# RC Car scaling Calculations

1. May 16, 2007

### DKTKD

Hello All,

I'm doing some fun at home experiments with my 1:6 scale RC car and I
wanted do some camparisons with its full scale counter part.
Mainly how jumping the two off a ramp (Duke's of Hazzard style).

I wanted to know if you can help me with confirming some of my scaling assumptions for mass, force etc.

1. Acceleration,velocity and distance:straight 1/6 scale.

2. Mass: I would like to add weight to the RC to scale the mass.
Since mass' relationship to density (p=m/v), the scale weight
would be 1/216 (1/6 ^3)of the full size car.

3. Force: Now the force required for the scaled mass to the acheive the scaled acceleration would be 1/1296 (1/6 ^ 4) scale of the original force.

4. Projectile motion (w/o drag): With the scaled veloctiy/accel i believe the
horizontal component will properly scale. However I don't believe the
calculations for the veritcal component will scale correctly, because the
hang time will not scale. This being that I can not scale gravity.

Since the hang time will not scale, this would effect the range
the scale model will travel in comparison to the full scale.

Is this correct? Is there a work around for this?

Thanks
RC Guy

2. May 16, 2007

### Mindscrape

Acc, vel, and position could potentially vary as more than 1/6, and position will certainly not factor as 1/6 because it will be at least be quadratic.

For the most part though, your approximations will probably work.