Rotor Blade Locking Geometry for Low-Drag Forward Flight
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Solution Overview
Problem
Aircraft with vertical takeoff and landing capability face increased aerodynamic drag during forward flight due to the use of vertical fans when they are not actively generating thrust.
Innovation Solution
The rotor blades of the vertical fans are configured to be locked into an aerodynamic position, facing more forward and backward, with smaller angles between blades in the front and back and larger angles to the sides, reducing drag by minimizing the surface area exposed to airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If vertical fans are used to generate vertical thrust for hover and vertical takeoff, then vertical thrust capability is improved, but aerodynamic drag increases during forward flight when fans are not actively generating thrust
Solution Approach 1:
The rotor blades are configured to rotate to different angular positions depending on flight mode. During hover and vertical takeoff, blades rotate vertically to generate thrust. During forward flight, blades rotate to an aerodynamic position (acrobatic configuration) to minimize drag. This dynamic reconfiguration allows the same propulsion system to optimize for different flight phases.
Solution Approach 2:
The angular position parameter of the rotor blades is changed based on flight conditions. By adjusting the blade orientation from a vertical thrust-generating position to an aerodynamic low-drag position, the system transitions between conflicting performance requirements. The blade angle becomes a variable parameter that adapts to flight regime.
2Object-affected harmful factors
If rotor blades are positioned to face forward and backward with smaller angles, then aerodynamic drag is reduced during forward flight, but thrust generation capability may be affected
Solution Approach 1:
The rotor blade configuration is dynamic rather than static. The same blades that are positioned at smaller angles for drag reduction can be repositioned to optimal thrust-generating angles when vertical thrust is required. This dynamic reconfiguration resolves the contradiction between drag reduction and thrust generation capability.
Solution Approach 2:
The rotor blade system serves multiple functions: it generates vertical thrust during hover/takeoff and minimizes aerodynamic drag during forward flight. By making the blade configuration adaptable, a single system achieves what would otherwise require different specialized components for each function.
Data Source
AI summary
Embodiments of the invention are directed to systems and methods for reducing drag on an aircraft. The aircraft can include at least one propulsion system with rotor blades configured to reduce aerodynamic drag when the propulsion system is deactivated. To reduce the amount of drag, the rotor blades can be locked into an aerodynamic position, and prevented from passively spinning. Additionally, the rotor blades can be configured to have angular positions that reduce drag. For example, the rotor blades as a group may be configured to generally point toward and/or away from an airflow current.