Entering a new hobby often presents many new terms that you may not be familiar with, and the RC soaring world is no exception. These definitions are in context to RC sailplanes. We hope this glossary helps make your entry into our fun and exciting hobby smoother:


The airfoil is the cross-sectional shape of the wing and determines the amount of lift and drag the wing produces. This directly affects the performance and handling of the model. 


ARF stands for “Almost Ready to Fly”. This means that the planes will require some work in the set-up, such as gluing or bolting some parts and installing the electronics. The ARFs can be half-built or almost completely ready with minimal assembly. 


All up weight. The ready-to-fly weight of the model, including assembly, servos, battery, receiver, ballast, ESC, motor, spinner, propellor and/or any other required equipment. 


Ballast is the weight that is added to the model glider to increase its flying weight. As the flying weight increases, the model increases its flying speed and stability and is useful in windy and turbulent conditions. 


Camber is the amount of curvature on the bottom of the airfoil. On models with wing control surfaces such as flaps and flaperons, the camber is usually referring to the deflection in the trailer edge of the wing. The deflection is set up for each flight mode, usually noted in relation to its moulded-flush position. More camber will yield more lift, and less camber will give you more penetration. Usually measured in mm. 


Center of gravity. This is the balance point of your model, measured at the root of the wing and measured from the leading edge of the wing. 


Discus launch glider. Non-motorized radio control gliders that are hand-launched into the air by spinning around and throwing like a discus. 


The electronic speed control (ESC) converts the signal from your receiving into commands for the brushless motor, allowing for proportionate control of the motor speed. 


An FAI multitask soaring competition class for hand launch gliders. 


An FAI multitask electric soaring competition class that originated from F3K. 


The failsafe is a safety setting that your radio control system reverts to when the signal between the transmitter and receiver is interrupted. Typically, a failsafe is either set to a pre-set control value or configured to hold the last input. 


Flaperons are single control surfaces on a wing-half that combine the functionality of the aileron and flaps. Flaperons are commonly used on DLGs. 

Flight mode 

Pre-determined settings on the transmitter for different phases of flight. Typical flight modes for a discus launch glider are Launch, Zoom, Speed, Cruise and Thermal. 


The main body of the model glider. 


Used to describe glider options in weight and sturdiness. The most common layups are Light, Standard and Strong. The Light layup will use a lighter-weight carbon fabric to lower the AUW, at the expense of wing stiffness and dent-resistance. Strong layup uses a heavier carbon fabric to increase the AUW, stiffness and dent-resistance.  


The nosecone is one type of cover for the opening of the fuselage nose. The nosecone slips onto the fuselage from the front and covers the entire nose section, rather than only covering the opening like a canopy. 


Used to describe how well a model can 'penetrate' the wind. Planes with better penetration will fly against a headwind better, useful when you are downwind and trying to come back to the field. 

Pull string tails 

A common type of tail linkage used in DLGs and other small RC gliders, pull string tails actuate the control surface with a torsion spring in one direction, while a wire pulls the control surface the opposite direction. 

Torsion spring 

A torsion spring is a part of the pull string tail linkage setup, and usually made from bent stainless steel wire. It is inserted into the hinge line of the tail control surface and glued in place. 


Pushrods are solid linkages between the servo arm on the servo and the control horn on the control surface. Pushrods on a RC glider are typically made with 0.8-1.5mm stainless steel wire, depending on the application. 


The receiver is part of the radio control system. It is installed inside the model and receives commands from the transmitter. These commands are then relayed to the servos, motors, and/or any other devices plugged into the receiver. 


The servo is a small electronic device that receives the user commands from the receiver and proportionally rotates. The servo moves the control surfaces through the connected linkage. 


The transmitter is part of the radio control system. It is held and controlled by the user and sends these commands to the receiver on the model. 

Wing loading 

The wing loading is the total mass of the model divided by the area of the wing or combined area of the wing and horizontal tail. 


This page is a work-in-progress. We will continue to update this as often as possible.