This video details the design, construction, and testing of a unique RC seaplane powered entirely by a "blown wing" system. Electric ducted fans (EDFs) are integrated into the wings, forcing high-pressure air through internal ducts and out over the entire upper surface. This technique, leveraging the Coandă effect, aims to prevent airflow separation, enabling extreme slow-flight and short takeoff (STOL) capabilities. The project involves CAD design, CNC machining of foam wings, and the use of specialized high-static-pressure EDFs.
Flight tests demonstrate remarkable success, with the aircraft achieving incredibly slow flight speeds for its weight and wing loading, far surpassing conventional STOL planes. However, the system proves to be extremely inefficient, leading to very short flight times and eventual hardware failure from excessive current draw. Analysis reveals the blown wing significantly increases the wing's stall angle to over 35 degrees. The creator concludes that while the system is highly effective for achieving slow flight, its practicality is limited by its massive power consumption, making it more of a technical marvel than a viable application.
100% Blown Wing: A Powerful but Impractical Feat of Engineering
0:00 - The "Blown Wing" Concept: The project's goal is to build an RC plane that gets 100% of its thrust from a "blown wing" system. This involves piping high-pressure air from electric ducted fans (EDFs) over the entire top surface of the wing to dramatically increase lift and prevent stalls, a concept based on the Coandă effect.
3:07 - Design and Construction: The plane is designed in Onshape and features a foam fuselage, a T-tail, and a mechanism to change the wing's angle of attack in flight. The wings are CNC-machined from XPS foam with internal cavities for airflow and are covered with carbon fiber plates.
5:40 - Specialized Fans: The plane uses two 50mm high-static-pressure metal EDFs, similar to those found in high-end hair dryers. These were chosen over standard hobby EDFs for their ability to effectively force air through the long, restrictive ducts inside the wing.
13:51 - Initial Flight Success: The seaplane takes off almost instantly and demonstrates incredibly stable and slow flight, even on its maiden voyage. The creator notes its graceful and almost physics-defying performance.
15:15 - First Crash and Key Learning: An early crash occurs when the servo controlling the wing's angle of attack stalls, causing an electrical brownout and a complete loss of power. This highlights the high electrical demands of the system.
19:04 - Extreme STOL Performance: With the wing locked at a high angle of attack, the plane achieves extremely short takeoffs and can fly so slowly that the creator can easily walk alongside it, even with no wind. Its performance far exceeds that of well-known STOL models with similar wing loading.
21:45 - Critical Dependency on Power: Flight tests reveal a major vulnerability: the plane is entirely dependent on the airflow from the EDFs. Cutting the throttle at a high angle of attack results in an immediate and aggressive stall, as the wing can no longer generate sufficient lift without the blown air.
23:56 - The Inevitable Burnout: While testing the plane's heavy-lift capabilities by loading it with three batteries, the extreme power draw (enough to make a large battery hot in minutes) eventually burns out an ESC and motor, leading to a final, unrecoverable crash.
26:50 - Quantifying the Effect: To get hard data, the wing is mounted on a car. Tests show that without power, the wing stalls at a normal 19° angle of attack. With the fans running, the stall is delayed until over 35°, proving the system's incredible effectiveness at keeping airflow attached.
29:11 - Inefficient but Effective: The creator concludes that while the blown wing system works wonders for slow flight, it's incredibly impractical. Calculations show that blowing air through the wing erases 27% of the fan's thrust, and the EDFs themselves are far less efficient than propellers, leading to abysmal flight times.
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