how to make a Winston cone

I need to make a large Winston cone. Ideally it would be made of some fairly lightweight rigid material that will accept mirror sheeting. Any ideas? Thanks

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Kiteman10 years ago
How large is "large"?

You could make it out of very thin plywood, laminated card, fibreglass.

Here's a thought - bend a lot of lengths of stiff wire into the shape of the cone's cross-section. Stack all the curves inside each other, each at an angle to the next to make a skeletal version of the cone. Weld or otherwise join them where they cross, then wrap the whole thing in your chosen material. When it's set/dry, pull out the skeleton (for later re-use?) and then climb inside with a dustmask and a lot of sand-paper.

Or, how about taking this instructable in a slightly lateral direction: https://www.instructables.com/id/EB96DTBQ13ES9J6YYX/
culinadge (author)  Kiteman10 years ago
Kiteman, I need one with an aperture (or large openening) of 5 to 6 feet in diameter. Since I want to use it as a solar collector I need to eventually make the base out of something that will be reasonably weather resistant. I would then use something like mirror sheeting for the reflective surface.
I am new to forums in general and this is my first post to any of them. Have a look at http://3c2y.com/images/pic_dehydrator.jpg which is a solar food dehydrator made by a friend and I can assure you it works very well. The main glass covered collector/solar box with black metal inside is set at 45 degrees, and the two reflectors are at 120 degrees to the glass. All the suns rays enter the solar collector in this set-up. As I understand it a winston cone is the equivalent of a magnifying glass concentrating the suns rays into a single spot which is not necessary for this food dryer application. The same friend also has a solar oven which can reach 450 degrees F, with reflectors on all four sides. This is similar in effect to the cone but it is square. Probably only 95% as efficient as an actual cone but make it 5% bigger to compensate!!
Kiteman culinadge10 years ago
I would go with Animal's Instructable. As for the formulae, google turned up a couple of sites that look useful:

> http://www.ericweisstein.com/research/thesis/node99.html
> http://www.eecs.umich.edu/~prjordan/papers/lightcollector.pdf
Here's what I came up with Culinadge. Theta =30 in this case. Concentration factor is 4 not including losses. Here's my paper prototype and the cad files.
lemonie10 years ago
Why do you need to make this? I made this with a T-shirt and resin, any relavence? L
culinadge (author)  lemonie10 years ago
Lemonie, I want to make one for use as a solar collector. Your shape definately has relevance. Can you tell me more about how you made it? I want to make a cone with a 5 to 6 foot diamater aperture.
lemonie culinadge10 years ago
I laid an old T-shirt over an aluminium cone, then soaked it in "fibre-gass resin", it does curve in a bit at the bottom, but not that much.The most important part of this project would be getting the curve right, and I wouldn't know how to do that.
here's how i did my parabolic reflector

Winston cone? I can't wait to see the instructable.
culinadge (author)  Tool Using Animal10 years ago
Tool Using Animal, Something like this may well do the trick. I am not sure if I can figure out the equations to make the shapes but I am sure someone out there would be able to figure that out. I am planning to use the cone as a solar collector and I want to make one with a 5 to 6 foot aperture. It would be somehwere around 5 to 6 feet tall as well.
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