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How Much Glass Cloth to Use for Various Size Fuselages

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Old 08-23-2012, 07:27 PM
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thomas.crown
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Default How Much Glass Cloth to Use for Various Size Fuselages

I'm sure this has been covered in the past, but I didn't run across it. I've started making molds and one of my projects is a .60 sized pattern plane for which I'mmaking a fuselage mold. I'm struggling with how much cloth and what weight to use when making a fuselage fromthe mold. I can makedecent molds but I need a bit more info on making the finished product. Is it betterto use multiple layers ofa lower weight cloth or asingle heavier piece?My initial testing was done with a .25 size plane and I feel confident in my techniques. My first completed fuselage from the mold isflyable although a bit heavy.The thing is almost bullet proof (I should have gone with kevlar) but ounces really matter insmall planes.

My focus is currently on making fuselages for .25, .40 and .60 sized planes and the odd cowl or some other part. Is therea formula or rule of thumb to determine the amount and weight of cloth to use for different size planes? I'm only concerned with fuselages at this point. I don't want to waste materials reinventing the wheel. If it matters, I will be using polyester resin rather than epoxy. Thanks for the help.
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Old 08-24-2012, 02:25 AM
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Default RE: How Much Glass Cloth to Use for Various Size Fuselages

Hey Thomas,
For a .60 sized plane you should be able to get by with total weight of cloth of 7 to 8oz. I would use a layer of 3oz followed by a layer of 4oz. Years ago it was common to use total weight of 10 to 12oz total weight but that is not necessary in my opinion. I layed a couple of Dirty Birdy fuses up for my father with 7oz total weight (epoxy resin) and it was plenty stiff.

Todd
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Old 08-24-2012, 04:43 AM
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Default RE: How Much Glass Cloth to Use for Various Size Fuselages

I wouldn't consider polyester for model parts especially when concerned about weight. I would probably do the 7oz lay up from the wing back and an extra layer of 3 oz from the wing forward.

I find multiple layers or thinner cloth much easier to lay in the mold. I usually start with either 2oz or 3.2oz for the first layer. My current project can be seen at: http://www.sidgates.us/HOBBIES/F-94C/F94C%20PROJECT.htm
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Old 08-24-2012, 07:58 AM
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Default RE: How Much Glass Cloth to Use for Various Size Fuselages

Multiple layers of fabric is typically stronger.  You often need fibers going in varying direction to make a part that has enough torsional and bending stiffness/strength.   Also putting the layers at varying orientations (0/90, +/-45) increases the toughness of the fuse.  If you put all the layers on the same orientation then the thin laminate is prone to "zippering" along the weave.
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Old 08-24-2012, 10:38 AM
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Default RE: How Much Glass Cloth to Use for Various Size Fuselages

Sidgates, Nice link and video

regards

Keith
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Old 08-26-2012, 12:28 PM
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thomas.crown
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Default RE: How Much Glass Cloth to Use for Various Size Fuselages

Thanks for all of the responses to my question. I think Ihave a very good idea of what to do now.
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