Quote:
Originally Posted by RedDevil
It would need to provide at least 50 Watt per kilo (25 Watt per pound) or its mass alone would hurt acceleration even at full output, assuming a typical 1000 kilogram econobox with an 50 kW engine.
Can you show a memory wire motor that can provide more than 25 Watt for every pound of its own weight?
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Well, considering that nitinol has a force of as much as 55 tons per square inch, and given that a one-foot length of the wire of 0.020" diameter weighs just 0.06 pounds, we get ~16 wires per pound, and approximately 50 wires per linear inch or 2500 wires per square inch. So to produce 55 tons of force, we'd need approximately 156 pounds of the stuff in foot-long wires. That'd produce about 41 watt-hours with a lever length of one foot.
So, with just 16 wires (one pound), we'd get a pull of 727 pounds. At a lever length of 1 foot, giving 727 pound-foot of force, that equates to 0.27 watt-hours.
That's a couple orders of magnitude below your benchmark.