Developed at the height of the Cold War, this flying saucer-shaped aircraft, as peculiar as it would seem, was not just an engineering marvel but also a reflection of the political tensions characterizing the era. In the course of this odyssey, we will explore the scientific wonders of the Avrocar’s propulsion system, its connections with Avro Canada, and its geopolitical context.
In 1948, in the midst of tensions with the Soviets, the U.S. Air Force partnered with the Canadian company Avro Canada to conceive a new aircraft under the codename Project 1794. This aircraft could be described as a Vertical Takeoff and Landing (VTOL) Flying Saucer. Throughout the history of this program, numerous names have designated the project. Avro referred to it as “Project Y,” and the two prototypes were named “Spade” and “Omega”. In its second version, with the U.S. Air Force joining the endeavor, it was assigned the codes and nicknames “WS-606A”, “Project 1794”, and “Project Silver Bug.” Finally, the U.S. Army also joined the program, and gave it its ultimate designation: “Avrocar VZ9”. This designation referred to the classification of vertical takeoff and landing aircraft in the “VZ” class.
At first glance, it seemed straight out of a science fiction movie: a saucer-shaped vehicle hovering a few centimeters above the ground. However, behind this seemingly fanciful design hid a complex propulsion system. The Avrocar aimed to achieve Vertical Takeoff and Landing (VTOL) capabilities, a technological feat that required innovative propulsion. Two massive turbo rotors provided lift, but what truly set the Avrocar apart was the use of exhaust gases for forward propulsion.
The Coandă effect
Henri Coandă was a Romanian engineer and inventor, born in 1886. He dedicated his life to aviation and engineering. One of his early notable works was the development of the Coandă-1910 Aircraft, which would become the world’s first jet-powered model. It was during these experiments that Coandă discovered the effect that would bear his name.
When Coandă tested his aircraft in 1910, he observed that exhaust gases had a surprising tendency to follow the wing’s curvature. This observation intrigued him because it seemed to contradict traditional principles of fluid flow. He had discovered the Coandă effect, although he did not name it as such at the time.
The Coandă effect occurs when a fluid, such as a gas or liquid, is directed toward a curved surface. Instead of moving away from this surface, the fluid adheres to it and follows its curvature. This attraction is the result of lower pressure on the surface, causing an adhesive force.
Several forces interact to produce the Coandă effect. First, there is the pressure force, which is lower on the concave side of the curved surface. Next is the adhesive force, which keeps the fluid attached to the surface. Finally, the curvature force, due to the shape of the surface, helps guide the fluid along this curve.
The Coandă effect can manifest in two ways: a traditional effect and a reverse one. In the first case, the fluid follows the curvature of the concave surface, while in the second, it follows the curvature of the convex surface. The practical applications of these two forms of the effect are numerous and found in various fields, from aviation to engineering and even medicine.
One of the most iconic applications of the Coandă effect in aviation history is its use in the design of Vertical Takeoff and Landing (VTOL) aircraft. By directing exhaust gases from the engines along the curvature of the aircraft, it is possible to generate sufficient lift to keep the aircraft in stationary flight or vertical movement.
Applications
Wind tunnels also use the Coandă effect to study fluid flows around objects. By directing air along curved surfaces, they can simulate specific flight or flow conditions, which is crucial for the design and testing of aircraft.
The Coandă effect has also found applications in medicine. Metered-dose inhalers utilize this effect to direct medications into the respiratory pathways.
In the field of engineering, the effect is fundamental to the design of bladeless fans. These devices exploit the Coandă effect to create a continuous and turbulence-free airflow, making them quieter and more energy-efficient.
Some artists and designers have also incorporated the Coandă effect into their artistic creations, using air jets to generate unique shapes or movements.
Beyond technical applications, the Coandă effect is present in our daily lives in many surprising ways. It is omnipresent in everyday situations. For example, when you open a faucet, water follows the shape of the sink or basin, an example of the reverse Coandă effect. Similarly, when you blow air over the surface of a spoon or a sheet of paper, you can observe the effect in action.
Many household appliances, such as vacuum cleaners and hand dryers, use the Coandă effect to efficiently direct air or liquids. The nozzles of these devices are designed to guide the airflow or water along curved surfaces.
With technological advancements, the Coandă effect has found new applications and contributed to the design of innovative systems. The effect is still widely used in modern aerospace, especially in the design of VTOL aircraft, drones, and spacecraft. Automotive manufacturers explore the Coandă effect to enhance the aerodynamics of their vehicles: by directing air along the body, they reduce drag and improve energy efficiency. This effect is an essential tool in fluid engineering, used to design more efficient ventilation systems, heat exchangers, and fluid distribution systems.
While the Coandă effect was a brilliant concept, it posed challenges for the Avrocar. The aircraft struggled to achieve the desired speeds and altitudes, and its stability was questionable. These issues would later impact its feasibility as a military aircraft.
Mr. Frost
The Avrocar was the product of the brilliant minds at Avro Canada, a subsidiary of the British aircraft manufacturer A.V. Roe and Company. Avro Canada had a rich history of innovation, including its famous jet interceptor, the Avro Arrow.
Born on June 25, 1915, John William Dunne Frost, a renowned aeronautical engineer, is best known for his essential role in the development of the Avrocar, a bold project that left its mark on aviation history.
John Frost was born in Bridgewater, England, a place that did not foreshadow the exceptional role he would play in the field of aviation. His youth was marked by insatiable curiosity and an early interest in flight. These early signs of passion led him to pursue studies in aerospace engineering at the University of Cambridge, an institution that would become a crucible for brilliant minds in aeronautics.
After graduating, John Frost settled in Canada, drawn by the opportunities offered by the country’s burgeoning aerospace industry. It was there that he joined Avro Canada, a subsidiary of the British company A.V. Roe and Company. At Avro Canada, Frost would make aviation history.
Frost was appointed chief engineer of the project, and he played a crucial role in the design of this revolutionary aircraft.
In addition to the Avrocar, Avro Canada was the birthplace of many other aeronautical innovations. Under John Frost’s leadership, the company continued to push the boundaries of aviation, contributing significantly to the aerospace industry.
Unfortunately, despite the ingenuity of John Frost and his team, the Avrocar failed to become an operational military aircraft due to stability, performance, and altitude limitation issues. The project was ultimately canceled. The Avrocar did not achieve the glory that the engineer had envisioned.
Frost left Avro Canada after the conclusion of the Avrocar project, marking the end of an era for an engineer who had dedicated so much effort to this innovative project.
John Frost passed away in 1979, leaving behind a legacy of innovation and ingenuity in the field of aviation. While his work on the Avrocar may have been cut short, he contributed to pushing the boundaries of aerospace engineering and inspired future generations of engineers and scientists.
The legacy of Avro Canada, in pushing technological limits, is not confined to the Avrocar. The company was a pillar in the history of Canadian aviation and had a significant influence on the global aerospace industry.
The development of the Avrocar took place during the Cold War, a period marked by intense rivalry between the United States and the Soviet Union. Geopolitical factors played a crucial role in the fate of this unusual aircraft. During the Cold War, the race to develop advanced military technologies was in full swing. The Avrocar was considered a potential asset, capable of flying over battlefields and providing unparalleled surveillance capabilities.
The U.S. military showed strong interest in the Avrocar, investing considerable funds in its development. However, the project underwent increasing scrutiny due to its limitations and concerns about its practicality on the battlefield.
As the geopolitical landscape evolved and military priorities changed, the fate of the Avrocar was sealed. The project was ultimately canceled, marking the end of this daring venture.
The experimentation with the Coandă effect as part of the Avrocar had a lasting impact on modern aviation.
Adding to its stability issues, the Avrocar’s engines were noisy and produced excessive emissions. These factors raised concerns, especially regarding the use of the aircraft in secret military operations.
Even though the Avrocar failed to become an operational military aircraft, its legacy endures in various aspects.
The Avrocar has also left a lasting imprint on popular culture as a symbol of futuristic technology and the mystery surrounding UFOs.
Main picture: Project 1794 Documents