A Levitated Annular Rotor System (LARS) is proposed to power and propel ultra-heavy vertical lift air vehicles in commercial and military markets. LARS is an invention derived from a conceptual redesign of the helicopter made possible by advancements in electromagnetic motor and energy storage/transport technology. It exploits advances across multiple fields of physics to include electromagnetism and high temperature superconductivity. LARS research aligns with NASA's roadmap for vertical lift technology and Urban Air Mobility.
LARS uses a scalable electromagnetic tip drive design that imparts mechanical torque to a rotor blade assembly within the confined space of the system annulus. The rotating blade assembly is magnetically suspended to minimize frictional energy loss. Comparatively, LARS’ integrates the disparate functions of a helicopter’s engine, gearbox and rotor system into one blended energy transfer system.
A first-generation LARS design has been completed that targets a performance power density of 20 kW/kg. Fully developed, LARS will integrate with companion electric Vertical Take-off and Landing (eVTOL) technology that are expected to achieve operational maturity date by 2030. Those companion technologies include liquid hydrogen-based aviation fuel cells, superconductive wires and ribbons for energy transmission and magnetic levitation. Liquid hydrogen will be dual purposed as the cooling agent for the superconductive subsystems, (energy transport for the Electromagnetic Polarity Drive and magnetic levitation and pressure for the Levitated Rotor Blade assembly).
Electric drive for a rotary wing propulsion is deemed the most effective approach to achieve the disruptive performance required for eVTOL payloads that have significant operational impact. The helicopter and its shaft- centric powertrain—invented circa 1950—is at its power density limit and will never be capable of ultra-heavy lift without a technological redesign. The LARS design leverages bearing-less motor technology with the application of high temperature superconductivity. The promise of applied superconductivity to electromagnetic machines is cited by industry experts as offering 60% more efficiency with 50% less weight and footprint when compared to non-superconductive peer designs.
With LARS, a well-designed novel air vehicle can carry a useful payload of 32,500 kg or one FEU (a Forty-foot Equivalent Unit or ISO 688 freight container). This useful payload capacity is of extreme value to US military combat sustainment which is reliant on mechanized ground vehicles, and therefore highly dependent on battlefield road infrastructure that may be access denied or threat laden.
The insertion of a vertical lift solution to supply-chain logistics will relieve the stress on national transportation infrastructure and expedite end-to-end consumer product delivery. Specifically, LARS research will redirect the US VTOL industry toward extreme heavy lift missions and introduce ship-to-shore FEU container transport as a new market opportunity. Such a VTOL option will augment current intermodal port infrastructure and provide relief to the pain points of highway congestion, road maintenance, and increasing operational costs. Ship-to-shore FEU container transport is an expanding market opportunity validated by research that indicates that there is no reversal on “containerization” as a method of logistic transport, and no upper limit to the number of containers projected far into the future.