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| AMT - carbon fibre tow | ||
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| Author | Post | ||
| DarthVader |
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 Medals: 0 Ribbons: 6  Registered Member #1997 Joined: Tue Feb 09 2010, 04:17AMPosts: 100 | I'm planning to buy a roll of carbon fiber tow from AMT this coming week .. it's sold on a 5kg roll so I will have plenty to sell on to anyone interested live to fly, fly to live. | ||
| DarthVader |
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| Medals: 0 Ribbons: 6 Registered Member #1997 Joined: Tue Feb 09 2010, 04:17AMPosts: 100 | here is a picture of what it looks like and an explination I found on google search... Question . Flat carbon fibre tow, What does "flat" mean, I thought that tows were untwisted "ropes" of carbon fibre strands and as such without form until impregnated with resin and cured. Answer. Tow is flat and the fibres should run straight with no twist. Twist would both damage the fibre as well as reduce the potential effectiveness. [ image disabled ] live to fly, fly to live. | ||
| Aragon |
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 Medals: 0 Ribbons: 11  Registered Member #251 Joined: Thu Mar 10 2005, 01:51AMPosts: 4561 | Neat! | ||
| SkyTrooper |
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 Medals: 0 Ribbons: 10  Registered Member #49 Joined: Fri Jun 25 2004, 01:38PMPosts: 693 | DV, i need the cloth that is wider, i need to make a seriously strong spar, i see you were also struck by the wobble dance. me, i just lost a lot more than you when it occurred. And i haven't tested my wood glue doubler reinforcment yet on a new spar. Partly because i am not confident it will work 100% even though it probably will! So i'm like hardwired into making an overkill spar even though a slightly stronger spar will do. Plane weighs in at 2.2 - 2.4 kg's. Maybe i'll order the wider ones if the wood doubler method fails my test when i finally do the test. [ Edited Mon Mar 08 2010, 12:39AM ] Let's go fly again.... T-Rex 450 V2 + bling T-Rex 600 E CF Raptor 90 3d CF E Tamiya Hotshot 1 x 2 Tamiya Thundershot Tamiya TB evolution 5, almost complete They have robbed me of my flying time... How could this be! | ||
| DarthVader |
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| Medals: 0 Ribbons: 6 Registered Member #1997 Joined: Tue Feb 09 2010, 04:17AMPosts: 100 | I was thinking.. I'm sure you can make a pretty serious spar with the tow if you just layer it many times ... IMHO.. the problem with cloth is that it is woven, so it can never be as strong as uni-directional tows ... the moment the fibers cross they in effect make themselves weak -- External Link -- live to fly, fly to live. | ||
| SkyTrooper |
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| Medals: 0 Ribbons: 10 Registered Member #49 Joined: Fri Jun 25 2004, 01:38PMPosts: 693 | DV i discussed this all over the net with people, and what you just mentioned was my first intention that i brought in front of them, (but using no stretch nylon fish string, also extremely strong instead of cf string) What Bex does is use the cloth fully saturated in epoxy and the way he does it looks like it would be very strong. But even that as me and Bex discussed might not be enough. I think i'll need a stronger spar to start with, but then i'm pushing the weight up, the plane is already at it's limit weight wise, if i add more weight landings will be too hot and i'll need a long runway. They said to me, wrapping the string may not be a good idea, so many against it, but i still think it could work, only problem is, how exactly, my idea is to wind it at an angle from tip to tip and then reverse the angle with the second layer so they cross over each other, but isn't that going to thicken the spar and make for an uneven surface when folding the correx over it. i also experimented with normal fishing line, it's easier said than done keeping the tension + the angle just right and so many winds needs to be done at constant tension. Also i'll probably need a "doubler" in the middle anyway before wrapping it. The cloth you just dip in epoxy apply and let dry. I think what it comes down to is that for me to be convinced i'd need a "youtube" of someone making a serious spar with string and then test it in front of my eyes on the vid. [ Edited Mon Mar 08 2010, 08:15AM ] Let's go fly again.... T-Rex 450 V2 + bling T-Rex 600 E CF Raptor 90 3d CF E Tamiya Hotshot 1 x 2 Tamiya Thundershot Tamiya TB evolution 5, almost complete They have robbed me of my flying time... How could this be! | ||
| lionelbrink |
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 Medals: 0 Ribbons: 4 Registered Member #2000 Joined: Wed Feb 17 2010, 12:28AMPosts: 77 | Hi, For F3B/F3J type spars which are capable of full pedal winch launches, we layup multiple layers of carbon tows across the desired spar width prior to vacuum bagging. The Composite BLOG contains some more info / local contacts regarding this at http://www.compositebuilding.blogspot.com/. For the "webbing" between spars, we often use carbon mesh "tube", also available from your favorite composites supplier, into which the spar is inserted & then allowed to cure. You can also use an aramid (Kevlar (TM)) tow to wrap the spar / wing joiner tightly before inserting into the wing. Never use carbon to wrap wing joiner boxes or wing doublers - this is simply too brittle for these high stress area & usually breaks. For correx type wings, it would probably be easier to bag a spar first (use angle aluminium as a cheap jig" to create the necessary size & shape) & once cured glue this onto the surface using a suitable high grade epoxy glue (as apposed to resin). Be careful of using too much epoxy whilst building - it only adds weight, which is counter productive to adding strength were it is needed. I try to mix the same amount of resin/hardener as the cloth weighs, then use paper towels to remove the wet spots. Of course this works with bagging, because once the cloth is saturated, the vacuum pressure will ensure a relatively even spread of fibres to full any remaining gaps & even then some resin will leak out. Regards, Lione l | ||
| SkyTrooper |
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| Medals: 0 Ribbons: 10 Registered Member #49 Joined: Fri Jun 25 2004, 01:38PMPosts: 693 | Hi Lionel, Thank you for sharing your knowledge. I Appreciate the information. i know F3j planes is cutting edge machines and every aspect needs to be super strong and super efficient. So applying that on my correx wing makes more than sense. I just don't fully visualize the "how to do it" concept when it comes to the whole bagging process, i'll try to find a YT on it or see if there is some illustrations/guides on the net. I want to keep it simple as possible but strong, if i need to do the whole bagging process in the end then i will go so far but what i had in mind was 1: glue a doubler say around 30cm long onto the spar with wood glue (i previously used superglue), so already a big difference in strength. If it fails my stress test then: 2. Wrap the spar in kevlar string including the doubler, plain and simple just wrap it so they overlap from one tip to the other. 3. If that fails then i guess the bagging process would have to be tried. Like you say in your anthem/motto "just wanna fly" I just want to get this correx plane up an flying, The sound of that 14x12 prop at full speed, the plane zipping by is just something i have to experience on a constant basis but sadly it's just not happening for i cannot decide on how to go about the spar issue, though abovementioned is my plan and i will experiment hopefully within the next 2 months so i can get this plane where it belongs, up in the blue. Thank You Let's go fly again.... T-Rex 450 V2 + bling T-Rex 600 E CF Raptor 90 3d CF E Tamiya Hotshot 1 x 2 Tamiya Thundershot Tamiya TB evolution 5, almost complete They have robbed me of my flying time... How could this be! | ||
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