Thank you very much for showing me that, it's exactly what i needed to understand.
Thats a comfortable way to get every data, great.Today I want to correct my work at the BB. It is not exactly there, where I expect it to be and a little sloped. And there are still missing some fixings. Then the frame is finally finished.
Stephan dirk.bonne@xxxxxxx wrote:
Stephan Schöling wrote:Hej Dirk, i'm not the best in theoretical physics, even not a good mathematician, so let me thank you for your lessons. Be honest if you think my skills are to low to understand these things or i am just boring you with that !Hey now Stephan, you are getting a wrong impression here.I did get the theoritical mechanics during my education but that is really very very long ago.dirk.bonne@xxxxxxx wrote:Hi Stephan, Stephan Schöling wrote:Hej Dirk, please, can you explain why you see a system with two weightpoints ? I only see the Center of Gravity (CoG) and can´t understand why the BB should be important.Well it is only to model the weight of the bicycle and the weight of the rider. Some of it is on the front part and some of it is on the rear part.Ok, i got that. We can measure the wight of the bike and the proportion front/rear easily. But how can we do this with a rider ? We would need 2 persons to read the scales under the wheels at _exactly_ the same time, which is nearly impossible. So we have no usable data of the weight proportions of the bike with the rider, or has anyone ?It is some work but doable: (not 100% precise). Here is a possibility: 1) take your bike in your hands, stand on the scale: totalw 2) Put bike on grond again, put the front wheel on the scale, rear wheel somethign whit the same height as the scale. Get on the bike and read the scale: frontw the rearw = totalw - frontw and Cog is: CoG = WB * frontw / totalw with CoG measured from the rear wheel. 3) Now the weight of the feet on the pedals. If you are willing to take a error into acount: sit on ground, put the scale in front of you, strech your legs and put your feet on the scale. That will be about the weight of your legs on the pedals (I get about 10kgs). legsbbw=10kg. The weight of the front part: part the python in two parts and weigh the front part. The CoG of the front part along can be found visually - not so difficult. Now in the newton model I would: put the weight of the front part in the CoG of the front part put the legsbbw at the BB put the totalw - legsbbw - frontpartw at the CoG of the bike. groetjes, Dirk ============================================================ This is the Python Mailinglist //www.freelists.org/list/python Listmaster: Jürgen Mages jmages@xxxxxxTo unsubscribe send an empty mail to python-request@xxxxxxxxxxxxxwith 'unsubscribe' in the subject field. ============================================================
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