-coordinator would drive a simple set of electronics that consumed less than 1 watt of total power. Three moving parts, no lubrication issues, etc. etc. But they were the proud owners of ARC who was already offering a line of autopilots that plagued with every failure mode that such devices might offer . . . > >Had JFK jr just let his autopilot fly his airplane, we would >probably have a light plane pilot high in our government hierarchy by now. Hmmm . . . you can lead a horse to water. . . All we can do as teachers/designers/suppliers is offer well considered advice backed by a history of recipes for success. Dr. Dee speaks of a human condition known as "cognitive dissonance" http://en.wikipedia.org/wiki/Cognitive_dissonance which we've all observed first hand: "I KNOW that smoking is bad for me . . . but I (like/need/want) to do it". We've all observed a pilot's worst ever day in the cockpit that appeared to rise from a dead-short-between-the-headphones. It's called the "bell curve". For the very best among us, there MUST be individuals who balance out the other end of the curve. > >'Tis a quandary indeed! Let us continue to strive for position on the upper slope of that curve . . . Bob . . . --------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) --------------------------------------- ________________________________ Message 6 _____________________________________ Time: 08:43:26 PM PST US From: Kelly McMullen Subject: Re: AeroElectric-List: p and retard leads I have those mags on my Mooney. The P-leads take one size round connector, the retard lead is a different size, so you can't mix them up. Jeff Peterson wrote: > I have an engine with bendix shower of sparks magnetos. > The mags have number S4LN-200 and S4LN-204. > > I need 2 ea. p-leads and 1 ea. retard lead to hook this up. > > > I dont know whether I need the hex nut or round nut connector, > nor where I can get same. > > -- > Jeff Peterson > > * > > > * ________________________________ Message 7 _____________________________________ Time: 09:05:36 PM PST US From: "DEAN PSIROPOULOS" Subject: AeroElectric-List: Air conditioning stuff for sale Don't know if any of you are contemplating an air conditioning system in your airplane or have an old R-12 system in your airplane (or car) that needs fixing but I may have what you need. Since I no longer own a vehicle that uses R-12 refrigerant I have seven 12 ounce cans available for sale at $35 dollars apiece (a repair shop now charges upwards of $100 a pound for R-12, if they can locate some). I also have an R-12 manifold gauge set (used to monitor the high and low pressures in an R-12 system while filling) and a tap for the R-12 cans ($35.00 for both of these). Let me know if you need any of these or, buy the whole ball of wax for $250.00. Dean Psiropoulos RV-6A N197DM Prop removed for radiographic inspection. ------------------------------------------------------------------------------------- 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.