i remember a few years ago, having flown overnight JFK - LHR, we were sat on the 757 shuttle ready to come back upto manchester. there was confusion with the number of bags in the hold, and this led to a 2 hour delay. eventually when we did set off - the 1 hour scheduled flight ended up being 23 minutes runway to runway. i seem to recall there was very little turning, so we might have gone in the most direct route possible, and when the engines roared on take off - they never seemed to throttle back until ready for approach at manchester.