I WANT ONE!! Take down DIY bow

[Adze]

Thought so... flexing the bow causes it to heat slightly - you can see this for yourself with a rubber band, stretch it quickly and touch it to your cheek and it'll feel hot. I suspect PVC is either better able to store the heat, which is another way of saying rubber in the rubber band is better able to dissipate it I suppose. Either way you look at it storing heat in the PVC makes it less able to store energy to propel the arrow, probably in much the same way as losing the heat from the rubber of a catapult elastic (when it's held in tension for too long), reduces the energy available to propel whatever you're shooting from it. Has anyone done similar experiments with wooden bows for comparison?

 

[Biker]

Thought so... flexing the bow causes it to heat slightly

Water cooling? I wonder since it's a pipe if you plugged one end and those joints were tight enough topping it off with water inside would keep it very nice and cool. Just an obvious thought off the top of me 'ead.

Alternatively. Make several and keep the others in the shade.

However given the response from Nick I'd still say you'd get a lot of life out of a very cheaply made bow - assuming you could get the materials of course. I suppose a search through the online DIY forums and YouTube is next on my must do list to find anyone in the UK who have actually made one of these puppies successfully.

 

[Adze]

Water cooling? I wonder since it's a pipe if you plugged one end and those joints were tight enough topping it off with water inside would keep it very nice and cool. Just an obvious thought off the top of me 'ead.

PVC is a very good insulator. It might make a small difference, but I doubt the advantage would be greater than the disadvantage of the hugely increased weight as water masses 1Kg per litre - that's without any exploration of how the incompressibility of a liquid water filling would affect the action of the bow. Given that it's a limitation of the material which affects multiple shots rather than the single shots required for it's envisaged 'survival bow' role, it's probably not worth engineering around - especially since more exotic cooling methods would likely seriously increase the cost of the materials, one of it's major charms.

 

[Biker]

PVC is a very good insulator. It might make a small difference, but I doubt the advantage would be greater than the disadvantage of the hugely increased weight as water masses 1Kg per litre - that's without any exploration of how the incompressibility of a liquid water filling would affect the action of the bow. Given that it's a limitation of the material which affects multiple shots rather than the single shots required for it's envisaged 'survival bow' role, it's probably not worth engineering around - especially since more exotic cooling methods would likely seriously increase the cost of the materials, one of it's major charms.

Very true, I typed the above without really giving it serious thought. It'd act as a dampening effect too within the limbs of the bow too, what with moving all that water sloshing about inside of them.
I'm sure weight for weight, even with the water in it, it'd probably weigh less than some compound bows or wooden ones. Still like the idea of doing a few of these if I can get the pipe of course.

 

[Dannytsg]

Just as a chip in. You can get 2 meter of 3/4 inch PVC from B&Q for £1.99. Well worth if for a tinker.

 

[dwardo]

I didnt think of the heat generated in the actual draw affecting the performance.
Like above for a "survival" bow although i dont realy know what one is, it is fine for the job.

Also 140fps is very impressive. But with all the limitations its the reason we still use wood!
Even when you consider a fiberglass bow is only a few fps off a well desinged wood bow.

 

[TeeDee]

Biker , Its a little bit more complicated but you may want to do a search for ( its either ) 'Woodland Flipper' or 'Survival Flipper'

 

[Biker]

Biker , Its a little bit more complicated but you may want to do a search for ( its either ) 'Woodland Flipper' or 'Survival Flipper'

Found it TeeDee, Thanks! Looks sweet as well.

[video=youtube;nplJ5C7WInE]http://www.youtube.com/watch?v=nplJ5C7WInE[/video]

 

[Biker]

Just as a chip in. You can get 2 meter of 3/4 inch PVC from B&Q for £1.99. Well worth if for a tinker.

I'm hoping to be in the UK around the 11th July for one night so I think a trip to B&Q is in order. Wuld be rude not to

Stay tooned folks.