The Ostwind in Aces High II
The Ostwind is one of two mobile AA guns based on the Panzer IV chassis. It is armed with a 37mm FlaK 43 L / 89, firing 150 rounds per minute. The other anti-aircraft platform based on the Panzer IV is the Wirblewind and that is armed with quad 20mm.
Fighting in the Ostwind
The Wirblwind is more common overall, as you have a higher volume of fire and better ballistics, but you're about as likely to see an Ostwind at a V base, or at a spawn being attacked by B-25's, or Il-2's (both are slow aircraft, that can absorb enough damage to make the osti useful). You also have a 7.62mm (.30 cal) hull gun, but this is never usefull unless you're turreted and see troops running. You're unlikely to escape well aimed bombs, so you're best bet would be to find some thick trees and reverse into them. This will shield you strafing, and bomb blast to a limited extent.
Fighting against the Ostwind
Two things to remember when combating an Ostwind while in an aircraft: although the Ostwind is not easy to aim it only takes a single hit from that 37mm to rip your aircraft apart. Ostwind players who have learned the trajectory are very dangerous. If possible, try and drop a bomb anywhere near it and it will damage the turret. Also, strafing runs with aircraft guns will usually destroy the turret as well. The turret armor is only really useful against small arms fire from the ground.
-The ostiwind is unlikely to hit you at even 1000yds, as poor balistics and low rate of fire make finding the right lead a problem.
-B-25's, Il-2's, and other large aircraft should be cautious of the ostiwind, as just a few hits will be enough to seriously damage or kill you.
-stay clear of multiple flackers in close proximity, the volume of fire makes hits near guaranteed.