Tail-Sitting VTOL Rotor-Blown Wing Transition Without Cyclic Pitch
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Solution Overview
Problem
Existing VTOL aircraft designs struggle to achieve safe and efficient transitions from vertical to horizontal flight modes, particularly due to reliance on complex cyclic pitch controls and inadequate lift generation during transitions, posing safety risks for manned vehicles.
Innovation Solution
A tail-sitting VTOL aircraft with nonplanar wing configurations utilizing rotor-blown airfoil-shaped cross section bodies and variable pitch proprotors, combined with multi-rotor setups, provides dual means of pitch control through rotor-blown induced lift and thrust differentiation, ensuring safe transitions and stable flight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cyclic pitch control is used for transition, then transition control is achieved, but device complexity increases and safety decreases
Solution Approach 1:
The patent removes the cyclic pitch control mechanism from the system, replacing it with a simpler transition method that uses differential thrust control of the proprotors combined with fixed geometric wings, thereby extracting the complex and unsafe cyclic control system while maintaining transition capability
Solution Approach 2:
The patent replaces the mechanical cyclic pitch control system with an aerodynamic solution using fixed wings and differential proprotor thrust, substituting a complex mechanical control system with a simpler aerodynamic-mechanical hybrid approach that improves safety and reduces complexity
2Device complexity
If traditional wing configuration is used during transition, then structural simplicity is maintained, but lift generation is insufficient at high angles of attack
Solution Approach 1:
The patent transitions from relying solely on aerodynamic lift at high angles of attack to a three-dimensional solution combining differential proprotor thrust (vertical dimension) with aerodynamic forces, adding a thrust vectoring dimension to solve the lift generation problem during transition
3Use of energy by moving object
If reliance on aircraft inertia is used for transition, then power requirement is reduced, but safety decreases for manned vehicles
Solution Approach 1:
The patent applies preliminary action by using differential proprotor thrust to create a controlled pitch moment that initiates and guides the transition, ensuring the aircraft follows a safe trajectory before aerodynamic forces become dominant, rather than relying on uncontrolled inertia
Solution Approach 2:
The patent implements feedback control through the flight control system that continuously monitors aircraft attitude and adjusts proprotor thrust differentially to maintain safe transition conditions, creating a closed-loop control system that ensures safety rather than relying on open-loop inertial behavior
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
The solution enables precise control and safe transitions between hover and airplane modes, even in adverse weather conditions, by eliminating the need for cyclic proprotor control and leveraging rotor-blown wings for enhanced stability and lift management.
Implementation Method 1
dual means of pitch control through rotor-blown induced lift and thrust differentiation
Implementation Method 2
The rotor-blown wings are configured to be in the slipstream of the proprotors and the proprotors are configured to generate and direct airflow around the rotor-blown wings
Implementation Method 3
variable pitch proprotors
Implementation Method 4
dual means of pitch control through rotor-blown induced lift and thrust differentiation
Implementation Method 5
The moment created by the force of the front facing wind, helps the transition from vertical to horizontal
Implementation Method 6
the proprotors are configured to generate and direct airflow around the rotor-blown wings
Data Source
AI summary
A tail sitting VTOL aircraft with nonplanar tandem rotor blown wing configuration, capable of traveling in an airplane mode with its fuselage oriented horizontally, and a hover mode during take-off and landing with its fuselage oriented vertically, with capability to have precise controlled hover, and capability of making controlled and safe assisted transition between two modes during a horizontal movement and without need for much headroom and overhead clearance. Transition from hover mode to airplane mode is performed by moving forward in hover mode and rotating the fuselage around the pitch axis by the assist of the moment created by differential thrust of the propellers, or the moment created by differential lift created by the rotor blown tandem airfoil-shaped cross section bodies or a combination of both.