Active Airflow System for Rotary Wing Drag Reduction
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Solution Overview
Problem
Conventional rotary-wing aircraft face limitations in forward airspeed due to drag, which affects power requirements, range, and efficiency, necessitating an improvement in the airlift-to-equivalent-drag ratio (L/DE) to enhance operational performance.
Innovation Solution
The implementation of an active air generation system that generates and directs airflow through strategically positioned active air discharge openings on the fuselage and rotor assembly to disrupt the airstream, reducing drag by interrupting the boundary layer airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional rotary-wing aircraft surfaces are used, then the aircraft structure is simple, but drag increases at high speeds limiting forward airspeed
Solution Approach 1:
The patent applies preliminary action by generating active airflow before the main airstream reaches critical drag-producing areas. The system预先 generates controlled airflow that interrupts boundary layer formation on the fuselage and rotor assembly surfaces, preventing drag accumulation before it limits forward airspeed
Solution Approach 2:
The patent employs pneumatic principles by using an active air generation system that produces and directs controlled airflow through discharge openings. This pneumatic approach manipulates air streams to disrupt boundary layers and reduce drag on aircraft surfaces, enabling higher forward airspeed
2Loss of energy
If drag reduction systems are added to the aircraft, then the lift-to-equivalent-drag ratio improves, but device complexity increases
Solution Approach 1:
The patent applies universality by designing an active air generation system that serves multiple functions: it reduces drag on the fuselage, controls airflow over the rotor assembly, and improves overall lift-to-equivalent-drag ratio. This multi-functional approach justifies the added device complexity through comprehensive performance improvement
Solution Approach 2:
The patent employs parameter changes by actively modifying airflow characteristics through the active air generation system. By changing parameters such as airflow velocity, direction, and distribution through controlled discharge openings, the system optimizes the lift-to-equivalent-drag ratio across different flight conditions
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 approach effectively reduces drag, enhancing the overall lift-to-equivalent-drag ratio (L/DE) and improving the operational envelope of rotary wing aircraft by creating localized drag reductions on various surfaces.
Implementation Method 1
generate and direct a flow of air through the active air discharge opening to disrupt an airstream flowing over the one of the plurality of surfaces of the fuselage and the one of the plurality of surface portions of the rotor assembly
Implementation Method 2
reducing drag by interrupting the boundary layer airflow
Data Source
Figure 1
Figure 2
Figure 3~6
AI summary
A rotary wing aircraft (10) includes a fuselage (12) having a plurality of surfaces. At least one engine (24) is mounted in the fuselage (12). A rotor assembly (18, 32) includes a rotor shaft (46) a plurality of rotor blades (34, 38) operatively connected to the rotor shaft (46). The rotor assembly (18, 32) includes a plurality of surface portions. An active air discharge opening (110) extends through one of the plurality of surfaces of the fuselage (12) and one of the plurality of surface portions of the rotor assembly (18, 32), and an active air generation system is mounted in the fuselage (12). The active air generation system is configured and disposed to generate and direct a flow of air through the active air discharge opening (110) to disrupt an airstream flowing over the one of the plurality of surfaces of the fuselage and the one of the plurality of surface portions of the rotor assembly (18, 32).