Rotary Blade Lock Angle Control to Reduce eVTOL Drag

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Solution Overview

Problem

In electric vertical take-off and landing aircraft, non-rotating rotary blades experience inefficiencies due to air resistance and potential defects from idle rotation, necessitating a method to lock them at specific angles.

Innovation Solution

The control device includes an angle acquisition unit and a lock control unit to lock the rotation of rotary blades within a set lock angle range, gradually reducing the rotation speed to a predetermined speed before locking, thereby accommodating non-rotating blades and minimizing air resistance and idle rotation issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If non-rotating rotary blades are left without locking mechanism, then the structure remains simple, but air resistance causes efficiency deterioration and idle rotation may occur

Engineering Contradiction:
Improveefficiency deterioration due to air resistanceVSAvoidlocking mechanism structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent replaces mechanical locking mechanisms with a magnetic field-based locking system. The lock control unit generates a magnetic field that interacts with magnetic particles embedded in the rotary blade, achieving locking without mechanical contact. This substitution eliminates complex mechanical structures while effectively preventing idle rotation and reducing air resistance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces magnetic particles as an intermediary between the lock control unit and the rotary blade. These particles serve as a medium to transmit the locking force from the magnetic field to the blade, enabling non-contact locking. This intermediary approach simplifies the overall system structure while achieving the desired locking effect.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If rotary blades are locked at specific angles, then accommodation in housing and air resistance reduction are improved, but control system complexity increases

Engineering Contradiction:
Improveair resistance of non-rotating bladesVSAvoidcontrol system for locking
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The lock control unit automatically determines the optimal locking angle based on the rotary blade's operational state and autonomously controls the magnetic field generation. This self-service capability eliminates the need for external control systems or manual intervention, achieving precise angle control while keeping the control system simple.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates feedback mechanisms that monitor the rotary blade's position and operational status, allowing the lock control unit to adjust the magnetic field accordingly. This feedback ensures the blade is locked at the optimal angle for minimizing air resistance while accommodating it properly in the housing.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4063268B1Control device of electric drive system, and electric aircraft
Publication Date: 2026.01.07 DENSO CORP
  • EP4063268B1 patent drawingFigure 1
  • EP4063268B1 patent drawingFigure 2
  • EP4063268B1 patent drawingFigure 3

AI summary

A control device (50) of an electric drive system (10) for rotationally driving one of a rotary blade (30) and a screw that are a rotating body. The control device has a lock control unit that locks a rotation of the rotating body within a set lock angle range.