Surely a big fat wobbly Chinook couldn't get out of the way that quick!
You'd be surprised how well a Chinook can turn. When you have the lever in your armpit, maxi chat on the ASI and you're pulling the 'wings' off in the turn at Flight Level Zero, the mighty wokka moves quite well and can look after itself against the average FJ threat. Bear in mind that a 2g turn at rotary speeds is, I think, equivalent to a 32g turn at FJ speeds, so the RW will always out turn the FJ. The rest is tactics manual stuff, so enough already.
A camoflaged helo at low level can be extremely difficult to visually acquire (I have always had to talk the jet jockey onto my position when playing Fighter Affil). The rotary can also play dirty by going ultra low and hiding or by trying to encourage the jet to stoof into the ground. If all this fails to work, a Chinny with a triple fit of 'lead laser' would probably bring tears to the eyes of many aggressors. Point the solid beam of glowing lead in their direction and watch them bug out and run for their hotel bar 500 miles behind the FLOT.