---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 06/02/09: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:16 AM - grounding to fuselage (thomas sargent) 2. 08:31 AM - Re: grounding to fuselage (Robert L. Nuckolls, III) 3. 08:52 AM - Re: grounding to fuselage (Vern Little) 4. 09:01 AM - Re: grounding to fuselage (Robert L. Nuckolls, III) 5. 02:27 PM - Re: Re: Engine mount as starter ground path (Robert L. Nuckolls, III) 6. 02:31 PM - Re: Re: Lightweight Aux Battery? (Robert L. Nuckolls, III) 7. 04:17 PM - Re: Lightweight Aux Battery? (sonex293) 8. 05:20 PM - Re: Re: Lightweight Aux Battery? (Robert L. Nuckolls, III) 9. 05:59 PM - Re: Lightweight Aux Battery? (sonex293) 10. 06:22 PM - Re: Re: Lightweight Aux Battery? (Robert L. Nuckolls, III) 11. 06:24 PM - Re: Re: Lightweight Aux Battery? (Robert L. Nuckolls, III) 12. 07:34 PM - Re: Re: Lightweight Aux =?UTF-8?Q?Battery=3F? () 13. 07:34 PM - Jabiru 3300 starter (jaybannist@cs.com) ________________________________ Message 1 _____________________________________ Time: 07:16:15 AM PST US Subject: AeroElectric-List: grounding to fuselage From: thomas sargent In general I am opposed to running current thru the fuselage, but in the case of the white tail light, I am willing to make an exception. Is there any "approved" way of doing this so as to avoid causing corrosion due to the contact of dissimilar metals? Is a tin plated (it is tin isn't it?) ring terminal against bare aluminum going to cause a problem? Should it be covered/sprayed with something to protect it from moisture? Or is this just a bad idea under any circumstances? Thanks, -- Tom Sargent, RV-6A final assembly. ________________________________ Message 2 _____________________________________ Time: 08:31:47 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: grounding to fuselage At 08:48 AM 6/2/2009, you wrote: >In general I am opposed to running current thru the fuselage, but in >the case of the white tail light, I am willing to make an >exception. Is there any "approved" way of doing this so as to avoid >causing corrosion due to the contact of dissimilar metals? > Is a tin plated (it is tin isn't it?) ring terminal against bare > aluminum going to cause a problem? Should it be covered/sprayed > with something to protect it from moisture? Or is this just a bad > idea under any circumstances? Local concerns for the attachment of wires to the airframe have been the topic of many pages of "how to" and "how not" to do. In the most hostile of environments, all the recommended processes and materials add longevity to the connection. Our airplanes are seldom operated in conditions that qualify as strenuous much less hostile. Design goals for local grounding/bonding speak to deleterious effects for failure to faithfully observe recipes for success but they seldom speak to the physics of the effects or relative risks. Keep in mind that for corrosion to occur, oxygen laden moisture must be present in the joint. Only then do the electrolytic effects of dissimilar metals in ionized solutions arise. Yes, the tin plating of copper terminals #1 task is an electrolytic "buffer" between copper and aluminum . . . but if you damage the tin layer in any way during assembly or maintenance of the joint, that barrier is breached and the original copper-aluminum couple is exposed. For all the fuss and froth about materials control, the very best prophylactic against corrosion call for making joints up with sufficient pressure to produce "gas-tightness" enhanced with a means by which future moisture ingress is retarded assuages 99.99% of your concerns. Join clean metals with robust, locking fasteners. Coat the metals with silicon grease before joining. And the joint will be fine for more than the lifetime of airplane. You can "drink from the fire hose" off grounding/bonding processes in section 15 of AC43-13 offers a rigorous study. There's nothing inherently evil about using the airframe to carry power system currents. Modern production aircraft made of aluminum have countless airframe grounds crafted with due diligence to the principals of gas-tightness and choice of materials. These function as desired for the lifetime of the airplane. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 3 _____________________________________ Time: 08:52:22 AM PST US From: "Vern Little" Subject: Re: AeroElectric-List: grounding to fuselage AC43.13-1B has an extensive discussion of aircraft bonding (grounding), including the proper procedure for connecting to the airframe and protection against corrosion. This document is available in .pdf format if you don't have a hardcopy. It's a bit large to email, so if you can find it online for download, that's good. If not, please let me know and I'll make other arrangements. Thanks, Vern Little www.vx-aviation.com ----- Original Message ----- From: thomas sargent To: aeroelectric-list@matronics.com Sent: Tuesday, June 02, 2009 6:48 AM Subject: AeroElectric-List: grounding to fuselage In general I am opposed to running current thru the fuselage, but in the case of the white tail light, I am willing to make an exception. Is there any "approved" way of doing this so as to avoid causing corrosion due to the contact of dissimilar metals? Is a tin plated (it is tin isn't it?) ring terminal against bare aluminum going to cause a problem? Should it be covered/sprayed with something to protect it from moisture? Or is this just a bad idea under any circumstances? Thanks, -- Tom Sargent, RV-6A final assembly. ________________________________ Message 4 _____________________________________ Time: 09:01:41 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: grounding to fuselage At 10:50 AM 6/2/2009, you wrote: >AC43.13-1B has an extensive discussion of aircraft bonding >(grounding), including the proper procedure for connecting to the >airframe and protection against corrosion. > >This document is available in .pdf format if you don't have a >hardcopy. It's a bit large to email, so if you can find it online >for download, that's good. > >If not, please let me know and I'll make other arrangements. AC43-13 is available for download at: http://www.aeroelectric.com/Reference_Docs/FAA/ Bob . . . ----------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ----------------------------------------- ________________________________ Message 5 _____________________________________ Time: 02:27:58 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Engine mount as starter ground path At 07:00 AM 6/1/2009, you wrote: >Bob, >The basis of my design is Z-14. Dual Odyssey 680 batteries aft with >cross-feed contactor (using one for startup and one for avionics >during starting-then switching avionics over to primary battery >after running-both batteries available if necessary for starting)) >but only one alternator (option to add second alternator later >depending on upcoming plane power product). okay >Diode inline allows alternator feed to one or both batteries. why diodes? close all the contactors and both batteries get charged by one alternator. > >Batteries really both need to be aft due to engine weight considerations. >So... is grounding both batteries at a common point aft in metal >plane a viable solution? Sure. Here's some exemplar battery grounds to airframe: http://aeroelectric.com/Pictures/Batteries/Battery_Install_OBrien_1.jpg http://aeroelectric.com/Pictures/Batteries/Battery_Install_OBrien_2.jpg http://aeroelectric.com/Pictures/Batteries/Battery_Install_OBrien_3.jpg >I note that you made reference to working on some info specific to >the RV-10. That would be great. Since the forest of tabs is on thin stainless (very poor conductor) it would be a good thing to put a 4 or 2AWG jumper from ground stud to similar structure as in photos above. Bob . . . --------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) --------------------------------------- ________________________________ Message 6 _____________________________________ Time: 02:31:33 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Lightweight Aux Battery? At 01:26 PM 6/1/2009, you wrote: > >Bob, > >This will be on an existing Jabiru 3300 installation using the Z-20 wiring . Hmmm . . . what are the anticipated loads and duration for the aux battery? In other words, how does the aux battery fit into your recipe for plan-b success? Bob . . . --------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) --------------------------------------- ________________________________ Message 7 _____________________________________ Time: 04:17:39 PM PST US Subject: AeroElectric-List: Re: Lightweight Aux Battery? From: "sonex293" sonex293 wrote: > Power requirements are calculated @ 8 amps. This would include Fuel Pump, Injectors, and EFI Controller. I was looking for a one hour run time. -- Michael Read this topic online here: http://forums.matronics.com/viewtopic.php?p=246526#246526 ________________________________ Message 8 _____________________________________ Time: 05:20:45 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Lightweight Aux Battery? At 06:15 PM 6/2/2009, you wrote: > > >sonex293 wrote: > > Power requirements are calculated @ 8 amps. > > >This would include Fuel Pump, Injectors, and EFI Controller. I was >looking for a one hour run time. How big is your planned main battery and what feature of its selection and installation suggests that you can't get what you need out of the main battery? Bob . . . --------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) --------------------------------------- ________________________________ Message 9 _____________________________________ Time: 05:59:06 PM PST US Subject: AeroElectric-List: Re: Lightweight Aux Battery? From: "sonex293" I'm currently flying with a Odyssey PC625 battery, which has a 16Ah capacity. I'm also currently flying behind an engine/carb/magneto combo that has no fuel pumps, so even in the event of full electrical/battery failure the engine will keep running. By switching to an endurance buss my current draw with the new fuel injection system would be around 14-16 amps, I don't think the PC625 can provide 16amps for an hour in the case of charging problems. What do you think? -- Michael Read this topic online here: http://forums.matronics.com/viewtopic.php?p=246537#246537 ________________________________ Message 10 ____________________________________ Time: 06:22:52 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Lightweight Aux Battery? At 07:57 PM 6/2/2009, you wrote: > >I'm currently flying with a Odyssey PC625 battery, which has a 16Ah >capacity. > >I'm also currently flying behind an engine/carb/magneto combo that >has no fuel pumps, so even in the event of full electrical/battery >failure the engine will keep running. > >By switching to an endurance buss my current draw with the new fuel >injection system would be around 14-16 amps, I don't think the >PC625 can provide 16amps for an hour in the case of charging problems. > >What do you think? Hmmmm . . . how much STUFF have you shoe-horned into this neat little airplane that needs that much snort? Your alternator is probably a PM machine so if you've got a robust rectifier/regulator, loss of engine driven power is rare. But assuming you do need to go battery only, what situation do you anticipate that you cannot get from where you are to where you need to be using the ultimate battery-only comm/nav/ lighting system . . . http://aeroelectric.com/Pictures/Misc/Vacination_for_Dark_Panel_Syndrom.pdf Also, those numbers seem high for a small engine. Have you ever seen real energy numbers from somebody who has one of these systems flying? I hate to see you carry around any more weight than is REALLY useful. I've been pondering a li-ion battery/ automatic charter pack for OBAM aircraft. It will be the very lightest of batteries for all services other than engine cranking . . . i.e. AUX service. But it's weight, volume and price is not zero or even really attractive for airplanes like yours. I'd like to explore all the plan-A, plan-B options available to you before you start adding the $time$, $cost$, $weight$ of an additional or larger battery. Oh yeah, consider making your existing battery BIGGER before adding a second battery. But let's talk . . . Who sells your power plant package? Let's get some real running numbers from them. Bob . . . --------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) --------------------------------------- ________________________________ Message 11 ____________________________________ Time: 06:24:18 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Lightweight Aux Battery? P.S. What's the driver for switching to the ECFI engine package? Does fuel efficiency go up so much that the additional complexity, power requirements and cost look like an attractive alternative? Bob . . . --------------------------------------- ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) --------------------------------------- ________________________________ Message 12 ____________________________________ Time: 07:34:43 PM PST US From: Subject: Re: AeroElectric-List: Re: Lightweight Aux =?UTF-8?Q?Battery=3F? Hi Michael What sort of upgrade do you have planned for your 3300? Enquiring minds, thinking likewise, would like to know? All the best. Peter Eedy Waiex 109 - 50% there. Newcastle. NSW. Australia. On Tue, 2 Jun 2009 16:15:52 -0700, "sonex293" wrote: > > > sonex293 wrote: >> Power requirements are calculated @ 8 amps. > > > This would include Fuel Pump, Injectors, and EFI Controller. I was looking > for a one hour run time. > > -- > Michael ________________________________ Message 13 ____________________________________ Time: 07:34:43 PM PST US Subject: AeroElectric-List: Jabiru 3300 starter From: jaybannist@cs.com I am helping a friend put together a power schematic for a Jabiru 3300.? I have seen several sample schematics that have both a starter solenoid and a starter contactor.? Is this really what is required and if so why ?? Is a starter contactor any different than a battery contactor? Jay Bannister ________________________________________________________________________ Email message sent from CompuServe - visit us today at http://www.cs.com ------------------------------------------------------------------------------------- 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.