Tri-rotor UAV with Variable Pitch and Tiltrotors
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Solution Overview
Problem
Current rotorcraft, including helicopters and drones, face limitations in size, efficiency, battery life, and versatility, with most drones having short battery life and being restricted to either air or water operations, and lacking safety features for emergency landings.
Innovation Solution
A tri-rotor design with swashless, variable-pitch rotors, tiltrotors, and an active yaw system, combined with autorotation capabilities and a modular, amphibious monocoque fuselage, allowing for efficient operation in both air and water with enhanced safety and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional multi-rotor designs with four or more propellers are used for yaw control, then yaw control is achieved, but vehicle size and weight increase
Solution Approach 1:
The patent extracts the yaw control function from the main lifting propellers and assigns it to a dedicated tail rotor system. This separation allows the main propellers to focus on lift generation while the tail rotor handles yaw control, reducing the overall vehicle size and weight compared to traditional designs that require larger propellers for combined lift and control functions.
Solution Approach 2:
The vehicle control functions are segmented into distinct systems: main propellers for lift, tail rotors for yaw control, and differential thrust for directional control. This functional segmentation allows each component to be optimized for its specific purpose, reducing overall vehicle weight while maintaining comprehensive control capability.
2Ease of operation
If propeller speed is varied to control elevation and direction, then position control is achieved, but energy efficiency decreases and battery life is reduced
Solution Approach 1:
The patent implements variable pitch mechanisms on the main propellers that allow blade angle adjustment without changing rotational speed. This dynamic pitch control enables elevation and directional control while maintaining optimal propeller RPM for energy efficiency, significantly reducing battery consumption compared to speed-variation methods.
Solution Approach 2:
The control system changes the pitch parameter of the propeller blades rather than changing the rotational speed parameter. This parameter substitution allows for efficient energy use because the propellers operate at constant optimal RPM while still achieving the desired control effects through pitch variation.
3Speed
If the entire vehicle is tilted for forward motion, then forward speed is increased, but aerodynamic drag increases significantly
Solution Approach 1:
The patent segments the forward motion function from the main fuselage and assigns it to tiltrotor components. The tiltrotors can pivot to optimize their angle for forward thrust while the main fuselage remains level, minimizing aerodynamic drag on the primary structure while still achieving increased forward speed.
Solution Approach 2:
Only the tiltrotor components change their orientation for forward motion, while the main fuselage maintains its optimal aerodynamic position. This localized quality change allows forward speed increase without subjecting the entire vehicle to the penalties of tilting, thereby reducing overall aerodynamic drag.
4Device complexity
If fixed-pitch propellers are used, then mechanical simplicity is maintained, but operational efficiency and adaptability are reduced
Solution Approach 1:
The patent introduces variable pitch mechanisms that allow the propeller blade angles to be dynamically adjusted during operation. This dynamic capability enables the system to adapt to different flight conditions and optimize performance, significantly improving operational efficiency while adding only moderate mechanical complexity.
Solution Approach 2:
The variable pitch propeller system serves multiple functions: it provides efficient lift generation, enables precise elevation control, and allows adaptation to various flight regimes. This multi-functionality increases operational efficiency and versatility without requiring separate systems for each function.
5Device complexity
If no autorotation capability is provided, then mechanical simplicity is maintained, but safety during engine failure is compromised
Solution Approach 1:
The patent incorporates autorotation capability through one-way hubs that allow the propellers to rotate freely in the event of engine failure. This beforehand preparation ensures that the vehicle can safely descend and land even when power is lost, providing a critical safety buffer without adding excessive mechanical complexity.
Solution Approach 2:
The autorotation system allows the propellers to serve themselves during engine failure by continuing to rotate and generate lift through aerodynamic forces alone. This self-service capability provides passive safety during emergencies without requiring active control or additional power sources.
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 design achieves superior performance, longer battery life, and increased versatility by reducing size and weight while ensuring safe emergency landings, with improved stability and control, enabling efficient and reliable operation in various environments.
Implementation Method 1
three swashless, variable-pitch vertical lift main rotors
Implementation Method 2
The two rear ('aft') main rotors can be, optionally, tiltrotors, which means they pivot to increase forward speed
Implementation Method 3
swashless, variable-pitch vertical lift main rotors... Movements are controlled through changes in pitch, allowing the motor(s) to maintain constant governed rotations per minute (RPM)
Implementation Method 4
The invention also has a fail-safe automatic disengage system that disengages the propellers from the power plant in case of engine failure. This allows the unit to auto-rotate, similar to the auto-rotation that a helicopter undergoes when it loses power.
Data Source
AI summary
A vehicle with superior performance and reliability. The vehicle, such as an unmanned aerial vehicle, is capable of vertical takeoff and landing, uses three swashless, variable-pitch vertical lift main rotors with a yaw tail rotor system. Two rear main rotors are optionally tiltrotors, which pivot to increase forward speed without the increased coefficient of drag inherent in tilting the entire vehicle. The three main rotors are positioned in an equilateral triangular configuration, improving balance, increasing load-bearing strength, and making it more compact in size. Movements are controlled through changes in pitch of the rotors, allowing the motors to maintain constant governed rotations per minute, maximizing drivetrain efficiency. Various embodiments allow for smaller vehicle size with greater performance than prior art vehicles.