According to the Guinness World Records, Germany’s Niels Herbrich flew a rocket-powered remote control plane to a record-breaking speed of 465.544 MPH back in 2018. Three days ago, California’s Spencer Lisenby shattered that record by piloting an RC plane to an astounding speed of 548 MPH, but their plane lacked one important feature: an engine powering it.
Lisenby’s glider does have an onboard battery that is used to power servos that operate its control surfaces and to communicate with the pilot’s remote control. But for propulsion, it uses a flying technique called Dynamic Soaring where pilots strategically take advantage of the interactions between air masses with different wind speeds. Air currents actually accelerate as they blow up a hill, and will take anything floating in the breeze along with them, be it a bird or a glider. Find a hill tall enough and an aircraft, particularly a small, light RC model, will be able to hit record-breaking speeds.
By flying in a continuous loop, first up the side of the hill and then back down again at a farther distance where the wind speeds are slower and create less resistance, an RC glider pilot can not only keep their plane flying indefinitely, they can also slowly build up incredible speeds.
But it’s not like you can walk into a hobby store, choose a glider off the shelf, and then make an attempt at a record-breaking flight. Lisenby’s gliders are custom designed with help from German aerodynamics experts and are built from reinforced materials like you’ll find in high-performance sports cars. The tight loops these gliders need to fly in can result in G-forces as high as 120g at peak strain. By comparison, at just 9g, the heart isn’t strong enough to pump enough blood to the brain for a human to remain conscious.
Piloting a glider flying at 548 MPH also takes an impossibly steady and skilled hand at the controls. At that speed, the craft covers just over 800 feet every second. In an interview with New Atlas, Lisenby acknowledges that other pilots have taken advantage of pilot assist devices that can automatically stabilize issues like roll so the person behind the controls can instead focus on making perfect loops, but they prefer the old-school approach where success lies entirely with the skill of the pilot and the design and construction of the plane.
That approach makes the new world record all the more impressive, but as that record continues to fall and these speeds start slowly creeping up on the sound barrier, the manual approach to flying might have to change as pilots start to reach the limits of human reaction times.