---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 10/14/03: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:06 AM - Re: Pins (Robert L. Nuckolls, III) 2. 07:47 AM - Re: Crowbar OV protection (Richard May) 3. 04:00 PM - Re: Crowbar OV protection (Robert L. Nuckolls, III) 4. 04:13 PM - Re: sizing wire and protection for pitot tube (Robert L. Nuckolls, III) 5. 07:08 PM - ELT in wingtip (Jim Bean) 6. 07:17 PM - Firewall Feedthru (Jim Daniels) 7. 08:42 PM - Re: Firewall Feedthru (Jim Jewell) 8. 09:26 PM - Re: ELT in wingtip (Larry Bowen) 9. 10:46 PM - Re: ELT in wingtip (Robert L. Nuckolls, III) 10. 10:48 PM - Re: Firewall Feedthru (Robert L. Nuckolls, III) 11. 10:52 PM - Re: Strobes and comm Ant (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:06:30 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Pins --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:29 PM 10/13/2003 -0700, you wrote: >--> AeroElectric-List message posted by: "Steve Richard" > > >Can the pin shown on the B&C web site (Part # S604P) be used for AMP CPC >connectors? Or are the pins shown on page 566 of the mouser catalog the >same as the B&C pins? > >http://www.bandcspecialty.com/cgi-bin/ez-catalog/cat_display.cgi?24X358218 > >http://www.mouser.com/catalog/615/566.pdf Yes, the CPC series 2 connectors use the same pins as the crimp D-Subs. The "20DM" (Dsub Military) pins in the Mouser catalog are the same as what's offered by B&C. Bob . . . ________________________________ Message 2 _____________________________________ Time: 07:47:35 AM PST US From: Richard May Subject: Re: AeroElectric-List: Crowbar OV protection --> AeroElectric-List message posted by: Richard May A fuse, hmm, good idea. My plane has a 60 amp alternator, and had a 40 amp breaker installed, due to, I suppose the previous owner not wanting to change the breaker when he upgraded the alternator. But that 40 amp breaker has never popped. So if I install a 60 amp fuse, the only way it would ever melt would be from a problem that I wouldn't want it back from anyway. This fuse, coupled with the crowbar OV module would represent a very sound and safe electrical system. ________________________________ Message 3 _____________________________________ Time: 04:00:39 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Crowbar OV protection --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:32 AM 10/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: Richard May > >A fuse, hmm, good idea. My plane has a 60 amp alternator, and had a 40 amp >breaker installed, due to, I suppose the previous owner not wanting to >change the breaker when he upgraded the alternator. But that 40 amp breaker >has never popped. So if I install a 60 amp fuse, the only way it would ever >melt would be from a problem that I wouldn't want it back from anyway. I'm not sure we're together here. The fuse I was referring to in my earlier post would have replaced any kind of 5A FIELD breaker that you might be worried about . . . never saw a fuse fail to open when hard faulted. The fuse you're talking about is in the alternator b-lead (output). See Figure 17-2 and associated text on page 17-7 of the 'Connection. The fact that you've never seen this breaker open says only that you have yet to generate the perfectly normal condition that will open it. If you choose to "fuse" this lead then consider the discussion in these threads: http://www.aeroelectric.com/articles/fusvsbkr.html and in particular the second half where I was taken to task for under-sizing a fast acting, JJN/JJS series b-lead fuse that we no longer offer nor recommend. http://www.aeroelectric.com/articles/fusvbkr2.html The device of choice is the ANL60 or even an ANL35. If you look at the fusing characteristics of these devices at http://www.aeroelectric.com/articles/anl/anl.pdf you'll see that you're unlikely to nuisance trip these devices on a 60A alternator on the coldest day. Irrespective of the circuit protection you choose for the b-lead, there is no bearing on the choice of configuration or operation of the ov protection system. The b-lead fuse protects the rest of the system from a hard fault inside the alternator while the ov protection system wards off effects of a failed regulator. Bob . . . ________________________________ Message 4 _____________________________________ Time: 04:13:18 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: sizing wire and protection for pitot tube --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > >Comments/Questions: Bob, looking thru your book trying to find a >chart/guide for selecting wire guage needed based on length of run, amps >required, and application. >Is there such a chart? If not, how is the wire size for a 15' run for a >heated pitot tube that draws 11 amps at 14 volts determined? That's a BIG pitot heater . . . It's covered in the book. First, wire has to be large enough not to run too hot for the current. The wire table (Figure 8-3) suggests 16AWG for loads up to 12.5A. Since 12A breakers are hard to come by, consider 14AWG wire protected at 15A. Now, with 11A load, the 2.5 milliohm/foot resistance of 14AWG will drop 11/2.5 or 27.5 millivolts per foot. A 15' run drops 413 millivolts . . . less than the 5% (700 millvolt) benchmark for 14 volt systems. Now, I presume we're talking about a metal airplane where you plan to use local ground for the pitot tube. If composite and the wire run round trip is TWICE the 15' figure cited, then your total drop with 14AWG would be 826 millivolts. Probably still okay . . . but it wouldn't hurt if you increased to 12AWG . . . the breaker/fuse could then be up-sized to 20A and still protect the wire. If your pitot tube really draws 11A continuous in operation, it will draw about twice that for several seconds during warm-up. If you're using fuses, the probability of nuisance tripping a 15A fuse is pretty good . . . a 15A breaker is much slower and would probably stay closed. So, the REAL criteria for selecting wire and fuse size may have more to do with the long and high value inrush characteristic of pitot tubes. 12AWG/20A is probably your best choice for either metal or plastic airplane. Bob . . . ________________________________ Message 5 _____________________________________ Time: 07:08:41 PM PST US From: Jim Bean Subject: AeroElectric-List: ELT in wingtip --> AeroElectric-List message posted by: Jim Bean What does the list think about putting the ELT in the wingtip of a metal AC. It's the only place "inside" where it can radiate. It would seem that the ELT would see the same deceleration as if in the fuselage. Also the wings often survive better that the fuselage, particularly if they are pulled off. The only problem I see is that the wingtip would have to be removed once a year to change the batteries. I have never seen this done so suspect that there MUST be something wrong with it. :) Jim Bean RV-8 ________________________________ Message 6 _____________________________________ Time: 07:17:24 PM PST US Subject: AeroElectric-List: Firewall Feedthru From: Jim Daniels --> AeroElectric-List message posted by: Jim Daniels http://terminaltown.com/Pages/BPT.html Has anyone tried one of these to get the master output to the starter relay? Or should I just run a 4 awg wire loop? I was thinking of the above and brass strips instead of wire with crimp/solder terminals. Thoughts? Some pics of a mockup: http://home.comcast.net/~jwdanie/temp.html Jim Daniels ________________________________ Message 7 _____________________________________ Time: 08:42:18 PM PST US From: "Jim Jewell" Subject: Re: AeroElectric-List: Firewall Feedthru --> AeroElectric-List message posted by: "Jim Jewell" Hi Jim, The only improvement I can see would be to substitute pure copper sheet in place of the brass that you intend to use. Admittedly the improvement that copper would provide would be small. In my limited experience I have only seen copper used for this purpose. Jim in Kelowna do not archive ----- Original Message ----- From: "Jim Daniels" Subject: AeroElectric-List: Firewall Feedthru > --> AeroElectric-List message posted by: Jim Daniels > > http://terminaltown.com/Pages/BPT.html > > Has anyone tried one of these to get the master output to the starter > relay? Or should I just run a 4 awg wire loop? I was thinking of the > above and brass strips instead of wire with crimp/solder terminals. > > Thoughts? > > Some pics of a mockup: > http://home.comcast.net/~jwdanie/temp.html > > Jim Daniels > > ________________________________ Message 8 _____________________________________ Time: 09:26:03 PM PST US From: "Larry Bowen" Subject: RE: AeroElectric-List: ELT in wingtip --> AeroElectric-List message posted by: "Larry Bowen" Lots of screw in those wingtips. So far, I like the placement of my Pointer ELT under the VS. Not flying yet..... - Larry Bowen, RV-8 finish Larry@BowenAero.com http://BowenAero.com > -----Original Message----- > From: Jim Bean [mailto:jim-bean@att.net] > Sent: Tuesday, October 14, 2003 10:05 PM > To: rv-list@matronics.com > Subject: AeroElectric-List: ELT in wingtip > > > --> AeroElectric-List message posted by: Jim Bean > > What does the list think about putting the ELT in the wingtip > of a metal > AC. It's the only place "inside" where it can radiate. It would seem > that the ELT would see the same deceleration as if in the > fuselage. Also > the wings often survive better that the fuselage, > particularly if they > are pulled off. The only problem I see is that the wingtip > would have to > be removed once a year to change the batteries. > I have never seen this done so suspect that there MUST be something > wrong with it. :) > Jim Bean > RV-8 ________________________________ Message 9 _____________________________________ Time: 10:46:49 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: ELT in wingtip --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:05 PM 10/14/2003 -0400, you wrote: >--> AeroElectric-List message posted by: Jim Bean > >What does the list think about putting the ELT in the wingtip of a metal >AC. It's the only place "inside" where it can radiate. It would seem >that the ELT would see the same deceleration as if in the fuselage. Also >the wings often survive better that the fuselage, particularly if they >are pulled off. The only problem I see is that the wingtip would have to >be removed once a year to change the batteries. >I have never seen this done so suspect that there MUST be something >wrong with it. :) >Jim Bean >RV-8 It's a pretty good idea to put the ELT in a position least likely to be wiped off or munched during the unplanned arrival with the earth. The tail section just forward of the vertical fin is an enclosed volume most likely to remain intact . . . the vertical fin provides a modicum of protection for an ELT antenna in a noseover. Bob . . . ________________________________ Message 10 ____________________________________ Time: 10:48:34 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Firewall Feedthru --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:14 PM 10/14/2003 -0600, you wrote: >--> AeroElectric-List message posted by: Jim Daniels > >http://terminaltown.com/Pages/BPT.html > >Has anyone tried one of these to get the master output to the starter >relay? Or should I just run a 4 awg wire loop? I was thinking of the >above and brass strips instead of wire with crimp/solder terminals. > >Thoughts? > >Some pics of a mockup: >http://home.comcast.net/~jwdanie/temp.html Copper strip is better. You can get flashing copper scraps from some roofing and/or plumbing companies. That feed through is a plastic insulator rated at 250F max . . . not especially resistant to fuel fed fire. Bob . . . ________________________________ Message 11 ____________________________________ Time: 10:52:35 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Strobes and comm Ant --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:42 PM 10/12/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "John Perry" > > >Friends, I'm building an AeroCanard and my Comm Ant are in the >winglets. Problem is I have to run the strobe wiring out the same >hole. Does anyone have an opinion on this? Will it work? Probably . . . but you might hear the strobes in the comm receiver even if you DO run the wires through separate holes. The risk is low. Give it a try. Bob . . .