From: Hex X37, Y15
The Biyalastok pocket was cleared by july 5 as far as I can determine. That is roughly two weeks from the start of the operation on june 22, which fits rather neatly in the time frame of WITE, one turn to surround them, one turn to mop them up. But I do agree that many pockets did take longer, and it seems that Soviet pockets were more resilent the longer the war lasted, that is why I suggested a connection with morale and leadership. And of course German isolated units were quite tough from the beginning.
Demyansk, Kholm or even Stalingrad are not possible to replicate in the game, they will fall much too fast. The air supply rule is a well intended, but since it is pure luck if you happen to have an airbase in the pocket, it is meaningless. I would be interested to hear if anyone has ever had any benefit from that rule?
IMHO normal air supply, provided it is possible to fly in a sufficient amount, and coupled with decent morale and leadership, should make surrounded units largely immune to isolation effects.
In my last game (versus AI on Hard) I held Orel surrounded for 4 turns in January/February 1942 (i.e., first winter) with a panzer division, an infantry division, and an airbase in the city. I saw that it was going to be surrounded, realized I wanted it held, and moved the airbase in deliberately. It was only attacked twice in 4 turns (and it was relieved of isolation at least once) but overall I was very happy with the results of a (small) pocket and an airfield.
Hmm, interesting, thanks! I don't think I would dare to do that against a human opponent though.