<q>Half as bad as the gasoline powered cars that are (so called) destroying the environment isn’t really a huge improvement.</q>

My experience with Cruise driverless cars in the Mission district of San Francisco is that they are a fucking menace. Last week, one kept randomly stopping in the middle of the street, then accelerating quickly to the speed limit, and then for no reason rapidly slowing down again. I’m guessing that the engineers were…

I think the last video (4 valves vs 2 valves) incorrectly calculates the cylindrical volume that air can enter the cylinders. The narrator calculates volume as πDH, but πD is the circumference, not area of a circle. I think you’d want the volume as πr^2h. When I do this, I actually find that the larger, single…