Designer Avery Flies has built and piloted a massive 27-foot radio-controlled thermal airship, blending custom sewing with specialized R/C components.
The massive nylon structure stretches 27 feet, dwarfing the standard drones and model airplanes that usually occupy the airfield. Designed and constructed by Avery Flies. this thermal airship operates on a simple. ancient principle: the lift generated by the temperature gap between hot air and the surrounding atmosphere.
Unlike traditional hot air balloons that drift at the mercy of the wind. this dirigible is equipped with control surfaces and a propulsion system. The pilot maintains command through a standard radio control setup. directing the craft through the air while a custom-built propane burner—fueled by two small green portable barbecue tanks—keeps the envelope inflated and buoyant.
Building the craft required a departure from typical hobbyist kits. The envelope itself, which takes up the first 15 minutes of the documentation of the project, required intricate sewing. Once the structure is airborne, it relies on a mix of technologies to maintain shape and maneuverability. A 70mm. or approximately 2¾-inch. electric ducted fan forces air into the balloon to preserve its rigid form. while an 18-inch (457mm) propeller driven by a large brushless DC motor provides the necessary thrust.
Steering presented a unique engineering hurdle. Instead of standard model aircraft components. the rudder—a meter-scale fabric surface—is manipulated by a repurposed winch servo taken from an R/C sailboat. The choice is deliberate; the physics of moving such a large fabric panel through the air align more closely with the mechanics of a sail than the aerodynamic surfaces of a traditional fixed-wing model.
While this project pushes the scale of amateur flight, it sits within a long history of experimentation. While the craft is physically imposing. it joins a diverse lineage of flying machines. ranging from giant-scale R/C aircraft to tiny blimps. that have been pushed to the edge of what is possible in remote-controlled aviation.
Avery Flies thermal airship R/C aircraft DIY drone propane burner radio control