---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 03/17/10: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:52 AM - Question on Z-13 in revision 12A (Jason Beaver) 2. 02:59 AM - Re: Z-19 question (Dennis & Anne Glaeser) 3. 04:05 AM - Re: Re: Knuckolls Z-12 Power Grid Questions (Valin & Allyson Thorn) 4. 06:24 AM - Re: Firewall penetration (Richard O Carden) 5. 06:24 AM - Re: Knuckolls Z-12 Power Grid Questions (user9253) 6. 06:57 AM - Re: Question on Z-13 in revision 12A (Robert L. Nuckolls, III) 7. 07:28 AM - RV ballscrew flap actuator performance (Robert L. Nuckolls, III) 8. 09:27 AM - How to tighten switch ring without scratching? (rparigor@suffolk.lib.ny.us) 9. 10:21 AM - Re: How to tighten switch ring without scratching? (George, Neal E Capt USAF ACC 505 TRS/DOJ) 10. 11:07 AM - Re: How to tighten switch ring without scratching? (Robert L. Nuckolls, III) 11. 11:29 AM - Re: How to tighten switch ring without scratching? (RGent1224@aol.com) 12. 06:31 PM - Re: Slowing down the trim (Robert L. Nuckolls, III) 13. 11:04 PM - Question about plumbing air, not electrons (rparigor@suffolk.lib.ny.us) ________________________________ Message 1 _____________________________________ Time: 02:52:42 AM PST US From: Jason Beaver Subject: AeroElectric-List: Question on Z-13 in revision 12A I noticed that the e-bus alternate feed design changed from revision 11 to revision 12A. In revision 11, the alternate feed path used a 7A fuse and was wired with 16AWG and a 20AWG fuselink. In 12A, it uses an 15A fuse and is wired with 14AWG, but still uses a 20AWG fuselink. Is this correct, or should it now use an 18AWG fuselink? Also at 7A, the formally specified 16AWG wire will already have a 10C temp rise, and the 20AWG fuselink would have a 35C temp rise. If we size the wires for a 15A feed at the same temperature rise, shouldn't we use a 10AWG wire with a 14AWG fuselink? At 15A, the currently specified 14AWG already has a 35C temp rise and have no idea how hot an 18AWG or 20AWG fuselink would be. Am I missing something? thanks, jason ________________________________ Message 2 _____________________________________ Time: 02:59:28 AM PST US From: "Dennis & Anne Glaeser" Subject: AeroElectric-List: Re: Z-19 question I have a cigarette lighter receptacle for each battery, fused off each battery's hot bus, on my IP. I made up a "Y" for my battery charger with lighter plugs, so when I want to charge the batteries, I just plug it into the receptacle(s). Dennis Glaeser ------------------------------------------------------ Hello all- I have implemented Z-19 (dual battery, redundant main and engine busses) for my bird. I would like to add the ability to easily hook up a float trickle charger to the aircraft to keep both batteries topped up while sitting in the hangar. Due to the design of Z-19, however, I can't see a simple way to accomplish this that doesn't result in the batteries being tied together in what would likely be an undesirable way. Is there a straight-forward way to do this? (without having to float charge the batteries separately, thus requiring 2 chargers). Thanks, Mark ________________________________ Message 3 _____________________________________ Time: 04:05:14 AM PST US From: "Valin & Allyson Thorn" Subject: RE: AeroElectric-List: Re: Knuckolls Z-12 Power Grid Questions Thanks Joe. Bob and you have convinced me that the Z-12 with the E-Bus set up this way is optimized. BTW, my AeroElectric Connection Rev 11 book doesn't have a Z-11 design in it. Guess yours is older...? The process of thinking through the logic behind the architecture, with yours and Bob's help, has been very helpful. Thanks again, Valin -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of user9253 Sent: Monday, March 15, 2010 6:26 PM Subject: AeroElectric-List: Re: Knuckolls Z-12 Power Grid Questions > "On the avionics contactor relay, I thought the diode was for if it was switching inductive loads to prevent back EMF. Is a diode still recommended for an avionics bus with resistive loads? Do I misunderstand the diodes role here?" A relay has two (or more) circuits. The coil is one circuit and the relay contacts are in another circuit. The two circuits can be completely isolated from each other. The purpose of a diode connected across a relay (or contactor) coil is to protect the controlling switch from high voltage spark generated by the relay coil when it is shut off by the switch. That high voltage has nothing to do with the load on the relay contacts, whether that load is inductive or resistive. In fact, a relay coil will produce a high voltage when it is shut off, even if nothing at all is connected to the relay contacts. The bigger the coil, the bigger the spark. A relay coil will not make as big of a spark as a contactor coil. Connecting a diode across a relay coil will prolong the life of the switch that controls it. The diode arrow should point towards positive. > "Thanks for pointing out that the avionics relay is a single point failure. What do you guys think about getting one fault tolerant by having two avionics bus relays/switches in parallel -=C3=A2=82=AC=9C maybe one passing power from the Battery Bus and one from the System Bus?" Yes, that will work. What you are proposing is similar to the E-Bus. And it is similar to what I proposed in my previous post, although I might not have explained it clearly. Even if you do use two relays, the diode must still be used to prevent high current from flowing from the avionics bus (AKA E-Bus) to the system bus. > "I'm not yet convinced that the Essential/Endurance Bus adds that much value." The important feature of an E-Bus is that is has two independent current paths. It would be easy to turn your avionics bus into an E-Bus by adding the alternate feed path from the battery bus and a diode to prevent back-feeding the system bus. > "It seems, though, that it might improve reliability more for Z-12 to have dual parallel battery contactors." Yes, that will work, but will cost more and weigh more than using a relay and diode along with an E-Bus that will accomplish the same thing. It can be satisfying to design one's own electrical system. However, there could be failure modes that you might not be aware of. The big advantage of using one of Bob's drawings is that they have been proven over time and scrutinized by many eyes. Any bugs have been worked out. Your schematic looks great in colors. After a couple of minor changes, it will be similar to Z-11. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=290394#290394 Attachments: http://forums.matronics.com//files/e_bus_106.jpg ________________________________ Message 4 _____________________________________ Time: 06:24:50 AM PST US Subject: AeroElectric-List: Re: Firewall penetration From: Richard O Carden Tony Bingelis shows how to make firewall penetration shields out of scrap firewall material, see "Firewall Forward", p. 66-67. I made a handful of the two-piece design out of left-over/scrap galvanized firewall material. Once you have a pattern, the process goes quickly. Dick Carden On Mar 17, 2010, at 2:55 AM, AeroElectric-List Digest Server wrote: > * > > ================================================= > Online Versions of Today's List Digest Archive > ================================================= > > Today's complete AeroElectric-List Digest can also be found in either of the > two Web Links listed below. The .html file includes the Digest formatted > in HTML for viewing with a web browser and features Hyperlinked Indexes > and Message Navigation. The .txt file includes the plain ASCII version > of the AeroElectric-List Digest and can be viewed with a generic text editor > such as Notepad or with a web browser. > > HTML Version: > > http://www.matronics.com/digest/digestview.php?Style=82701&View=html&Chapter 10-03-16&Archive=AeroElectric > > Text Version: > > http://www.matronics.com/digest/digestview.php?Style=82701&View=txt&Chapter 10-03-16&Archive=AeroElectric > > > =============================================== > EMail Version of Today's List Digest Archive > =============================================== > > > ---------------------------------------------------------- > AeroElectric-List Digest Archive > --- > Total Messages Posted Tue 03/16/10: 12 > ---------------------------------------------------------- > > > Today's Message Index: > ---------------------- > > 1. 06:55 AM - Re: AeroElectric-List Digest: 8 Msgs - 03/15/10 (Lapsley R. and Sandra E. Caldwell) > 2. 07:16 AM - Re: Continued: Preferred Method for Redundant Power Sources to Single Input (Robert L. Nuckolls, III) > 3. 07:51 AM - Re: Running Big Battery Wire Through Firewall (John Grosse) > 4. 12:12 PM - Z-19 question (Mark R. Supinski) > 5. 01:56 PM - Re: Running Big Battery Wire Through Firewall (William Slaughter) > 6. 02:29 PM - Re: Z-19 question (Sam Hoskins) > 7. 02:29 PM - Re: Continued: Preferred Method for Redundant Power Sources to Single Input (jon@finleyweb.net) > 8. 03:08 PM - Re: Running Big Battery Wire Through Firewall (John Grosse) > 9. 03:27 PM - Re: Running Big Battery Wire Through Firewall (Richard Tasker) > 10. 04:08 PM - OT: vacuum pump (ray) > 11. 07:03 PM - Re: Running Big Battery Wire Through Firewall () > 12. 08:44 PM - Re: Running Big Battery Wire Through Firewall (Robert L. Nuckolls, III) > > > > ________________________________ Message 1 _____________________________________ > > > Time: 06:55:59 AM PST US > From: "Lapsley R. and Sandra E. Caldwell" > Subject: AeroElectric-List: Re: AeroElectric-List Digest: 8 Msgs - 03/15/10 > > > Fred > > It would be interesting if you could remember if you could remember id > the position of the flaps about blowing the fuse was fully up or down. > > Also keep in mind that there have been at least two versions of the Flap > drive mechanism. > > As to the clutch, if you operate the flaps without the engine running > you can hear the flap clutch slip at the fully up or down position (if > you don have any limit switches installed). > > Roger > > On 3/16/2010 2:55 AM, AeroElectric-List Digest Server wrote: >> Time: 04:53:31 AM PST US >> From: "Fred Stucklen" >> Subject: AeroElectric-List: : Re: Flap motor draw for Rv-7A >> >> Interesting. I've tried 5 AMP fuses on three different RV's to date, and >> all blew the fuses while >> >> Trying to deploy the flaps during the first flight. Installing a 10 Amp >> fuse always solved the problem. >> >> >> Frederic Stucklen >> > > > ________________________________ Message 2 _____________________________________ > > > Time: 07:16:49 AM PST US > From: "Robert L. Nuckolls, III" > Subject: Re: AeroElectric-List: Continued: Preferred Method for Redundant Power > Sources to Single Input > > At 07:18 PM 3/15/2010, you wrote: >> Hi Bob, >> >> Regarding this archive >> thread: >> http://forums.matronics.com/viewtopic.php?p=272463#272463 >> >> I am interested to know the answer to the final question. It was >> also the first question that came into my head after reading your >> response. I'm not sure whether or not the answer matters but suspect >> that knowing the answer will answer that question!! ;-) >> >> Gordon Smith wrote: >> "In this case when the two always-on sources differ by a volt or >> two, for whatever reason, Do the sources provide power >> proportionally to their voltage or will it be a 100% feed from the >> highest voltage source?" > > The two either-or sources feeding a pair of diodes > need differ by only a few hundred millvolts for the > HIGHER of the two to pick up all loads downstream > of the diodes. > > Bob . . . > > ________________________________ Message 3 _____________________________________ > > > Time: 07:51:59 AM PST US > From: John Grosse > Subject: Re: AeroElectric-List: Running Big Battery Wire Through Firewall > > > I'm sorry, but I'm not understanding something. The devices below look > more secure to me than a wire through a hole in the firewall filled with > fire putty. I can see that the bolt could conduct heat from a fire, but > then so could a wire. The concept with these devices seems the same to > me as a bulkhead fitting for hydraulic lines which is apparently okay. > So could someone explain why these electrical fittings are incompatible > with firewall security. > > Thanks. > > John Grosse > > Robert L. Nuckolls, III wrote: >> At 08:37 AM 3/10/2010, you wrote: >>> >>> David, >>> >>> I can tell you there is more than one way to skin a cat, but if you look >>> at one of the gazillion Piper Cherokees out there, the cable runs from >>> under the back seat along the left panel through the generally dry >>> rotted grand-daddy grommet to the contactor mounted on the firewall. >>> Size does matter but for 2 or 4 GA that won't make a difference. Good >>> enough for Piper... >> >> I don't think I've yet seen a commercial-off-the-shelf firewall >> feedthru where the insulating material would have stood off >> Jack Thermin's "puff the magic dragon" test. Electrically >> and mechanically, these critters function as advertised. >> The price is low and they seem adequately robust. >> >> However, if one subscribes to the notion of protecting >> firewall integrity with processes like . . . >> >> http://www.aeroelectric.com/articles/Firewall_Penetration/firewall.html >> >> then devices like . . . >> >> Emacs! >> >> >> and . . . >> >> Emacs! >> Are incompatible with the design goal cited in the >> article. So if your design goals include attention >> to details of fire-wall integrity, then perhaps >> single fat-wires are best brought through grommets >> with fire-shields and application of fire-putty >> per Tony B's writings. >> >> Bob . . . > > > ________________________________ Message 4 _____________________________________ > > > Time: 12:12:12 PM PST US > Subject: AeroElectric-List: Z-19 question > From: "Mark R. Supinski" > > > Hello all- > > I have implemented Z-19 (dual battery, redundant main and engine > busses) for my bird. I would like to add the ability to easily hook > up a float trickle charger to the aircraft to keep both batteries > topped up while sitting in the hangar. Due to the design of Z-19, > however, I can't see a simple way to accomplish this that doesn't > result in the batteries being tied together in what would likely be an > undesireable way. > > Is there a straight-forward way to do this? (without having to float > charge the batteries separately, thus requiring 2 chargers). > > Thanks, > > Mark > > > ________________________________ Message 5 _____________________________________ > > > Time: 01:56:41 PM PST US > From: "William Slaughter" > Subject: RE: AeroElectric-List: Running Big Battery Wire Through Firewall > > > The plastic insulator portion would be incinerated within seconds, leaving a > hole in the firewall for the fire to pass through to the cockpit. > > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of John > Grosse > Sent: Monday, March 15, 2010 7:19 PM > Subject: Re: AeroElectric-List: Running Big Battery Wire Through Firewall > > > I'm sorry, but I'm not understanding something. The devices below look > more secure to me than a wire through a hole in the firewall filled with > fire putty. I can see that the bolt could conduct heat from a fire, but > then so could a wire. The concept with these devices seems the same to > me as a bulkhead fitting for hydraulic lines which is apparently okay. > So could someone explain why these electrical fittings are incompatible > with firewall security. > > Thanks. > > John Grosse > > Robert L. Nuckolls, III wrote: >> At 08:37 AM 3/10/2010, you wrote: >>> >>> David, >>> >>> I can tell you there is more than one way to skin a cat, but if you look >>> at one of the gazillion Piper Cherokees out there, the cable runs from >>> under the back seat along the left panel through the generally dry >>> rotted grand-daddy grommet to the contactor mounted on the firewall. >>> Size does matter but for 2 or 4 GA that won't make a difference. Good >>> enough for Piper... >> >> I don't think I've yet seen a commercial-off-the-shelf firewall >> feedthru where the insulating material would have stood off >> Jack Thermin's "puff the magic dragon" test. Electrically >> and mechanically, these critters function as advertised. >> The price is low and they seem adequately robust. >> >> However, if one subscribes to the notion of protecting >> firewall integrity with processes like . . . >> >> http://www.aeroelectric.com/articles/Firewall_Penetration/firewall.html >> >> then devices like . . . >> >> Emacs! >> >> >> and . . . >> >> Emacs! >> Are incompatible with the design goal cited in the >> article. So if your design goals include attention >> to details of fire-wall integrity, then perhaps >> single fat-wires are best brought through grommets >> with fire-shields and application of fire-putty >> per Tony B's writings. >> >> Bob . . . > > > ________________________________ Message 6 _____________________________________ > > > Time: 02:29:31 PM PST US > Subject: Re: AeroElectric-List: Z-19 question > From: Sam Hoskins > > Mark, > > Yes there is. Simply connect a 16 gauge wire to the positive terminals of > each battery, and connected to a regular panel-type switch. When charging > the batteries, simply flip the switch on and both will charge. > > It's working well in my setup. > > Sam > www.samhoskins.blogspot.com > > > On Mon, Mar 15, 2010 at 9:26 PM, Mark R. Supinski > wrote: > >> mark.supinski@gmail.com> >> >> Hello all- >> >> I have implemented Z-19 (dual battery, redundant main and engine >> busses) for my bird. I would like to add the ability to easily hook >> up a float trickle charger to the aircraft to keep both batteries >> topped up while sitting in the hangar. Due to the design of Z-19, >> however, I can't see a simple way to accomplish this that doesn't >> result in the batteries being tied together in what would likely be an >> undesireable way. >> >> Is there a straight-forward way to do this? (without having to float >> charge the batteries separately, thus requiring 2 chargers). >> >> Thanks, >> >> Mark >> >> > > ________________________________ Message 7 _____________________________________ > > > Time: 02:29:32 PM PST US > Subject: Re: AeroElectric-List: Continued: Preferred Method for Redundant Power > Sources to Single Input > From: jon@finleyweb.net > > =0ASuper - Thanks Bob!=0A =0AJon=0A =0ADO NOT ARCHIVE=0A=0A-----Original Me > ssage-----=0AFrom: "Robert L. Nuckolls, III" > =0ASent: Tuesday, March 16, 2010 8:14am=0ATo: aeroelectric-list@matronics. > com=0ASubject: Re: AeroElectric-List: Continued: Preferred Method for Redun > dant Power Sources to Single Input=0A=0AAt 07:18 PM 3/15/2010, you wrote: > =0AHi Bob,=0A =0ARegarding this archive thread: [http://forums.matronics.c > om/viewtopic.php?p=272463#272463] http://forums.matronics.com/viewtopic.p > hp?p=272463#272463=0A =0AI am interested to know the answer to the final > question. It was also the first question that came into my head after readi > ng your response. I'm not sure whether or not the answer matters but suspec > t that knowing the answer will answer that question!! ;-) =0A =0AGordon > Smith wrote:=0A"In this case when the two always-on sources differ by a vol > t or two, for whatever reason, Do the sources provide power proportionally > to their voltage or will it be a 100% feed from the highest voltage source? > " =0A=0A The two either-or sources feeding a pair of diodes=0A need diffe > r by only a few hundred millvolts for the=0A HIGHER of the two to pick up > tp://www.matronics.com/Navigator?AeroElectric-List] http://www.matronics.co > ======== > > ________________________________ Message 8 _____________________________________ > > > Time: 03:08:44 PM PST US > From: John Grosse > Subject: Re: AeroElectric-List: Running Big Battery Wire Through Firewall > > > Okay, I get that. I thought that was a metal part. Guess I should have > checked the specs. > > John > > William Slaughter wrote: >> --> AeroElectric-List message posted by: "William Slaughter" >> >> The plastic insulator portion would be incinerated within seconds, leaving a >> hole in the firewall for the fire to pass through to the cockpit. >> >> >> -----Original Message----- >> From: owner-aeroelectric-list-server@matronics.com >> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of John >> Grosse >> Sent: Monday, March 15, 2010 7:19 PM >> To: aeroelectric-list@matronics.com >> Subject: Re: AeroElectric-List: Running Big Battery Wire Through Firewall >> >> --> AeroElectric-List message posted by: John Grosse >> >> I'm sorry, but I'm not understanding something. The devices below look >> more secure to me than a wire through a hole in the firewall filled with >> fire putty. I can see that the bolt could conduct heat from a fire, but >> then so could a wire. The concept with these devices seems the same to >> me as a bulkhead fitting for hydraulic lines which is apparently okay. >> So could someone explain why these electrical fittings are incompatible >> with firewall security. >> >> Thanks. >> >> John Grosse >> >> Robert L. Nuckolls, III wrote: >> >>> At 08:37 AM 3/10/2010, you wrote: >>> >>>> --> AeroElectric-List message posted by: >>>> >>>> David, >>>> >>>> I can tell you there is more than one way to skin a cat, but if you look >>>> at one of the gazillion Piper Cherokees out there, the cable runs from >>>> under the back seat along the left panel through the generally dry >>>> rotted grand-daddy grommet to the contactor mounted on the firewall. >>>> Size does matter but for 2 or 4 GA that won't make a difference. Good >>>> enough for Piper... >>>> >>> I don't think I've yet seen a commercial-off-the-shelf firewall >>> feedthru where the insulating material would have stood off >>> Jack Thermin's "puff the magic dragon" test. Electrically >>> and mechanically, these critters function as advertised. >>> The price is low and they seem adequately robust. >>> >>> However, if one subscribes to the notion of protecting >>> firewall integrity with processes like . . . >>> >>> http://www.aeroelectric.com/articles/Firewall_Penetration/firewall.html >>> >>> then devices like . . . >>> >>> Emacs! >>> >>> >>> and . . . >>> >>> Emacs! >>> Are incompatible with the design goal cited in the >>> article. So if your design goals include attention >>> to details of fire-wall integrity, then perhaps >>> single fat-wires are best brought through grommets >>> with fire-shields and application of fire-putty >>> per Tony B's writings. >>> >>> Bob . . . >>> >> >> >> > > > ________________________________ Message 9 _____________________________________ > > > Time: 03:27:38 PM PST US > From: Richard Tasker > Subject: Re: AeroElectric-List: Running Big Battery Wire Through Firewall > > > Because the plastic holder melts/burns/disappears in a fire, leaving a > hole for fumes (and possibly creating fumes), flames and a short from > the "bolt" to the firewall. > > Dick Tasker > > John Grosse wrote: >> >> >> I'm sorry, but I'm not understanding something. The devices below look >> more secure to me than a wire through a hole in the firewall filled >> with fire putty. I can see that the bolt could conduct heat from a >> fire, but then so could a wire. The concept with these devices seems >> the same to me as a bulkhead fitting for hydraulic lines which is >> apparently okay. So could someone explain why these electrical >> fittings are incompatible with firewall security. >> >> Thanks. >> >> John Grosse >> >> Robert L. Nuckolls, III wrote: >>> At 08:37 AM 3/10/2010, you wrote: >>>> >>>> David, >>>> >>>> I can tell you there is more than one way to skin a cat, but if you >>>> look >>>> at one of the gazillion Piper Cherokees out there, the cable runs from >>>> under the back seat along the left panel through the generally dry >>>> rotted grand-daddy grommet to the contactor mounted on the firewall. >>>> Size does matter but for 2 or 4 GA that won't make a difference. Good >>>> enough for Piper... >>> >>> I don't think I've yet seen a commercial-off-the-shelf firewall >>> feedthru where the insulating material would have stood off >>> Jack Thermin's "puff the magic dragon" test. Electrically >>> and mechanically, these critters function as advertised. >>> The price is low and they seem adequately robust. >>> >>> However, if one subscribes to the notion of protecting >>> firewall integrity with processes like . . . >>> >>> http://www.aeroelectric.com/articles/Firewall_Penetration/firewall.html >>> >>> then devices like . . . >>> >>> Emacs! >>> >>> >>> and . . . >>> >>> Emacs! >>> Are incompatible with the design goal cited in the >>> article. So if your design goals include attention >>> to details of fire-wall integrity, then perhaps >>> single fat-wires are best brought through grommets >>> with fire-shields and application of fire-putty >>> per Tony B's writings. >>> >>> Bob . . . >> >> > > > ________________________________ Message 10 ____________________________________ > > > Time: 04:08:59 PM PST US > From: ray > Subject: AeroElectric-List: OT: vacuum pump > > > Hope some of you composite builders can help me. I just dug out a > vacuum pump I got a while ago. It didn't have any instructions with it. > I'm hoping for some info on the 2 jars on the inlet/outlet. Any info or > web site I can can find info on would be appreciated. > > Thanks, > Raymond Julian > Kettle River, MN. > > do not archive > > > ________________________________ Message 11 ____________________________________ > > > Time: 07:03:10 PM PST US > From: > Subject: RE: AeroElectric-List: Running Big Battery Wire Through Firewall > > > The plastic from which they're made=2C (at least most of them) melts=2C the > n burns leaving you with flames on the "wrong" side of the firewall and an > open hole admitting more smoke and flames. Also you now have a bare=2C unin > sulated=2C live heavy wire=2C (stud) arcing like crazy against the firewall > sheetmetal. Doesn't seem like a "safe" penetration to me. The intumescent > caulk idea swells up with heat keeping the hole sealed and insulating the i > nterior from flames and smoke and preventing the wires=2C even if they them > selves are compromised=2C from shorting to the firewall. > > > Bob McC > > >> Date: Mon=2C 15 Mar 2010 19:18:30 -0500 >> From: grosseair@comcast.net >> To: aeroelectric-list@matronics.com >> Subject: Re: AeroElectric-List: Running Big Battery Wire Through Firewall >> > et> >> >> I'm sorry=2C but I'm not understanding something. The devices below look > >> more secure to me than a wire through a hole in the firewall filled with > >> fire putty. I can see that the bolt could conduct heat from a fire=2C but > >> then so could a wire. The concept with these devices seems the same to >> me as a bulkhead fitting for hydraulic lines which is apparently okay. >> So could someone explain why these electrical fittings are incompatible >> with firewall security. >> >> Thanks. >> >> John Grosse >> >> Robert L. Nuckolls=2C III wrote: >>> At 08:37 AM 3/10/2010=2C you wrote: >>>> >>>> David=2C >>>> >>>> I can tell you there is more than one way to skin a cat=2C but if you > look >>>> at one of the gazillion Piper Cherokees out there=2C the cable runs fr > om >>>> under the back seat along the left panel through the generally dry >>>> rotted grand-daddy grommet to the contactor mounted on the firewall. >>>> Size does matter but for 2 or 4 GA that won't make a difference. Good >>>> enough for Piper... >>> >>> I don't think I've yet seen a commercial-off-the-shelf firewall >>> feedthru where the insulating material would have stood off >>> Jack Thermin's "puff the magic dragon" test. Electrically >>> and mechanically=2C these critters function as advertised. >>> The price is low and they seem adequately robust. >>> >>> However=2C if one subscribes to the notion of protecting >>> firewall integrity with processes like . . . >>> >>> http://www.aeroelectric.com/articles/Firewall_Penetration/firewall.html >>> >>> then devices like . . . >>> >>> Emacs! >>> >>> >>> and . . . >>> >>> Emacs! >>> Are incompatible with the design goal cited in the >>> article. So if your design goals include attention >>> to details of fire-wall integrity=2C then perhaps >>> single fat-wires are best brought through grommets >>> with fire-shields and application of fire-putty >>> per Tony B's writings. >>> >>> Bob . . . >> > ========== > ========== > ========== > ========== >> >> >> > > > > ________________________________ Message 12 ____________________________________ > > > Time: 08:44:28 PM PST US > From: "Robert L. Nuckolls, III" > Subject: Re: AeroElectric-List: Running Big Battery Wire Through Firewall > > At 07:18 PM 3/15/2010, you wrote: >> >> I'm sorry, but I'm not understanding something. The devices below >> look more secure to me than a wire through a hole in the firewall >> filled with fire putty. I can see that the bolt could conduct heat >> from a fire, but then so could a wire. The concept with these >> devices seems the same to me as a bulkhead fitting for hydraulic >> lines which is apparently okay. So could someone explain why these >> electrical fittings are incompatible with firewall security. > > The legacy wire penetration technique calls for > bringing the wire through a standard grommet which > is then all but totally covered on the engine side > with a two-piece stainless steel shield. See: > > http://tinyurl.com/ycx9dv9 > > This combination of hardware provides for physical > security of the firewall penetration and a good deal > of protection for the grommet against fuel-fed fire. > The final touch is addition of the fire-putty fillet > around the wire and to cover about half the surface > area of the grommet on the engine side. This > adds relative gas-tightness for CO and protection > of the exposed insulation/grommet from fire. > > Bob . . . > > > > > > > > ________________________________ Message 5 _____________________________________ Time: 06:24:52 AM PST US Subject: AeroElectric-List: Re: Knuckolls Z-12 Power Grid Questions From: "user9253" You are welcome, Valin You can get an update to your book here: http://www.matronics.com/aeroelectric/R12A/AppZ_12A4.pdf It includes Z-11. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=290592#290592 ________________________________ Message 6 _____________________________________ Time: 06:57:28 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Question on Z-13 in revision 12A At 02:11 AM 3/17/2010, you wrote: > >I noticed that the e-bus alternate feed design >changed from revision 11 to revision 12A. In >revision 11, the alternate feed path used a 7A >fuse and was wired with 16AWG and a 20AWG >fuselink. In 12A, it uses an 15A fuse and is >wired with 14AWG, but still uses a 20AWG >fuselink. Is this correct, or should it now use an 18AWG fuselink? > >Also at 7A, the formally specified 16AWG wire >will already have a 10C temp rise, and the >20AWG fuselink would have a 35C temp rise. If >we size the wires for a 15A feed at the same >temperature rise, shouldn't we use a 10AWG wire >with a 14AWG fuselink? At 15A, the currently >specified 14AWG already has a 35C temp rise and >have no idea how hot an 18AWG or 20AWG fuselink would be. > >Am I missing something? Sort of. The Z-figures are NOT detailed wiring diagrams for your airplane. They're suggestions for architectures that offer failure tolerant solutions to design goals. The sizes of batteries, alternators, wires, breakers, contactors, relays, switches and the quantities of such things are dependent on your particular suite of components. While strict observance of any suggested wire sizes in a Z-figure will yield a 'functional' system, it may not conform to the best we know how to do. Check out examples of e-bus architectures across the various Z-figures, they're not identical. And don't get wrapped around the AC43-13 wire-sizing exercise axle. Suggest you size wires using suggested current ratings in the chart on page 8-8. Keep in mind too that the 'ratings' are EXCEEDINGLY conservative. 20A through a 22AWG wire doesn't smoke it. See: http://aeroelectric.com/Pictures/Wire/22AWG_20A.pdf Finally, if a fusible link is to FUNCTION as a fusible link, then it MUST be thermally stressed at some level much greater than the feeder it protects, so yes, it will run warmer than the feeder. Bob . . . ________________________________ Message 7 _____________________________________ Time: 07:28:44 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: RV ballscrew flap actuator performance At 06:49 AM 3/16/2010, you wrote: >Caldwell" > >Fred > >It would be interesting if you could remember if you could remember >id the position of the flaps about blowing the fuse was fully up or down. > >Also keep in mind that there have been at least two versions of the >Flap drive mechanism. > >As to the clutch, if you operate the flaps without the engine >running you can hear the flap clutch slip at the fully up or down >position (if you don have any limit switches installed). The "slip clutch" on commonly used ball-screw actuators are a bit deceiving. When one holds an unmounted actuator in hand, the ball-nut seems to magically "disconnect" and spins freely at each end of travel. This type of nut features non-circulating balls held in a cage. The grooves in the nut are not matched to the screw (helical) but are instead circular raceways. See: http://tinyurl.com/ylkv85l When the ballscrew is working in the normal mode between stroke limits, the cage is driven by the balls and rotates at 1/2 the velocity as the nut. But at the end of travel, the cage hits a stop pin which locks it to the screw. The balls now slip in their circular raceways. When the nut-screw junction is not axially loaded, the 'freewheeling' effect is quite pronounced. One gets the impression that there's a near total disconnect for energy from the motor. However, when the actuator is loaded (like at end of travel for extending flaps), the load shedding to the motor is not so pronounced. In fact, when operating the actuator at it's full load capabilities (which is probably many hundreds of pounds) there IS a sharp INCREASE in load on the motor as the actuator hits the stop. Yes, the 'slip clutch' does a nice job of replacing limit switches in terms of setting absolute limits on system stroke but there are electrical considerations driven by how much the current spikes at end of travel. Obviously, retracting flaps has very low force on the ball- nut at up-limit. Further, exercising flaps on the ground suggests that the end-of-travel event for flaps extension is pretty benign too. AND IT MAY BE no big deal in flight . . . if real force is say 200 pounds out of a 1000 pound rated ball-screw. The point is, until somebody puts the gauges on it to go find out, we can debate the DESIGN of flap system circuits for a long time. I suspect the extend-limit spike is rather benign given that many folks have told us they're flying with 10A or even 5A fuses to protect the motor circuit. Just be aware that until you actually fly the airplane to load the flaps -AND- depending on how long you hold the flap switch in the DOWN position after the system reaches the limit is what sizes the fuse. It would be interesting and most useful if we could get some in-flight current measurements on extend-limit current draw with the airplane flying at the IAS limit (top of the white arc) for full flap extension. Bob . . . ________________________________ Message 8 _____________________________________ Time: 09:27:19 AM PST US Subject: AeroElectric-List: How to tighten switch ring without scratching? From: rparigor@suffolk.lib.ny.us I have some nice knurled threaded switch rings I purchased from B+C. How do i tighten without scratching off the black finish? Thx. Ron Parigoris ________________________________ Message 9 _____________________________________ Time: 10:21:37 AM PST US Subject: RE: AeroElectric-List: How to tighten switch ring without scratching? From: "George, Neal E Capt USAF ACC 505 TRS/DOJ" Set the knurled ring to give the desired projection on the front of the panel, and tighten the hex nut on the back side. Neal ==================== I have some nice knurled threaded switch rings I purchased from B+C. How do i tighten without scratching off the black finish? Thx. Ron Parigoris ________________________________ Message 10 ____________________________________ Time: 11:07:05 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: How to tighten switch ring without scratching? That works. I've ground wrenches down to VERY thin cross-section for just that purpose. Of course, this pre-supposes that you can get enough "swing" on the wrench between .8" spaced switches to do the job. There ARE nut-drivers specific to this task. I've not looked for one in many years and I had some difficulty finding it then. Don't recall now where I located it. There is RISK too that the knurled nuts you have on hand are not fabricated to the same dimensions as the driver you purchase. There is no doubt a standard practice form factor for nuts made in the US over the years. But then, EVERYBODY thinks they can build nuts nowadays. One fewer or greater peaks in the knurl and the driver won't fit. This is one reason why I abandoned the use of the decorative nuts some years ago and went 100% to hex nuts. I have some special nut drivers which I have smoothed, put radii on sharp corners, and otherwise polished so that they cannot scratch a panel. Bob . . . At 12:15 PM 3/17/2010, you wrote: Set the knurled ring to give the desired projection on the front of the panel, and tighten the hex nut on the back side. Neal ==================== I have some nice knurled threaded switch rings I purchased from B+C. How do i tighten without scratching off the black finish? Thx. Ron Parigoris ________________________________ Message 11 ____________________________________ Time: 11:29:03 AM PST US From: RGent1224@aol.com Subject: Re: AeroElectric-List: How to tighten switch ring without scratching? Put electrical tape on the jaws of your pliers/wrench Dick In a message dated 3/17/2010 11:28:15 A.M. Central Daylight Time, rparigor@suffolk.lib.ny.us writes: I have some nice knurled threaded switch rings I purchased from B+C. How do i tighten without scratching off the black finish? Thx. Ron Parigoris (http://www.matronics.com/Navigator?AeroElectric-List) (http://www.matronics.com/contribution) ________________________________ Message 12 ____________________________________ Time: 06:31:53 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Slowing down the trim >I realize that most people will not want to bother installing a >separate 9 volt supply but it does work. >For those interested the shack 5 amp regulator has a schematic and >parts list on the back of the package. >Contact me off-line for my trim schematic. It is in autocad format. There was some discussion about trim speed control here on the List some years back. The discussion prompted (or grew out of) these two postings to the website . . . http://www.aeroelectric.com/PPS//Flight/Trim/Two_Speed_Trim_2.pdf http://www.aeroelectric.com/articles/Trim_System_Failures.pdf Bob . . . ________________________________ Message 13 ____________________________________ Time: 11:04:12 PM PST US Subject: AeroElectric-List: Question about plumbing air, not electrons From: rparigor@suffolk.lib.ny.us What sealant if any should I be using on 1/8" NPT connections for pitot, static and AOA on instruments? *Brass female and Brass male *Brass female and Aluminum male *Brass female and Nylon male *Aluminum female and Nylon male Is it acceptable to use.250" OD .125" ID Tygone tubing going over .1875" OD(before single barb) nipple for pitot, static and AOA plumbing? A little heat on tubing from a heat gun and it slides right on.Would it be worth it to put a double wrap of .020" safty wire on Tygon tubng near root to act as a clamp? I have a two pneumatic switches, one to select between static and total energy for Ilec variometer and one to function to allowalternate static. these switches have a stainless body with female 10-32 straight threaded ports. The .1875' ODnipplesI want to use are male straight threaded 10-32 that come with a flat sealing washer. What if anything shouldI be putting on threads as a sealant? Thx. 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