Looks like Antoine Albeau's track from 8 years ago, it has got a 500m speed of 51.8 kts
wonder why it has been posted now?

Cool tracks, thanks for posting! It took him about 6 seconds to go from 20 to 40 knots, that's crazy acceleration (up to 4 knots/second). Deceleration is even crazier - 4 seconds from 50 to 20 knots, with a max of 10 knots/second.