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John

John

Built it with my Grandchildren Scouts. Has a built-in motor that turns two hot dogs at a time. is powered with solar cell charged batteries. Reflector is polished flashing aluminum accurately curved into a true parabolic shape with a focal length of 18 inches. Takes 3 minutes with midday sun on a cloudless day. Positioning is done by locating shadow of hot dogs on a a central line drawn on the parabolic surface