Tiltable Proprotor Aircraft With Autorotating Central Rotor
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Solution Overview
Problem
Current aircraft, such as helicopters and gyroplanes, face inefficiencies in energy operation and lack the ability to perform vertical takeoff and landing (VTOL) efficiently, limiting their operational flexibility and range.
Innovation Solution
The design incorporates a fuselage with a tiltable rotor system, featuring proprotors that can tilt between vertical and horizontal positions, and a rotor assembly with adjustable blade pitch, allowing for efficient transition between vertical and horizontal flight modes, enabling VTOL capabilities and extended data gathering or observation without the need for a runway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a helicopter uses a fixed vertical shaft with swash plates and links to the rotor head to modify pitch and generate lift, then vertical takeoff and hovering capability is achieved, but operating energy efficiency deteriorates compared to fixed-wing aircraft
Solution Approach 1:
The patent applies dynamics by making the rotor shaft tiltable rather than fixed. The rotor shaft can pivot between a vertical orientation (for hover/VTOL) and a forward-leaning orientation (for forward flight). This dynamic reconfiguration allows the aircraft to switch between helicopter-like vertical flight and gyroplane-like efficient forward flight, resolving the energy efficiency penalty of fixed vertical shaft helicopters.
Solution Approach 2:
The rotor system serves multiple functions through the tiltable shaft design. In the vertical position, it provides hover and VTOL capability like a helicopter. In the forward-leaning position, it enables efficient forward flight like a gyroplane. This multi-functionality allows a single aircraft design to achieve both vertical flight versatility and forward flight energy efficiency.
2Use of energy by moving object
If a gyroplane uses an unpowered rotor in autorotation to develop lift with forward thrust from an engine-driven propeller, then operating energy efficiency improves compared to helicopters, but the ability to take off and land vertically deteriorates
Solution Approach 1:
The gyroplane's fixed shaft is replaced with a tiltable shaft that can dynamically adjust its orientation. When tilted forward, the aircraft operates efficiently in forward flight mode. When tilted vertical, the aircraft gains VTOL capability. This dynamic adjustment resolves the contradiction between energy efficiency and vertical flight capability.
Solution Approach 2:
The shaft angle parameter is made variable rather than fixed. By changing the shaft angle from forward-leaning to vertical, the aircraft transitions between efficient forward flight and vertical takeoff/landing modes. This parameter change enables the aircraft to overcome the gyroplane's inherent limitation of being unable to perform vertical operations.
3Ease of operation
If a gyrocopter uses a fixed pitch rotor with zero blade pitch for autorotation, then the rotor can spin freely to provide lift during forward flight, but the ability to achieve vertical takeoff deteriorates due to lack of variable pitch control
Solution Approach 1:
The fixed zero-pitch rotor configuration is replaced with a variable pitch rotor system. The rotor blades can now adjust their pitch angle dynamically. This allows the rotor to maintain autorotation for lift during forward flight while also enabling positive pitch angles needed for vertical takeoff and hover operations, thus resolving the capability limitation.
Solution Approach 2:
The blade pitch parameter is changed from fixed zero to variable. This allows the rotor to adapt its pitch angle based on flight conditions: near-zero pitch for efficient autorotation in forward flight, and positive pitch for vertical flight operations. This parameter variability enables both autorotation ease of operation and vertical takeoff adaptability.
4Adaptability or versatility
If a helicopter uses blades that drive air from top downwards to create thrust and lift, then vertical flight is achieved, but the device complexity increases due to fixed vertical shaft, swash plates, and links
Solution Approach 1:
The complex swash plate and link mechanism is extracted and replaced with a simpler tiltable shaft design. Instead of using swash plates to vary blade pitch, the invention uses a tiltable shaft that changes the rotor's orientation in space. This extraction of the complex mechanism while retaining vertical flight capability reduces device complexity.
Solution Approach 2:
The mechanical swash plate pitch control system is replaced with a gyroscopic tilt control system. Instead of mechanically varying blade pitch through swash plates and links, the invention tilts the entire rotor assembly to achieve vertical flight. This substitution of mechanical systems reduces complexity while maintaining functionality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances flight efficiency, allowing for seamless transitions between flight modes while maintaining stability and control, enabling aircraft to operate beyond traditional helicopter ranges without requiring a runway for takeoff and landing.
Implementation Method 1
a rotor rotatably coupled to an upper end of the mast opposite the lower end, a rotor motor disposed at the upper end of the mast and configured to cause rotation of the rotor in a first direction
Implementation Method 2
a first proprotor tilt servo configured to control an orientation the first powered proprotor between at least a horizontal tilt angle and a vertical tilt angle
Implementation Method 3
A gyroplane (also known as a gyrocopter or autogyro) is an aircraft that uses an unpowered rotor in autorotation to develop lift. Autorotation is a rotor state in which the rotor derives from the freestream 100% of the power required to rotate it
Data Source
AI summary
Aircraft capable of vertical takeoff and landing, hovering, and efficient forward flight are described. An aircraft includes two side mounted tiltable proprotors and a central rotor disposed above the proprotors. The proprotors are tiltable between at least a horizontal position for forward flight and a vertical position for vertical or hovering flight. The central rotor may be powered for vertical and transitional flight modes and may turn by free autorotation during forward flight. The proprotors may be differentially tilted during vertical or hovering flight to counter torque effects of the central rotor. The central rotor may be foldable and/or easily detachable from the aircraft to facilitate storage and transportation. Left and right proprotors may provide both forward thrust and attitude control. Control inputs to left and right proprotors may be connected directly to an autopilot creating closed loop actuation using motor RPM feedback.