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Downhill + 240 LBS = Torn off ligaments and three fractures


ImpulseZeo9201

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1 hour ago, Adrian Stevens said:

Tobe's debacle with the hill was down to operator error. He was riding two wheels (one under each foot) along a bumpy track at the top of a pretty steep slope. Upon "dismounting" his wheel (not mine luckily) began to head down the hill and then started to tumble and get faster and faster. When it got to the bottom of the hill, luckily it missed the river and bounced across a stone bridge and came to a halt the other side on a rocky path. Tobe eventually reached it, turned it off, flicked it back on and rode it back up the path. It was his original Airwheel X3 and astonishingly it survived with a few scratches. He did eventually kill that X3 by drowning it!
It's at 2m19s of the linked movie.

 

Youth! I wish I could continue to fall again and again with impunity :-)  Imagine how good he'll be if he keeps this up over the years. That last fall where the wheel got away from him was epic.

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On 19/11/2016 at 8:30 AM, Smoother said:

4.  Constant speed better that speeding up ...

(Old topic, but I think this aspect was left incorrect.)

I don't agree. The very steep downhills I take on every week, I'm sure my Lhotz would've slipped on ahead if I'd tried to keep a steady speed. Inversely, same goes for uphill, once you go steep enough the EUC can't maintain the speed and will slow down. Rider aboard or not.

I often imagine a free rolling bowling ball when I decide how much torque I'm requesting from my EUC, or when squeezing out the last drop of battery to get home. Let go of the ball and it accelerates/decelerates without any battery power. That's why I let the speed slow down on steep uphills, and let it speed up for the length of a steep downhill.

Letting the speed go up downhill one must ofcourse never exceed the limits of the EUC, rider or the environment. It's done slowly, clearly not by leaning forward but breaking a bit less. So far it has been easy to estimate for relatively short downhills.

Especially for Gotways, frying the board seems to be a real danger and I don't yet know all the situations where the amperage may shoot too high. Still I strongly believe that in avoiding falling down, letting the speed go up on a downhill is safer than trying to keep a steady speed.

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3 hours ago, mrelwood said:

I don't agree. The very steep downhills I take on every week, I'm sure my Lhotz would've slipped on ahead if I'd tried to keep a steady speed. Inversely, same goes for uphill, once you go steep enough the EUC can't maintain the speed and will slow down. Rider aboard or not.

I often imagine a free rolling bowling ball when I decide how much torque I'm requesting from my EUC, or when squeezing out the last drop of battery to get home. Let go of the ball and it accelerates/decelerates without any battery power. That's why I let the speed slow down on steep uphills, and let it speed up for the length of a steep downhill.

I totally agree with your technical reasoning, but I wouldn't advise to do so when around traffic! Going down a steep hill already reduces you stopping capabillities quite a bit, and if you go even faster, thats not getting better. You should always keep that in mind!

Further, if you have a longer decline, you can't keep accelerating all the way down, because, as you correctly mentioned, you must not exceed your wheel speed capacity! However, maintaining a higher speed gives more air resistance which helps with braking, but on the other hand, even more power needs to be dissipated due to the higher speed (more m*g*h per time). There should be a point above which power lost in air resistance air resistance grows quite a bit faster with speed, as power from loss of potential energy rises linear with speed whereas resistance has a cubic dependency to speed.

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3 hours ago, Slaughthammer said:

I totally agree with your technical reasoning, but I wouldn't advise to do so when around traffic!

So true. I am stuck thinking about the steep fine gravel hills in the woods where I've been at my EUC's limits lately. When I was happily unaware of this being a potential issue, I rode down a very long hill at around 24kph, and at some point the Lhotz gave up an ended up bouncing in the car lanes. No cars or people (besides me) were hurt, but it could've been bad.

Quote

However, maintaining a higher speed gives more air resistance which helps with braking, but on the other hand, even more power needs to be dissipated due to the higher speed (more m*g*h per time.

My guess is the air resistance is not big enough at these speeds yet to overcome the increased demands on the EUC. I'm sure it has an effect, and without it I would've fell down just a bit sooner. 

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There is a steep short hill that I go to work through most days. I turned on WheelLog after my recent crash just to see what my energy use was.

--going downhill rather slowly uses the most energy I've ever seen, above 800 watts and spiking higher than that (1000 + ?).

--conversely going uphill, which feels painful, difficult, and straining, only uses between 400-600 watts. So it's probably psychological...I doubt I've ever used the near maximum output of my wheels. Scared to.

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1 hour ago, LanghamP said:

--going downhill rather slowly uses the most energy I've ever seen, above 800 watts and spiking higher than that (1000 + ?).

This is very good info! Could you measure the used wattage if you went down a bit faster? As long as it feels safe ofcourse!

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11 hours ago, mrelwood said:

This is very good info! Could you measure the used wattage if you went down a bit faster? As long as it feels safe ofcourse!

I've gone double the speed, 8 vs 4 mph, but the wattage was so spiky I couldn't tell what the difference between speeds is. 

Looking at WheelLog shows braking at the bottom of the hill requires massive energy, and really spiky at that. Everywhere else my wattage is pretty smooth and consistent but going downhill...it's sketchy.

Until I used WheelLog I would not have guessed braking downhill uses the most energy. With such huge energy surges I'd recommend riders treat going downhill as somewhat dangerous, and the braking at the bottom of the hill as exceptionally dangerous.

That said, never had a problem going downhill

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Did you look at the battery voltage during these experiments? Such power surges should produce a notable voltage drop. Maybe wheellog does not record the power usage correctly, that would be a matter that's not entirely unheard of...

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