Miniature engines to replace batteries

Also, they can run for two years on a single squirt of lighter fluid.

One issue engineers faced was how to deal with the heat produced from the tiny engines. The engines became so hot they burned themselves out and couldn't be reused. Heat-resistant materials such as ceramic or silicon carbide solved this problem. Other applications for the mini engines include driving microair vehicles for military operations and microrobots for reconnaissance, communication relays, and microcameras.