The Little Engine

Abstract

This article focuses on research and development works in the field of silicon-gas turbine engines to enable them produce power for portable devices. Alan Epstein, a professor of aeronautics and astronautics at the Massachusetts Institute of Technology, and his team are working on tiny silicon gas-turbine engines that could soon power laptops or cell phones. The group chose pressurized gas bearings, which can hold more weight relative to their size as they get smaller. Thrust bearings with spiral grooves and holes in their centers are self-pumping and keep the rotor in the right position. Epstein’s group considered magnetic bearings early on, but found that in addition to the manufacturing difficulties, the magnetic materials had too Iowa Curie point and would not stay magnetic at the temperatures at which the engine would operate: Instead, they chose pressurized gas bearings, which conveniently can hold more weight relative to their size as they get smaller. Thrust bearings with spiral grooves and holes in their centers are self-pumping and keep the rotor free and in the right position. While there is clearly plenty of room for improving efficiency, the microengine may very well end up as the only significant way to power, say, a laptop, an iPod, or a soldier's thermal weapon sight, to say nothing of a palm-size plane.