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Outward drifting vehicles gradually reach a lower speed while drifting

Discussion in 'General Discussion' started by Mister Wu, Jul 4, 2016.

  1. Mister Wu

    Mister Wu

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    Just a small thing I noticed while I was testing the angular velocity of outward and inward drifting vehicles, mostly relevant for the 200cc class.


    When looking at the trails left by the wheels in the icy part of GCN Sherbet Land, it can be noticed that outward drifting vehicles form a spiraling trail that gradually narrows until it becomes a circle, while inward drifting vehicles form a circle, with a little indentation in the point where the Super Mini-Turbo is charged.


    To understand what the origin of the spiraling trail was, the angular velocity while the trail was still a spiral was measured. The reason is simple: when going in a circular path, the radius of curvature, r, can be expressed as v / ω, where ω is the angular velocity while v is the speed of the vehicle. If a spiral trail whose radius decreases over time is formed, it means that either angular velocity is increasing or the speed of the vehicle is decreasing.
    The test is the following:


    And as a reference point a small polygonal shape in the ice was used:
    D2.jpg
    In this image the shape used as reference is right behind the rear wheel.

    The resulting time needed to reach that shape again was measured in four consecutive circles, the first one starting from the first time the shape was met, on frame 5492 of the video. Here are the measured times:

    1st circle: 245 frames
    2nd circle: 245 frames
    3rd circle: 246 frames
    4th circle: 245 frames

    Therefore, the angular velocity isn't significantly affected, meaning that the reason why the the spiraling trails are formed is that outward drifting vehicles gradually reach a lower speed while drifting.
    It's important to point out that this doesn't happen with inward drifting bikes, meaning that they don't gradually reach a lower speed while drifting. Indeed, angular velocity was measured also in the case of inward drifting bikes using as refrence point the frame where the ice tower on the left of the ice arc disappeared.
    DRef2.png
    The reference point for inward drifting bikes.

    The resulting time needed to reach that reference point was measured in four consecutive circles, the first one being measured from the first time the reference point was met, on frame 13342 of the video (shown above to illustrate the reference point). Here are the measured times:

    1st circle: 263 frames
    2nd circle: 262 frames
    3rd circle: 263 frames
    4th circle: 263 frames

    Therefore, angular velocity doesn't change with time also with inward drifting vehicles. Since the trails left by the wheels form circles, the radius of curvature doesn't change as well and as a consequence, the speed of the bikes stays constant when they drift.

    Finally, a last interesting aspect was studied: what happens when the outward drifting vehicles start drifting with a speed lower than the lowest speed reached when drifting? This video clarifies what happens:


    Simply put, the outward drifting vehicle gradually accelerates until it reaches this lowest speed while drifting, meaning that this lowest speed acts as an asymptote and makes the vehicle reach a lower top speed than the one it would reach if it was going straight and it was not drifting.

    So, as take-home message, outward drifting vehicles gradually reach a lower speed while drifting, while inward drifting bikes maintain their speed while drifting.
    Furthermore, this lower speed while drifting acts as top speed for the vehicles that are drifting while still accelerating, causing them to reach a lower top speed than the one they would reach if they were going straight and weren't drifting.
     
    Sarantis and SuperNardful like this.
  2. Sarantis

    Sarantis

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    Awesome! I'm glad Indrift bikes have AT LEAST a minor advantage over outdrift vehicles when it comes to speed, speed boosts, etc.!
     
  3. Plexy

    Plexy

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    Bumping old thread...

    Anyways, can softdrifting prevent this in any way? Seems possible because it allows you to start a drift faster, so you should be able to lose less speed.
     
  4. Mister Wu

    Mister Wu

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    Thanks for the interest!
    You can see the GamePad D-Pad softdrifting case at 2:18 in the second video ("MK8 - A possible explanation for the spiral trails when using outward drifting vehicles"). The spiral trail is still present, although the effect is less pronounced. This apparently indicates that with outward drifting vehicles, the speed reached while drifting for long times depends on how sharp the drift is - the sharper the drift, the lower the speed reached.

    If we consider this loss of speed alone, with oD vehicles one should release the Mini-Turbo/Super Mini Turbo as soon as possible so that the drift lasts as little as possible and not much speed is lost. Softdrifting would help in this as well, as the MT is charged with the same speed as the sharpest drifts, allowing to release the MT and SMT sooner.

    So, as a tl;dr, with oD vehicles softdrifting makes this effect less pronounced and even allows a faster release of MTs and SMTs without enforcing sharp drifts, but doesn't prevent it completely - it's always there unless an iD bike is used.

    An interesting consequence, though: when accelerating with an oD vehicle, softdrifting is definitely recommended as it leads to a less penalizing lower speed while drifting, which acts pretty much as a speed cap for the vehicle that is drifting while still accelerating.
     
    Plexy likes this.
  5. Plexy

    Plexy

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    Interesting. Thanks for clarifying.:)
     
  6. Rhodechill2

    Rhodechill2

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    How long tdo they ave to drift before losing speed? Lie, how long is it safe to hold a SMT/MT in time trial?



    What ice tower/ice arc?
     
  7. Mister Wu

    Mister Wu

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    Thanks for the question, I made some additional experiments about the speed loss while drifting and here are the results in % of top speed (D-Pad softdrifts are softdrifts in the direction of the turn with up and the direction of the turn on the GamePad's D-Pad, in this case mostly right):
    {EDIT: I had to remake the experiemnts, as the 3% to 4% speed loss, which is a 5% to 7% speed loss when considring the actual speed at which I was testing, is the speed loss of the Mushroom Boost which i was using to start the dirfts, I found another method to start them that doesn't have such a huge speed loss)

    NEUTRAL AND WIDENED DRIFTS: 0 to 2% of top speed, the method I'm using makes it very difficult to precisely determine this amount, but it seems always greater than 0%
    D-PAD SOFTDRIFTS with iD bikes: 1.27% which is actually 2% of top speed, reached around 8 seconds after sharpening the drift
    SHARPEST DRIFTS WITH iD BIKES: 4.93%, which is actually 8% of top speed, reached around 8 seconds after sharpening the drift
    D-PAD SOFTDRIFTS with oD BIKES (and oD vehicles in general, as you can see above): 1.86%, which is actually 3% of top speed, reached around 9 seconds after sharpening the drift
    SHARPEST DRIFTS WITH oD BIKES: 7.44%, which is actually 12% of top speed, reached around 14 seconds after sharpening the drift

    Essentially, softdrifting has a modest speed loss when compared to the sharpest drifting, which has around 4 times the speed loss. Inward drifting bikes are effectively faster when drifting in both conditions, with a 1% of top speed advantage while softdrifting that becomes a 4% advantage when drifting sharply. Surprisingly, when starting from a wide drift, even inward drifting bikes reach the lower speed slowly, although apparently not as slowly as oD vehicles.
    The arc is the one in the screenshot above, the ice towers are those tall ice buildings that can be seen also on the left of this arc when using the screenshot above as reference point (I was drifting toward the right).
     
    Last edited: Apr 25, 2017 at 2:09 AM
  8. Mister Wu

    Mister Wu

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    Sorry for double posting, but I had discovered that the method I used was flawed and couldn't determine the actual speed loss while softdrifting. I therefore measured that and the speed loss while drifting sharply with higher precision, reaching slightly different conclusions, although iD bikes are still faster when drifting.
     

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