Fine wire tensile strengths?
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From: Ken S. Tucker on 1 Aug 2010 11:49 On Aug 1, 7:30 am, John Fields <jfie...(a)austininstruments.com> wrote: > On Sun, 1 Aug 2010 04:52:10 -0700 (PDT), "Ken S. Tucker" > > <dynam...(a)vianet.on.ca> wrote: > >"Stretching" is commonly used here, > >http://en.wikipedia.org/wiki/Strain_gauge > >(as I'm sure yo'all know). > > > The aircraft are all weather, and quite light weight, that said, > >in a hefty wind or heavy snow load is what needs to be designed > >for, and sometime the a/c will do a kind of snap oscillation that > >causes a load spike. > > --- > What I'd do would be to use a length of piano wire as the strength > member from which to hang the airplane and then just run the wiring > next to it for the electric part. > > If your lighting is incandescent I doubt whether a spike would hurt > it. To be safe, though, you could connect a couple of unidirectional > TVSs in aseries opposition across the load. > > Something like a couple of Littelfuse 1.5KE160A: > > http://www.littelfuse.com/data/en/Data_Sheets/Littelfuse_TVS-Diode_1.... > > should work. > > You could also use a single bidirectional part but they're harder to > find. > > JF Thank you Mr. Fields. The heads up (pun) on lightning (Voltage transients) is important. This AM we tested fine wire to breaking, it broke at 100 gms, so I figure it's AWG 36, practically invisible, so we might try to wrap that around 8# monofilament. Regards Ken PS: My Doctor says I drink to much, then she asks, "what are you going to do about it". I answered, "I'll get a divorce".
From: Nunya on 1 Aug 2010 14:11 On Aug 1, 7:30 am, John Fields <jfie...(a)austininstruments.com> wrote: > On Sun, 1 Aug 2010 04:52:10 -0700 (PDT), "Ken S. Tucker" > > <dynam...(a)vianet.on.ca> wrote: > >"Stretching" is commonly used here, > >http://en.wikipedia.org/wiki/Strain_gauge > >(as I'm sure yo'all know). > > > The aircraft are all weather, and quite light weight, that said, > >in a hefty wind or heavy snow load is what needs to be designed > >for, and sometime the a/c will do a kind of snap oscillation that > >causes a load spike. > > --- > What I'd do would be to use a length of piano wire as the strength > member from which to hang the airplane and then just run the wiring > next to it for the electric part. > > If your lighting is incandescent I doubt whether a spike would hurt > it. To be safe, though, you could connect a couple of unidirectional > TVSs in aseries opposition across the load. > > Something like a couple of Littelfuse 1.5KE160A: > > http://www.littelfuse.com/data/en/Data_Sheets/Littelfuse_TVS-Diode_1.... > > should work. > > You could also use a single bidirectional part but they're harder to > find. > > JF You got it right. Use a high tensile strength carrier strand and spiral dress a bifilar pair over that, which is able to pass the needed current level. Hard mounted battery packs and LED lighting would work too. ;-)
From: John Fields on 1 Aug 2010 14:54 On Sun, 1 Aug 2010 08:49:39 -0700 (PDT), "Ken S. Tucker" <dynamics(a)vianet.on.ca> wrote: >On Aug 1, 7:30 am, John Fields <jfie...(a)austininstruments.com> wrote: >> On Sun, 1 Aug 2010 04:52:10 -0700 (PDT), "Ken S. Tucker" >> >> <dynam...(a)vianet.on.ca> wrote: >> >"Stretching" is commonly used here, >> >http://en.wikipedia.org/wiki/Strain_gauge >> >(as I'm sure yo'all know). >> >> > The aircraft are all weather, and quite light weight, that said, >> >in a hefty wind or heavy snow load is what needs to be designed >> >for, and sometime the a/c will do a kind of snap oscillation that >> >causes a load spike. >> >> --- >> What I'd do would be to use a length of piano wire as the strength >> member from which to hang the airplane and then just run the wiring >> next to it for the electric part. >> >> If your lighting is incandescent I doubt whether a spike would hurt >> it. To be safe, though, you could connect a couple of unidirectional >> TVSs in aseries opposition across the load. >> >> Something like a couple of Littelfuse 1.5KE160A: >> >> http://www.littelfuse.com/data/en/Data_Sheets/Littelfuse_TVS-Diode_1.... >> >> should work. >> >> You could also use a single bidirectional part but they're harder to >> find. >> >> JF > >Thank you Mr. Fields. >The heads up (pun) on lightning (Voltage transients) is important. >This AM we tested fine wire to breaking, it broke at 100 gms, >so I figure it's AWG 36, practically invisible, so we might try >to wrap that around 8# monofilament. --- Great idea! One caveat... 36AWG has a resistance of about 0.415 ohms per foot and incandescent lamps have a very nonlinear temperature coefficient of resistance, so you may wind up with the lamps being dimmer than you'd like and the wire hotter than the monofilament might like. Lightning strikes? All bets are off! ;)
From: John Larkin on 1 Aug 2010 16:16 On Sun, 1 Aug 2010 06:03:23 -0700 (PDT), "Ken S. Tucker" <dynamics(a)vianet.on.ca> wrote: >On Jul 30, 7:01 pm, "Ken S. Tucker" <dynam...(a)vianet.on.ca> wrote: >> I've been asked to 'light-up' aircraft models, such as, >> >> http://www.flickr.com/photos/35156618(a)N03/4754110575/ >> >> It is suspended from a rope. >> I need to use very fine 120V wire (like magnetic wire), >> the model uses 8# test monofilament right now and weighs >> 1/2 # , but a strong wind requires that 8# test. >> Is there a table that gives wire gauge & tensile strength? >> The current will likely be a max of 1/2 amp. >> Ken > >We put a a/c display into operation yesterday, as you guys >can see (compared to the top photo) the suspension wire is >too heavy. > >http://www.flickr.com/photos/35156618(a)N03/4848740731/ > >The wire is ~24 gauge gray stranded speaker wire, very safe >and strong but too visible compared to 8# monofilament fish >line. >Regards all and thanks for your interest. >Ken How about using LEDs? That are more efficient than incandescents, wildly so if you want colors. John
From: Ken S. Tucker on 1 Aug 2010 19:39
On Aug 1, 11:54 am, John Fields <jfie...(a)austininstruments.com> wrote: > On Sun, 1 Aug 2010 08:49:39 -0700 (PDT), "Ken S. Tucker" > > > > <dynam...(a)vianet.on.ca> wrote: > >On Aug 1, 7:30 am, John Fields <jfie...(a)austininstruments.com> wrote: > >> On Sun, 1 Aug 2010 04:52:10 -0700 (PDT), "Ken S. Tucker" > > >> <dynam...(a)vianet.on.ca> wrote: > >> >"Stretching" is commonly used here, > >> >http://en.wikipedia.org/wiki/Strain_gauge > >> >(as I'm sure yo'all know). > > >> > The aircraft are all weather, and quite light weight, that said, > >> >in a hefty wind or heavy snow load is what needs to be designed > >> >for, and sometime the a/c will do a kind of snap oscillation that > >> >causes a load spike. > > >> --- > >> What I'd do would be to use a length of piano wire as the strength > >> member from which to hang the airplane and then just run the wiring > >> next to it for the electric part. > > >> If your lighting is incandescent I doubt whether a spike would hurt > >> it. To be safe, though, you could connect a couple of unidirectional > >> TVSs in aseries opposition across the load. > > >> Something like a couple of Littelfuse 1.5KE160A: > > >>http://www.littelfuse.com/data/en/Data_Sheets/Littelfuse_TVS-Diode_1.... > > >> should work. > > >> You could also use a single bidirectional part but they're harder to > >> find. > > >> JF > > >Thank you Mr. Fields. > >The heads up (pun) on lightning (Voltage transients) is important. > >This AM we tested fine wire to breaking, it broke at 100 gms, > >so I figure it's AWG 36, practically invisible, so we might try > >to wrap that around 8# monofilament. > > --- > Great idea! > > One caveat... 36AWG has a resistance of about 0.415 ohms per foot and > incandescent lamps have a very nonlinear temperature coefficient of > resistance, so you may wind up with the lamps being dimmer than you'd > like and the wire hotter than the monofilament might like. Oh-oh, time for homework, what I'll write needs to be tested. Looked up max current for AWG 36, 1/4 Amp looks ok as it is well cooled. Over 10' the Ohms is ~4, max power to bulbs at 120V is 30W, the wire takes 1 volt and therefore 1/4W. In comparison, this unit, (day photo), http://www.flickr.com/photos/35156618(a)N03/4850643793/ takes 7+5+5 W = 17W. So yeah AWG 36 would be pushed. > Lightning strikes? > All bets are off! ;) Lightning strikes are most dangerous if somehow they ignite something, but a strike a few hundred feet away can produce weird transients that attention to grounding 'should' alleviate. Regards Ken PS: Incidentally, the haze in the photo is smoke from local forest fires caused by lightning (in BC Okanagan Valley). |