Three-wheelers.... the way of the future?

Discussion in 'Polaris Slingshot vs The Competition' started by voyager, May 23, 2016.

  1. voyager

    voyager Member

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    I think we drifted away from the subject, which is about three- or semi three-wheelers... Not offroad 4WD.
     
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  2. Blitzkrieg

    Blitzkrieg Well-Known Member

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    No drift. My points are pertinent.

    The SS doesn't need complicated sway technology, it does fine as is. ;-)

    Sometimes simpler is better. That's my point.
     
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  3. voyager

    voyager Member

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    Btw... does the Slingshot use Ackermann steering?
    Means that the front wheels have a different turn-in radius to have a matching imaginary center point.
    I suppose it does.
    And is the so-called Ackermann point located where the rear wheel is?
    Below Ackermann is indicated for a standard four-wheel car.
    Principles are the same.

    [​IMG][​IMG]
     
    Last edited: Jun 7, 2016
  4. voyager

    voyager Member

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    ... Exaggerated, this is what you get, using Ackermann with co-steering rear wheels, so rear-wheels that steer up to a certain degree in the same direction as the front wheels. Lateral (or centrifugal) forces, that would make a narrow vehicle roll over, are reduced, since the vehicle 'vectors' into the bend. But you do get a sense of 'siding' or sliding sideways into the bend... I guess actual tests with a demo vehicle have to determine how that really feels...

    Below you see the narrow vehicle changing direction not by heading into the bend. The benefit is that the vehicle does not get out of balance that easily... Less roll.

    [​IMG]
     
    Last edited: Jun 7, 2016
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  5. WI_Hedgehog

    WI_Hedgehog Winner of the "Most Factory Defects" award Staff Member Moderator

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    Above is kind of a reverse-slide, pretty unsettling, like you're going to be carried over the edge of the curve. What a fun-house ride for the passenger, annoying for the driver since they have their view of left-hand turns blocked by the A-pillar.

    With the Toyota i-Ride it's a true sliding feeling as the rear wheel steers and actually hangs the corner wide; another odd thing is having to steer in advance to activate the tilt system and electronically controlled rear steering. Not quite as fun for the passenger, as they're forced into that "happy bunny" position if they're over 4' tall.

    [​IMG]
    Depiction of standard driver/passenger seating positions
     
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  6. voyager

    voyager Member

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    Good point... about the A-pillar. All depends on where the A-pillar is located. I know the Toyota i-Road. Point is that you need to have a really narrow vehicle, which forces you to use tandem-seating. A let's call it not-so-narrow vehicle, like the one I suggested, will hit the road surface if it tilts the way the i-Road does.

    Regarding the unsettling feeling of 'sliding the bends', I guess that it all depends on the degree of co-steering of the rear-wheels. Engineering firm ZF (TRW) recommends 5 degree. The Porsche 911 uses 3 degree. I'll check what Honda and Renault are using.

    Btw, a counter-steering rear-wheel like on the i-Road is reportedly only feasible at lower speeds, and probably only with smaller wheelbase vehicles. It forces the i-Road into tilting position. Counter-steering my vehicle is a no-no, since it would induce roll-over (without proper tilt).
     
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  7. voyager

    voyager Member

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    It will need getting used to... Less thrown from side to side as a passenger when taking the twisties.
    Instead, a bit more slide into the bends....

    [​IMG]


    If you use what's called 'crab steer' (all wheels pointing in the same direction), the body tends to move almost not at all, like you see below.
    [​IMG]
     
    Last edited: Jun 7, 2016
  8. WI_Hedgehog

    WI_Hedgehog Winner of the "Most Factory Defects" award Staff Member Moderator

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    Yeah, I can imagine how well that works with a left-hand sweeper.

    The concern with "unique" steering is it tends to be idealized as above, when in reality all sorts of crazy sh!t happens that is in no way approximated by the model.

    You're thinking this:
    sign1.png

    But what you have is this:
    sign2.png

    And I'm driving like:
    sign3.jpg
     
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  9. voyager

    voyager Member

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    Food for thought: three-wheelers vs stock market darling Tesla... However, the 'commuter' three-wheeler, as Paul Elio sees it, can do better... Replace the car on most runs? Mind you, the SS stands on its own, as a fun piece of kit.

    [​IMG]
     
  10. WI_Hedgehog

    WI_Hedgehog Winner of the "Most Factory Defects" award Staff Member Moderator

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    @voyager, where are you trying to go with that? Both Tesla and Elio are better at failing than anyone else from the respect they keep doing it successfully with few if any consequences. Tesla finally produced a product, we have to wonder if by accident.

    Polaris hit a homer at first bat. (Or at least a triple given a few of us have major problems that many more are starting to experience.)

    The difference is Tesla and Elio promise a revolutionary product that will save the planet while being more convenient than anything currently available. Polaris makes a cheap concept vehicle and sold it for a steal (although longevity and the parts supply chain were unknowns for consumers taking the risk). They promise nothing and deliver tons of awesome, until it breaks, then they fix it (in two weeks from tomorrow). Huge lesson car companies forgot.

    And let's not forget Polaris has been under constant pressure from different levels of government who outlawed the vehicle. Somehow they managed to convince appointed burocrats they should let this sneak under the radar. :-$

    The Slingshot works because people can't stop looking at it. It looks fun. The owner looks like they're having fun. Everything about the vehicle exudes fun. That's a huge part of what makes it a success, regardless of any shortcomings.
     
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  11. voyager

    voyager Member

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    LIke I wrote, the SS stands on its own as a fun piece of serious kit.
    The whole thread was about three-wheelers in a far more ambitious role: a fun vehicle you'd actually prefer to do all your trips with, as long as you don't need to carry more than two passengers... Just testing the waters, nothing amphibious meant...;)
     
    Last edited: Jun 14, 2016
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  12. James McKinney

    James McKinney Well-Known Member

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    @WI_Hedgehog brother you nailed it. When they first introduced the drawings of the SL I knew I had to have one. I plopped down that $1000 deposit and waited 6 months before mine was delivered. Everyone in this forum bitched and moaned about the wait but it was worth the wait plus some. I love my Sl (the red fast one) and appreciate what Polaris has done to keep us rolling. Just my opinion, but in my case that is all that matters anyway duchess.png .
     
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