I am in the process of designing an electric motorcycle, and would like to approximate the acceleration from various motors to inform my decision. I have written simple software to produce performance graphs, but my results seem a bit off - so i'd like to check my calculations.(adsbygoogle = window.adsbygoogle || []).push({});

Here is the basic setup:

To simplify things I first calculated the effective radius of the wheel based on the gearing (as if driving the wheel directly from the motor):

r = Wheel radius / (Gear2/Gear1) * (RearSproket/FrontSproket)

Then used: Motor torque (T) = Fd and F=ma to get a = T/mr.

From this I calculate velocity at time intervals using: v = u+at and distance: S=ut + 0.5at^2

Now the bit where I think I'm going wrong (if not already) - Incorporating drag.

Using the drag equation: https://wikimedia.org/api/rest_v1/media/math/render/svg/144ce01ab76e5e8a0662dbf0f5b922abfa726e9c I am using a coefficient of 0.5, and area of 0.4m^2.

When calculating the torque at the rear wheel, i'm doing (Motor torque * 0.9) - (Drag force * r). The 0.9 is just to add a bit of mechanical loss. But I can't work out if i'm applying the drag correcly. Any input welcome.

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Automotive Calculating acceleration from electric motor

Have something to add?

Draft saved
Draft deleted

Loading...

Similar Threads - Calculating acceleration electric | Date |
---|---|

Torque & Inertia calculation for a wheel | Apr 4, 2016 |

Calculating acceleration constant for linear actuator | Aug 3, 2015 |

How to calculate the max acceleration | Jun 24, 2015 |

Calculate car velocity, acceleration and drag | Oct 20, 2014 |

How to calculate bicycle acceleration | Jun 7, 2011 |

**Physics Forums - The Fusion of Science and Community**