hold on everybody, They start about 100 feet in the air with 99a wheels at almost vertical drop. The dude invented the mega ramp, 50mph seems plausible, that doesn't mean that everyone hits 50. I doubt he's lying. Someone could figure out this probably mathematically, it would just take awhile to figure it out.
Danny way didn't invent the Mega Ramp we use today. He created a "mega" halfpipe to break a high air record back in 1997, but Andy McDonald definately had some influence from his ramp used in the Guiness World Record long jump in 1999. I would say that the today's Mega Ramp is a collaberation of these two ideas.
About Andy Macdonald:
In October 1999 *, Macdonald secured a Guinness World Record, where along with his watch sponsor Swatch, he constructed an Evel Kneivel-style skateboard ramp * and proceeded to jump over four parked cars for a total distance of 52 feet 10 inches. In typical Andy style, his record would not last long. Just a few months later, in a competition held in Lake Havasu, Arizona *, Andy managed to not only out-distance the other competitors, but he outdid his own record with a jump of 56 feet 10.75 inches.