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Old 06-09-2021, 11:21 AM   #6 (permalink)
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Join Date: Jul 2012
Location: Austin, UT USA
Default Corrected erroneous total energy calculation

It was pointed out to me on another forum that my total blade kinetic energy calculation was incorrect. I was erroneously adding the linear KE term (KElin) to the rotational KE term (KErot) to come up with the total KE (KEtot). It turns out that the second term in the KErot equation is the blade's linear KE so there was no need to add the KElin to get KEtot.

I've updated the calculator to eliminate the unneeded KElin, KEtot and vb parameters. Here's what the UI looks like now: (The default values now approximate the blade on the Blackbird DDWFTTW vehicle traveling at 50 mph.)

Once again, if anyone can see any errors/improvements on my calculator, please chime up.

BTW, while building this little app, I came across an excellent series of physics lectures presented by an MIT professor. This one in particular provided a very handy refresher in rotational kinetic energy. (His discussion of rotating neutron stars at the end was particularly mindblowing.)

8.01x - Lect 19 - Rotating Objects, Moment of Inertia, Rotational KE, Neutron Stars (41 min 0 sec)
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