Thermal soaring or flat field soaring uses columns of warm, rising air called thermals to provide lift enabling the rc glider to stay in the air. Thermal soaring can be practiced from any relativiley flat field using a variety of launch methods which are discussed below.
Thermal Soarer Launch Methods
Hand launching – this simply involves throwing the glide by hand.
Towline Launch – here the glider is towed into the air using a line whilst the pilot controls it. The towline is either pulled by
another person or an electric / manual winch is used.
Bungee/Hi-start launch – the model glider is attached to a length of elastic cord or rubber tubing and line which is attached to
the ground. The bungee is stretch and released.
Piggyback launch – here the thermal soarer is attached to a powered rc aircraft using a cradle mounted top or bottom. A radio
controlled mechanism is used to release the glider when a suitable height has been attainted.
Discus launch – the rc glider is launched into the air using a discus type throw. The pilot holds the tip of a wing, spins 360° and
then releases the the model allowing it to launch at high speed. A special type of glider is used that can withstand the stresses of being launched in this manner. Discus Launched Gliders (DLG) are used in the F3K contest class which is rapidly gaining in popularity.
Aerotow launch – a rc aircraft known as a tug is used to tow the model glider to a suitable height before it is released. This method
is often used for scale gliders.
Competition classes for thermal soaring include
F3B – Launching is by: hand towing, electrical powered winch or hand operated pulleys. The total length of the winch line is 200 m. The length of the hand tows is 175 m.
F3H – Launching shall be by electric powered winch Maximum line length 600m with turnaround 300 metres from winch. Object is to fly the course non-stop with one model. Fastest time wins. Any pilot of the team may fly the model. If all flights are less than the course length then the longest flight wins. In the case of ties, the shortest time wins.