---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 02/04/08: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:48 AM - leaking battery? (Robert L. Nuckolls, III) 2. 05:48 AM - Re: SL30 nav com radio (Robert L. Nuckolls, III) 3. 06:10 AM - Re: Z-13/8 Re: P/E-Mags Bus Feed (Robert L. Nuckolls, III) 4. 07:32 AM - Z-13/8 Re: P/E-Mags Bus Feed (jayb) 5. 08:55 AM - Re: Z-13/8 Re: P/E-Mags Bus Feed (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 05:48:01 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: leaking battery? > >Comments/Questions: Bob, >I have an RV-8A with two batteries (Odyssey PC560, I think). They are >mounted on the side, under the floor panels. I am in the process of a >condition inspection and was surprised to find that a liquid (now dry) in >the region of the battery had removed the wash primer used by Van for the >quickbuild kits. I removed one of the batteries where the liquid had >pooled, as it appeared that this could have been battery acid, however, >the battery looks perfect and I see no evidence of leaking (I assume that >this is not possible anyway. >It is possible that was I am seeing is a result of the plane being cleaned >with an alkaline-based cleaner that ran down the interior of the >fuselage? Any other ideas? > >Thanks much for your time. I think it unlikely. RG batteries contain so little liquid that you would have to squeeze the plate/ separator array with a great deal of pressure in order that you recover any liquid. I think it more likely that you're seeing the results of a pooling of condensation. The interior surfaces of every airplane gets wet when descending from cold flight environments into warmer and moister airport environments. The 'hell hole' behind the rear pressure bulkhead of a biz-jet literally rains inside as the airplane descends. We had to build rain "gutters and downspouts" into certain areas of the cabin, under the upholstery to prevent water dripping on the passengers during descent. In any case, where ever the liquid came from it wasn't from the battery. Bob . . . Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 2 _____________________________________ Time: 05:48:39 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: SL30 nav com radio At 11:01 AM 2/3/2008 -0700, you wrote: > >It would be relatively easy to setup a relay to provide power to the SL30. > The 28V bus provides the control signal for the relay - driving the coil. > The relay switching the 14V feed to the COM. If 28V power is lost, the >relay opens, disabling the COM portion of the radio. > >Since COM functionality isn't really a safety of flight issue, I wouldn't >be concerned about the added parts count associated with having an extra >relay in the circuit. > >You could also (instead) use 28V to control a relay in line with the PTT >circuit on the COM portion of the radio. Drive the power input to the COM >portion straight through with 14V. Then even after loss of 28V power you >could still safely receive on the COM - the transmitter would be disabled >- possibly useful. > > >Matt- Good thinking! Bob . . . ________________________________ Message 3 _____________________________________ Time: 06:10:34 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-13/8 RE: P/E-Mags Bus Feed At 02:59 PM 2/3/2008 -0700, you wrote: >Looking carefully at the drawing the inset in the lower right side shows >the P-Mag fed from the "Main Bus" and the E-Mag fed through the S700-2-10 >switch from the "Battery Bus". Then if you look at the upper left hand >part of the drawing at the "Main Battery Bus" you see both the right and >left ignitions coming off this bus. I think my question is this...Is the >"Battery Bus" and the "Main Bus" nomenclature in the lower right inset >really the "Main Battery Bus" and not the Battery Bus and the Main Power >Distribution Bus? The distribution suggestions you've cited are artifacts left over from the Pre-Emag era where individuals with electrically dependant engines are encourage to run all engine feeds from the battery buss. This would include up to 2 two electronic ignitions including E-mags. In the new era of best-we-know-to-do for aircraft ignitions, the earlier architecture still holds for two E-mags. However, the special nature of the P-mag's internal power supply combined with the owner/operator's desire to occasionally test a P-mag for full functionality, running the P-mags (whether one or two devices) from the main bus keeps the switching simple while allowing for the occasional testing of the P-Mag's alternator. So the short answer to your question is, it depends. If you have any combination of ignition system products that depend on the ship's electrical system, run them from the battery bus. If you have one or two P-mags, run them from the main bus. Bob . . . ________________________________ Message 4 _____________________________________ Time: 07:32:25 AM PST US Subject: AeroElectric-List: Z-13/8 RE: P/E-Mags Bus Feed From: "jayb" Devices hanging off the battery bus (like EMags or electronic ignition) don't have any way to be shut down when the master is switched off. Each of the above must therefore have it's own switch to de-energize that circuit, right? Jay do not archive Read this topic online here: http://forums.matronics.com/viewtopic.php?p=162316#162316 ________________________________ Message 5 _____________________________________ Time: 08:55:55 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-13/8 RE: P/E-Mags Bus Feed At 07:28 AM 2/4/2008 -0800, you wrote: > >Devices hanging off the battery bus (like EMags or electronic ignition) >don't have any way to be shut down when the master is switched off. Each >of the above must therefore have it's own switch to de-energize that >circuit, right? Seems like the way to go. If you were flying a J-3 with NO electrical system, you'd still have a couple of switches that control the magnetos. Further, operation of those switches would be addressed in your pre-fight/post-flight protocols. The supporting simple-idea is that one selects the accessories that are needed to meet design/mission goals for the aircraft. Then figure out ways to minimize weight, parts count, pilot workload, costs of ownership, and still have an acceptable failure mode effects analysis (favorable = failure tolerant). The collection of switches, the things they control, the manner in which they are operated and the sources for power are all ingredients that go into the recipe for success. Further, there are MANY recipes for success that select from a HUGE array of ingredients. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ------------------------------------------------------------------------------------- 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.