Whenever I am on a 737 (of any kind), or for that matter, most planes that I have been on, when on approach (usually short final) the airplane produces contrails but not coming from the ends of the wings, rather from the middle of the wing, near the the flaps.Here is a video to describe what I mean
(goto about 2:20 for the best view of this). Looking at the pictures on facebook and others that have been posted, I just started to wonder when/why those different spots produce the same effect? The only fs addon that does this for me is my Quality Wings 757 and I don't know if any of the others should.ThanksRegards