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Traction and Battery Placement

Traction and Battery Placement

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Old 02-20-2017, 06:52 PM
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Default Traction and Battery Placement

Hello everyone!
Maybe somebody knows the answer to this question:
Obviously battery placement towards the front of the vehicle increases steering response.

This shifting of center of gravity would have the complete opposite effect in a real car (more understeer).
In a real car the lateral force on the front tires increases with the mass towards the front but the friction of the tire to the surface stays (nearly) constant -> more understeer

So in an RC Car the friction on a front tire must INCREASE with mass. Does anybody know why?
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Old 02-23-2017, 10:32 AM
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Because you can't compare real cars to 1/10th scale cars.

If you scale up these little cars to real world size, they would weight 150kg and have a top speed of 400mph

Get it?
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Old 03-12-2017, 08:34 PM
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Originally Posted by ZEe_NYC View Post
Because you can't compare real cars to 1/10th scale cars.

If you scale up these little cars to real world size, they would weight 150kg and have a top speed of 400mph

Get it?
Actually, since physical objects are in 3 dimensions, length, width, height, so too must the weight as it is scaled up.

A 1/10 scale car weighting 3lbs would be a 3000lbs car scaled fully (3x10x10x10).

Next is speed. Scale speed is roughly equal to the square root of the scale factor. So if a full size car is going 100mph, it's TRUE scale speed is 31.6mph for a 1/10th scale version. So if your mod touring car is clocked at 63.2 mph down the main straight at your local track, the real life scaled up version is not going 632mph, but more like 200mph--closer to real life than we expect.

You don't simply divide/multiply by 10. Why? Because gravity is constant no matter the scale, at least on Earth.

This is a simplistic take, but bear with me here, and if you have the kinematic know how to work this out, please do work it out for yourself as it is quite fascinating:

Take a ball 10 meters from the ground, drop it and record the time it takes to fall that height. Now take a ball 1 meter from the ground (1/10th the distance) do the same and record the time. The ball dropped from the lower height will only need roughly 31.6% the time it takes for the ball from a height 10 times higher.
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