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Cybertruck is NOT aerodynamically efficient - why the shape?

Discussion in 'Cybertruck: Interior & Exterior' started by Doc Brown, Nov 22, 2019.

  1. Doc Brown

    Doc Brown Member

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    The Cybertruck is not aerodynamic. It's just not. Hard corner surfaces aren't good for aerodynamics.

    I just don't see how this design s revolutionary. Sure - it's different (futuristic?) - from, from an efficiency perspective - I think it's poorly designed. It seems to me that Tesla's pitch has been about making cars more efficient, getting better range, saving the planet . . . . This truck doesn't move Tesla towards that goal.

    Can those that think this car is aerodynamically "efficient" please explain how? A teardrop is the most efficient, with a cube being the least. That's why cars look the way they do - as everyone tries to better mileage (efficiency), they continue to work towards a more aerodynamic shape (as long as they can still sell cars).

    [​IMG]

    Read about aerodynamic efficiency in car design and then discuss.

    The Future of Automotive Aerodynamics

    Air Resistance: The Invisible Enemy in Vehicle Design
     
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  2. omgwtfbyobbq

    omgwtfbyobbq Active Member

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    Sharp corners matter insofar as they diverge from the optimal fineness ratio for a given shape.

    For the cybertruck, it looks like Tesla's doing a good job with the aero because they're maintaining the fineness ratio of a streamlined body in air from the highest point of the truck to the back of it and also doing something similar on the sides/bottom.

    Obviously extending the back completely with a full boat tail would be better for aero, but not the best for looks and functionality.

     
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  3. Eno Deb

    Eno Deb Active Member

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    It's difficult to judge just from looking at it, but with the bed cover closed, it approximates what's called a "streamlined half-body" in your diagram. I doubt it's that bad.

    BTW, what kills aerodynamics in regular pickup trucks is primarily the open bed.
     
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  4. Ace Treadmore

    Ace Treadmore Member

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    *OP pulls claim out of ass and will be proven incorrect in short order via official stats from Tesla

     
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  5. Doc Brown

    Doc Brown Member

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    Thanks for the thoughtful reply. The reality is that faceted surfaces are terrible for aerodynamic efficiency. Do you know why the F-117 Nighthawk is faceted? Because, at the time, we couldn't figure out how else to reduce radar profile of more efficient aerodynamic surfaces. The F-117 was (and is) an "unstable" aircraft because of its shape.

    But whatever - it's a Tesla . . .
     
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  6. omgwtfbyobbq

    omgwtfbyobbq Active Member

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    If the cybertruck ever approaches mach 1, then yeah, the faceted surfaces would be an issue.

    At low speeds, whatever matters the most for most vehicles is pressure drag as the radii diverge from the optimal fineness ratio. Tesla did a good job minimizing that with the truck, just like they have with their other vehicles.
     
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  7. MacGreiner

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    The Motortrend report sheds some light on this:
    " Tesla might have erased the problem with active suction to bend the boundary-layer downward just aft of that peak. Gordon Murray's McLaren F1 used this trick, and SpaceX has plenty of expertise in active measures to manipulate airflow around its re-entering Falcon 9 first stages. However, with the bed cover deployed, the angle of its vast descending surface is evidently shallow enough for the flow to naturally reattach. The benefit being that it harvests a useful fraction of the air pressure that blocky, open-bed trucks almost entirely forfeit. Actually, the tougher aerodynamic trick has been coaxing the temperamental flow around those sharp A-pillars."
     
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  8. Ostrichsak

    Ostrichsak Active Member

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    I've been trying to explain fluid dynamics to people since last night. People keep saying it looks like that because it's the most aerodynamic pickup they could make. Uhm... no. It's not. It's just simply not. It was done to achieve a specific design characteristic and could easily be changed slightly to not only look better IMO but also to achieve a better coefficient of drag.
     
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  9. iconoclast

    iconoclast Member

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    So... if we're willing to sacrifice a little aerodynamic efficiency we could get something with the "performance of a Porsche" that also has a reduced radar profile? I can now justify redirecting some of my annual speeding-ticket budget toward paying for this thing!
     
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  10. corduroy

    corduroy Member

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    After seeing how the tonneau cover rolls back under the cab and rolls out when closed to create the "vault", that has to be a major reason why the truck has it's shape. Also now that we know there will be a solar roof option, that huge flat space makes total sense for the design.
     
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  11. jelloslug

    jelloslug Active Member

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    You need to forward this ASAP to the Engineering department at Tesla and CC Elon. I don't think they have seen this. In fact, you should offer your engineering expertise.
     
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  12. Reeler

    Reeler Decade of Pure EV Driving

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    Did they give stats on the aerodynamics? Shoving a brick through the wind is bound to be bad.
     
  13. Ostrichsak

    Ostrichsak Active Member

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    Say what will but he's not wrong.
     
  14. omgwtfbyobbq

    omgwtfbyobbq Active Member

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    Tesla can go full boat tail to maximize aerodynamics, but the truck would be too long for most parking spaces, probably less functional, and I imagine less appealing. I think Tesla did a good job optimizing everything.
     
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  15. WarpedOne

    WarpedOne Supreme Premier

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    Yes, 500 miles of EPA range bad ...
     
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  16. garrett5688

    garrett5688 Member

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    There will soon be a time that no one cares about efficiency and aerodynamics because energy is cheap, plentiful, and renewable. So make it whatever shape you want.
     
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  17. electracity

    electracity Banned

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    Musk probably didn't show the final design. The original solar roof turned out to be impractical The current solar roof, which probably will be sold, is a dumbed down version of the original.

    The Cybertruck doesn't handle like a Porsche of have a 500 mile range because it's a prototype with undoubtedly many unsolved problems.
     
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  18. omgwtfbyobbq

    omgwtfbyobbq Active Member

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  19. DanCar

    DanCar Active Member

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    Tesla decided that low cost manufacturing, not having expensive stamping equipment, having straight panels, was more important than the benefit of additional aero sleekness.
     
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  20. scottf200

    scottf200 Active Member

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    Does it also line up with the characteristic of the metal being used as well as the glass being used? ie. do either of their strength characteristics go down when in a different shape. -- maybe your right and both have to do with manufacturing.
     

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