Variable-Solidity Propeller for Vertical Takeoff and Cruise

Solution Overview

Problem

Propellers designed for high subsonic speeds lack sufficient aerodynamic solidity for vertical takeoff and hovering, while those optimized for hovering degrade in efficiency at higher flight speeds.

Innovation Solution

A variable-solidity propeller design featuring a first and second rotor configuration, where the blades can be adjusted between extended and retracted positions to change the propeller's average solidity, allowing for optimal performance in various flight modes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If propeller blade chord and span are increased to provide sufficient aerodynamic solidity for vertical takeoff and hovering, then thrust for vertical flight is improved, but propeller efficiency degrades at high subsonic speeds

Engineering Contradiction:

ImprovethrustVSAvoidpropeller efficiency

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The propeller implements variable solidity through movable blades that can change their radial position. The blades are mounted on hubs that allow them to move between extended and retracted positions, enabling the propeller to dynamically adjust its aerodynamic characteristics. This dynamic configuration allows high solidity for vertical flight and low solidity for high-speed flight, resolving the contradiction between thrust and efficiency across different flight modes

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the solidity parameter of the propeller based on flight conditions. By adjusting the radial position of the blades, the effective chord length and thus the solidity ratio are varied. This parameter change enables the propeller to optimize performance for different flight regimes - high solidity for vertical takeoff/hovering and low solidity for high subsonic cruise

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If propeller is designed with low aerodynamic solidity for efficient high subsonic flight, then propeller efficiency at high speed is improved, but thrust for vertical takeoff and hovering becomes insufficient

Engineering Contradiction:

Improvepropeller efficiencyVSAvoidthrust

Core Design Contradiction:

Loss of energyVSForce

Solution Approach 1:

The propeller implements variable solidity through movable blades that can change their radial position. The blades are mounted on hubs that allow them to move between extended and retracted positions, enabling the propeller to dynamically adjust its aerodynamic characteristics. This dynamic configuration allows high solidity for vertical flight and low solidity for high-speed flight, resolving the contradiction between thrust and efficiency across different flight modes

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the solidity parameter of the propeller based on flight conditions. By adjusting the radial position of the blades, the effective chord length and thus the solidity ratio are varied. This parameter change enables the propeller to optimize performance for different flight regimes - high solidity for vertical takeoff/hovering and low solidity for high subsonic cruise

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If a single propeller design is used for all flight modes, then device complexity is reduced, but performance and efficiency cannot be optimized for all flight conditions

Engineering Contradiction:

Improvepropeller configurationVSAvoidflight mode performance

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The propeller implements variable solidity through movable blades that can change their radial position. The blades are mounted on hubs that allow them to move between extended and retracted positions, enabling the propeller to dynamically adjust its aerodynamic characteristics. This dynamic configuration allows high solidity for vertical flight and low solidity for high-speed flight, resolving the contradiction between thrust and efficiency across different flight modes

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The variable solidity propeller design enables a single propeller to perform multiple functions across different flight modes. By adjusting blade position, the same propeller can be optimized for vertical takeoff, hovering, and high subsonic cruise flight, eliminating the need for separate propellers for different flight regimes while maintaining optimal performance in each mode

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables efficient propulsion across multiple flight modes, including vertical takeoff and high-speed horizontal flight, with improved thrust and efficiency by adjusting blade solidity based on flight conditions.

Implementation Method 1

A propeller includes a number of airfoil-shaped blades attached to a hub which is rotated by a prime mover in order to generate thrust

Methodology Applied

Scientific EffectAerodynamic lift: Aerofoil

Implementation Method 2

the aerodynamic characteristics of the propeller must be closely matched to intended operating conditions

Methodology Applied

Scientific EffectAerodynamic drag: Drag

Data Source

PatentUS10501177B2Convertible propeller

Publication Date: 2019.12.10 GENERAL ELECTRIC CO

AI summary

A variable-solidity propeller apparatus, comprising a propeller having at least one rotatable hub carrying at least one row of propeller blades, wherein the propeller has a first configuration in which the propeller has a first average solidity, and a second configuration in which the propeller has a second average solidity which is greater than the first average solidity.