Aeroflux Contactless Brake

What it does

Conventional multiple-disc carbon brakes rely on friction to stop an aircraft. They wear very quickly and need constant replacement. Aeroflux brakes use the principle of eddy current braking to stop an aircraft without friction, and therefore without wear.

Your inspiration

As a child, I wanted to be a pilot. I still love flying as much as ever, but I now realize that aviation must become more sustainable in order to address the global threat of climate change. Aerospace manufacturers worldwide have committed to reducing aviation CO2 emissions by 50% from 2005-2050. However, there is still a long way to go. One of the most wasteful systems on a modern aircraft are the brakes. Their high wear rate means that every year, an aircraft’s brakes must be completely replaced. This wastes a tremendous amount of money, natural resources, and energy. I decided to tackle this problem and help make flying more sustainable.

How it works

A magnetic field is applied to both sides of two conductive, non-ferromagnetic discs (rotors). The rotors are keyed to the aircraft wheel and rotate through the magnetic field when the wheels are spinning. As the rotors move across the stationary magnetic field, small circular electric currents (eddy currents) are induced in the rotors according to Faraday’s law of induction. The eddy currents primarily circulate on the surface of each rotor. According to Lenz’s law, the eddy currents generate their own magnetic field in a direction that opposes the stationary magnetic field. The interaction of these fields applies a drag force on the rotors that results in a braking torque. The torque produced is proportional to the angular velocity of the wheel. The kinetic energy of the aircraft is converted into heat through the electrical resistivity of the metal rotors. The particular method of generating the magnetic field and its exact distribution is patent pending.

Design process

I developed this design in my final year capstone project as a mechanical engineering undergraduate. My design was ultimately chosen by my capstone team as the final design for the project. I did not limit myself based on the constraints of existing brakes, which would have prevented me from developing a conceptually different brake design. Instead, I started from a blank slate. I used a variety of concept generation methods to push for design creativity, including the 4-3-5 Method, TRIZ, and SCAMPER. By using different concept generation methods, I created a wide variety of alternative conceptual designs. I evaluated my alternative designs against important design objectives using an objective tree analysis and weighted decision matrix. When I made a major design decision, I always went back and checked how it impacted the satisfaction of objectives. Prototyping was critical to my design process. My team helped me build a prototype to prove the superiority of my design compared to existing eddy current brakes. The prototype was also used to validate finite element models that predicted the braking performance of my final design. Experimental data showed a 78% reduction in stopping time for the Aeroflux brake compared to existing eddy current brakes of equal volume and weight.

How it is different

High-speed trains do use electromagnetic disc eddy current brakes to slow down. However, these brakes require extremely powerful electromagnets which use a lot of power, are extremely heavy, and very large. This makes them impossible to use on an aircraft, where space in the landing gear bay is incredibly constrained and weight savings are paramount to fuel efficiency. The key to my design is a patent pending electromagnetic array that creates a very specific magnetic field distribution across the discs. The magnetic field is distributed in just the right way so as to concentrate magnetic flux in areas of the disc that result in the greatest constructive interference between circulating eddy currents. This results in a much higher eddy current density in the disc and therefore a larger braking torque. This technology means that my design uses almost no power, weighs only slightly more, and fits within the exact same envelope as a conventional aircraft brake.

Future plans

After receiving a lot of encouraging feedback from professors, colleagues, and engineers working in the aerospace industry at UofT’s capstone showcase, I decided to pursue this idea further. My design was accepted into the University of Toronto Entrepreneurship Hatchery to further research and develop the concept. I am currently working on a second generation prototype to test new improvements made to the design. I intend to file two additional patents based on progress made over the course of this summer. Ultimately, I want to see this brake on a real aircraft, and hopefully make a small contribution to future aviation sustainability.

Awards

2019 Richard M. Clarke Prize for Leadership in Engineering Design 2019 Clarke Category Prize for Design Excellence University of Toronto Entrepreneurship Hatchery NEST 2019 United States Provisional Patent Serial No. 62/822,502