Durations depend on the the plane and WT Strength slider setting. Also, planes next to you generate more WT than those in front of you.

purchased activesky 6.5 about three weeks ago ... i'd given up waiting for MS to fix the continued problems with their real-world weather server.enjoy the product and the wake turbulance simulation. hit three or four patches yesterday during a flight ... damn AI flying the incorrect altitudes during cruise. plane bounced a bit, and no barrel rolls.also expereienced wake turbulance on takeoff a few times. enjoy that level of 'realism'. AIsmooth has kept me out of problems during short approach and landings.--

It is certainly pokey and can hang around for a while. IIRC when I was flying GA here in OZ the figure for a light aircraft movement waiting after a heavy aircraft movement was 15 minutes. Thank goodness FSX ATC doesn't simulate that. :(

15 min is completely overkillIn the USA, it's two minutes with a small (ie piper warrior) following a heavy's (ie B747/A340) departure from the same runway as long as the small is also departing full length, otherwise it's 3 minutes from an intersectionThere is no time distance required if there is a small and a large (B737/A320 etc) and the small departs full length - only a "caution wake turbulence" is required from the controller.

I do not know how ASE simulates WT effect, but in real world, the vortex travels outside (left of runway and right from runway) the active runway. Of course it depends on winds.Consider two parallel runways (i.e. KSEA) with ~90/xx wind. You are in light A/C, to Your right Jumbo has just taken off. It is much possible that You will hit his wing tip's tubrulences when airborne too late. But Cessnas and Pipers do not need so long runway, You can rotate much earlier and turn to the left to avoid WT.To dig deeper I highly recommend googling - You will see it (pictures, videos) and read how to avoid this.