AeroElectric-List Digest Archive

Fri 01/04/13


Total Messages Posted: 5



Today's Message Index:
----------------------
 
     1. 05:07 AM - Re: Advisability of using anti-corrosion lubricant on contacts (toddheffley)
     2. 07:18 AM - Re: Re: Advisability of using anti-corrosion lubricant on contacts (Robert L. Nuckolls, III)
     3. 08:07 AM - Re: Re: Advisability of using anti-corrosion lubricant on contacts (rayj)
     4. 09:33 AM - Re: Re: Advisability of using anti-corrosion lubricant on contacts (Robert L. Nuckolls, III)
     5. 06:38 PM - Re: Aeroled wiring (Rick Lark)
 
 
 


Message 1


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    Time: 05:07:37 AM PST US
    Subject: Re: Advisability of using anti-corrosion lubricant
    on contacts
    From: "toddheffley" <public@toddheffley.com>
    Wow....Talk about the subject that will not die! I have watched this controversy in my industry (large cabin executive jet maintenance) for some time now, and much like the discussion here, it will not die. Some airframers do not want corrosion inhibitors between the antenna and the airframe. Conversely, I worked for a MRO that requires Pentrox Type 2 (grey) for every antanna installation. (conductive paste, feels like toothpaste, non-hardening) My anecdotal experience tells me that antenna footprints are the first and worst hideouts for corrosion on many aircraft. Particularly lower antennas. My experience is 1 to 1 without exception. If a removed antenna has Pentrox under the foot print, it has no corrosion. I come down as a strong advocate for adding Penetrox. I have two theories: one is that Airframers live in perfectly clean factories with brand new airplanes that never corrode. Antennas are installed on perfectly clean ground planes, and that thinking is inviolate. MRO's live with 30 year old airplanes, thus the difference between the two. Theory number 2 is that the clamp up force of an antenna is very low because of the large size of the footprint. Use of some type of "magic goo" seems more reasonable, because one can never achieve a vapor tight fit up over the entire footprint of the antenna. I doubt there is a wooden stake for this vampire, but I would like Bob's thoughts related to HBC background vs. OBAM background. I come from a maintenance background , not a build background, so ....grain of salt.... Todd -------- WWW.toddheffley.com www.theinterconnectco.com for lighting products AV-TS.com for Jet Aircraft Test Equipment Read this topic online here: http://forums.matronics.com/viewtopic.php?p=391595#391595


    Message 2


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    Time: 07:18:51 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Advisability of using anti-corrosion lubricant
    on contacts At 07:06 AM 1/4/2013, you wrote: ><public@toddheffley.com> > >Wow....Talk about the subject that will not die! Not sure why anyone would want it to 'die' . . . >I have watched this controversy in my industry (large cabin >executive jet maintenance) for some time now, and much like the >discussion here, it will not die. > >Some airframers do not want corrosion inhibitors between the antenna >and the airframe. > >Conversely, I worked for a MRO that requires Pentrox Type 2 (grey) >for every antanna installation. (conductive paste, feels like >toothpaste, non-hardening) There's a BIG difference between the situation you are citing and the conversations we've had here on the list. >My anecdotal experience tells me that antenna footprints are the >first and worst hideouts for corrosion on many aircraft. >Particularly lower antennas. My experience is 1 to 1 without >exception. If a removed antenna has Pentrox under the foot print, it >has no corrosion. I come down as a strong advocate for adding Penetrox. Absolutely. But the identification of successful remedies for specific issues does not translate into a general applicability as a prophylactic measure. I.e. using Penetrox to offset a specific vulnerability does not suggest that dipping the whole airplane into Penetrox is a good idea. >I have two theories: one is that Airframers live in perfectly clean >factories with brand new airplanes that never corrode. Antennas are >installed on perfectly clean ground planes, and that thinking is >inviolate. MRO's live with 30 year old airplanes, thus the >difference between the two. > >Theory number 2 is that the clamp up force of an antenna is very low >because of the large size of the footprint. Use of some type of >"magic goo" seems more reasonable, because one can never achieve >a vapor tight fit up over the entire footprint of the antenna. > >I doubt there is a wooden stake for this vampire, but I would like >Bob's thoughts related to HBC background vs. OBAM background. Some years ago I published this drawing http://tinyurl.com/6rwodso that spoke to the value of high mate-up forces in the vicinity of mounting hardware along with a suggestion that paint be removed from skin ONLY around the holes. It was a toss-up then as to how moisture might be prevented from taking up long term residence under the antenna. THIS is a problem. I suggested a bead of RTV on the outside because it can be inspected and renewed as needed. A gasket is NOT called for because it upsets the design goal for gas-tight bonding at the bolt holes. Silicon grease would be good for protecting the bonds and is probably the preferred technique . . . but that stuff is a high viscosity liquid with very good wetting properties. This means that the stuff migrates out from under the antenna base and stains surrounding surface while adding dust collection. Looks like @#$@#. >I come from a maintenance background , not a build background, so >....grain of salt.... So you're quite right that there's a unique and challenging problem to seek the elegant process by which long-lived antenna installations can be made . . . certainly more than a 'grain of salt'. In retrospect, given that electronic grade RTV in the uncured state has no significant compression strength, It would be interesting to try an overall, liquid gasket approach under the antenna using the silicone sealant. I think it would extrude out of the gas-tight contact areas as the bolts are torqued up. Squeeze- out around the base is easily cleaned after the bolts are tightened. Overall water tightness should be quite good. I'll put that into my list of experiments to try . . . One could overlap 3" wide strips of say 1/8" and equivalent thicknesses for skin and doubler. Do the 'bonding' thing around 4 holes with 10-32 hardware in them. Dope the interface between 1/8" and 'skin' with rtv and clamp it up. Do a test on bonding integrity of the two surfaces after the RTV has cured. Repeat without RTV and compare. Bob . . .


    Message 3


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    Time: 08:07:38 AM PST US
    From: rayj <raymondj@frontiernet.net>
    Subject: Re: Advisability of using anti-corrosion lubricant
    on contacts Greetings Bob, May I suggest that you try "3M Marine Adhesive Sealant 5200" instead of RTV for your tests. I have used it undermany fittingsabove and below the waterline on boatswith excellent results. They also make a 4200 that is easier to remove which might be more appropriate for antenna installations. Raymond Julian Kettle River, MN. "And you know that I could have me a million more friends, and all I'd have to lose is my point of view." - John Prine On 01/04/2013 09:17 AM, Robert L. Nuckolls, III wrote: > <nuckolls.bob@aeroelectric.com> > > At 07:06 AM 1/4/2013, you wrote: >> <public@toddheffley.com> >> >> Wow....Talk about the subject that will not die! > > Not sure why anyone would want it to 'die' . . . > >> I have watched this controversy in my industry (large cabin executive >> jet maintenance) for some time now, and much like the discussion >> here, it will not die. >> >> Some airframers do not want corrosion inhibitors between the antenna >> and the airframe. >> >> Conversely, I worked for a MRO that requires Pentrox Type 2 (grey) >> for every antanna installation. (conductive paste, feels like >> toothpaste, non-hardening) > > There's a BIG difference between the situation you > are citing and the conversations we've had here on > the list. > >> My anecdotal experience tells me that antenna footprints are the >> first and worst hideouts for corrosion on many aircraft. Particularly >> lower antennas. My experience is 1 to 1 without exception. If a >> removed antenna has Pentrox under the foot print, it has no >> corrosion. I come down as a strong advocate for adding Penetrox. > > Absolutely. But the identification of successful > remedies for specific issues does not translate > into a general applicability as a prophylactic > measure. I.e. using Penetrox to offset a specific > vulnerability does not suggest that dipping the > whole airplane into Penetrox is a good idea. > > >> I have two theories: one is that Airframers live in perfectly clean >> factories with brand new airplanes that never corrode. Antennas are >> installed on perfectly clean ground planes, and that thinking is >> inviolate. MRO's live with 30 year old airplanes, thus the difference >> between the two. >> >> Theory number 2 is that the clamp up force of an antenna is very low >> because of the large size of the footprint. Use of some type of >> "magic goo" seems more reasonable, because one can never achieve a >> vapor tight fit up over the entire footprint of the antenna. >> >> I doubt there is a wooden stake for this vampire, but I would like >> Bob's thoughts related to HBC background vs. OBAM background. > > Some years ago I published this drawing > > http://tinyurl.com/6rwodso > > that spoke to the value of high mate-up forces > in the vicinity of mounting hardware along > with a suggestion that paint be removed from > skin ONLY around the holes. It was a toss-up > then as to how moisture might be prevented from > taking up long term residence under the antenna. > > THIS is a problem. I suggested a bead of RTV on > the outside because it can be inspected and renewed > as needed. A gasket is NOT called for because it upsets > the design goal for gas-tight bonding at the bolt holes. > Silicon grease would be good for protecting the bonds > and is probably the preferred technique . . . but that > stuff is a high viscosity liquid with very good wetting > properties. This means that the stuff migrates out from > under the antenna base and stains surrounding surface > while adding dust collection. Looks like @#$@#. > >> I come from a maintenance background , not a build background, so >> ....grain of salt.... > > > So you're quite right that there's a unique and > challenging problem to seek the elegant process > by which long-lived antenna installations can > be made . . . certainly more than a 'grain of salt'. > > In retrospect, given that electronic grade > RTV in the uncured state has no significant > compression strength, It would be interesting > to try an overall, liquid gasket approach > under the antenna using the silicone sealant. > I think it would extrude out of the gas-tight > contact areas as the bolts are torqued up. Squeeze- > out around the base is easily cleaned after > the bolts are tightened. Overall water tightness > should be quite good. > > I'll put that into my list of experiments to > try . . . One could overlap 3" wide strips of > say 1/8" and equivalent thicknesses for skin > and doubler. Do the 'bonding' thing around 4 > holes with 10-32 hardware in them. Dope the > interface between 1/8" and 'skin' with rtv > and clamp it up. > > Do a test on bonding integrity of the two > surfaces after the RTV has cured. Repeat > without RTV and compare. > > > Bob . . . > >


    Message 4


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    Time: 09:33:49 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Advisability of using anti-corrosion lubricant
    on contacts At 10:06 AM 1/4/2013, you wrote: >Greetings Bob, > >May I suggest that you try "3M Marine Adhesive Sealant 5200" instead >of RTV for your tests. I have used it under many fittings above and >below the waterline on boats with excellent results. They also make >a 4200 that is easier to remove which might be more appropriate for >antenna installations. Good info. Actually, there are a host of suitable sealants. In this case, cured sealant exposed to the environment is a very thin 'gasket edge' that is quite protected. I rather suspect that any quality caulking compound would suffice. I thought of EGRTV only because it's stuff I have around and I KNOW it to be non-corrosive . . . unlike similar products with the smell of acetic acid. What ever we test should be something that a builder can readily acquire at low cost. Hardware store acrylic caulk seems an attractive alternative. Bob . . .


    Message 5


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    Time: 06:38:37 PM PST US
    Subject: Re: Aeroled wiring
    From: Rick Lark <larkrv10@gmail.com>
    Mike, Sorry to hear you've got a problem. I'm assuming you used the shielded, 3 conductor 20 ga wire that Aeroled recommends? Did you run the wire separately or in wire bundles and/or with any coax antennae cable? Any help is appreciated. Regards, Rick On Thu, Jan 3, 2013 at 6:32 PM, Mike Fontenot <mikefapex@gmail.com> wrote: > I have the AeroLeds (two of the combined nav light/white strobe units) > installed on my trike (Z19 RB). I wired up as per their instructions but > they exhibit a small 'three click' noise in my headsets every time they > flash. Not very loud but frustrating since all the other electrics work > just fine. > > I've not had time to do further debugging since early last year/2012 but > I tried their suggestions of ferrite wraps. This did not help. > > On Wed, Jan 2, 2013 at 7:39 PM, Robert L. Nuckolls, III < > nuckolls.bob@aeroelectric.com> wrote: > >> At 07:43 PM 1/2/2013, you wrote: >> >> Bob, I believe the "victim"(s) are coax antenna and associated radios. >> The "antagonist", I'm not sure. I did speak to Dean at Aeroled, and I >> remember him talking about these lights not having a capacitor discharge, >> therfore the noise characteristics were different than "Whelan" type >> strobes. How the shielding breaks the propagation of noise, I have no idea. >> >> It's going to be months before I will have the strobes and radios powered >> up, but I'll let you know how I make out. Wiring has been installed, but no >> connections made. I'm planning to go to Sun & Fun so hopefully the >> Aeroled people are there and I will have a talk with them again. >> ** >> >> >> Yes, the noise is very different. While >> h.v. strobe systems are replete with fast-rise >> current/voltage waveforms at the flash rate >> of the strobes, the LED supply noise is >> an artifact of the switchmode, constant >> current power supply typically used to >> drive leds. >> >> If the AEROLED product generates noises at >> unacceptable levels, it's likely to be >> CONDUCTED noise that will propagate right >> down the power lines, shielded or not. >> >> Have Dean give me a call any time. My mobile >> phone is 316-209-7528. I'd like to explore >> his perceptions of noise issues for his product. >> I think we can be of service and perhaps save >> future customers from jumping unnecessary >> hoops. >> >> I'm 99% sure that shielding these wires is >> of no value. If there are noise problems to >> be addressed, then filters located at the >> source are called for. >> >> >> ** >> >> ** Bob . . . >> >> * >> >> _blank">www.aeroelectric.com >> .com" target="_blank">www.buildersbooks.com >> ="_blank">www.homebuilthelp.com >> _blank">http://www.matronics.com/contribution >> ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List >> tp://forums.matronics.com >> ========== >> >> -- >> Mike >> >> ====== >> Mike Fontenot >> Apex Consulting & Services LLC >> Lakewood, Colorado >> 303 / 731-6645 >> >> mikef AT apexconsultingservices DOT com >> =============================== >> * >> >> * > > * > >




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