My campaign time following the second time through for missions where I didn't get Ace Rating the first time through Campaign is 11:07 hrs... and I think I even got the Colonel rating before completing Ace on Berlin.
The number of Air, Ground, and Sea targets destroyed may also factor into how soon you become Colonel... on many missions I was able to destroy more than the minimums required by generally keeping my wingmen in formation mode (I found it was the easiest way to ensure getting Ace rating for each mission).
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by peterrobson156:
Flying time, I am sure that you get it after about 14 hrs.
I donot think you can get it any other way. </div></BLOCKQUOTE>