Nissan Test Pics...

Discussion in 'Nissan' started by xcel, Dec 7, 2015.

  1. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi All:

    While waiting for the gallery and direct upload, I am just trying a few things from a Xenforo picture gallery.

    [​IMG]

    Wayne
     
  2. NeilBlanchard

    NeilBlanchard Well-Known Member

    Their design language is becoming cohesive. This is obviously not a new Leaf, but it seems to be a precursor.
     
    xcel likes this.
  3. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Neil:

    I really like this new direction as you can tell by the last few review write-ups and videos. I am actually hoping we see the IDS almost unchanged from the Tokyo show as the next gen LEAF as it incorporates much of Nissan's Energetic Flow Design Language.

    2017 Nissan IDS Concept

    [​IMG]
    [​IMG]
    [​IMG]

    My fingers are crossed and I hope yours are too! :D

    Wayne
     
  4. NeilBlanchard

    NeilBlanchard Well-Known Member

    If the IDS is the new Leaf, then it leaps from near the bottom to the top of the class. My fingers are definitely crossed.
     
    xcel likes this.
  5. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Neil, me too!

    Wayne
     
  6. Xcel-Test

    Xcel-Test New Member

    Hi All:

    Just checking to make sure I can upload a pic as a registered user.

    Murano Steady States Night Pic.jpg

    Wayne
     
  7. NeilBlanchard

    NeilBlanchard Well-Known Member

    xcel and BillLin like this.
  8. NeilBlanchard

    NeilBlanchard Well-Known Member

    kbergene, xcel and BillLin like this.
  9. Carcus

    Carcus Well-Known Member

    Looks like a more aerodynamic (lower, longer nose) Chevy Bolt.
     
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  10. NeilBlanchard

    NeilBlanchard Well-Known Member

    Actually, a lower longer nose is not as good for aero - a blunt short nose is better. The back of the car is where most of the drag is generated.

    A rendering based on these camouflaged cars:

    [​IMG]

    It seems accurate EXCEPT the trailing edge of the roof. It is similar to the above renderings, but better, I think.
     
    BillLin likes this.
  11. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    Neil , are you still building your car ? I haven't looked at ecomodder for a long time.
     
    BillLin likes this.
  12. BillLin

    BillLin PV solar, geothermal HVAC, hybrids and electrics

    5-door cars are starting to look the same to me, with the same basic shape. Height/width/length variations, but still basically the same shape that the Prius started. Okay, I don't know that Prius was the first, but you know what I mean... If they can figure out how to implement a front crush zone with a teardrop shape with rounded end up front, maybe we'll see that someday.

    I do like the new Leaf rendition. Good job Carscoops for doing the rendering. The "floating" roof is quite a familiar carryover from the first generation Leaf. (edit: oops on the last sentence; I don't remember where that floating design came from...) (edit2: might have been the BMW I3?...)
     
    Last edited: Mar 30, 2017
  13. Carcus

    Carcus Well-Known Member

    I'm not sure I'm buying that.

    If you look at the latest "aero intense" cars from Honda, GM, Toyota, and now (apparently) Nissan [Civic, Volt, Prius, Leaf(?)] .... they all have the same profile view of the nose --- long. Some "bluntness" or "angular" shapes are showing close to the corners, .. To get an "aero curtain" or "aero fender skirt" to help eliminate drag around (through) the front wheels/wells would be my guess.

    The "low" I was referencing was height of the car and ground clearance.

    /add,.. there's several things about the Bolt that seem to say GM doesn't really intend for it to be a long range highway machine. Also some evidence that the Bolt range takes a substantial (more than others) hit at higher speeds or less than ideal conditions, but I have yet to see a range vs mph chart on it.
     
    Last edited: Mar 30, 2017
  14. NeilBlanchard

    NeilBlanchard Well-Known Member

    Mercedes Bionic car, with a Cd of 0.19:

    [​IMG]
    [​IMG] This is an "ideal" aerodynamic profile overlaid on the Bionic (aka Boxfish) car.
    [​IMG]

    Also, the granddaddy of low drag cars - the Schlörwagen aka Pillbug, with a modern estimated Cd of 0.18 (Dr. Schlör in the picture estimated it at 0.13 back in that very early windtunnel):

    [​IMG]

    Please keep in mind that aero drag at speeds up to 250MPH are what I am talking about. Above that, a pointy nose is better.
     
    kbergene likes this.
  15. Carcus

    Carcus Well-Known Member

    There's a wind tunnel world, .. and then there's the real world.

    Put that boxfish out on the open highway at 70 mph on a windy day and see what happens. On the grandaddy, Nobody's going to build a production car with actual skirts on the front wheels.
     
    Last edited: Mar 30, 2017
  16. NeilBlanchard

    NeilBlanchard Well-Known Member

    Huh? Fluid dynamics are consistent. Those vehicles are low drag, and they have blunt noses. All vehicles at speeds under 250MPH have the same challenges in terms of aerodynamics.

    For crosswinds, we can add a tail fin to stabilize lateral air pressure - that is a separate discussion.
     
  17. Carcus

    Carcus Well-Known Member

    Do wind tunnels have adjustable crosswind components, .. or is the "wind" just from one specific direction (on the nose)? I think it's the latter.

    So if you designed a "single piece of plywood car", standing up tall with the skinny edge into the wind, it would have a very low drag in the wind tunnel. But start introducing some crosswind and all the force needed to keep it straight down the road, the 'drag' (or more accurately "power required") goes up significantly.


    So now if you take into account that crosswinds will eat up mpg. And crosswinds can vary significantly in the first few feet off the ground, then you can see how a "van shaped" or "high profile" vehicle (like the boxfish car) might show a very different real world mpg from a low slung (i.e. 1st gen Honda insight) even though the boxfish may have a better Cda. -- it's taking a " mpg robbing, crosswind double whammy" -- bigger profile AND taller.

    I use the term "durable" mpg. Cars with low profiles will have more "durable" mpg.... even though it may not show up in the wind tunnel.

    https://septiankmasdi.files.wordpress.com/2012/05/profil-kecepatan.gif


    ---------

    And ,.. how are you going to keep the drag out of the front wheel wells/wheels with a blunt nosed car, unless you are planning on using actual front fender skirts? I think I remember seeing a reference (maybe from ecomodder) that 1/3 of the drag is under the car, and the majority of that is from the front wheels.
     
    Last edited: Mar 31, 2017
  18. NeilBlanchard

    NeilBlanchard Well-Known Member

    You are conflating several issues - pointy noses don't help at normal vehicle speeds, and they have nothing to do with stability in crosswinds. And crosswind stability has doesn't change the Cd and therefore it doesn't affect the efficiency.

    A vertical sheet shape is a straw man argument. The height of a vehicle is unrelated to the Cd - and stability in crosswinds can be engineered for low or tall vehicles.

    Height to width has everything to do with the interior volume of a vehicle, and how practical it is. A lower Cd allows a larger vehicle be as efficient - or more efficient - than a smaller high drag vehicle.
     
  19. Carcus

    Carcus Well-Known Member

    I'm talking about more than one issue, but not conflating. ... and you didn't have a response to any of the issues I brought up. -- If anything, I would say you are "deflecting".

    Good luck with your car.

    (wind is a big deal)
    http://privatenrg.com/indexOldSite.html#NoWind
     
    Last edited: Apr 3, 2017
  20. NeilBlanchard

    NeilBlanchard Well-Known Member

    I responded directly to your points. If I was not clear, then I'd be happy to discuss it further.

    I am fully aware of issues with solar racers - I have a book about the aerodynamics of those type of vehicles, and how they have all-wheel active alignment that allow the vehicle to yaw into the wind as it moves down the road. Those are extreme cases.

    If you want high efficiency, you have to have low drag. And stability is a different goal than always maintaining super low drag.

    If you want a more practical space inside the vehicle, you need to be closer to square in the frontal area. The shape has to be determined by the air flow, and plan and profile taper means the best space for the people is forward and center. The thing that my CarBEN and the Schlörwagen, is the center driver. This adds safety (all else being equal) because the structure can protect the driver better there, vs the conventional side position.
     

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