thermal R/C – Engineering enthusiast Avery Flies has pushed the boundaries of remote-controlled flight, successfully building and launching a massive, propane-powered thermal dirigible.
The sight of a 27-foot-long airship drifting through the sky is unusual enough. but watching one trailing a literal flame from its undercarriage is something else entirely. For designer Avery Flies. the fire isn’t a malfunction—it is the engine that keeps his latest project. a thermal dirigible. airborne.
Thermal airships operate on a simple principle of physics. using the density difference between hot air and the surrounding atmosphere to generate lift. Unlike traditional hot air balloons, however, this craft is fully maneuverable. It features an integrated engine and control surfaces. allowing the operator to pilot the balloon via radio control rather than simply drifting with the breeze.
The construction of the vessel is a hybrid of sewing and mechanical engineering. Avery Flies spent the first 15 minutes of his project documentation focused solely on designing and sewing the massive nylon envelope. Once the structure was ready. he turned to the world of remote-controlled aviation to provide the necessary hardware for flight control.
Inside the rig, the components create a unique mix of technologies. A pair of small green propane tanks—the kind typically used for portable barbecues—feed a burner that generates the necessary heat. While the heat source is combustion-based, the propulsion system is entirely electric. A 70mm electric ducted fan forces air into the envelope to maintain the balloon’s shape. while a large brushless DC motor spins an 18-inch propeller to provide forward thrust. The steering mechanism is particularly ingenious: Avery repurposed a winch servo from an R/C sailboat to manage the meter-scale fabric rudder. a choice necessitated by the fact that the oversized rudder behaves more like a sail than a standard aircraft control surface.
This build sits in an interesting category of experimental flight. While the community has seen everything from miniature blimps to massive. giant-scale R/C aircraft. this 27-foot thermal airship represents a rare middle ground where traditional ballooning physics meets modern radio-control hobbyist components.
Avery Flies R/C airship thermal dirigible DIY engineering model aircraft radio control