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EP-4741286-A1 - ROTOR AIRCRAFT WITH DUAL FLIGHT MODE

EP4741286A1EP 4741286 A1EP4741286 A1EP 4741286A1EP-4741286-A1

Abstract

A vertical take-off and landing (VTOL) aircraft designed for both vertical and horizontal flight features a fuselage that houses essential stability and propulsion components. The aircraft includes a main rotor (2) and wide-chord blades (1) with a fully proportional cross-section, enabling high lift in both VTOL and fixed-wing modes. The flight control system facilitates smooth transitions between flight modes by adjusting the orientation of the blades (1), switching between the main rotor (2) and a rear pusher propeller (5) driven by a gas engine (16). Stability in VTOL mode is maintained by front and rear duct fans (6, 6') and ailerons (4, 4'), while in horizontal mode, stability is provided by front and rear skids (3, 3'). The aircraft is further enhanced by solar panels (14) on the fuselage, allowing for battery recharging during horizontal flight, extending operational endurance. A payload compartment (10) maintains the aircraft's center of gravity across flight modes.

Inventors

  • SKULSKIS, Donatas

Assignees

  • UAB PB Group

Dates

Publication Date
20260513
Application Date
20241107

Claims (9)

  1. A VTOL aircraft for vertical and fixed-wing horizontal flight, comprising: a fuselage serving as the main body, housing the components for stability and for propulsion; a main rotor (2); blades (1); characterized in that the aircraft additionally comprises: two blades (1) with a fully proportional cross-sectional shape, configured to generate high lift in both VTOL mode and fixed-wing mode during horizontal flight; and a flight control system for transitioning the aircraft from VTOL to horizontal flight, configured to manage stability and control in both VTOL and horizontal flight modes.
  2. The aircraft, according to claim 1, characterized in that components for the aircraft stability comprise: a set of duct fans (6, 6') positioned at the front and rear of the fuselage, configured to counteract the torque generated by the main rotor (2) during VTOL operations; the front and rear skids (3, 3') that function as vertical stabilizers during horizontal flight to enhance aerodynamic stability; the front and rear ailerons (4, 4') configured to control roll, pitch, and yaw in both flight modes by redirecting airflow around the fuselage.
  3. The aircraft, according to any of claims 1, 2, characterized in that components for the aircraft propulsion comprise: a main rotor (2) driven by an electric motor (8) powered by onboard batteries (9, 15) for generating vertical lift in VTOL mode; a gas engine (16) for powering a rear pusher propeller (5) for sustained horizontal flight in fixed-wing mode.
  4. The aircraft, according to claim 3, characterized in that the solar panels (14) are mounted on the top of the fuselage to recharge the batteries (9,15) during horizontal flight to extend operational endurance.
  5. The aircraft, according to any of claims 3, 4, characterized in that the flight control system is configured to enable a smooth transition from VTOL to horizontal flight by: switching the orientation of the wide-chord blades (1) from rotational to fixed-wing alignment; deactivating the main rotor (2) and activating the rear pusher propeller (5), switching off the duct fans (6, 6'); and adjusting the front and rear ailerons (4, 4') for stable horizontal flight.
  6. The aircraft, according to any of claims 5, characterized in that horizontal stabilization is managed by front and rear skids (3, 3').
  7. The aircraft, according to any of the previous claims, characterized in that, further comprising a payload compartment (10) centrally mounted in the fuselage, designed to maintain the aircraft's center of gravity during both VTOL and horizontal flight modes, allowing for a variety of payload types.
  8. A method for operating the aircraft according to any of claims 1-7, comprising the steps of: activating the electric motor (8) to drive the main rotor (2) with the wide-chord blades (1) for vertical take-off; controlling the roll, pitch, and yaw of the aircraft in VTOL mode using front and rear ailerons (4, 4') and duct fans (6, 6'); transitioning to horizontal flight by switching off the main rotor (2), locking the wide-chord blades (1) to a fixed-wing alignment, and activating a gas engine (16) that drives a rear pusher propeller (5); stabilizing the aircraft in horizontal mode using front and rear skids (3, 3') that serve as vertical stabilizers, and managing aerodynamic stability with ailerons (4, 4') adjusted according to airflow conditions.
  9. The method for operating the aircraft according to claim 8, characterized in that, recharging the onboard batteries (9, 15) via solar panels (14) mounted on the top of the fuselage during horizontal flight.

Description

FIELD OF THE INVENTION The present invention falls within the field of aerospace engineering, manned aircraft and unmanned aerial vehicles (UAV), specifically focusing on rotor aircraft capable of vertical takeoff and landing VTOL (Vertical Takeoff and Landing). This invention further pertains to aircraft with hybrid propulsion systems that utilize dual propulsion types for seamless transitions between vertical and horizontal flight modes. Additionally, the invention includes control systems for hybrid propulsion to manage torque, enhance stability, and optimize energy efficiency. BACKGROUND OF THE INVENTION AND ANALYSIS OF PRIOR ART VTOL (Vertical Takeoff and Landing) and aircraft technology have advanced significantly in recent years, driven by increasing demand for autonomous air mobility, military applications, cargo delivery, and aerial surveillance. Aircraft generally fall into two main categories: multi-rotor aircraft and fixed-wing aircraft, each offering unique strengths and limitations. Many traditional multi-rotor UAV are constrained by their reliance on electric batteries, which provide limited flight time and range. These UAV are typically suited for short missions, as their battery capacity cannot support long-duration or long-distance operations. High energy consumption limits multi-rotor constructions to 20-30 minutes of flight, restricting long-range missions. And these UAV generally were slow, operating below 50 km/h, making them unsuitable for applications needing faster travel. Current multi-rotor UAV constructions struggle with limited payload capacity due to their relatively small size and energy limitations. Increasing the payload often comes at the cost of reduced flight time, further complicated mission planning and use in industrial or delivery settings. Energy consumption is often inefficient in multi-rotor systems, such as maintaining hover or performing vertical takeoff and landing operations requires continuous use of power. Fixed-wing aircraft, on the other hand, are more energy-efficient in horizontal flight but lack the ability to take off or land vertically. Fixed-wing aircraft cannot hover or perform stationary flights, making them unsuitable for close-up inspections or deliveries in tight spaces. Many UAV designs are optimized for either vertical flight (hovering and takeoff) or long-range horizontal flight. However, a few UAVs effectively combine both functionalities in a single system, leading to compromises in versatility and operational capabilities. Traditional UAV designs that require advanced rotor control mechanisms, such as swash plates, are prone to mechanical failure, high maintenance costs, and design complexity. This complexity can affect reliability, making these systems less attractive for long-term or demanding operations. Transitioning from vertical to horizontal flight (and vice versa) remains a critical challenge for many hybrid UAVs. Ensuring stable and controlled transitions without losing altitude or causing instability is a significant technical hurdle that many systems fail to overcome smoothly. It is known a document US9821909, describes a tail sitter aircraft with rotatable wings that transition between vertical and horizontal flight configurations. While this design addresses runway limitations and aims for efficient flight, it has drawbacks such as potential instability during vertical takeoffs and landings due to its high center of gravity, and increased drag from retractable landing legs or large tails used for stability. Document US10054958 describes a VTOL UAV that includes retractable wings and a contra-rotating propeller disk for providing vertical thrust in hover mode and horizontal thrust in level flight mode. While it achieves VTOL capabilities and offers efficient flight in both modes, it relies heavily on mechanical complexity, such as retractable wings and contra-rotating propellers, which can increase the risk of mechanical failure and maintenance costs. Document US10246185discloses a VTOL aircraft system designed for vertical takeoff and landing, utilizing a fixed-wing design with contra-rotating propellers for rearward propulsion during takeoff and forward propulsion during horizontal flight. While it effectively manages VTOL operations, it relies on a complex propulsion system with a nose-down configuration, which complicates the transition between flight modes and may reduce stability during takeoff and landing. Document US20180281942 describes a flying wing VTOL aircraft with foldable wings and rigid rotor propellers, designed to optimize storage and reduce weight. While this design eliminates the need for tail sections, reducing weight and complexity, it relies heavily on foldable wings and complex rotor systems that add mechanical risk and require precise control for stability. Document US20180354612 describes a UAV rotor system with coaxial counter-rotating rotors, enabling vertical takeoff and landing (VTOL) operations. Th