US69 Posted February 7, 2017 Share Posted February 7, 2017 Hey Folks, i want to report about a very nice test done with my KS18, but First Things First: This test is a KS18 1200Watt 1360wh, produced March/2016, imported from China...The wheel has its Flaws!!! Important: It is from one of the first 1200W Batches, where there have been some highspeed fall reports. Also Important:This special KS18 DOES NOT Represent the current state or Quality of the KS18's!!! I have been compensated long ago by the chinese seller/KS, from my side everything is OK with the wheel as -and as stated often before- i am totally fine with a usage at about 30kmh!!! So: It would be a pleasure if we can keep the discussion in this thread on the treadmill test itself, and not on this partly not so good wheel! thanx :-) Now the main Thing As (THIS) KS18 only had a "lift off max speed" of about 43kmh...(and not 48-49kmh like nowadays KS18) i was always eager to know what it would be able to deliver under load, with my 90-100kg on it. In the latest Video's of german seller "electro-sport.de", YouTube Channel Name "great 850", in Person named Ferenc, i stumbled over his latest DIY tool to test wheels in a more real life Scenario, without putting his Drivers to a risk: He has build a "EUC-Treadmill" where you can set a specific load, concrete slabs, to the EUC, and where the treadmill is also connected to a Generator/lightmashine to set up a specific resistance! (street-wind-resistance) After a nice conversation he made me an really good offer to test my wheel on his treadmill and record the outcome of this test on Video!!! How could i resist that?!?! A few days later i send my KS18 to Ferenc, and actually on the same day he recieved the wheel he started his tests :-) A small part of this tests you can see here, as Ferenc has put some of it on his Youtube Channel, with my approval: But thats not all he has recorded! As i got my wheel back by post, i got a complete DVD of the testing series! Really great Job! In our latest communication he also revealed that in a second or later expansion of the testplant he will go for simulating bumps and pottholes by giving force to the attached Generator. I am writing this thread, as i think Ferenc really deserves some Applause for the things he is doing for the community and for Electric unicycling! Also i believe, that i am for sure not the only (EUC)Freak, who is interested in the behaviour of his wheel on extreme situations? Or? Am i? If someone else is interested in testing his machine on some specific things on this testplant....feel free to contact Ferenc, you will find his contacts on his Website electro-Sport.de As you can think, that Service can not be for free, as he is investing some hours in the testprocess alone, charging etc etc.... not to say in carrying your wheel around to the post Office..... but i have to say -for me- it was worth every penny i spent!!! Link to comment Share on other sites More sharing options...
Mono Posted February 7, 2017 Share Posted February 7, 2017 10 hours ago, KingSong69 said: i was always eager to know what it would be able to deliver under load, with my 90-100kg on it. I don't quite understand the relevance of the load in this scenario. If the tilt angle is zero, the load should be irrelevant. As the wheel accelerates, the tilt angle is apparently positive (how much is it?). One question which comes immediately into mind: what is the actual torque the wheel must generate? It doesn't seem that the wheel would fall over if it would only generate minimal torque. Therefore I don't quite understand the role of the load and how that would be related to "the real world". Link to comment Share on other sites More sharing options...
US69 Posted February 7, 2017 Author Share Posted February 7, 2017 31 minutes ago, Mono said: I don't quite understand the relevance of the load in this scenario. If the tilt angle is zero, the load should be irrelevant. As the wheel accelerates, the tilt angle is apparently positive (how much is it?). One question which comes immediately into mind: what is the actual torque the wheel must generate? It doesn't seem that the wheel would fall over if it would only generate minimal torque. Therefore I don't quite understand the role of the load and how that would related to "the real world". You can not see that exactly in the Video, but weight is completly Lasting on the pedals like a Person Standing on it. Then by a Lever or Hand gear, the weight is shifted, the concrete slaps lean in the front, so the wheel accelerates. i dont see any big difference to me or a Person leaning in front.... Also i see -a lot- of difference from a "free Spinning" accelerating wheel....and a wheel that is pressured down with 90kg on some street simulating rolls which have to accelerate a Generator...even if i dont know the exact torque which has to be used here... But for sure that still is not 100% the same as "reallife"......what nobody even tried to say. Link to comment Share on other sites More sharing options...
Mono Posted February 7, 2017 Share Posted February 7, 2017 8 hours ago, KingSong69 said: You can not see that exactly in the Video, but weight is completly Lasting on the pedals like a Person Standing on it. Then by a Lever or Hand gear, the weight is shifted, the concrete slaps lean in the front, so the wheel accelerates. i dont see any big difference to me or a Person leaning in front.... The difference is that the wheel cannot faceplant. If the wheel doesn't provide "enough" torque, what will happen? I don't quite see that anything bad will happen here. As long as the wheel cannot fall over, I don't see how the weight on the axle has much of a significance to the setup, other than that the axle could brake and that we should see a slightly increased friction (from bearings and tire). Link to comment Share on other sites More sharing options...
US69 Posted February 7, 2017 Author Share Posted February 7, 2017 1 hour ago, Mono said: The difference is that the wheel cannot faceplant. If the wheel doesn't provide "enough" torque, what will happen? I don't quite see that anything bad will happen here. As long as the wheel cannot fall over, I don't see how the weight on the axle has much of a significance to the setup. Ok, Thanks, got it now.... Exactly like in the tiltback dicussion, where you Interpret a working force against a Person leaning in an as "not needing power"... ...we seam to have diametrical opposed opinions of how EUC's or even physical laws work.... Just for the notes: A freespining V3 67Volt goes to 53kmh... Tests on this testplant with an V3 67 Volt have reveiled the exact same result as some People have had with their V3 in real life(faceplant): Cutoff at 46kmh....also seeable at "great850"... So there seams to be some or much truth in this test. I leave this discussion over to others.... Link to comment Share on other sites More sharing options...
Chris Westland Posted February 7, 2017 Share Posted February 7, 2017 2 hours ago, Mono said: I don't quite understand the relevance of the load in this scenario. If the tilt angle is zero, the load should be irrelevant. As the wheel accelerates, the tilt angle is apparently positive (how much is it?). One question which comes immediately into mind: what is the actual torque the wheel must generate? It doesn't seem that the wheel would fall over if it would only generate minimal torque. Therefore I don't quite understand the role of the load and how that would related to "the real world". I agree @Mono the relevance of the rider weight is the inertial resistance ... downward force is irrelevant. You can simulate inertial resistance with added braking torque on the flywheels, but just adding bricks on top of the EUC does nothing. The Russian dyno tests did this as well, and in their case, all it does is flatten the tire; their 500 lb flywheel measured essentially a 500 lb rider using the wheel. Also, any dyno test needs to be able to tilt the EUC forward and backwards to simulate a rider, which this setup does well I think. But ... this information also needs to be a part of the datastream that is ultimately analyzed, and I can't tell if that is the case for the setup in the video. I have plans for a dyno that can do this, which is very simple like this setup. I'll post when the parts arrive and I get it together. Link to comment Share on other sites More sharing options...
Mono Posted February 7, 2017 Share Posted February 7, 2017 @KingSong69, the difference between the above experiment and a free spinning wheel is that the dyno-rolls have resistance. Therefore we see a different cutoff speed. This resistance however depends only marginally on the weight, AFAICS. Indeed, you could argue that this is the same in reality: The torque needed to keep up a certain (high) speed depends mainly on wind resistance and only marginally on weight, and the torque needed additionally for moderate acceleration, which depends on the weight, might in comparison be rather small. If the speed is large enough, this will always become true, the question is only whether 30km/h qualifies for large enough and what moderate acceleration means. It's not too difficult to estimate these numbers, but I just don't have time right now to do it. That the weight isn't relevant in both cases however doesn't help in terms of reality check: To see the "real" cutoff speed, the dyno resistance would need to reflect the wind resistance at the current speed. Link to comment Share on other sites More sharing options...
US69 Posted February 7, 2017 Author Share Posted February 7, 2017 @Mono What i dont like is that you are always "picking" the arguments, that are to your dislike...in this case the wheel weight...and jumping -hours or even days long - on this same argument...even if that "friction" or "abrasion" has its thing in it... i allready said, and what you seam to ignore: - There is a force by the wheel running against a generator.... - this test is FOR SURE not a 100% reality test - but it has proved to be the same result as some real life cutouts, so the "generator" force, even if not named exactly, can not be that wrong on what its doing It is sooooooo easy to bash against that setup and call it : not realistic, bla blah bla blah.... ....much easier as setting up a testplant in several hours and shooting videos about it by yourself...... So i will quote myself: 7 hours ago, KingSong69 said: I am writing this thread, as i think Ferenc really deserves some Applause for the things he is doing for the community and for Electric unicycling! Also i believe, that i am for sure not the only (EUC)Freak, who is interested in the behaviour of his wheel on extreme situations? Or? Am i? And now i'm out and thinking about a --at least-- 24hour break, like @Smoother Link to comment Share on other sites More sharing options...
Mono Posted February 7, 2017 Share Posted February 7, 2017 16 hours ago, KingSong69 said: What i dont like is that you are always "picking" the arguments, that are to your dislike... I am different then.^1 I like if someone is picking an argument which to me appears reasonable and then tries to expose its problems. Then I learn something, given the picking was justified. I guess that's one reason why I do it. BTW, I don't pick on arguments because I dislike them, but because they seem to be incomprehensible or misleading or false. In the above case I didn't understand, and still don't, why they put 90kg load when load doesn't seem to make any apparent difference from the physics view point. 16 hours ago, KingSong69 said: i allready said, and what you seam to ignore: - There is a force by the wheel running against a generator.... that's what I meant when I said that the difference between the above experiment and a free spinning wheel is that the dyno-rolls have resistance. So no, I did not ignore it. 16 hours ago, KingSong69 said: - but it has proved to be the same result as some real life cutouts, so the "generator" force, even if not named exactly, can not be that wrong on what its doing right, and the result has shown that it is independent of the weight, which was, I believe, my original point. I also conceded/realised that at high speeds, weight is probably not important in practice as well, so in this sense the test rig seems to perfectly reflect reality. 16 hours ago, KingSong69 said: ....much easier as setting up a testplant in several hours and shooting videos about it by yourself...... Because I didn't setup a testplant myself I am discouraged to critically interpret the results of others? Sorry, that does not make any sense whatsoever and I wouldn't call that showing interest in the actual behaviour of EUCs. ^1 if you dislike my posts you can choose to ignore them all-together, there is an option for that in the top right forum pull down menu. Link to comment Share on other sites More sharing options...
Smoother Posted February 7, 2017 Share Posted February 7, 2017 W. W. What! Someone mentioned my name? Oh noooo! Leave me out of this, and let me finish my beer quietly in the corner here. ? Link to comment Share on other sites More sharing options...
MaxLinux Posted February 8, 2017 Share Posted February 8, 2017 45 minutes ago, Rehab1 said: There has been so much anger on this forum lately! Why? I did not sense anger, just strong opinions. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted February 8, 2017 Share Posted February 8, 2017 I think that's quite a good setup to test failure speeds as you can vary the "rider" weight easily enough. 75 kg is about 165 pounds. If manufacturers developed a similar testing rig, they could publish some tables of maximum speeds related to rider weight and battery charge / condition so people have a better idea of where their wheel can fail. I think the applied weight on the EUC is important to consider as it affects the tire contact patch and rolling resistance. An EUC running a high pressure might be able to achieve a faster top speed and longer range of riding than one with a low tire pressure where there is more drag from the tire being squished more. Link to comment Share on other sites More sharing options...
Smoother Posted February 8, 2017 Share Posted February 8, 2017 Actually I am going to chime in here, now that I've finished my beer. Firstly, thanks to @KingSong69 for sharing this data with us. In 1687 Sir Isaac Newton ( another profoundly influencial Britt, like myself ?) published Principia Mathmatica ( Latin, and not the full title) . In it he lays out three laws of motion. the first law of motion states more or less: A body in motion will stay in motion unless acted upon by another force and A body at rest will stay at rest unless acted upon by another force. end now I'm no physicist, and I didn't play one on TV, AND I didn't stay at a Holiday Inn Express last night ( American humour) but I do drive a heavy car, and have owned light cars too. What I know from theses experiences, and from my old college roommate, Mr Newton, is that once ANY car, motorcycle, EUC , whatever, is moving at a steady speed ( all things being equal) the WEIGHT of it does not affect the energy needed to keep it moving at that speed; wind resistance, yes, hills, yes, but not weight. Think of a space ship in zero atmosphere a long way from any heavenly bodies, once up to its 15,000 miles per hour, it stays at that speed because no other forces are acting upon it. Now before you start typing about mass and wind resistance, and acceleration, and hills, let me try and clear all those up now. Mass, and wind resistance can be considered the same here, a bulky person ( maybe he's wearing a lot of winter cloths, and a more compact person of the SAME weight; oh let's say cruising along a sunny beach in Spain in shorts and a tee shirt ( any similarities between person B and myself are purely coincidental ?) will have different masses relative to their frontal area, this will affect their wind resistance, BUT, once moving at a steady pace, the the amount of energy consumed, although different for both, remains constant; wind resistance on Ferenc's treadmill is supposedly simulated by the alternator attached to the rollers. I'm not sure if it's actually putting out a speed related current, because there is no metre on display, and I know that an automotive alternator needs a current applied to its coils in order for it to produce electricity ( load) maybe Ferenc has this sorted, I don't know. I would assume yes. Acceleration. IS another force, that changes Newton's equation, and for that matter deceleration too. So, to paraphrase Newton, once acted on by another force, will change the speed or lack thereof of the object. Acceleration is not being tested in this video. hills. Hills, both up and down, including small ramps, speed bumps, etc, deliver a force to the equation known as gravity. Gravity, as a force and concept was defined by someone else, no wait, it was good old Newton again, with his Apple falling from the tree story, followed by years of study. Gravity is a force, so once applied to our object in motion/at rest, causes a change of velocity. Hills are not being tested in this video. ah ha! You say, but gravity acts on us all the time, but when we stand still on a flat surface, or move along a horizontal road, we don't accelerate downwards. No, that's true, because, in this case gravity is exhibiting a form of energy called potential energy. It has the potential for energy, but the force of gravity is being counteracted by an equal upward force from the surface the object is standing on , or moving along if the object is moving horizontally, and once these forces are in equilibrium, neither object moves, up or down, yet the moment the upward force is less than the gravitational force, the object will begin to move downwards, think of a brick on a empty damp cardoard box, or you reach a downward slope. Everything not as low as it could go, has potential energy. The computer you are staring at while thinking, this Smoother, he is some kinda genius! ?, has potential energy. If the desk, lap, etc suddenly disappeared what would it do? Gravity would turn its potential energy into actual energy and accelerate it towards the floor. so what does all this have to do with the treadmill? I don't believe that any weight higher than that necessary to keep the tire in contact with the rollers, and not slip, is sufficient for ANY rider of ANY weight, for the purpose of testing top speed, period. Which, is what Ferenc is doing in this video, UNLESS the rider is trying to carry an 8'x4' sheet of plywood home from the store, in which case the resultant wind resistance would be significantly high to impede his progress. Specific weights are only necessary to test acceleration and deceleration runs BUT, AND THIS IS IMPORTANT, THE WEIGHT NEEDS TO BE ADDED TO THE ROTATING MASS OF THE FLYWHEEL, NOT ON TOP OF THE WHEEL, or additional electrical load need to be added proportionally with the speed of rotation. This is the only way to simulate rider mass for the purposes of acceleration/ deceleration. Why? Because that extra mass/ electrical load on the flywheel ALSO has to be accelerated in its rotation and this takes different amounts of energy depending on how much mass/ electrical load is added, in the same way I light rider can out accelerate a heavier rider on the same type of wheel? No amount of weight added to the pedals will simulate rider weight on a stationary testing apparatus for the purpose of top speed testing, or acceleration, or braking. This is how real dynamometers do it btw; weights are added to the rolling mass appropriate to the weight of the vehicle. so in conclusion I agree with the "weight on top means nothing in this test " crowd. what about rolling resistance? Right! Who gives a flip. If your heavy pump it up some more. Weigh less; not so much. @zlymex reported that tyre pressure has little effect on range ( he has data) and I don't believe it has any noticeable effect on acceleration or top speed, unless your tire is flat, in which case you have other things to worry about, like how to get home. Finally, I would like to applaud Ferenc of electro sport for actually making his treadmill, and using it. I bought my ks14c from him btw. EDITED FOR CLARITY AND ROLLING RESISTANCE Link to comment Share on other sites More sharing options...
Rehab1 Posted February 8, 2017 Share Posted February 8, 2017 3 hours ago, Smoother said: Firstly, thanks to @KingSong69 for sharing this data with us. Perfect way to start a conversation! Thank you for all your hard work @KingSong69! Link to comment Share on other sites More sharing options...
Mono Posted February 8, 2017 Share Posted February 8, 2017 9 hours ago, Hunka Hunka Burning Love said: I think the applied weight on the EUC is important to consider as it affects the tire contact patch and rolling resistance. An EUC running a high pressure might be able to achieve a faster top speed and longer range of riding than one with a low tire pressure where there is more drag from the tire being squished more. The difference in top speed is likely to be marginal, because above about 25km/h the wind resistance dominates all other terms. http://mccraw.co.uk/wind-resistance-cycling-speed EUCs probably have a little larger wind resistance than bicycles due to their larger front face. As for the range I am still on the fence, as there are reports that tire pressure influences range only marginally. Maybe this is for the same reasons though, as we expect the dependency to show only up to moderate speed, say 20km/h or below. Link to comment Share on other sites More sharing options...
Mono Posted February 8, 2017 Share Posted February 8, 2017 11 hours ago, Rehab1 said: There has been so much anger on this forum lately! Why? I wouldn't necessarily quantify it as much, but I think the main trigger is persistence in openly expressing opposing opinions Link to comment Share on other sites More sharing options...
Mono Posted February 9, 2017 Share Posted February 9, 2017 On 07/02/2017 at 2:44 PM, KingSong69 said: where you Interpret a working force against a Person leaning in an as "not needing power" FTR, this is not my interpretation. My interpretation is that tiltback in itself does not change the force/pressure and if the driver changes the force/pressure as a reaction to tiltback the needed power translates into added forward momentum of the wheel. Link to comment Share on other sites More sharing options...
meepmeepmayer Posted February 9, 2017 Share Posted February 9, 2017 Crazy to see how big the difference is depending on the battery percentage! Almost 10 km/h! Too bad he did not make a 20% test (or even 10%) that would have been very helpful as the worst (realistic) case. Nice lending your wheel for testing @KingSong69 how did that happen? Link to comment Share on other sites More sharing options...
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