zlymex Posted October 31, 2016 Share Posted October 31, 2016 It is not like this: there exist a safety speed(for a given weight, given EUC) below which the rider is absolute safe. Safety degree is gradually change with speed. What can be said is something like this: it's relatively safe at 30, very safe at 20. Even if there is a safety speed, it not only depends on the power and the rider's weight, there are many other things as well. IMHO, as a general rule to avoid faceplant, don't press the pedal too hard(either on the front or back). The more the speed, the lighter it should be. Hard press on pedal may happens when 1. Accelerate hard There are many EUCs that can be hard accelerated especially at low speed, such as Rockwheel 16/12, IPS T260. However at higher speed, it cannot. 2. Hard break Normally, EUCs that can be hard accelerated also can be hard braked. Avoid situations needing a hard brake. 3. Uphill A better skill to climb a hill(that beyond the ability of the EUC or overweight of the rider) is to gradually slow down on the hill, keep the body slightly backward leaned. When the speed becomes lower, a harder press can be applied, because the EUC can produce high torque at low speed, and also because the rider has a much better chance to get rid of faceplant at low speed even if the EUC gives in. Power=speed*force, force is equivalent to torque and in turn determines the max steep a hill you can climb at constant speed. Therefore, reducing speed is the way not to over power the EUC to climb a hill, if the torque is also allowed. 4. Bumpy road The faster you go, the more bumpy it feels, and the more force applied to the pedal in order to keep balanced. Curl the legs a little to absorb the shake thus lesson the press on the pedal. A soft pedal setup on the app(instead of hard) will also help. 5. Obstacle on the road. If an obstacle(a ditch or a bump) is about to encounter and there is only 1 to 2 seconds to respond, just brake, and curl the legs to absorb the impact. The larger the obstacle, the more lean back needed to avoid faceplant at relatively high speed. 6. A gust of wind Just let it be, do not respond vigorously. Riding against wind is also very power consuming. Link to comment Share on other sites More sharing options...
volavoile Posted October 31, 2016 Share Posted October 31, 2016 I agree with @zlymex, the curve I did goes in the same direction. It just gives the speed number which is very different to the one given (not given in fact) by the constructor! They only give a maximum speed which is not the safe speed! at 25 in gotway 1500 W, you are on the safe side for sure, not on a ninebot, unless you are a 40 kg shrimp! Link to comment Share on other sites More sharing options...
zlymex Posted October 31, 2016 Share Posted October 31, 2016 16 minutes ago, volavoile said: I agree with @zlymex, the curve I did goes in the same direction. It just gives the speed number which is very different to the one given (not given in fact) by the constructor! They only give a maximum speed which is not the safe speed! at 25 in gotway 1500 W, you are on the safe side for sure, not on a ninebot, unless you are a 40 kg shrimp! I read you chart, I think it is generally correct for ideal riding conditions such as flat road, no wind, no hills, and the skill of the rider is average. No doubt, power and weight are the two main factors determining how fast one can go. However, power is not the only factor determines the ability of an EUC. Take V2 for example, there are three versions: HS, MS and HT, and all rated at 1000 Watts, but the speed limits are different. Another example is the Gotway V3 67.2V, 84V and 22 inch, these three are all rated at 1500 Watts, but the 'safety speed' is quite different. Link to comment Share on other sites More sharing options...
volavoile Posted October 31, 2016 Share Posted October 31, 2016 I did calculate 2 options : 5 and 10% slope. 10% is of course safer? But I did it with a very optimistic hypothesis: constant power whatever the speed is.. which one is obviously too optimistic. That's the reason why the calculation is done with the best of high torque and high spped option. the real safe speed shall be even lower! The maximum speed for high torque or high speed is different, but is doesn't mean maximum safe speed, but speed you can reach in ideal conditions... due to frequency inverter capacity...? Link to comment Share on other sites More sharing options...
Mono Posted October 31, 2016 Share Posted October 31, 2016 28 minutes ago, volavoile said: I did calculate 2 options : 5 and 10% slope. 10% is of course safer? But I did it with a very optimistic hypothesis: constant power whatever the speed is.. which one is obviously too optimistic. That's the reason why the calculation is done with the best of high torque and high spped option. the real safe speed shall be even lower! The maximum speed for high torque or high speed is different, but is doesn't mean maximum safe speed, but speed you can reach in ideal conditions... due to frequency inverter capacity...? Did you consider in your calculations that the power output of the motor depends on its speed? Can you give the formulas you used? Link to comment Share on other sites More sharing options...
zlymex Posted October 31, 2016 Share Posted October 31, 2016 While power(rated, of the motor) is an very important factor, it is actually temperature/heat related. That is to say, you cannot operate the motor at over the rated power(also at rated temperature, rated voltage and rated speed) for a long time, otherwise the motor will be over heated. That means the actual output power can be exceeded in a short period of time provided the temperature of the motor is low. For instance, V3 is specified as >3000 Watts peak power. This peak power(rather than rated power) is very useful for an EUC to overcome a sudden rough road, or climb a steep but short slope. Of course both power and peak power are speed related, thus can be difficult to be used for max safety speed calculation. A better way to do this might be the speed torque curve, which can also be tested more easily. Link to comment Share on other sites More sharing options...
volavoile Posted October 31, 2016 Share Posted October 31, 2016 Constant maximal power... but I can easily introduce any curve you have! I'll put the file shen I will be back home, may be in a separate general topic!? Link to comment Share on other sites More sharing options...
nomad Posted October 31, 2016 Share Posted October 31, 2016 I just found a full stack of new MCM M boxes!! and had a disappointing moment... Link to comment Share on other sites More sharing options...
volavoile Posted November 2, 2016 Share Posted November 2, 2016 On 31/10/2016 at 10:30 AM, zlymex said: I read you chart, I think it is generally correct for ideal riding conditions such as flat road, no wind, no hills, and the skill of the rider is average. No doubt, power and weight are the two main factors determining how fast one can go. However, power is not the only factor determines the ability of an EUC. Take V2 for example, there are three versions: HS, MS and HT, and all rated at 1000 Watts, but the speed limits are different. Another example is the Gotway V3 67.2V, 84V and 22 inch, these three are all rated at 1500 Watts, but the 'safety speed' is quite different. With "only" 1500W, the 22 inches will never reach safely 50 km/h since all power will be for the drag at this speed! Do not hope going safely faster with a 22 inches than with a 18 inches... you will simply ride more comfortable! Link to comment Share on other sites More sharing options...
zlymex Posted November 2, 2016 Share Posted November 2, 2016 2 minutes ago, volavoile said: With "only" 1500W, the 22 inches will never reach safely 50 km/h since all power will be for the drag at this speed! Do not hope going safely faster with a 22 inches than with a 18 inches... you will simply ride more comfortable! I'm simply saying that even the power and the weight are the same, the safety speed is different. Link to comment Share on other sites More sharing options...
zlymex Posted November 2, 2016 Share Posted November 2, 2016 On 2016/10/31 at 9:38 PM, volavoile said: Constant maximal power... but I can easily introduce any curve you have! The max power is very difficult to obtain. Link to comment Share on other sites More sharing options...
volavoile Posted November 2, 2016 Share Posted November 2, 2016 2 hours ago, zlymex said: The max power is very difficult to obtain. It is the reason why the calculation I made are very optimistic, despite the fact that safety speed calculated are much lower than the one most riders use to consider... Haven't you seen some people trying to ride at 45 km/h with their MS3 or ACM 16? What was the result at the end????? Is it safe to ride a ninebot at 25 klm/h for a 90kg rider? With the same power, safety speed will not be higher... wait and see the results of accidents when this new monster will be avaiable.... Many people will force their chance.... Link to comment Share on other sites More sharing options...
Cerbera Posted November 2, 2016 Share Posted November 2, 2016 I'm a good candidate to test the MS3 at the higher speeds because I am right at the left side of the chart at 50kg. Ok, maybe 55 with armour. According to that should be good for 37 kph max. So I'll let you know how that goes Have been testing my new 661 pressure suit 2016 body armour today. Haven't fallen off yet, but it works very well if you throw yourself at the ground. Will do a video review of that if anyone is interested... Whilst I I very much enjoy the feeling of safety and support this brings, I do notice that extra reassurance having a slightly dramatic effect on my average speed. Heard the warning beeps for the first time today, but won my race with the bicycle Don't worry - was on a totally clear cycle path ! Link to comment Share on other sites More sharing options...
volavoile Posted November 2, 2016 Share Posted November 2, 2016 Consider that calculations could be false and optimistic... I do not want to be faulty... But with your weight, I'm not so afraid at 37! This is only safe speed, not maximal speed you can reach! Link to comment Share on other sites More sharing options...
Cerbera Posted November 2, 2016 Share Posted November 2, 2016 Just now, volavoile said: Consider that calculations could be false and optimistic... I do not want to be faulty... But with your weight, I'm not so afraid at 37! This is only safe speed, not maximal speed you can reach! Ah yes I could do more, but I think 35-37 is a safe maximum for me - I don't feel the need to go much faster than that. Link to comment Share on other sites More sharing options...
volavoile Posted November 2, 2016 Share Posted November 2, 2016 My surgeon did explain me that over 20km/h, a fall is considered for our body as "high energy accident....". Some can be Lucky, other not.... I wasn't! So, safe consider the "acceptable risk to have cut off", not acceptable in case you fall! Link to comment Share on other sites More sharing options...
zlymex Posted November 3, 2016 Share Posted November 3, 2016 @volavoile My point is, calculate the speed limit as precise as possible, and let the rider decide the speed reserve according to his/her own skill, protection and attitude. Using peak power is not precise, it is not even specified for most EUCs. Link to comment Share on other sites More sharing options...
zlymex Posted November 3, 2016 Share Posted November 3, 2016 12 hours ago, Cerbera said: I'm a good candidate to test the MS3 at the higher speeds because I am right at the left side of the chart at 50kg. Ok, maybe 55 with armour. According to that should be good for 37 kph max. So I'll let you know how that goes Have been testing my new 661 pressure suit 2016 body armour today. Haven't fallen off yet, but it works very well if you throw yourself at the ground. Will do a video review of that if anyone is interested... Whilst I I very much enjoy the feeling of safety and support this brings, I do notice that extra reassurance having a slightly dramatic effect on my average speed. Heard the warning beeps for the first time today, but won my race with the bicycle Don't worry - was on a totally clear cycle path ! Very nice. I recommend you use Wheellog and make recording while you test, also noted the road conditions, tire pressure and wind speed. Link to comment Share on other sites More sharing options...
ImpulseZeo9201 Posted November 15, 2016 Share Posted November 15, 2016 I'm just recovering rom a major fall. broke my leg and ankle in three places going down a somewhat steep hill in SF. I am 240 lbs and I assume the thing couldn't handle me. I was on a GW V3 and also my motor just cut out and there goes my leg.. Link to comment Share on other sites More sharing options...
Cerbera Posted November 15, 2016 Share Posted November 15, 2016 24 minutes ago, ImpulseZeo9201 said: I'm just recovering from a major fall. broke my leg and ankle in three places going down a somewhat steep hill in SF. I am 240 lbs and I assume the thing couldn't handle me. I was on a GW V3 and also my motor just cut out and there goes my leg.. Oh man - Sorry to hear you had such a bad fall. I think you are right - 240 lb is at the top end of the range that Gotway say those wheels can support, and reading the forums here suggests they are a little over-optimistic. It's good to have your report. Hopefully others can learn from this... do you mind a few questions ? What were you wearing, protection-wise ? How did you fall in such a way that your leg broke ? Did you come off it backwards or forwards ? (I'm guessing the latter if you were downhilling) Was there any warning at all before your motor cut out ? What happened to the wheel after the accident - did it get much damage, how far away from you did it get, and did it contact anything else ? What was your battery charge like ? Thanks CBR Link to comment Share on other sites More sharing options...
ImpulseZeo9201 Posted November 15, 2016 Share Posted November 15, 2016 Hey, Thanks those are good questions. I was actually at work so I was wearing a suit and sneakers. low rise sneaker Nope, no warning. Funny though I was just thinking. I hope that I am not triggering a threshold similar to top speed current or what not thresholds. and then bam. my knee goes left I go right. The thing was tumbling in a tree where I heard the wheel spin while beeping. It got pretty dirty and when I saw the firemen trying to move it made strange sounds as if the motor was stuttering or so. Haven't touched it since but yeah that's that. Feel free to ask more questions Link to comment Share on other sites More sharing options...
MaxLinux Posted November 15, 2016 Share Posted November 15, 2016 On 10/31/2016 at 0:41 AM, zlymex said: When the speed becomes lower, a harder press can be applied, because the EUC can produce high torque at low speed The manual for my IPS 121 states: "Carefully control the unicycle on a low speed when you go uphill. Since the ability of going uphill and downhill is limited due to the motor power and torque value, we suggest to ride on a low speed when you go uphill and downhill. The unicycle is more capable at climbing and protected from damage because of a greater torque." Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.