Gulfstream Aerospace Corp.in Sept 2010 announced that its ultra-long-rang e, ultra-large-cab in Gulfstream G650 reached Mach 0.995 as part of its 1,800-hour flight-test program. Accomplishment establishes G650 as world’s fastest civil aircraft.Howeve r North American X-15 , a vriant of B52 Bomber is the fastest piloted aircraft ever.It holds 4,520 mph world speed record.For your reference , ( At sea level at 20 degrees Celsius (68 degrees F) and an atmospheric pressure of 29.92 inches of mercury,) Mach one is 761 MPH.So this was almost 6.5 Mach .Wow!!!!

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