Mono Posted June 3, 2023 Share Posted June 3, 2023 14 hours ago, mrelwood said: He said “maximum attainable”, so the target speed will be lower if there is a head wind, incline, etc. One does need to monitor the PWM while riding to get the exact speed of course. But 70% of the free spin speed might be close to 80% while riding at a steady speed on a level ground. How about going downhill with tailwind? This does not count for "maximum attainable"? I kinda don't see how to translate 80% duty cycle into some meaningful top speed without referring right back to 80% duty cycle. And the latter also covers the pretty relevant case of acceleration. 1 Quote Link to comment Share on other sites More sharing options...
Poker Posted June 3, 2023 Share Posted June 3, 2023 The most fair way of measuring top speed is on flat ground with no wind. Most EUCs have insane top speed if they are free falling from an airplane. 2 Quote Link to comment Share on other sites More sharing options...
techyiam Posted June 3, 2023 Share Posted June 3, 2023 1 hour ago, Mono said: How about going downhill with tailwind? This does not count for "maximum attainable"? Yup, some on YouTube attain their top speed going down a slope with a tailwind and claimed higher top speed. How about sitting down? Quote Link to comment Share on other sites More sharing options...
Mono Posted June 3, 2023 Share Posted June 3, 2023 (edited) 4 hours ago, techyiam said: How about sitting down? True, indefensible neglect in my shortlist. Rethinking the safety margin in this light, it makes less sense. The amperage which a bump takes out of the system grows with increasing speed. Hence any fixed (like 20%) duty cycle safety margin becomes with increasing speed less safe whereas I'd prefer to have rather more safety leeway at higher speeds (where the stakes are higher). Edited June 3, 2023 by Mono Quote Link to comment Share on other sites More sharing options...
techyiam Posted June 3, 2023 Share Posted June 3, 2023 (edited) 1 hour ago, Mono said: The amperage which a bump takes out of the system grows with increasing speed. Hence any fixed (like 20%) duty cycle safety margin becomes with increasing speed less safe whereas I'd prefer to have rather more safety leeway at higher speeds (where the stakes are higher). Some people actually pay attention to the % duty cycle safety margin as they ride. Over time, they will have a good idea as to what will work for them. The 20 % duty cycle PWM safety margin is only for my own definition of top speed, not necessarily how fast I am willing to ride up to. Moreover, I don't run at the highest speeds unless I know my surrounds well, and can control the variables. Edited June 3, 2023 by techyiam 1 Quote Link to comment Share on other sites More sharing options...
mrelwood Posted June 3, 2023 Share Posted June 3, 2023 1 hour ago, Mono said: The amperage which a bump takes out of the system grows with increasing speed. Hence any fixed (like 20%) duty cycle safety margin becomes with increasing speed less safe whereas I'd prefer to have rather more safety leeway at higher speeds (where the stakes are higher). Then the common KS & IM 30% might work for you. While giving a meaningful number for an unlimited wheel’s top speed is indeed difficult due this sliding scale, one has to have some number for it that can be compared to other wheels in the same conditions. For that a 80% PWM utilization on flat ground without wind on a 80kg rider would work reasonably well. Safety margin going up and down depending on all of the mentioned circumstances (and then some) is a fact of life, and it would be important for all riders to understand this. It’s been obvious on some overleans that they do not. 1 Quote Link to comment Share on other sites More sharing options...
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