Imagine the world’s most efficient engine design running off the heat of your coffee mug.
When the heat expands the air, the air pushes up on the piston. When the air cools, it contracts, pulling the piston down. This heating and cooling moves the piston, making the propeller turn.
Made of metal parts with wood propeller. Available in both kit form (30825-19) and pre-assembled (30825-20).