1/16 Scale speed -> Yellow TT 1:48 gearbox - Reasonable?

[ziddan]

Hey all!

So im now working on my first 1/16 tank, doing a panzer 2.

For motors im currently looking at the common Yellow TT gearboxes with a 48 to 1 ratio as a possible motivational force.

My intent is to use separate ESCs and a 2s lipo.

Looking at some vids the gearbox seems to do about 250rpm at 7volt without any load.

Putting that and a drive sprocket diameter of 58mm into a wheel speed calculator gives very close to 3km/h, multiplied by 16 for the scale gives a scale speed of 48km(h which is in the just above ballpark for a panzer 2, with the load from the weight of the tank it will probably be right in the ballpark.

With the space constraints im working in i may need to do a gear on the output shaft from the gearbox to the shaft of the drive sprocket to move the gearbox back a little in the hull so i will easily be able to further gear it down a bit.

So my questions on this are:

Did i get the speed calculation right?
Should i further gear it down? (as i guess top speed isnt something one expects to be driving scale tanks at)
and
does anyone have experience and opinions on the yellow TT gearboxes?

Thanks!