Here we have a sighting of a UFO by 4 fighter pilots in 2 seperate aircraft. With a combination of on board radar and measurements using finger spans against the canopy, later calculations showed the object to be between 600 feet and 1000 feet in diameter.
As the fighters closed in to a distance of 8 miles the UFO accelerated vertically, with the rate of climb estimated to be 5 MILES PER SECOND.
This report by 4 highly skilled fighter pilots has been sitting for 52 years in the files with no apparent interest taken by anyone. This confirmed rate of acceleration would be about 800g, or 800 times the rate of our gravity.