Comments by "Keit Hammleter" (@keithammleter3824) on "Rotary Valves Make Normal Valves Look Silly - Why Aren't We Using Them?" video.

  1. The twerp that made this video understands nothing. He says at 12:05 that the valve train consumes power due to the spring. That's nonsense as when the spring is allowed to expand, it returns its stored energy back to the camshaft and thus to the crankshaft. Typical car engines have a volumetric efficiency (ratio of air mass drawn in versus the air mass that fits at BDC) exceeding 95% at maximum power RPM, so any improvement in mass flow has to be negligible. Usually the inlet valve is made larger than the exhaust, since inlet is at low pressure. Even so, when the exhaust valve opens the gases leave supersonically (its the supersonic boom that makes thee noise when there is no muffler.) and most of the mass has left the cylinder before the piston has travelled up even half way. With rotary cylinder valves, the combustion space extends up to the rotating part - this dramatically increases combustion space surface area and thus causes more combustion heat to be lost to coolant instead of being converted to mechanical power. He claims manufacturers won't change because of their investment in poppet valves. Thats the well-known sunk cost fallacy. They would change in an eye blink if there was any practical advantage. There isn't.
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