First go read this very funny rant on how car companies overdesign their cars, or: no more clever gizmos please. I'm sympathetic as having seen some of the new cars out are clever enough to tell you your instaneous gas mileage, how many miles you can continue driving on your tank, but then they put the cup holder directly behind the shift stick. I guess those of us who still drive a manual aren't taken into account because how am I supposed to feed my coffee habit when I'd be knocking it over with my elbow every time I change gears. Or I could hold it, you know, if it didn't take two hands to drive a stick.
Then watch this clever (or not?) new development for engines, a nutating disk from AFRL. The disk appears to be able to perform both the compression and ignition cycles of a typical engine piston in a single stroke. They talk up the goal of this as being to save weight for UAVs. But whenever they talk about something being application specific for UAVs, it's probably because it lacks in other arenas. Perhaps it's not as hearty, not as powerful, or maybe not as reliable. Neat looking concept though.