# Calculating max speed at a turn with downforce

1. May 15, 2012

### anru

Hi guys..

I want to find out how to find the maximum speed of a slotcar at a unbanked turn with a permanent magnet which have a downforce of 200 grams and a electromagnet which can brake in the interval 0-560grams.

My slotcars topspeed is 5m/s and the wheight is 200grams.
The coefficient of friction of the slotcar on a unbanked raceroad is 0,65.
The radius of the turn is 0,33m.

There are 3 types of turns 45,90 and 180 degree turns.

I have calculated that if the slotcar didn't have the electromagnet or the permanent one, it had a maximum speed of 1,45134m/s

Can someone help me?

Last edited: May 15, 2012
2. May 15, 2012

### K^2

Permanent magnet is likely to generate tangential force in addition to downforce. And I'm not sure what you mean by saying that electromagnet can brake. Which direction does it apply force in?

Without any tangential forces involved, (mv²/R)/(mg+Fd)=μ. If you are doing forces in grams, then take g=1. μ is your friction coefficient, R is the turn radius, m is the car's weight, and Fd is the sum of all downforces. The length of the turn doesn't make a difference. Rear wheels can begin to slide at much slower speeds, depending on where the magnet is located and how the weight is distributed.

3. May 15, 2012

### anru

Hi. Thanks for the reply. The magnetic downforce is a downgoing force (hoslotracer.com/content/magnetic-down-force-measurements)