The HK3 viewed from above. Notice the diaphragm working against the juice lids and the fine craftsmanship of the razor-sharp fan blades. Keep this one on a shelf and away from young children.
Here's a closeup of the diaphram lever and displacer bushing. Note also the cooling fins and tougher grade structual tubing.
Here is the final unit. The expansion chamber is two beef stew cans fused together in the center with high temperature cement.
Another closeup of the mechanical workings of this engine. Notice how the vertical diaphragm movement is translated into greater horizontal crank movement. Horizontal cranking eliminates the need for a double crank. Those who have tried to bend a double crank will appreciate this improvement a great deal.
This unit generates a good breeze when powered by a solar reflector dish or a candle. Ice or snow can be put on top of the cooling fins for greater cooling power and more RPM. I've had this unit running over 1000 RPM.
I made a solar reflector out of tinfoil and some cardboard. It works amazingly well. An even better reflector can be made by stretching some reflective plastic over a circular frame and then sucking out some of the air. It won't be exactly parabolic, but it will be close enough for these projects!
The sterling engine home page.