Step 7: Conclusions, Template and pdf of my results
What I have made is a much more usable stand alone solar cooker!
The compound parabolic shape means that it does not need to be pointed exactly at the sun. The dish has to be in an area from the focus to the back of the dish. In my case the focus is at 10 or 11 inches from the back so my pot is almost perfect.
Here is a template so that you can make your own.
I think if you make the template from plywood, then use the plywood to cut the shapes in mylar, you can easily make 12 segments. Then just tape them together at the back and you should have a umbrella cooker the same shape as mine.
Use thin wire to keep your umbrella open (Up to you to figure out how!) and start cooking.
Graphs of my results in 2 tests heating 7 liters of water in a pot are shown in the other photos.
I also include a draft pdf file so you can check out my results.
Please note that I have a new instructable that is devoted to making your own template using basic technical drawing skills or a computer design program. If you can read a house plan and elevation, you can probably make a template!