We had the same thing in the T-34C during Navy primary pilot training. It was placarded as the “relief tube”. We were advised by our instructor pilots not to use it...and I followed that advice...which was fairly easy since our sorties in the T-34C only lasted 1.0 to 1.5 hours.
Been away from the forum for a few days due to a health scare with the new grandson, all sorted now though. Still the Tudor, interesting reflection at 6 o’clock!
Thanks Wayne (allwoundup) for cannibalizing your Zo’ SW to help fix mine... Your selfless act of watch heroism does not go unnoticed! Bravo Zulu..