A drone with no engines (or gliders) but it can reach speeds of up to 881 km/h. This is a record set by Spencer Lisenby, who broke the previous record of Germany’s Niels Herbrich, also with a model aircraft but fitted with rocket engines, maximum cruising speed at 750 km/h. H.
Lisenby’s glider, except without engines, still has all the components of an RC plane with batteries, servos to control the wings, radio communication system to receive remote control commands. In order for this glider to fly without an engine at very high speeds, Lisenby exploited an aerodynamic form called Dynamic Soaring. Wind can reach extremely high speeds as it blows to the top of a hill, and since the ’60s, drones have used this power to keep planes flying almost forever. No engine needed.
The fast-moving air mass over the hill will have friction with the stationary air mass on the other side of the hill, the area of friction between these two air masses creates gas turbulence or shear layer. Taking advantage of this, the controller of the RC plane will let the aircraft fly in a loop, get a great lift and thrust in the direction of the wind to the top of the hill, then plunge into the still air mass, the altitude can be close to the ground. and back to the fast-moving air mass above. Thus the glider will be able to fly continuously without the need for an engine.
In the wild, black-footed albatrosses also exploit dynamic soaring to fly continuously without flapping their wings. It exploits the wind speed difference created by the waves to fly farther, flying continuously without much energy.
However, it’s not as simple as going to the store to buy a model roller coaster and then climbing the hill and dropping it, you can achieve “altar” speed like Lisenby. Lisenby’s glider was designed with the help of aerodynamic experts from Germany and is made of materials commonly used in sports cars. Flying in these loops, the glider can be subjected to a G-force of up to 120G and try to imagine, a normal person would pass out with a G-force of only 9G because the blood cannot pump to the brain because the heart is squeezed.
Controlling a glider flying at speeds of up to 881 km/h is not easy, requires superior control skills and especially Lisenby does not use automatic systems to support stability of the glider. like many other players. Lisenby is a professional RC glider, he holds many world records and is also a pioneer in glider design. He said the glider that made the last record could reach a speed of 933 km / h. His record-setting attempt was made at Mount Parker, where a very strong northeasterly wind blew.