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Does anyone know the owner of this Prius?

Discussion in 'Gen 3 Prius Fuel Economy' started by boywander, Feb 14, 2019.

  1. boywander

    boywander Junior Member

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  2. bisco

    bisco cookie crumbler

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    that would be me :oops:
     
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  3. boywander

    boywander Junior Member

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    I actually thought of it when I got Prius fever lol.
     
  4. davecook89t

    davecook89t Senior Member

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    Nice try at gaining some more respect, @bisco, but the car has a PA license plate. I'm not buying it.;)
     
  5. bisco

    bisco cookie crumbler

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  6. Pluggo

    Pluggo Senior Member

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    It looks a bit over-designed in the rear. They eliminated the Kamm-tail and threw away decades of aerodynamic theory. Here's an excerpt from Wikipedia at Kammback - Wikipedia The key here is that "cutting off the tail resulted in minimal increase in drag." Everyone does it now.

    "The ideal shape to minimize drag is a teardrop. However researchers including Kamm found that abruptly cutting off the tail resulted in minimal increase in drag.[3] The reason for this is that a turbulent wake region forms behind the vertical surface at the rear of the car. This wake region mimics the effect of the tapered tail in that air in the free stream does not enter this region (avoiding boundary layer separation), therefore smooth airflow is maintained which minimises drag.[9]

    Kamm's design is based on the tail being truncated at the point where the cross section area is 50% of the car's maximum cross section,[3][11] which Kamm found represented a good compromise—by that point the turbulence typical of flat-back vehicles had been mostly eliminated at typical speeds.

    The Kamm tail presented a partial solution to the problem of aerodynamic lift, which was becoming severe as sport car racing speeds increased during the 1950s. The design paradigm of sloping the tail to reduce drag, carried to an extreme on cars such as the Cunningham C5-R, resulted in an airfoil effect lifting the rear of the car at speed, that could result in instability or loss of control. The Kamm tail decreased the area of the lifting surface while creating a low pressure zone underneath the tail."
     
  7. El Dobro

    El Dobro A Member

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    Porsche tried it with their Langheck tail racers.
    [​IMG]
     
  8. boywander

    boywander Junior Member

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    I’m curious to know what’s mpg is the Prius is getting.
    Even though Pluggo wrote about Kamm’s aerodynamic theory, seeing it believing in case of the aerocivic. Imagine that..
     
  9. ALS

    ALS Active Member

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    I'd say with all those mods the owner probably hangs over on Ecomodder.com
     
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  10. Vman455

    Vman455 Senior Member

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    He or she isn't throwing away any aerodynamic theory; Kamm's design (actually invented by Koenig-Fachsenfeld for buses three years before Kamm published his first description of the design in 1939) was intended to maximize usable interior volume while minimizing drag, not to be the lowest-drag form possible at any cost. As Wolf-Heinrich Hucho described it in his monumental Aerodynamics of Road Vehicles:

    "In essence the result was as follows: Beginning at the maximum cross-section, the downstream contours of the body are carefully tapered so as to keep the flow attached. This produces a steady increase of static pressure in the flow direction. Just ahead of the location where the flow would want to separate, the body is truncated vertically, resulting in a plane base whose cross-section is small in comparison to the frontal area. The wake behind the vehicle is narrow, and negative static pressure on the flat base is moderate due to the upstream pressure recovery. Both contribute to low drag. Looking at Fig. 1.34 the advantages of this so-called "Kamm-back" (or in an often used abbreviation, K-back) becomes evident at once. In comparison to the shape of Lay, the headroom in the rear is far higher; compared to the contour of Klemperer, a good part of the length is saved" (Hucho, W-H. Aerodynamics of Road Vehicles, 4th ed. Warrendale: Society of Automotive Engineers, Inc., 1998, 29).

    Kamm's designs were still high drag by modern standards. He estimated his K3 (1939) at Cd .24, but testing the car (which still exists) in the VW wind tunnel in the 1980s indicated its actual drag coefficient is .37. The ideal length:depth ratio for low drag is somewhere around 4:1 to 5:1, much longer than K-form cars; this is evident when you look at low drag production and concept cars:

    [​IMG]
    Mercedes C111 III, 1977: Cd .18

    [​IMG]
    Volkswagen XL1, 2014: Cd .189

    [​IMG]
    GM Aero 2002, 1983: Cd .14

    [​IMG]
    Ford Probe V, 1985: Cd .137

    [​IMG]
    Mercedes-Benz Concept IAA, 2015: Cd .19 (tail extended)

    It's really, really hard--if not impossible--to get Cd numbers like that without a long, tapered tail.
     
  11. Zeppo Shanski

    Zeppo Shanski Active Member

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    One of my favorite cars ... it's original model to the U.S.. ... In addition to its hybrid drive system, the Insight was small, light and streamlined — with a drag-coefficient of 0.25. At the time of production, it was the most aerodynamic production car, ever.

    HondaInsight.jpg Honda_Insight_Back.jpg
     
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  12. KennyGS

    KennyGS Senior Member

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    I agree, and always compliment the owner when I have an opportunity. (y)
     
  13. orenji

    orenji Senior Member

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    I had one for a few years. Liked it but kept have smog equipment failures.
     
  14. KennyGS

    KennyGS Senior Member

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    What was the issue?
     
  15. DLC82SV

    DLC82SV Member

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  16. orenji

    orenji Senior Member

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    Smog senors would fail. Honda always covered the repair, but if I had to pay it was like $800.00. So that was the reason I sold it.

    Original Honda Insight.
     
    #17 orenji, Mar 2, 2019
    Last edited by a moderator: Apr 9, 2019
  17. Judgmental Kitty

    Judgmental Kitty New Member

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  18. ALS

    ALS Active Member

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    Someone asked on a board if you were to convert a car to a hybid what would you use. Well if I was under six foot tall I would choose a SAAB Sonett III. It had a .32Cd and weighed in around 1900 Lb's. The reason I said IF I was under six foot tall is this car is tiny.

    Saab_Sonett_III_1.jpg
     
  19. Prodigyplace

    Prodigyplace Senior Member

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    How about a fiberglass bodies Bricklin SV-1?

    [​IMG]