Pretty neat
http://sploid.gizmodo.com/how-the-gun-turrets-work-on-a-b-29-bomber-1746148228
Nice video and I might point out, this was the same system used on the B-50 and B-36 aircraft!
As far as engine cooling was concerned, the latest "C" models, of the 29, had improved "baffling" on the engines to better direct air to the rear "bank" of cylinders, which were the problem with that engine! This was the same engine used on the Lockheed 1049G "super Connie", which flew for many years for various airlines with no more than normal cooling problems on climb out!
I rode a "Connie" once from Dallas to Atlanta, and it was interesting to see the "compound" pots, turn a "cherry red" when in flight, on the R-3350 "compound" engine! I am sure that sight scared more than one passenger in the years that engine was used!