All of these small drag reduction changes were tested in the wind tunnel, and again on the prototype G550, and they worked. Rolls-Royce kicked in with a fuel efficiency improvement at cruise from the BR710 engines, and the result was a new tanks-full range of 6,750 nm with full reserves while cruising at Mach .80, which equals 460 knots true airspeed. Push the power up to cruise at Mach .85 and the G550's max range is up from 5,750 nm to 6,000 nm. Even more remarkable, at the maximum cruise speed of Mach .87-which equals 499 knots true airspeed-the G550 flies 5,000 nm compared to 4,700 nm for the GV. As cruise speed goes up, drag reduction becomes more complicated and demanding, so you can see how successful Gulfstream's Pres Henne and his engineering team were.