Free Flight model airplanes follow the wind and soar in rising thermal currents of warm air. They set their own course and are free of any control from the ground. If you have ever tossed a folded paper airplane or a dime store balsa glider, you have flown a free flight model in its most basic form. Free flight models are of two basic types: those that are flown indoors, and those which are flown outdoors.
Indoor Models are very light, slow flying models powered by twisted rubber strips driving a large propeller. Hand launched gliders and gliders that are catapulted into the air by a loop of rubber strip are also flown indoors. They are flown in school gymnasiums, auditoriums, and similar large open spaces. Indoor models are one of the least expensive and simplest ways to get started in modeling and suitable flying sites are available in most locations.
Outdoor Models are typically larger and heavier than Indoor models. Advanced types are capable of very high performance. Some have stayed in the air for nearly and hour in a single flight under ideal conditions Others have been carried dozens of miles before coming back to earth. the most advanced types can glide for ten minutes or more after only 5 seconds of powered flight.
In order to keep from losing them, most outdoor free flight modes are equipped with timer operated devices to limit the amount of time the engine runs (or rubber strip(s) loop in our case. Other timers or thermal couples (T/C) operate in a similar way to bring the model safely to earth before it is carried away in a thermal.
If you want further information about Free Flight, A wonderful discussion can be found on the Wikipedia web site. Do a search for Free Flight (model aircraft).
For more information on the model aircraft we build and fly, see the page “What is Aeromodeling?”