Confirmed units of measurement used in Supreme Commander:

VisionRadius: Tiles
MaxRadius: Tiles
MaxSpeed: Tiles/Second
RateOfFire: Shots/Second
TurnRate: Degrees/Second
MaxAcceleration: Tiles/Second^2
MuzzleVelocity: Tiles/Second
FiringRandomness: Degrees
RackRecoilDistance: Tiles

Where 1 Tile = 19.53125 meters (size of a wall section, 5km / 256 Tiles)
1.0 3DS Max unit is equal to 1 Meter! So 19.5 in 3ds max units should roughly equal to 1x1 tile.
As for Blender, I don't know. If you do know, feel free to share.

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***Speed calculations for supreme commander in m/s and km/h and mach number.
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"S" = speed in Tiles/seconds
"N" = km/h is in kilometers/hour
"X" = 19.5m/s is the approximate distance per Tile tile in game

to find S use the equation...

F(N)=N/3600(1000)/X = S speed in tiles per second

example: F(3560)=3560/3600(1000)/19.5 = 50.71 Tiles/second

and Multiply S*X = to get speed in meters/second

to find "N"

F(S)=S(X)(3600/1000) = N speed in kilometers/hour

example: F(50.71)=50.71(19.5)(3600)/1000 = 3560km/h

(fun fact: 3560km/h is the maximum speed of the SR-71 Blackbird; worlds fastest aircraft.)

to find the average mach number ((optional))
M = N/V ; where "V" = 1093km/h or the speed of sound in the medium.

(Note this is just a estimate not a real value since Mach number depends on the ratio of the moving particle over the speed of sound in the altitude the particle is traveling.)

example: M = 3560/1093 = mach 3.25