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Old 01-13-2021, 03:12 PM   #1 (permalink)
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2013 Land Rover

Some general thoughts on Adrian Gaylard's 2013 Land Rover:
1) On page-72 he gives a 'baseline' Cd 0.340 for the SUV.
2) On page-2 he mentions that ' the wake flow generated by a blunt ended cars typically causes more than one-third of their aerodynamic drag.'
3) If we take Cd 0.340 as the Rover's drag, and if one third of that is 'wake' drag, then we're looking at 'wake drag' = Cdw = 0.1132.
4) If the addition of a boat-tail eliminated the wake, then Cd 0.340 - 0.1132 = Cd 0.2268.
5) A 'boat-tailed' Land Rover would come in between a Tesla Model S, and a Porsche Taycan Turbo. Much like Kamm's Cd 0.23 K-car of the 1930s.
6) Similar to Thomas Scott Breidenbach's GM full-size SUV, wind tunnel-tested boat-tail, which would quantitatively drop the Chevy Tahoe hybrid from Cd 0.34, to Cd 0.2414. A 98-count reduction. ( US Patent # 8590961, February 21, 2012 )
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Old 01-13-2021, 03:28 PM   #2 (permalink)
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Have you calculated the length of the boat-tail required? It would probably need wheelie bars.

(vBulletin doesn't like 'boat tail', I'll adopt the hyphenation.)
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Old 01-13-2021, 03:39 PM   #3 (permalink)
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length

Quote:
Originally Posted by freebeard View Post
Have you calculated the length of the boat-tail required? It would probably need wheelie bars.

(vBulletin doesn't like 'boat tail', I'll adopt the hyphenation.)
It is what it is.
The slotted-wing is good for 2-counts.
The boat-tail is good for 98-counts.
Elephant in the living room.
'Practicality' is a thread by itself, and we should have one, if there isn't already an existing one, buried somewhere.
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Old 01-13-2021, 04:37 PM   #4 (permalink)
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Quote:
Originally Posted by aerohead View Post
Some general thoughts on Adrian Gaylard's 2013 Land Rover:
1) On page-72 he gives a 'baseline' Cd 0.340 for the SUV.
2) On page-2 he mentions that ' the wake flow generated by a blunt ended cars typically causes more than one-third of their aerodynamic drag.'
3) If we take Cd 0.340 as the Rover's drag, and if one third of that is 'wake' drag, then we're looking at 'wake drag' = Cdw = 0.1132.
4) If the addition of a boat-tail eliminated the wake, then Cd 0.340 - 0.1132 = Cd 0.2268.
5) A 'boat-tailed' Land Rover would come in between a Tesla Model S, and a Porsche Taycan Turbo. Much like Kamm's Cd 0.23 K-car of the 1930s.
6) Similar to Thomas Scott Breidenbach's GM full-size SUV, wind tunnel-tested boat-tail, which would quantitatively drop the Chevy Tahoe hybrid from Cd 0.34, to Cd 0.2414. A 98-count reduction. ( US Patent # 8590961, February 21, 2012 )
Only Ockham's Shaving Cream improves upon his Razor!
If only it were all as simple as sitting at a desk, typing and subtracting notional drag changes of appendages from a total! I guess it's nearly as much fun as overlaying a template and pretending that's the solution.
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Old 01-13-2021, 05:36 PM   #5 (permalink)
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Quote:
'Practicality' is a thread by itself, and we should have one, if there isn't already an existing one, buried somewhere.
I use 'use case'. One person's practicality is another's what-was-I-thinking.

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