For decades, the future of aviation has been imagined through increasingly futuristic vehicles. Yet beneath the sleek renderings of flying taxis and autonomous aerial systems, one engineering reality has remained remarkably unchanged:
Most aircraft still rely on propulsion philosophies developed generations ago.
Whether in helicopters, drones, or emerging eVTOL (electric vertical take-off and landing) platforms, the dominant model of flight continues to depend on exposed propellers, rotors, or turbine-based thrust systems. While these technologies have evolved significantly in efficiency and control, their underlying architectural logic remains familiar.
As urban air mobility (UAM) moves from concept demonstrations toward real-world deployment, that continuity is becoming more significant.
The challenge facing the industry is no longer simply whether aerial mobility is technically possible. Increasingly, the question is whether existing propulsion systems are fully compatible with dense urban environments over the long term.
Noise generation, mechanical exposure, maintenance complexity, aerodynamic inefficiencies, and public safety concerns remain persistent issues across much of the sector.
In many cities, these limitations may ultimately shape regulatory acceptance more than the aircraft themselves.
This growing pressure has encouraged a broader engineering discussion around propulsion architecture itself.
Rather than continuing to optimise conventional rotor systems incrementally, some researchers and independent inventors have started exploring whether future mobility might require fundamentally different methods of generating thrust.
One example attracting attention in recent mobility discussions is the propulsion concept proposed by Iranian-German inventor and mechanical engineer Mohsen Bahmani.
Bahmani first became publicly known years earlier through an unconventional invention known as the “Floating Shoes,” a concept reportedly inspired by disaster-response thinking and emergency rescue scenarios. After relocating to Germany and studying mechanical engineering at the Karlsruhe Institute of Technology (KIT), His work evolved toward larger-scale propulsion and mobility systems.
His more recent patent proposes a propulsion architecture that attempts to reduce reliance on conventional exposedpropellers by using internally coordinated reaction units operating inside a controlled loop-based structure.
Unlike traditional aerial propulsion systems, the concept approaches thrust generation through synchronised cycles of acceleration, motion transfer, and controlled directional force management within a closed framework.
Importantly, the proposal has consistently been described as operating within established Newtonian mechanics rather than claiming any form of “reactionless” propulsion. According to available technical explanations, the system still depends on reaction forces and interaction with an external working medium, remaining aligned with conventional physical laws.
That distinction matters because unconventional propulsion concepts often encounter scepticism associated with speculative or scientifically unsupported claims. In this case, however, the proposal positions itself as an alternative engineering configuration rather than an attempt to redefine physics itself.
Whether such systems can eventually compete with mature rotor-based technologies remains uncertain.
Modern propulsion systems benefit from decades of optimisation, industrial refinement, certification experience, and operational testing. Any alternative architecture would ultimately need to demonstrate measurable advantages in areas such as efficiency, controllability, durability, manufacturability, and operational safety.
Large-scale validation also remains a major challenge for all emerging propulsion concepts. Thermal management, synchronisation complexity, energy transfer efficiency, and long-duration reliability represent substantial engineering hurdles.
At the same time, the emergence of alternative propulsion research may reflect something broader happening within the aerospace sector.
Urban mobility systems are beginning to encounter structural limitations that incremental optimisation alone may not fully resolve. In response, some engineers are shifting attention away from improving individual components and toward reconsidering the architecture of propulsion itself.
That transition mirrors patterns seen repeatedly throughout technological history.
Major industrial shifts rarely begin with universally accepted solutions. More often, they begin with experiments that challenge assumptions industries have long treated as fixed.
One factor often overlooked in public discussions surrounding new technologies is the level of scrutiny required before a patent reaches the European stage.
Bahmani’s propulsion concept did not emerge overnight, nor did it advance through the patent process without extensive examination. The invention ultimately received European patent recognition under patent numberEP3565971B8, a process that involved multiple stages of technical review, prior-art analysis, legal examination, and formal assessment by patent specialists.
European patents are widely regarded as among the most rigorously evaluated forms of intellectual property protection. Applicants must demonstrate novelty, inventive step, and industrial applicability while navigating detailed examination procedures designed to challenge both the originality and technical validity of a concept. The process can take years and often involves extensive dialogue between inventors, patent attorneys, and examiners.
For Bahmani, the challenge was amplified by the unconventional nature of the invention itself.
According to individuals familiar with the development process, one of the most difficult aspects was not simply engineering the system, but communicating it. Because the propulsion architecture follows a non-traditional pathway that differs significantly from conventional propeller- and turbine-based thinking, explaining its operational logic has reportedly required extensive technical discussion even among specialists.
Supporters of the project argue that this difficulty stems not from any conflict with established physical laws, but from the fact that the concept approaches motion generation through an unfamiliar engineering framework. At the same time, certain technical elements remain confidential due to intellectual property and development considerations, adding another layer of complexity to public understanding.
The result is a technology that has generated both scepticism and curiosity two reactions that often accompany unconventional inventions long before broader consensus is reached.
