Good news! If you've been searching for a simple, easy to build, inexpensive, very portable, and virtually unbreakable sun-powered cooker, you need look no further. The fine people from the Volunteers in Technical Assistance (VITA) organization have already designed and tested (worldwide!) precisely the unit you want.
It's big enough to cook up a pot of stew, soup, greens, meat, or whatever to feed a whole family. It's constructed of commonly available materials (Masonite, aluminum foil or aluminized mylar, wood, small strips of iron). It's very easy to put together. It's rugged enough to shrug off the bumps that break most of the solar cookers on the market. It's simple to repair when it is damaged. Its cooking "stem" pops right out when you've finished with it (giving this solar stove near-maximum portability with near-minimum fuss), and you can build the little darlin' — even during this Age of Inflation — for under $10. That's a powerful lot of goodies for one neat package to offer!
The secret of the VITA cooker's ability to deliver so much for so little is the way in which it gathers sunlight and focuses the heat on the bottom and sides of a container of food. Instead of the fragile, heavy, and expensive glass mirrors that so many other sun-powered stoves use for this job, the VITA unit collects and condenses solar energy with a tough, relatively lightweight, and inexpensive "Fresnel" reflector. (Which is nothing but several concentric rings of aluminum foil-covered Masonite progressively "dished" so that they all focus on roughly the same spot.) This approach to the problem has yet another advantage: Reflective rings can be added or removed, as desired and with little trouble, to increase or decrease the cooker's "wattage".
"And it works!" says MOTHER EARTH NEWS researcher Emerson Smyers who, following VITA instructions, has built and tested one of the stoves. "All the VITA dimensions are given in metric measurements, however, unless you want to spend a couple of hours converting centimeters and millimeters to inches, you should buy a metrically scaled tape measure before you start this one: Once you get past that, though, there's nothing to the project. And the finished cooker will bring a pound of stew to a rolling boil in less than 20 minutes!"
Convinced? Then order your own VITA Solar Cooker Construction Manual. It's available as a free download from the Volunteers in Technical Assistance website.