While being considered unmanned aerial vehicles, electric rc gliders sailplanes have a different structure and way of operation than rc planes or quadcopters. In this article, we are going to explain what is a glider and how it differs from other radio-controlled aerial vehicles.

What are electric rc gliders sailplanes

Generally speaking, a glider, or sailplane (USA), is an aircraft that doesn't use an engine or any other kind of propulsion to fly. The lack of propulsion is compensated with a wide wingspan, improved aerodynamics of the fuselage, and light materials. The definition has been altered over time, with new gliders being created that have some sort of propulsion that helps them to take off or to gain lift in critical moments. However, the source of propulsion added is not enough to make the glider fly like a plane.

Electric rc gliders fall under the modernized definition mentioned above. They have an electric engine that is not able to increase the speed of the glider or bring it to great heights. It is just used to add a slight lift when the aircraft starts losing altitude and make the device more maneuverable and stable. For example, when the glider gets unstable during flight, the pilot can use propulsion to stabilize it.    

Wings

One of the most visible peculiarities of a glider is the unusual ratio of the fuselage size and wing size. The wings of a glider are significantly longer than the wings of a plane with the same length of the fuselage. This is made to increase the lift, by penetrating more air which ends up in more lift force. At the same time, the wings of a sailplane are extremely thin, which has a role in improving the aerodynamics, reducing the air resistance, and making the aircraft lighter. 

Still, exaggerated wingspan has also a drawback. It makes the glider less maneuverable, reducing the capability of turning left or right, which makes it hard for the pilot to react promptly to an obstacle. The glider will fly straight ahead most of the time, being pushed forward by the air currents that manipulate its direction.     

Aerodynamics      

Another feature of a glider that is easy to notice is its perfect aerodynamics. The fuselage is round, smooth and thin, deprived of steep and sharp shapes that help manipulate the airflow, making it exert less pressure on the aircraft and generate more lift.

Also, gliders don't have a cockpit area which is typical of engine-powered jets and alters a bit the shape of the aircraft. While the plane pilots are sitting on the chair, the glider's pilot is lying like a Formula 1 pilot, which is a way to preserve the streamlined design of the fuselage. The effect provided by this feature is not quite noticeable in an rc glider because it doesn't have a human pilot. Which is even better, because the manufacturers can make the sailplane as aerodynamic as possible.

Take off

The glider's take off also differs from the launch of a drone, helicopter or any other rc vehicle powered by a motor.  Once the aircraft is equipped with an engine, it can take off by itself as soon as you press the take-off button on the radio control. In the case of an rc sailplane, the launch is not as simple, as it doesn't have the needed propulsion to get to the air. The electric motor cannot send the aircraft in the sky, because it is too small and weak. This is why you will have to perform the launch yourself. You will have to take the glider in your hand and give it a fast and firm push from the height of your head.

Make sure that the aircraft is perfectly horizontal when it leaves your hand. If it looks upwards, it may stall and crash. You are better off launching the glider from a hillside or clifftop, so that it catches the wind and starts soaring. The reason the glider will soar more if launched from a hill has to do with the air currents that tend to climb to the top of the hill, so your sailplane can use these waves to gain lift.  

On the whole, rc gliders are aircrafts that use air currents to soar across the sky. They don't rely much on their electric propulsion, as it's insignificant, but rather use their long wings, aerodynamic fuselage and lightweight to gain lift and perform long-range flights.