Retractable Stacked Propellers for Low-Drag VTOL Cruise
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Solution Overview
Problem
Existing vertical takeoff and landing (VTOL) aircraft face inefficiencies in both vertical and forward flight due to separate rotors for lift and thrust, leading to increased motor weight, drag, and design complexity, as well as low cruise efficiency optimized for hover.
Innovation Solution
A VTOL aircraft design featuring stacked propellers that transition from vertical takeoff and landing to cruise mode by deploying propellers on wingtips, wings, and tail, with co-rotating blades that adjust pitch and speed to reduce drag and noise, allowing for efficient lift and thrust during different flight phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate non-articulating rotors are used for vertical lift and forward thrust, then the aircraft can provide dedicated lift and thrust functions, but motor weight and aircraft drag increase
Solution Approach 1:
The patent applies universality by designing a single set of rotors that can perform both vertical lift and forward thrust functions. The rotors are articulated to tilt between vertical and horizontal positions, allowing the same rotor system to provide dedicated lift during vertical flight and dedicated thrust during forward flight, eliminating the need for separate motor systems for each function.
Solution Approach 2:
The patent applies dynamics by making the rotors articulated and tiltable rather than fixed. The rotor assembly can dynamically change its orientation angle, transitioning from a vertical configuration for lift generation to a horizontal configuration for thrust generation. This dynamic adjustment allows the system to adapt to different flight phases without requiring separate static rotor systems.
2Reliability
If separate non-articulating rotors are used for vertical lift and forward thrust, then the aircraft can provide dedicated lift and thrust functions, but aircraft drag increases
Solution Approach 1:
The patent applies universality by designing a single set of rotors that can perform both vertical lift and forward thrust functions. The rotors are articulated to tilt between vertical and horizontal positions, allowing the same rotor system to provide dedicated lift during vertical flight and dedicated thrust during forward flight, eliminating the need for separate motor systems for each function.
Solution Approach 2:
The patent applies dynamics by making the rotors articulated and tiltable rather than fixed. The rotor assembly can dynamically change its orientation angle, transitioning from a vertical configuration for lift generation to a horizontal configuration for thrust generation. This dynamic adjustment allows the system to adapt to different flight phases without requiring separate static rotor systems.
3Weight of moving object
If distributed tilting propulsors are used to provide both vertical lift and forward thrust, then motor weight and aircraft drag are reduced, but design complexity increases
Solution Approach 1:
The patent applies universality by designing a single set of rotors that can perform both vertical lift and forward thrust functions. The rotors are articulated to tilt between vertical and horizontal positions, allowing the same rotor system to provide dedicated lift during vertical flight and dedicated thrust during forward flight, eliminating the need for separate motor systems for each function.
Solution Approach 2:
The patent applies merging by combining the lift and thrust functions into a single rotor system rather than using separate distributed propulsors. The articulated rotor assembly integrates both vertical and horizontal flight capabilities in one unified mechanism, reducing the total number of independent motor-rotor units required while maintaining functional versatility.
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 balanced vertical and forward flight with reduced weight, drag, and complexity, improving cruise efficiency and noise reduction by optimizing propeller configuration and deployment during various flight modes.
Implementation Method 1
During vertical ascent of the aircraft, stacked propellers are deployed to provide lift to the aircraft
Implementation Method 2
Each stacked propeller includes two propellers, a first propeller and a second propeller, each including two blades coupled to a blade hub
Implementation Method 3
The first propeller and the second propeller can rotate at the same or different speeds
Implementation Method 4
The first propeller and the second propeller have a variable pitch and the first propeller and the second propeller can rotate at the same or different speeds
Implementation Method 5
The first propeller and/or the second propeller can stop rotating and retract into an internal cavity to reduce drag during forward flight
Data Source
AI summary
An aircraft can include a stacked propeller to generate lift during assent and descent. The stacked propeller includes a first propeller and a second propeller that co-rotate about an axis of rotation. In one embodiment, the blades are coupled to a rotor mast that contains an internal cavity. In one mode of operation, the first propeller and/or the second propeller can be stored in the internal cavity in order to reduce drag during flight. The aircraft can include one or more stacked propellers, such as a port propeller and a starboard propeller, which rotate in opposite directions during one or more modes of flight.