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Old 04-15-2024, 10:58 AM   #1 (permalink)
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Driving a Four-Bolt Chariot

A neighbor who grew up where I live is now teaching teachers, and has been appointed guru of the STEM program, north, in Gainesville.
She talked me into doing an Earth Day program on the 23rd.
Anyway, on the eclipse trip, south of San Antonio, I had some time to think about what disadvantaged youth might value from, pertaining to transportation.
The 85-MPH toll-road between Austin and San Antonio nudged my brain into the 'twisted zone,'
Considering the defunct, twenty-year, 55- MPH national speed limit, some of the numbers I'd run for the Chevy BOLT kind of leaped off the page.
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1) I took the brake horsepower-equivalency requirement for the BOLT, at 55-MPH, and set that as a 'BOLT' power unit baseline.
2) I found multiples of this power requirement at 73-mph, 84-mph, and 93-mph ( the BOLT's top speed ).
3) At 73-mph, a BOLT driver would be experiencing the equivalence of driving 'two' Bolts, compared to 55-mph.
4) At 84-mph, a BOLT driver would be experiencing 'three' BOLTS.
5) At 84-mph, into a 9-mph headwind ( 93-mph air speed ), the BOLT driver would be experiencing the power consumption of 'four' BOLTS.
6) Using the EPA's 100%-to-zero% SOC metric for range, the 'chariot's' range would vary between 374-miles, and 157-miles.
7) Drive time would vary between 6-hours, 49-minutes, and 1-hour, 41-minutes.
8) Energy consumption would vary between 173 Wh/mi, and 412-Wh/mi.
9) It's about as good an example of the aerodynamic power-cubed law as I might be able to conjure up.
10) The posted speed limit on I-35 through Gainesville is 75-MPH, so the kids will be able to connect close to the 73-MPH value in the 'math.'
11) And I have a full-color geometric Road Load power graph for the BOLT which allows quick-comparisons between any 'SPEED' and the power requirement associated with that 'speed'; rolling-resistance and aero..
12) Brake Thermal Efficiency-equivalency ( BTE-e ) is 95%, so arriving at any chosen bhp-e is just a matter of dividing the road load of interest by 0.95.
Wonder what Spartacus would have thought?

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Old 04-24-2024, 11:28 AM   #2 (permalink)
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Earth Day sees 'Four-Bolt Chariots', Southbound on I-35

I exhibited Spirit of EcoModder.com outside of the Gainesville High School cafeteria, and exhibited the ITworks' scale-wind tunnel, inside the cafeteria, for the 2024 Earth Day celebration yesterday.
I'd provided 350 black and white, and 50, color data sheets for the children/parent participants, which included the formulas, calculations, data sets, and graphical representations which led to the 'chariot' data.
The wind tunnel ran for two-hours, with hands-on 'shapes' that the kids and parents could place in the wind stream, and actually experience the physical difference in aerodynamic drag, as a function of 'shape.'
1) The mirror-image phenomena of automobile bodies was emphasized.
2) The fineness-ratio as related to drag was emphasized.
3) And the aerodynamic velocity-cubed law was emphasized.
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The sky wizards provided auspicious 20-MPH south winds yesterday, and since all the 'parents' buy the gasoline and diesel for the family car, they all picked up on what the difference at the pump might be, driving 75-mph 'into' a 20-mph 'headwind' ( 95-mph airspeed ), versus, 75-mph with a 20-mph 'tailwind ' ( 55-mph airspeed ) [ 'four-BOLT chariots ].
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The 240-mph Peregrine Falcon I brought kinda clinched the deal on the importance of 'streamlining'.
I had one of Paul Jaray's airships with me, and they picked up on that, and were surprised to learn that my Cd 0.12 'baby template' car was based upon Jaray's 1922 design.
They could see a direct connection to the 1950, 198-mph So-Cal Belly Tank Lakester which I exhibited.
And the 1987 GM OLDSMOBILE AEROTECH longtail, which still holds the land speed record for it's class.
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Everyone held my all-aluminum, 3:1 streamline body of revolution in the airstream, and agreed that it 'had no perceptible' drag.
And looking at NASA's full boat tail on the Space Shuttle Discovery, seemed to produce ' lightbulb' moments for participants.
'Spirit's' 'up to' 39.9 mpg HWY raised some eyebrows.
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It took an hour to dissemble and pack up the exhibits. We got a free supper and desert.
The Sun went down.
We'd had a tailwind driving North.
And then a tailwind driving South, home.
All in all, a pretty good day.
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Perhaps the folks will never think the same about 'what' cars look like.
PS,
presently, 284,367 'views' have accumulated at the 'Aerodynamic Streamlining Template. Part-C' thread, from back in 2009.
I'll improve on it as new empirical evidence rears it's lovely head.
Perhaps Dr. Jeff Howell et al., at Loughborough University will have something new for us one day.

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Last edited by aerohead; 04-24-2024 at 11:40 AM.. Reason: add PS
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