not audio but interesting IMO

JohnRoberts · Nov 4, 2022

The TV show myth busters is mostly about blowing stuff up, but they occasionally expose something scientific. They were exploring a myth that dirty cars get better gas mileage than clean cars (they don't). I recently waxed my car and it clearly "feels" more slippery. For chuckles they compared smooth gold balls to dimpled golf balls and confirmed the superior distance thanks to reduced drag. Since they had time and budget they covered their test car, already rigged to measure gas mileage, with modeling clay, and carved dimples in the surface. Remarkably the dimpled car realized 10% better gas mileage.

I can't imagine car buyers embracing dimples but 10% better gas mileage is something.

JR

PS: Besides dimples on golf balls, there is another friction reducing phenomenon related to the interleaved fish scales.

scott2000 · Nov 4, 2022

Silver lining of hail storms

AnalogPackrat · Nov 4, 2022

laminar flow, turbulence, and boundary layer dynamics. Fun times.

JohnRoberts · Nov 4, 2022

AnalogPackrat said:
laminar flow, turbulence, and boundary layer dynamics. Fun times.

Car makers spend lots of wind tunnel time measuring and reducing Cd (coefficient of drag).

My brother says the later generation Tesla comes with a special plastic hub cap that is more aerodynamic than the previous version, and were responsible for increased battery range. He says they look cheesy and break easily, and cost $60 to replace after parking dings, so his 3 good ones are in his garage.

I don't think my brother is as cheap as me... I think he just prefers the look of the Tesla wheels without covers.

JR

living sounds · Nov 4, 2022

JohnRoberts said:
I can't imagine car buyers embracing dimples but 10% better gas mileage is something.

I would. That's a no brainer.

But if they finally release it (here in Europe, of all things) I'll get an Aptera. 1600 km reach and solar power. No need to fuel it any way for the amount I drive.