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    Model Aeroplane Rubber

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    yulzari
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    Model Aeroplane Rubber

    Post by yulzari on Wed Dec 19, 2018 4:18 pm

    There is much discussion and examples of using latex tubing, office rubber bands, exercise bands and tubing and spear gun tubing. Most of this is about long draw lengths to suit the available materials.

    Long ago I researched the use of rubber for single seat racing cars and the industry experts recommended rubber in compression for inherent hysteresis (useful in the context to dampen the rubber movement in rebound) and that it should be in small bits squashed hard. Issues were set and softening with internal heat affecting the ride height. Now in the catapault context the requirements are opposite by and large. Thinner tubes/strips stretched to ideal lengths in draw used in multiples allows a shorter overall draw length, which eases the installation. They have a greater surface area so will lose heat more easily which is considered a problem for our use but this also means that they rapidly attain a stable constant power.

    The next step down is to obtain stretchy rubber which is yet thinner and this is easily found in the rubber used to power model aeroplanes. It is very thin. Although not very powerful individually it is thin enough to use far more strands than one normally sees in our devices. Kept suitably lubricated they will slide over each other without raising stress points or friction heat. Use enough and you can avoid all the pulley problems of installations to simplify installation. Either as gathered one piece strand bundles or as a continuously looped strand. Catastrophic failure is unlikely as the failures would be in increasing numbers of individual strands so allowing replacement before the whole bundle breaks unlike other systems whereby a breakage is of the whole band or tube. 

    Has anyone any experience of this material in bows or any views on the matter?
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    kenh
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    Re: Model Aeroplane Rubber

    Post by kenh on Thu Dec 20, 2018 5:26 am

    Interesting information, but the vast majority of folks here are involved with 'real' crossbows, not rubber-powered gadgets.  Check with Joerg Sprave's Slingshot Channel, that's were the rubber stuff is happening.

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    Re: Model Aeroplane Rubber

    Post by chaz on Thu Dec 20, 2018 9:05 am

    ditto

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    Re: Model Aeroplane Rubber

    Post by c sitas on Sat Dec 22, 2018 10:57 am

    Yulzan, I 've used a lot of things experimenting. You would surely want to try divers rubber tubeing.  I buy it on Ebay. Great stuff , lots of power. I use the 5/8" thick on two bows I,ve made. Study into how to fasten to them . It's all divers stuff and simple. The net is full of info. I followed a member by the name of Jeep here.We talked back and forth. He is now deceased, but I think you could still search him  here. He had a brilliant mind and went with lot of the chinese stuff with the crossbow.
    They were also brilliant when it came to the crossbow.We have a member here who has invented the fastest arrow slinger in the world but, it's not really a true crossbow.

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