By Dawn M. Zoldi
The advanced air mobility sector has never been short on ambition. From Joby Aviation’s tilt-rotor configurations to Lilium’s distributed electric propulsion jets, the industry’s race to populate urban skies with quiet, clean, and efficient aircraft has generated an extraordinary range of engineering approaches. Most share the foundational assumption that thrust requires a rotating blade, a jet nozzle or some externally expelled medium to push against. A European patent has come to our attention that challenges that assumption. In doing so, it raises questions worth examining carefully.
The Architecture in Question
German-Iranian inventor Mohsen Bahmani, working alongside co-inventor Hossain Vafaey, was granted European Patent EP3565971B8 on January 25, 2023. The patent, titled “Method and a System for Generating Fuel Efficient Force by Accelerating Object and Using Centrifugal Force,” was filed in November 2017 and completed a multi-year examination process at the European Patent Office (EPO) before grant. The patent is classified under F03H99/00, a CPC code reserved for reactive propulsive thrust produced by means not otherwise specified, which itself signals the unconventional approach presented.
The system’s core concept is organized around a looped track containing multiple small-scale reaction engines, specifically, electric impellers driven by high-RPM brushless motors. According to the patent documentation, these impellers are activated at the start of the first straight segment of the loop, accelerate along it building kinetic energy, then deactivate and transfer that energy to the track structure via centrifugal force as they traverse the first curved section. They coast through the return path at reduced speed and re-enter the cycle continuously. Critically, the impellers expel air outside the vehicle’s frame of reference throughout, a design point the inventor emphasizes to distinguish this system from purely internal, reactionless concepts. Power is delivered to each moving impeller wirelessly via electromagnetic induction based on Faraday’s law, using a high-frequency alternating current wound around the track, a method already proven in medical device technology and claimed to achieve up to 90 percent transfer efficiency.
Bahmani pursued formal mechanical engineering education at the Karlsruhe Institute of Technology (KIT) and has attracted notable media attention for both this and earlier work. His 2006 “Floating Shoes” concept, a buoyancy-assisted water locomotion device inspired by disaster rescue scenarios, established him as a problem-oriented thinker willing to challenge engineering norms. His work has been referenced in broader commentary on independent innovation, including within discussions by philosopher Alain de Botton on the role of original thinking in modern engineering.
The EPO Examination Standard
The EPO examination process is more substantive than a simple registration. Each application is evaluated by a panel of three examiners with relevant technical qualifications, all of whom must reach consensus before a grant is issued. Among the criteria the panel applies is industrial applicability. This means the invention must be capable of operating as described and must not contradict established scientific law.
Where examiners require additional evidence of functionality, the EPO process allows them to request laboratory experiments or a functional prototype, a copy of which is retained on file. That no such prototype request was made in this case reflects the examiners’ technical assessment of the claims as submitted. The patent grant in this case carries genuine evidentiary weight, even as it remains distinct from full independent experimental validation under real-world operating conditions.
Where the Scientific Questions Remain
The analytical reviews provided alongside this patent raise measured but important questions about whether the architecture delivers on its performance claims in practice. The impeller configuration introduces synchronization complexity. It involves multiple moving units that must maintain precise phase alignment under dynamic operating conditions and the control system demands scale with the number of interacting components. Thermal management is a further engineering challenge, as compact induction-powered units operating continuously may generate localized heat concentrations affecting reliability and efficiency.
The wireless power transfer mechanism, while elegant in concept and already validated in other industries, faces a nontrivial challenge in maintaining consistent electromagnetic coupling efficiency at variable speeds along the track. Recent aerospace research has demonstrated high-frequency rotary induction systems achieving up to 95.9 percent efficiency, a benchmark that any scaled implementation of this architecture would need to approach. However, these are genuine engineering questions characteristic of the development stage.
Why the AAM Sector Should Pay Attention
This concept is worthy of rigorous independent testing. The AAM sector is, in fact, in urgent need of propulsion innovation. Electric motors have enabled eVTOL configurations that were impractical under combustion power, but battery energy density remains the defining constraint on range and payload.
Noise, primarily rotor noise, remains the single greatest public acceptance barrier for urban air mobility operations. An architecture using smaller internal impellers rather than large-diameter external rotors offers a structurally slimmer vehicle footprint and, according to the inventor’s documentation, a meaningfully reduced acoustic signature. That these advantages are conditional on performance validation does not make them speculative. It makes them testable..
The U.S. Department of Transportation’s 2025 AAM National Strategy explicitly frames the sector as a collection of emerging technologies requiring parallel investment across propulsion, autonomy, and infrastructure. Within that context, architecturally novel patents, particularly those that have cleared rigorous multi-examiner review, serve a legitimate function as documented records of inventive thought that can stimulate derivative research and expand the design space.
A Reasonable Assessment
Mohsen Bahmani’s propulsion patent represents something the AAM field encounters periodically: a formally granted, earnestly developed invention that proposes a path genuinely different from the industry’s consensus direction. That alone justifies analytical attention. The EPO’s multi-year, three-examiner process confirms the concept’s novelty, inventive step and industrial applicability as presented.
What it does not yet have is the one thing that separates an intriguing patent from a validated technology: experimental confirmation by independent researchers. A working prototype measured by third-party engineers under controlled conditions, with instrument-grade thrust measurements, efficiency analysis, thermal evaluation, and full disclosure of energy inputs and outputs, would resolve the outstanding performance questions decisively. That the underlying physics appear sound is necessary. The next step belongs to the laboratory.
The AAM sector’s appetite for breakthrough propulsion, though, remains very real. The stakes involve quieter skies, lower emissions and genuinely urban-scalable aircraft. These alone should be significant enough to warrant rigorous scrutiny of every serious candidate. The next chapter for EP3565971B8 belongs not to patent examiners or journalists, but to independent engineers with instruments and no stake in the outcome.