Jmac Posted February 26 Share Posted February 26 I was probably 12 mph riding up a bit slight grade damp pavement. Hit a tiny bump and the EUC took off straight up the road. Hot a curb 15 yd away probably 20 mph. Fortunately in flinging backward both elbows and both palms hit the payment simultaneously and all I have is scratches and bruised palms. And uninjured I was able to watch it try to destroy itself across the street. No direction change. Even pressure left and right feet in a word symmetric and stable riding before I was ejected. So I figure the combination of slight bump + wet pavement + engineering which probably looks to deliver torque demanded by my foot angle (in motor design and in programming) .. then upon descending the bump, rubber friction on damp pavement was reduced, revs increased in spinout, then when traction was quickly restored under my full weight, KS accelerated consuming the added energy of the faster wheel revs. My mass didn't accelerate with the KS and there I am flat on my back. It all happened so fast. It's been difficult to figure out but very important to me so that I can continue to enjoy and not ride a mystery machine 1) Is there a fault in my analysis? 2) why did the KS continue to accelerate into its high-speed crash? 3) it seems this is more likely when there is higher torque demand, like like up a grade. 4) I think I am appropriately nervous about wet pavement. 5) I need to constantly keep my knees slightly bent. I may have been stiff-legged. . 2 1 Quote Link to comment Share on other sites More sharing options...
Chriull Posted February 26 Share Posted February 26 4 minutes ago, Jmac said: 1) Is there a fault in my analysis? Euc's function is very simple. If there is some torque turning the wheel forward like putting ones weight on the front of the pedal the wheel accelerates forward to counter this torque and keep the pedal straight. Same is true for the other durection. If one puts weight in the back half of the pedal (torque turnng the wheel back) it decelerates forward motion until it accelerates backwards. 4 minutes ago, Jmac said: 2) why did the KS continue to accelerate into its high-speed crash? Is the wheel nose heavy? If one holds the wheel at standstill does it tilt forward and accelerate? Otherwise it would be strange that the unmanned wheel keeps accelerating. Especially up an incline. But there are some EUCs videos showing them riding along alone... 4 minutes ago, Jmac said: 3) it seems this is more likely when there is higher torque demand, like like up a grade. Imho no. Downwards about every euc accelerates and goes straight. As written upwards is a strange - if it's not nose heavy. 4 minutes ago, Jmac said: 4) I think I am appropriately nervous about wet pavement. You mean some malfunction by the electronics getting wet? Afair that:s not common with the 18XL? But eucs are not really weatherproof 1 Quote Link to comment Share on other sites More sharing options...
Panzer04 Posted February 27 Share Posted February 27 It sounds like you lost contact with the EUC. Do you use pads, or are you just standing on it? If you were stiff-legged, or lost footing on the EUC all bets are off - you no longer have control of it for that moment. If you were still standing on it when it skids and regains traction it should have righted itself, although it probably would have felt sketchy and made you bail. If you weren't in good contact then it could have done whatever. The wheel should not be able to accelerate uncontrollably while you are standing on it - and the fact it remained upright is indicative of this, since it would have tilted back out from under you had you been in good contact with the pedals, which would have caused the wheel to stop trying to accelerate. Likely the main factor is keeping your knees properly bent IMO. Quote Link to comment Share on other sites More sharing options...
Cerbera Posted February 27 Share Posted February 27 (edited) Most of the time EUCs do OK on wet pavement, so we shouldn't be overly suspicious about that in itself. But there are those odd sections of it you find that are covered in leaf rot or some sort of slime mould, or just skiddy mud coupled with camber or incline, and those surfaces don't always look that different to the ones that are just wet but are very treacherous for us one-wheelers, especially if we are not aware of them in advance. As for how the wheel continued forward once you were no longer on it I had one fall, back in the day, that I was reminded of by your crash, in which I fell off backwards for some reason, but as I departed the wheel my toes somehow pushed down making it accelerate hard just at the moment my feet left it, so the last input it had from me was a kick forward, which led to it rolling a fair distance by itself before it fell over. Mine was not on an incline so made it further than yours and crashed about 30 m up the road. But I can sort of see how that kind of event could happen if you were unlucky with your last inputs to the wheel... I would try and put this accident down to 'terrain weirdness' and rebuild trust in the wheel slowly over a number of (initially drier) days until the continued evidence you get that it is not dropping you relaxes your worry levels to enjoyable minimums again ! Edited February 27 by Cerbera 1 Quote Link to comment Share on other sites More sharing options...
Planemo Posted February 28 Share Posted February 28 Jesus H how lucky was it that no cars, or worse, motorcycles were travelling down that main road as it crossed Or, how lucky that it only just failed to go over the barrier and not go into the opposite track! Could have been total carnage from that incident, did you also do the lottery that day?! Quote Link to comment Share on other sites More sharing options...
novazeus Posted February 28 Share Posted February 28 6 hours ago, Voyager said: Reading your post reminded me of this from quite a few years ago. I remember thinking 'anomaly' at the time, and how fortunate that a car wasn't coming. I had saved the YouTube link in my wtf folder Video is 'unlisted' according to YT (probably embedded in a thread at the time). For the purposes of this thread though, I think it's fair use. My reply is obviously not an analysis as to what happened, but does seem to show something very similar to what you have described. Analyse away folks.... brings back bad memories. what a painful little pos to ride. sold mine. Quote Link to comment Share on other sites More sharing options...
Planemo Posted February 29 Share Posted February 29 5 hours ago, Voyager said: That car on the other side of the road was coming just at the same time also.. Thats what I meant! Unbelieveable. I also forgot to mention the wheel managed to make its way inbetween those 2 concrete bollards at the beginning. Its almost like the wheel had grown a conscience, gone into suicide mode and was determined to get in front of a car! 5 hours ago, Voyager said: Just to clarify, it wasn't me riding. So no lottery ticket was bought. Well, not by me anyway.. Ah apologies I didnt know that. Shame about the rider too, didnt look like he did anything wrong at all, they are the guys I feel really sorry for. Not like the usual folk who ride like nutters. As for running after it, yeah probably adrenaline and the blanking out of everything else. A bit like when folk have a crash on a motorway and the first thing they do is start taking pictures and yakking in live lanes rather than just getting themselves the hell off a 70mph road! 1 Quote Link to comment Share on other sites More sharing options...
Jmac Posted February 29 Author Share Posted February 29 Thanks for everyone's ideas. And input. The video looks quite familiar. There was certainly no deceleration of that wheel after he departed. Can't see if it accelerated. For sure mine accelerated but it didn't have a chance to go far because it ran straight into a fairly high curb. And the video was on flat ground where his mine was on a slight upgrade. I wonder if the acceleration is related to the upgrade. As for managing the fear, yes, slow and sure take each lesson each observation as a point of suspicion. Watch close to see if it replicates. I love the fact that you can exit these wheels with any concern at reasonable speeds by just A slight jump which seems put heel force and slow the wheel after I'm clear. And to be avoid confusion I was not in Hop off mode during my incident just writing and observing the pavement in front with the little bump. Quote Link to comment Share on other sites More sharing options...
Jmac Posted February 29 Author Share Posted February 29 55 minutes ago, Jmac said: Thanks for everyone's ideas. And input. The video looks quite familiar. There was certainly no deceleration of that wheel after he departed. Can't see if it accelerated. For sure mine accelerated but it didn't have a chance to go far because it ran straight into a fairly high curb. And the video was on flat ground where his mine was on a slight upgrade. I wonder if the acceleration is related to the upgrade. As for managing the fear, yes, slow and sure take each lesson each observation as a point of suspicion. Watch close to see if it replicates. I love the fact that you can exit these wheels with any concern at reasonable speeds by just A slight jump which seems put heel force and slow the wheel after I'm clear. And to be avoid confusion I was not in Hop off mode during my incident just writing and observing the pavement in front with the little bump. Has anyone seen or heard of such incident of Wheels other than KS? Quote Link to comment Share on other sites More sharing options...
Cerbera Posted February 29 Share Posted February 29 6 hours ago, Jmac said: The video looks quite familiar. There was certainly no deceleration of that wheel after he departed. Can't see if it accelerated. Looking at it in slow-mo, it seems it leaves the ground and angles itself radically (almost 90 degrees) backwards, then lands, the pedals stay at that high 'tiltback-looking' angle, but it continues to accelerate forwards, which is behaviour I have never seen before in any wheel, and quite worrying... Quote Link to comment Share on other sites More sharing options...
DavidB Posted March 1 Share Posted March 1 (edited) 4 hours ago, Cerbera said: Looking at it in slow-mo, it seems it leaves the ground and angles itself radically (almost 90 degrees) backwards, then lands, the pedals stay at that high 'tiltback-looking' angle, but it continues to accelerate forwards, which is behaviour I have never seen before in any wheel, and quite worrying... +1 clearly accelerating as it goes through the bollards. Amazing gyro. Looks like he road over something (wet leaf?) immediately prior and was probably slowing. Hmm maybe a jetski type kill switch if riding a large wheel near pedestrians could be a consideration. Edited March 1 by DavidB Quote Link to comment Share on other sites More sharing options...
Cerbera Posted March 1 Share Posted March 1 Well there's the case for leashes ! It can't run away and kill itself it it falls flat on its arse right after you ! Quote Link to comment Share on other sites More sharing options...
Panzer04 Posted March 1 Share Posted March 1 13 hours ago, Cerbera said: Looking at it in slow-mo, it seems it leaves the ground and angles itself radically (almost 90 degrees) backwards, then lands, the pedals stay at that high 'tiltback-looking' angle, but it continues to accelerate forwards, which is behaviour I have never seen before in any wheel, and quite worrying... I suppose the gyro ended up off-kilter, and the accelerometer correction slowly applied but it was already so off-center it took ages to correct itself (you can see the wheel is slowly leveling out while it rides away XD) Only recently learnt that EUCs use a gyro to figure out if its tilting and accelerometer to eliminate tilt angle offsets. Explains a lot about why they slowly settle to level if they aren't level already. Quote Link to comment Share on other sites More sharing options...
Jmac Posted March 1 Author Share Posted March 1 That is really interesting. Thanks for offering that. Do you think this accelerometer + gyro technology is in all EUCs? And how does this factor into acceleration with no Rider in my incident? Something about the demand I was giving going up a slight slope and the instant loss of traction? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.