Aerodynamic streamline template - online tool (view streamlined extension on any car)

[aerohead]

Originally Posted by Vekke

Why arent this or the other clearer templates pictures in use on the template tool?

The architecture of the 'template' is a function of ground clearance,and exactly where the location of the roof apex occurs.It's completely based upon ground reflection.
Without this context,the 'template' is useless.
Use of the 'template' as presented, prevents any confusion about it's methodology.

[aerohead]

Sorry for not linking, but surfing the web I came across this UFO:
Carlisle ARINC 791 SATCOM

[Vekke]

Tool uses the old template could somebody update the AST-II version of the template to the tool.

[aerohead]

Originally Posted by Vekke

Tool uses the old template could somebody update the AST-II version of the template to the tool.

I'd help if I could, but I've never had anything to do with creating this thread.

[dremd]

Do any of you guys have thoughts on how to use the template regarding Tesla model X fixed rear spoiler? I am considering building a hitch mounted cargo box/ boat tail. Does the spoiler stick out into airflow above template, or does it define part of the template? I kinda want it to define the template so I get additional height inside the storage box/ boat tail. Completely planning on blocking tail lights and license plate just run trailer lights and secondary license plate bracket. Good news about stuff like this is on a Model X is I’m unlikely to make it any uglier.

[freebeard]

The template is a generic solution and your Model X is a specific case. It lacks the semicircular cross section the template wants.

I'd start with Mair.

[aerohead]

here's my 'two-cents' :
1) While all streamlined profiles originate from bodies of revolution, their performance is NOT strictly limited to bodies of 'circular' cross-section.
2) Streamline profiles simply provide a super-velocity deceleration ramp, free of any adverse pressure gradient, which, if otherwise present, would trigger premature flow separation, and attendant higher pressure drag.
3) The AST-III ought to perform satisfactorily for the Model X, as it's original pop-up, three-position, rear deck spoiler's tearing edge appears to intersect the imaginary contour defined by the AST-III.
4) This is true of all Tesla passenger cars, especially the generation- II Roadster.
5) Following Franz von Holzhausen's development of the Model X rear slope, one observes three 'contours' with each following contour correcting aerodynamic 'sins' of it's preceding contour.
6) The backlight 'droops' to 24-degrees, which for a 40.7% roofline, well exceeds W. A. Mair's 22-degree downslope angle maximum recommendation.
7) Aside from all US NAVY torpedoes respecting Mair's 22-degrees, one also observes that all PGA & WPGA regulation golf balls happen to demonstrate flow separation at, or very-near 22-degrees slope angle, beyond which the boundary layer throws in the towel and leaves town.
8) The Von Mises inflexion sculpted into the Model X's deck relaxes the 24-degrees, down to 19-degrees.
9) The tearing edge of the pop-up spoiler further relaxes the 19-degree departure angle of the deck down to 12-degrees, which happens to coincide with the imaginary contour of the AST-III.
10) A fully-streamlined Model X would be 294-inches in length, vs 197- inches.
11) A 24" tail extension affixed to cargo platform would net a 221-" body length.
12) Rendering a fineness-ratio of 3.31969.
13) This is MORE 'slender' than:
* IONIQ 6, Cd 0.21
* Tesla Model S Plaid, Cd 0.208
* Lucid Air, Cd 0.20
* Mercedes-Benz EQS, Cd 0.20
* Rovomobil CAD, Cd 0.196
* VW XL1, Cd 0.189
* Lightyear 0, Cd 0.175
14) The 'elongated' Model X's ultimate Cd would be contingent upon plan-taper, and diffuser geometry, however, it would reside within Cd 0.21, to Cd 0.175 territory.
15) Aero wheels would enhance the boat-tails' performance.
16) Rear skirts would also enhance the tail's performance [ Lightyear's partial rear skirts provide a Cd 0.0033 ( 1.9% ) drag reduction, and additional 15-km range ]
Full rear skirts on the SAAB 9.3 sedan generated a Cd 0.016 ( 6.42% ) drag reduction.