03-03-2022, 10:40 AM
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#71 (permalink)
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Quote:
Originally Posted by agfosterjr
OK, it's a big lie but it's feasible in sunny climes.
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No longer waiting for explication.
Quote:
octothorpe
ŏk′tə-thôrp″
noun
The symbol (#).
The hash or square symbol (#), used mainly in telephony and computing
The American Heritage® Dictionary of the English Language, 5th Edition.
More at Wordnik
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03-03-2022, 11:42 AM
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#72 (permalink)
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lower longer
Quote:
Originally Posted by Isaac Zachary
Nobody. But everything I've researched suggests that lower and longer will get better fuel mileage than taller and shorter. There have been examples of station wagons with more interior space that have more power, cost less and get better fuel mileage than similarly specked crossovers.
Plus the longer and shorter roof is better for amateur radio antennas. One of my car antennas is 17.5 feet long and works best smack dab in the middle of the Prius's roof. 
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1) We have at least one empirical example where lowering had no effect on drag, so we can't make 'blanket' 'truths' about outcomes.
2) There is an historical precedent associated 'length' and low drag, however, again, we have empirical evidence for 'short, stubby, blunt' vehicles with lower drag than relatively-longer vehicles in in same market segment.
3) If vehicles are reduced to normalized 'bar-graph' components, using length divided by square-root of frontal area, and compared by drag coefficient, you find that the Schlorwagen, Renault Vesta-II, M-B Bionic Boxfish, and Aero-modded Audi A2 are of the lowest drag vehicles ever offered.
4) That said, these four examples will all demonstrate lower drag with elongation and attention to sectional density.
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03-03-2022, 01:55 PM
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#73 (permalink)
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Quote:
...using length divided by square-root of frontal area...
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Popular discussions neglect the vehicle width, so 
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03-03-2022, 02:44 PM
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#74 (permalink)
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Quote:
Originally Posted by aerohead
3) If vehicles are reduced to normalized 'bar-graph' components, using length divided by square-root of frontal area, and compared by drag coefficient, you find that the Schlorwagen, Renault Vesta-II, M-B Bionic Boxfish, and Aero-modded Audi A2 are of the lowest drag vehicles ever offered.
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(1) None of those vehicles are available where I live.
(2) Only a couple of them may be considered large family vehicles.
Quote:
Originally Posted by aerohead
4) That said, these four examples will all demonstrate lower drag with elongation and attention to sectional density.
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That's the thing. If you take any of those vehicles and shorten the hight and make up the interior space difference by elongating them they will be more aerodynamic then they all ready are.
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03-03-2022, 03:09 PM
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#75 (permalink)
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the thing
Quote:
Originally Posted by Isaac Zachary
(1) None of those vehicles are available where I live.
(2) Only a couple of them may be considered large family vehicles.
That's the thing. If you take any of those vehicles and shorten the hight and make up the interior space difference by elongating them they will be more aerodynamic then they all ready are.
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1) I presented examples of 'shapes' which were optimal.
2) 'Large' was not a given constraint.
3) 'Shortening' will do exactly as you say, and lengthening will do exactly as you say with respect to interior volume.
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03-03-2022, 04:39 PM
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#76 (permalink)
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High Altitude Hybrid
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Quote:
Originally Posted by aerohead
1) I presented examples of 'shapes' which were optimal.
2) 'Large' was not a given constraint.
3) 'Shortening' will do exactly as you say, and lengthening will do exactly as you say with respect to interior volume.
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(1) A certain level of practicality is needed, therefore a certain level of interior space for cargo and passengers.
(2) There are four general ways of increasing or decreasing interior volume, roof height, floor height, width, and length, as well as door and wall, roof, floorboard and engine bay thicknesses (related to, but not exclusively, crumple zones)
(3) Taking any shape and making it wider or taller in order to increase interior space to an acceptable amount increases cross-sectional area and therefore increases drag.
(4) Increased length does induce a small amount of surface friction against the fluid (air) but usually makes up for it by allowing more gradual curves.
(5) Once you reach a Cd of 0.04 then increasing the length will induce greater drag but not near as much as increasing the height or width to the same interior volume mainly due to increased cross-sectional area.
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03-03-2022, 04:48 PM
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#77 (permalink)
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Clearly the solution is to colonize the moon, as that instantly makes all aero concerns moot.
Mars aero considerations could probably mostly be ignored.
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03-03-2022, 05:07 PM
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#78 (permalink)
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Moon
Quote:
Originally Posted by redpoint5
Clearly the solution is to colonize the moon, as that instantly makes all aero concerns moot.
Mars aero considerations could probably mostly be ignored.
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Hence, the book, 'Driving on the Moon', with 'supersonic' Prius.
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03-03-2022, 05:17 PM
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#79 (permalink)
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1- 5
Quote:
Originally Posted by Isaac Zachary
(1) A certain level of practicality is needed, therefore a certain level of interior space for cargo and passengers.
(2) There are four general ways of increasing or decreasing interior volume, roof height, floor height, width, and length, as well as door and wall, roof, floorboard and engine bay thicknesses (related to, but not exclusively, crumple zones)
(3) Taking any shape and making it wider or taller in order to increase interior space to an acceptable amount increases cross-sectional area and therefore increases drag.
(4) Increased length does induce a small amount of surface friction against the fluid (air) but usually makes up for it by allowing more gradual curves.
(5) Once you reach a Cd of 0.04 then increasing the length will induce greater drag but not near as much as increasing the height or width to the same interior volume mainly due to increased cross-sectional area.
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1) 'practicality' has turned out to be highly subjective.
2) yep!
3) 'acceptable' gets back into the 'subjective zone .'
4) Yes, and it's the gentle curves which protect the boundary layer and provide the pressure recovery which reduces the pressure drag, the major drag component.
5) Yep, although, I'd qualify Cd 0.04, as the basic body drag one would derive, lets say, the Cd 0.08 body from, which would grow to Cd 0.13 when wheels were added, then reduced to, say, Cd 0.10 or 0.09 when the same wheels were faired into the body.
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03-30-2022, 12:30 PM
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#80 (permalink)
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EV vs BEV cost of Truck towing trailer
There's a video of an F150 hybrid and a Rivian R1T (large pack 4 motor) towing. The F150 cost about 20% more than the Rivian on DC fast chargers.
Unfortunately I can't post the link due to low post count (Thanks admins!) but it's titled
"Towing With An Electric Truck - Is It Cheaper Than Gas? Rivian R1T vs Ford F-150 PowerBoost"
by Out Of Spec Reviews.
Remove spaces in link:
https: // youtu.be / XcZ_7qR_KBE
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