A few days ago a group of dynamic soaring R/C aircraft enthusiasts set a new (there’s no sanctioning organization) speed record by using a method that sailplane pilots and birds know but that the rest of us powered-plane fanatics are sadly unaware.
The method is called dynamic soaring, and the concept is actually pretty simple, though its application to human-piloted craft is largely inadvisable, for reasons you’ll see.
When there are two air masses, one moving fast and the other, not at all, a craft can climb from the still-air mass into the one moving rapidly toward it, a headwind. As the plane enters that new airmass, it immediately gains airspeed, and as it turns 180 degrees—looping is the preferred method—it keeps the airspeed it gained and greatly adds to its groundspeed because it’s now flying downwind. The loop continues until the plane is going really fast.
In this case the aircraft is a model built specifically for this kind of flying. It’s really slick and super strong. Strong is an absolute must, as these craft can pull as much as, and this is not a typo—100 Gs. The flying skill of the R/C pilot has to be great, and, yes, if somebody got hit by this thing, it would definitely be lights out. That said, as you’ll see, this particularly hill, favored by dynamic soaring folks, is in the middle of nowhere. The wind differential, by the way, between the two air masses is around 65 mph.
Oh, and while the method can be used by full-size sail plane pilots when there’s a strong wind shear aloft, such gradients are more commonly found close to the ground, so, yeah, not advisable. This is not to mention that people start to black out before 10 Gs, never mind 100.
The video is not great, but you can get the idea for how fast the plane is going, if you can even see it. Look for a tiny white blur of pure speed. At its top speed, it hit 548 mph, measured by radar. Congrats to the team, which included pilot Spencer Lisenby and radar operator Bruce Tebo.
