> if it ends up being less effective at protecting the humans inside Of course. Who cares if you can just reset the flywheel (as opposed to scrapping the crum

> if it ends up being less effective at protecting the humans inside Of course. Who cares if you can just reset the flywheel (as opposed to scrapping the crumpled car) if you still have to scrap the people off of the dashboard? My whole point is that there are devices like this one that may be more effective, given some R&D, but that get neglected. Let me put forward another, perhaps less physically controversial, example: the "Rolomite". > Rolamite is a technology for very low friction bearings developed by Sandia National Laboratories in the 1960s. It is the only elementary machine discovered in the twentieth century and can be used in various ways such as a component in switches, thermostats, valves, pumps, and clutches, among others. > The Rolamite was invented by Sandia engineer Donald F. Wilkes and was patented on June 24, 1969. It was discovered while Wilkes was working on a miniature device to detect small changes in the inertia of a small mass. After testing an S-shaped metal foil, which he found to be unstable to support surfaces, the engineer inserted rollers into the S-shaped bends of the band, producing a mechanical assembly that has very low friction in one direction and high stiffness transversely. It became known as Rolamite. https://en.wikipedia.org/wiki/Rolamite https://en.wikipedia.org/wiki/Rolamite Or the Hilsch-Ranque vortex tube: > The vortex tube, also known as the Ranque-Hilsch vortex tube, is a mechanical device that separates a compressed gas into hot and cold streams. The gas emerging from the "hot" end can reach temperatures of 200 °C (392 °F), and the gas emerging from the "cold end" can reach −50 °C (−58 °F). It has no moving parts. https://en.wikipedia.org/wiki/Vortex_tube https://en.wikipedia.org/wiki/Vortex_tube Now these you can actually buy. They sell little ones that go on the end of an air compressor hose to deliver "spot cold" as it's called. I once emailed a company who makes them to ask what would happen if you set it up so that the cold (or hot) output chilled (or heated) the incoming air, would you get a feedback loop? But they weren't interested. The vortex tube is less efficient than a heat pump, so there are good reasons not to use it in every potential application, but I feel that there are good applications that go completely unrealized. That's my original point. Just because some cool technology exists doesn't guarantee that it will be used well, or at all.