My first face plant - ouch

[Smoother]

7 hours ago, Bob Eisenman said:

Why not pick a smoother path for a change ? I'm fairly convinced that in mud or wet mucky gravel my chances of staying up get slim.

That's an interesting question. Initially, like all newbies, I chose the flattest, smoothest surfaces I could.  Then one day I decided to cross about ten feet of rocky gravel that connected two flat pieces of surface. Soon, that became no big deal, and so rougher stuff, that once impeded my progress, got conquered; one surface type at a time. Now I go anywhere I think I have a moderate chance of staying on. I never thought I could ride on a sandy beach until I tried it recently, that was fun.  I took a coastal run the other day that had almost every conceivable terrain except snow, and ice.  It's so much fun.  I was going to film it but was in fear for my phone.  Yes I enjoy the smooth flat stuff (where most of the dog doo is btw) but now, when the road ends I keep going. Sure, I get thrown off now and then, but it's always at a low speed so it's easy to walk it off, and I have my safety gear on.

aside: I never "don't go" because I "only have a 14" wheel". I use its agility to micro-adjust my path to avoid the biggest rocks and holes.  I'm truly surprised at the rough terrain it can navigate, and so are the people I pass.  And I'm convinced that once I add pedal extensions, I'll be able to power out of stoppies that currently just tip me off the front of the pedals before enough torque is applied.  @Bob EisenmanThanks for the virtual cookies

[Smoother]

6 hours ago, Mono said:

So a softer reaction leads to push the foot more down, but this is not the same as lean even further. The necessity to push the feet more than expected is a strong feed back to not lean more, well, at least it has proven to work well for me. When it happens

Yes @Tilmann I feel my ks 14 does this to me, on rough surfaces, in corners, going down Hill, or any combination of the three.  Its very hard to ride fast with your feet tipped forward, as @Mono described.  I find myself bending my knees to compensate for the angle of my ankles and in order to keep my body weight over my feet, which prevents going faster, unless I'm really determined. Maybe it would be easier to ride through it with longer pedals, as I start to feel like my feet are slipping  off the front, and my toes are already level with the front of the casing as it it. ? Not a fun feeling going round a down hill bend on a cobblestones, let me tell you, but you learn to adjust.  I suspect, though, that if this happened  in a fast take off situation like the OP described, it might still result in a run off/ face plant, as there is little time to compensate.  I've had to step off at walking pace, when, during a tight turn my wheel went from tilted forward on entry, to tilted back on exit in the space of 2 feet and 2 seconds...Too many variables at one time.

[MaxLinux]

1 hour ago, Smoother said:

I never "don't go" because I "only have a 14" wheel". I use its agility to micro-adjust my path to avoid the biggest rocks and holes.  I'm truly surprised at the rough terrain it can navigate,

I have been surprised at the capabilities of some 14 inch wheels.

Nomad was riding his V5F+ much faster than I expected, very successfully on a dirt and gravel trail.

Djquestionthis took his MCM4 on a dirt trail at much higher speeds than I would have imagined possible.

Marty's KS14C handled the dirt amazingly well.

When I'm on a 14 inch wheel I can't ride like these examples. Without seeing these examples, I would not have thought it was possible to ride this way on a 14 inch wheel. Whenever the surface is rough I feel like the wheel is about to lose control at any moment. I really notice a much more secure feeling riding a 16 inch wheel.

[Smoother]

Thanks for that @MaxLinux  you've inspired me to get my camera out next time I'm on the surface of the moon. Sorry @Marty Backe I laughed again when your wheel didn't come out of that crater.  But I think you will agree, at a different  angle you would have pulled it off, and probably have since then.

[Smoother]

11 hours ago, MaxLinux said:

When I'm on a 14 inch wheel I can't ride like these examples. Without seeing these examples, I would not have thought it was possible to ride this way on a 14 inch wheel. Whenever the surface is rough I feel like the wheel is about to lose control at any moment. I really notice a much more secure feeling riding a 16 inch wheel.

You're not wrong necessarily.  My 14" is quite flickable, but I got used to it, and use it to my advantage.  Tire pressure is important too.  Last month I was rock climbing at 65psi and I was pinging off everything like a ping pong ball.  Since then my air pressure has leaked down to ??? And now paths that were energetic and bouncy, are now Cadillac smooth.  I may loose some "mpg" but it's worth it.  And anyway @zlymex calculated the loss as minimal.  So I'm finally taking the advice of many here, to not run at max psi.

[Mono]

I think the most limiting factor in rough terrain with my 14" Gotway MCM2 is not wheel size but pedal height. I have to choose the path very carefully to not catch the ground with the feet or the pedals. Besides that, I cut the shell to catch any hump for sure with the tire instead of the shell first.

[chopsywa]

28 minutes ago, Mono said:

I think the most limiting factor in rough terrain with my 14" Gotway MCM2 is not wheel size but pedal height..

Same on my MCM3. It also catches on fast corners and I have had a big spill where my foot hit the ground on a smooth pavement taking a fast bend. Still love it though. I would love a 16", but the small size and weight makes it a great "grab and go" unit.

[Starry night]

Ouch, glad you had helmet on, it's annoying that you are experienced yet still had the unexpected, and that the unexpected was awful.  Hope you haven't lost too much confidence.  Good luck.

[Marty Backe]

8 hours ago, Smoother said:

Thanks for that @MaxLinux  you've inspired me to get my camera out next time I'm on the surface of the moon. Sorry @Marty Backe I laughed again when your wheel didn't come out of that crater.  But I think you will agree, at a different  angle you would have pulled it off, and probably have since then.

Hey, I included the footage for everyone's enjoyment   As has been noted elsewhere, when rock climbing with a wheel the concerns of falling off the wheel pretty much disappear due to the low speeds involved. Usually it's easy to run it out.

[Bob Eisenman]

The potential for softer falls ?

 

[Planetpapi]

Will snow damages like water? Once it gets in it will melt and become like water. just wondering.

[Robi Bobi]

On 24.01.2017 at 6:01 PM, Slaughthammer said:

Ok, so that makes this a classic overlean faceplant. Thanks for the info, makes me a bit more confident about the reliabillity of the Lhotz.

Yes, of course this happens fast. If you've been accelerating around max power, you will be at about 16-18 kph after 15 feet. Your knees will be on the ground before you realise you're in trouble

I had the same "classic overlean faceplant" with my KS16, followed by cart fast accelerating, dn't know speed when it happened, 

Should KS16 say the info about over curent if I was below 30 km/h, As I remember once time KS said the warning message   but not this time.My speed settings where to max, and rider, 80% battery.

[Belly laughing]

On 1/25/2017 at 8:57 AM, Tilmann said:

Lol - never saw it that way: EUCs of the airwheel breed may be the only ones allowing you to explore the edges of the "safe envelope" without imminent pain when you found the limits. Try the same on a GotWay and it's gonna hurt.

Problem is: with most other machines we use, we are conditioned to the telling signs of 'close calls': screaching tires, screaming engines, cracking noises before something brakes. EUCs don't give us any of these signs. You can accelerate hard and use 99.9% of available power and it feels and sounds perfectly healthy and ok. There is no way of knowing, how close the call just was. There may not even be a beep if your power demand was very short.

I believe, there is a lot of room for improvement. Present EUCs know 3 very poor methods of feedback from the wheel to the rider (not counting app functions): the beeper, tilt back and some have voice alarms. Out of these 3, tilt back and voice are way to slow to help with overleans. That leaves the silly beeper. Why silly? Because out of all the different sounds a human ear can hear, those stupid beepers produce exactly one. So, with overspeed alarms, they resort to something like morse code: 1st alarm - 1 beep per second, 2nd alarm - 2 beeps per second, etc.  In the age of carefully engineered sound of car doors closing, how poor is that? Plus: exactly the same beeps are used for speed alarms, triggered by reaching a certain speed (regardless of power used) and by consuming >80% of available power. Thus, the more daring types amongst us tend to hear those beeps quite regularly - without punishment for this ignorance 99% of the time.

When accelerating close to the limits, I want to hear a high pitch noise with increasing distortion the closer I get to disaster. When my wheel is just a hair away from cutting power to save it from burning something, it should not sound happy and healthy, it should sound tormented and panicked! No rocket science required to make that happen; no costly components either. 

@Linnea Lin Gotway can you discuss that thought with your developers, please? That would be one very affordable feature for GW to lead the competition.

Then, does this happen to all EUC including the famous Kingsong models?   Intriguing....   I think EUC relies on electric motor which is mostly good but sometimes bad, thinking of this aspect.   When the technology of measuring power consumption at runtime or load without perturbing the system is fully matured, EUC could give us incremental noises or signs of warning which you've just mentioned: the technology securing our safety is not full grown yet.

[Tilmann]

1 hour ago, Belly laughing said:

Then, does this happen to all EUC including the famous Kingsong models?   Intriguing....   I think EUC relies on electric motor which is mostly good but sometimes bad, thinking of this aspect.   When the technology of measuring power consumption at runtime or load without perturbing the system is fully matured, EUC could give us incremental noises or signs of warning which you've just mentioned: the technology securing our safety is not full grown yet.

I don't think it matters in this context, whether an EUC is powered by electricity, steam or rocket fuel: it's a systemic weak point of self balancing vehicles, at least those without a steering bar in front of you which can limit effectively your lean forward angle (like Segways do). With all EUCs, you can throw all of your weight far to the front when starting and that will lead inevitably to a face plant. Even if the machine had unlimited motor power, eventually the limits of tire grip would make it impossible to balance out a radical overlean.

That leaves two methods to prevent it from happening: self restraint (i.e. the rider keeps conservatively to moderate acceleration) or instant, unmistakable feedback before it happens. 

[JimB]

31 minutes ago, Tilmann said:

... With all EUCs, you can throw all of your weight far to the front when starting and that will lead inevitably to a face plant. Even if the machine had unlimited motor power, eventually the limits of tire grip would make it impossible to balance out a radical overlean. ...

I think it's important to note that this overlean condition results in a cut off.  I'm not sure that this is the most rider-friendly response.  It's not a limitation of physics; it's a decision of the firmware.

Consider that the wheel is capable of acceleration X.  You're leaning forward so far, that the wheel needs X+1 acceleration (which it can't do) to compensate.

Should the wheel continue with acceleration X?  You'll probably still fall off the front, but you might have time to adjust.

Should the wheel rapidly decelerate to zero (X-1, X-2... 0)?  You'll almost certainly fall off the front, but you might have time for a step.

Should the wheel suddenly cease power - which considering your forward lean would instantly cause the pedals to lose all lift, and the wheel would be pushed backwards out from under you.  (This is what happens.)

It's somewhat like the difference between tripping, and having your legs yanked backwards.  You might recover from tripping, but if your legs are yanked backwards, you're on your face.

You can see in this video, where the guy intentionally causes an overlean and steps off (https://youtu.be/8NB9SgjM65k?t=3m09s)  The wheel starts forward motion, and at the moment of overlean, the forward motion stops dead.  As the wheel falls away, it slides backwards slightly.

[Mono]

5 hours ago, Tilmann said:

it's a systemic weak point of self balancing vehicles, at least those without a steering bar in front of you which can limit effectively your lean forward angle (like Segways do). With all EUCs, you can throw all of your weight far to the front when starting and that will lead inevitably to a face plant. Even if the machine had unlimited motor power, eventually the limits of tire grip would make it impossible to balance out a radical overlean.

It's a little bit like saying the systemic weak point in cars is that you can push down the throttle to the bottom and crash head-on into a wall or in a group of pedestrians. It's really no more difficult to push the car throttle all the way down than to heavily lean into an EUC.

4 hours ago, JimB said:

I think it's important to note that this overlean condition results in a cut off. 

I think this depends on the wheel. If this is the case, I consider it a design failure and I would try to avoid buying these.

On the other hand, max speed cut off is difficult to circumvent algorithmically, because otherwise a lifted spinning wheel would spin until the battery is empty. 

[lizardmech]

There's probably some variables that mean it's near impossible to give sufficient warning of over current, if the motor stator reaches magnetic saturation limits applying more current will not result in more torque, so the control loop would demand exponential amounts of current. Sometimes over current shutdown isn't even handled by the cpu to enable fast response, so if the current sensor signal has a glitch the MCU will halt PWM and reset itself.

[meepmeepmayer]

@Tilmann is exactly right. One should be able to hear the EUC utilization, at least near the limits.

If that is technically hard as @lizardmech suggests, that's a design problem, isn't it? After all the motor characteristics are known to the manufacturer. Maybe PLEV will force the issue. Or manufacturers professionalize with growing numbers of wheels.

You have no idea how close you've been to doom... that is just dumb.

[Mono]

9 hours ago, lizardmech said:

if the motor stator reaches magnetic saturation limits applying more current will not result in more torque, so the control loop would demand exponential amounts of current

Not quite. More current will result in more torque. The maximal possible current is however limited by the available voltage. And this limit goes down linearly with increasing speed. That means, the faster the wheel goes the easier it can be outleaned. So yes, it is virtually impossible to prevent outleaning (and running with high speed into a wall), but the wheel can and indeed should always warn the rider when the known torque limit is close.

[Belly laughing]

8 hours ago, Mono said:

Not quite. More current will result in more torque. The maximal possible current is however limited by the available voltage. And this limit goes down linearly with increasing speed. That means, the faster the wheel goes the easier it can be outleaned. So yes, it is virtually impossible to prevent outleaning (and running with high speed into a wall), but the wheel can and indeed should always warn the rider when the known torque limit is close.

I totally agree with you.   The torque is the key that if it is well monitored with some ingenious technology, we can prevent face-plant from happening for sure.