Yes, it was used to get the estimated run distance of the torpedo depending on the "shooting range" ;) but its not really neccessary for the simulation of this computer

How would it look like in real life? Is it a series of little lights that turn on at the calculated range?

No, its a turning cylinder with a scale on it :)

Hmm... It's pretty small compared to the other gauges. Unlikely that it could be made readable if I were to model it after the original, but I would still prefer to have it in some form.

Do you think a text-like display would be acceptable? Like a rotating number gauge similar to a trip meter?

I made the scale a plane texture like a shape that could move up and down behind the front panel, so it looks like rotating ;) its just not programmed, as it was left and not important. So you mean a rotating number gauge...personally i love the realistic look of this machine and dont like the idea of adding some non original thing :D so, if this should be added, we must find a way to add some new code for this dial. So we link the movement of the texture to the torp distance knob.

Heres a detailed pic of this dial

http://www.tvre.org/images/22_fot_11.png

Ohhh! So it doesn't show you the actual torpedo run length, instead it shows you the maximum initial distance to the target you're allowed to set, otherwise risking firing at a target which will be out of range, correct?

I thought that gauge would make it easier to estimate the torpedo run distance, and therefore the time before the impact.

If my algebra is correct, I would get the estimated run length (ignoring parallax) with the following equation:

V_t = E * sin (AOI - β) / sin (β)

AOI is calculated by the TDC, E and β are set by the operator.

Was such an equation used after firing to get the ETA of the impact? Or did they wait until the torpedo reached the distance set by the operator, plus some amount of seconds, before exclaiming the torpedo missed the target?