Adaptive Rotor and Reconfigurable Tail for High-Speed Rotary Aircraft
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Solution Overview
Problem
Conventional helicopters face limitations in high-speed operational capabilities due to low cruise speeds, increased rotor power requirements, and drag issues, which are exacerbated by the addition of wings intended to compensate for these problems, leading to reduced payload capacity, increased costs, and operational challenges.
Innovation Solution
A rotary-wing aircraft design featuring an adaptive main rotor system with active devices and a reconfigurable tail rotor that functions as an auxiliary propulsor, allowing for efficient high-speed forward flight without the need for a wing, by optimizing thrust and power sharing between the main rotor, fuselage, and tail rotors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the main rotor forward tip angle is increased to increase cruise speed, then the operational speed is improved, but rotor flapping increases and propulsive efficiency decreases
Solution Approach 1:
The main rotor system incorporates active adaptive devices that allow real-time adjustment of rotor blade characteristics during flight. This dynamic adaptation enables the rotor to maintain optimal performance across a wider range of forward speeds, reducing the energy losses associated with fixed-geometry rotors operating at high forward tip angles.
Solution Approach 2:
The invention changes physical parameters of the rotor system, including the active adaptive devices on rotor blades that modify blade geometry or aerodynamic properties. These parameter changes allow the rotor to operate efficiently at higher forward speeds without the severe propulsive efficiency penalties of conventional helicopters.
2Reliability
If a wing is added to provide additional lift and increase stall margin, then the stall margin is improved, but empty weight increases and payload capability decreases
Solution Approach 1:
The main rotor system is designed to perform multiple functions: it provides lift during hover, maintains increased stall margin during forward flight, and enables high-speed operation. This multi-functionality eliminates the need for a separate wing structure, reducing empty weight while maintaining reliability and stall margin.
3Force
If a wing is added to compensate for fuselage download, then the lift is improved, but parasitic drag increases and cruise power requirement increases
Solution Approach 1:
The main rotor system provides both lift and forward thrust, eliminating the need for a separate wing. This multi-functional approach generates the necessary lift force to compensate for fuselage download without introducing the parasitic drag that would result from adding a wing structure.
Solution Approach 2:
The invention extracts the lift-generating function from a separate wing component and integrates it into the main rotor system. This eliminates the parasitic drag associated with wing structures while maintaining the necessary lift force.
4Ease of operation
If a conventional tail rotor is used, then the anti-torque control is improved, but drag due to tail rotor hub position and H-force increases
Solution Approach 1:
The tail rotor assembly is designed with movable mounting that allows dynamic repositioning between lateral and rearward orientations. This dynamic capability enables the system to optimize anti-torque control while minimizing drag by positioning the tail rotor in the most favorable location for each flight condition.
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
Enables operation at speeds exceeding 220 knots with reduced power requirements, increased lift-to-drag ratio, and improved maneuverability, while eliminating the need for a wing, thus enhancing efficiency and reducing operational penalties associated with conventional helicopter designs.
Implementation Method 1
A main rotor assembly is operably connected to the airframe and includes a plurality of rotor blades operably connected to a rotor shaft
Implementation Method 2
A tail rotor is operably connected to the extending tail. The tail rotor is rotatable about a tail rotor axis, the tail rotor axis movable from laterally-extending to rearward-extending
Implementation Method 3
one or more active adaptive devices located at one or more rotor blades of the plurality of rotor blades. The one or more active adaptive devices are operably connected to an aircraft flight control system such that, when activated, the one or more active adaptive devices change one or more operational characteristics of the rotor assembly
Data Source
AI summary
A rotary wing aircraft includes an airfame and an extending tail extending from the airframe. A main rotor assembly is operably connected to the airframe and includes a plurality of rotor blades operably connected to a rotor shaft, and one or more active adaptive devices located at one or more rotor blades of the plurality of rotor blades. The one or more active adaptive devices are operably connected to an aircraft flight control system such that, when activated, the one or more active adaptive devices change one or more operational characteristics of the rotor assembly. A tail rotor is operably connected to the extending tail. The tail rotor is rotatable about a tail rotor axis and the tail rotor axis movable from laterally-extending to rearward-extending.