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About hyperair

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  • Birthday 10/15/1990

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    Gotway MCM with Microworks internals, Inmotion V5F, Inmotion V8, Rockwheel GT16

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  1. Nah, actually I quite like it like this. In the default configuration, the pedal scrapes against the case and leaves a lot of grit and sand on it when folded. The magnets in this setup keep the pedal from hitting the case so that no longer happens. Also I used two magnets on each side because one wasn't strong enough.
  2. @Chriull That's a really nice animation. Could you share the OpenSCAD code please?
  3. I had a similar issue where my V8 was stuck in deep tiltback mode after exhausting the battery and recharging to full. Power cycling it that way solved the issue.
  4. Update: turns out the Gotway pedals had magnets in them, so I stuck a pair of neodynium magnets onto the case with gorilla tape. Works really well.
  5. Try power cycling it -- unplug the battery (yellow XT60 connector and 5- or 7-pin JST SM wire connector), wait a few seconds for the green light on the controller to fade, and plug the battery back in.
  6. Some wheels (including most newer King Song wheels) have a diode somewhere along the charging circuit for safety, so you won't be able to probe the voltage of the battery pack through the charging port unless the charger is connected. The benefit from this is that you can no longer blow out the charging port from dropping a metal object into it. TL;DR: Yes, your theory stands true.
  7. Hi, I recently bought a second-hand GT16 and noticed some weirdness with the odometer -- it never gets out of the 700+km range, and seems to glitch randomly within that range. I've attached a graph of totaldistance vs time as captured by WheelLog. I thought this might be a bug in WheelLog's handling of the Rockwheel bluetooth protocol at first, but it looks like the stock GT16 app shows the same value. Has anyone else noticed something similar?
  8. Thanks @Chriull. Just to make it obvious that there's no identity theft going on here, @Chow Loong Jin is me.
  9. I just got mine recently too. They came with Gotway pedals on them, installed by the previous owner. They need to be shimmed (mine had a metal shim epoxied onto the pedal block) to fit though, so you can't simply swap them back to the original GT16 pedals after. They feel very nice and wide, but they scrape against the shell and getting them to stay folded while I'm pushing it around by the trolley handle is annoying (they sort of flop open to 30 degrees).
  10. I haven't actually tried this, but I am quite interested in finding a viable solution to do this that doesn't make me more likely to clip my pedals on something. This was a theory that I came up with while trying to work out the physics for this sometime back. I didn't actually manage to confirm this -- this was my estimation based on how the batteries are mounted, and also the fact that the GT16 stock pedals are much heavier than anything else I've held (700g from my vague memory). The GT16 is also a really zippy wheel, feeling about as zippy as the V8 despite being ~20kg with the trolley handle compared to the ~15kg of the V8, and much zippier than the V10 which is of similar weight and wheel diameter. I attribute this to V8's high CG (battery above motor) and the V10's even higher CG (both the larger battery as well as the heavy extended handle) as well. Oh yeah you're right, whoops. I haven't actually worked through the math for how the angle change works yet, but I suspect that the angle at which force is applied gets closer to the tangential direction once the wheel starts accelerating, due to the positive feedback loop I mentioned earlier.
  11. I think what you actually feel can be boiled down to "I've leaned this much, but the wheel isn't responding", and this happens in two ways: the pedal dips forward (motor can't match the rider's torque), or the rider falls off the front of the wheel, e.g. when a lightweight rider rides a Monster. In the first case, your wheel can't keep up with your body. This is an overlean where you've gone beyond your wheel's torque margin, causing the motor to lose the "push of war" against you on the EUC body, causing the EUC body to tilt forwards. If you arch your back to take your CG offline from the vector that your wheel is pushing you, and keep the pressure on your toes, you can occasionally recover from this, especially if you approached the torque limit slowly, so you have time to react. In the second case, you haven't managed to request the correct amount of torque from the motor. It's like standing straight up (as opposed to bracing yourself properly against the ground), and trying to push a heavy rock. The rock doesn't budge, but you've pushed yourself backwards. In this case, the pedals feel rock-solid, but you've fallen off the front of your wheel. But this doesn't only depend on the weight of the wheel. A few other things matter as well, like you realized -- if your pedal arms are shorter, it pushes against you harder. Then there's also the balance of the EUC body/placement of its centre of mass: EUC body CG above the axle (e.g. Inmotion V5, V8, V10): Creates a negative feedback loop where an accelerating wheel causes the EUC body's CG to pull back and resist the rider's torque on the EUC body, like a seesaw. EUC body CG below the axle (e.g. Rockwheel GT16): Creates a positive feedback loop where an accelerating wheel assists the rider in torqueing the EUC body forward. EUC body CG in front of the axle: Biases the wheel towards accelerating EUC body CG behind the axle (Gotway Monster): Biases the wheel towards braking/reversing Then there's also the rotational inertia of the hub motor's rotor -- it's basically a flywheel with significant mass and radius, so you need some amount of torque to change its angular velocity as well. So an interesting, low-effort mod to make to make your wheel feel snappier would be to stick weights below your pedals, or use heavier pedals. You're right about it being quite degenerate. A wheel without a rider is an inverted pendulum. The rider is an external body that manipulates the pendulum to control the wheel. And if the rider fails to manipulate the pendulum, then the pendulum just does whatever it wants but the rider falls off.
  12. The wheel isn't weightless. The equation is closer to F = (M + m) * a1, where M is the mass of the wheel, and m is the mass of the child. 10x heavier rider would convey 10x torque, causing 10x linear force, i.e. 10F = (M + 10m) * a2. Substitute in a sufficiently large value of M (Gotway Monster, 32kg), and you'll realize that a2 is larger than a1: The actual equations are a lot more complicated than this, but riders of a different mass don't get the same amount of acceleration from the same amount of lean on the same wheel.
  13. I think it's more accurate to think of the wheel's balancing in terms of torque, rather than CG -- you can stick your CG past the front of your wheel but simply fall off if you don't manage to push down the front of the wheel down hard enough to make it accelerate to catch you. The EUC senses its own orientation, not yours. The EUC body is rigidly coupled to the pedals. In order for pedals to remain level, the body must remain upright. When you lean forward on the wheel, you torque the body of the EUC forwards, either by leaning on the pedals, or pushing the top of the wheel forward with your knees. In order for the EUC body to remain upright, the motor must exert an equal and opposite torque to the body of the EUC. If the motor's torque is less than the torque the rider is providing, then the pedals dip forwards. If the motor's torque is more than the torque the rider is providing, then the pedals tilt backwards. WIth the understanding that the rider torque must be equal to the motor torque to maintain balance, and that torque is tangential force multiplied by the lever arm, a few things start to stand out: Larger pedal clearances decrease the distance from pedal to axle, so you convey less torque to your wheel for a given amount of "lean". Conversely, the wheel pushes back harder, giving the feeling of a stiffer pedal. Larger wheel diameters increase the torque required to induce the same linear acceleration, so you need to push harder to make a larger wheel accelerate in the same way Powerpads or cushions with sufficient friction allow you to use your knees to convey torque to the EUC body, allowing you to lean harder without falling off Now, it's possible for a large, powerful wheel to feel sluggish to a light rider -- the feeling of it is similar to standing on the edge of a step, and then leaning forwards and pushing back with your toes. You'll end up propelling yourself forward just like when starting a sprint, but the platform doesn't budge. If you cause your own body to accelerate faster than the wheel accelerates, then you'll end up separating from your wheel and you will faceplant. However, this only holds as long as the wheel's linear acceleration is 0 (i.e. the wheel hasn't begun accelerating yet). If you start the acceleration more gently, i.e. you focus your weight on the front of the pedal, then just brace yourself against the pedal as the wheel starts to accelerate (like when standing on an accelerating train facing the rdirection of travel), then the accelerating wheel will push the pedal further into your feet, causing a positive feedback loop where the wheel's own acceleration increases the torque that the rider is exerting on the wheel. This is why a lightweight rider may feel like there's a "delay" in power delivery in a larger wheel, or that a larger wheel feels "sluggish" (the opposite of the very snappy feeling of the IPS i5). Until you enter the positive feedback loop, you only have your weight against the frontmost part of the pedal to exert the torque on the wheel body and begin the acceleration.
  14. For what it's worth, I have a V8 at 9197km mileage, and it hasn't shown the bucking problem. What it has shown, though, is a brief forward pedal dip when I accidentally push it too hard at <60% battery (overlean), which is recoverable if you pull back immediatey.
  15. I dunno, I seem to recall conceding this point a few posts up, but you seem oddly hung up on dismissing everything I'm saying based on this one point alone. @EUC Extreme is extreme, but he's also human, like the rest of us. These are techniques and preparations that are possible for humans to execute with some training. And even if we can't execute his techniques perfectly, even getting it halfway gets you some results. Did you even watch the video? They spent a lot of time sliding on their backsides, elbows, knees, and I don't know, everything not covered by gloves. If the pucks are only on their gloves, I really don't see how that counts as sliding on pucks. Many of them weren't even geared up beyond casual clothes and pucked gloves. I'll also point out that slippery smooth asphalt is the condition I was riding on. Eh, suit yourself. I shared data from my most recent crash on the thread because I thought it was relevant to a thread about... you know, proper safe riding postures and falling techniques. Looks like it's not welcome and people should just focus on gearing up aggressively instead, so I'll just shut up now.
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