Scale speed

[Meter Rat]

How do people work out the scale speed, of their models? That is if you are concerned about these things.

This is a formula I found while looking for a simple method. I did not want to go down the whole time, distance thing, as I will be honest, my maths ain’t that great.

Apparently mathematicians. And engineers who build boats for use in test tanks use this formula for obtaining scale speed.

SS=RS/SQRT(S
SS=Scale speed
RS=Real speed
S=Scale

To calculate a scale speed, divide the real speed by the square root of the scale.

How accurate would this formula be? My view is if boat designers use it, must be right?

Most people on FB have decided that to get scale speed, you just divide by 1/16. So a full size tank covering 16km in one hour is travelling at 16kmh. Their logic is a 1/16 tank will travel at 1kmh as 1km is 1/16 of 16km. This just looks wrong and is painfully slow. It may look correct for a WW1 tank, but for a modern MBT

[keilau]

How do people work out the scale speed, of their models? That is if you are concerned about these things.

Most people on FB have decided that to get scale speed, you just divide by 1/16. So a full size tank covering 16km in one hour is travelling at 16kmh. Their logic is a 1/16 tank will travel at 1kmh as 1km is 1/16 of 16km. This just looks wrong and is painfully slow. It may look correct for a WW1 tank, but for a modern MBT

I am one of those people who believe speed is a linear length scale. I measure the RC tank speed and multiple it by 16 to get the scale speed. No square root was used.

A 16 kilometer per hour speed is very fast for WW1 tank. The modern Abrams can go as fast as 60 kilometer per hour on highway for transport operation. The 16 kilometer per hour speed translates to 0.9 feet per sec which is a decent speed for the 1/16 scale RC tank in rough terrain but is at the slow end. Most of my 1/16 RC tank with 390 motor can go 3 feet+ per second in straight line. Too fast for maneuver control, but fun to run straight line.