The Nitinol Engine

Build yourself a VERY unusual heat engine!

The heart of this engine is a thin ring of Nitinol wire (0.3mm). Some warm water is enough to make the Nitinol Engine run. Nitinol is an alloy of nickel and titanium which has exceptional properties: at low temperatures it is soft and bendy, but as soon as it is heated above a certain transition temperature, it instantly becomes hard and flexible like spring steel. As soon as the temperature drops again, it returns to its bendy state. Nitinol is a so-called memory metal: above the transition temperature it instantly assumes any shape that has been impressed on it during manufacture.

The transition temperature of our wire ring is 45ºC above which it becomes stiff and straight. Nevertheless the part of the wire that is immersed in the warm water lies around the drive wheel. When it straightens out, it is forced to move off the wheel and out of the water where it becomes bendy again. At the same time it pulls a new piece of wire into the water and the process continues, leading to a constant rotation of the drive wheel. The principle of this engine was developed by Frederic Wang in 1985. It works with only a small temperature difference and shows great potential for future applications.

This AstroMedia kit is the first mass-produced engine of its type, worldwide. Anybody interested in engineering and physics will be fascinated by this kit. A fantastic model and a great present!