Optical Propeller Pitch Tuning Tool for Wind Tunnel Precision

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Solution Overview

Problem

Existing tools for tuning the pitch of model propeller blades in wind-tunnel tests lack precision and are time-consuming, with ±0.1 degree accuracy being insufficient and prone to subjective errors due to vernier reading, contact-based measurement, and mechanical wear.

Innovation Solution

A tool using optical means, such as laser transducers, to determine the pitch of propeller blades with ±0.05 degree precision by measuring distances on the suction face, eliminating contact-based errors and allowing for precise and objective angle adjustments, with the option to use standard propellers for calibration and interpolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If contact-based measurement tools with vernier scales are used to tune propeller blade pitch, then the device complexity is reduced and ease of operation is improved, but measurement precision deteriorates to ±0.1 degree and is prone to subjective errors

Engineering Contradiction:

Improveblade pitch measurement precisionVSAvoidtool structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical contact-based measurement systems (vernier scales, shoes contacting the blade) with optical measurement systems. Laser transducers or optical sensors non-contactly measure the position and orientation of propeller blades, eliminating mechanical wear and subjective reading errors while achieving higher precision. The optical system uses light beams to detect blade pitch angles without physical contact.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces optical fields (laser beams, light paths) as intermediaries between the measurement system and the propeller blade. Instead of direct mechanical contact, the optical intermediary carries measurement information from the blade position to the detection system, enabling precise non-contact measurement and reducing measurement uncertainty.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If traditional vernier-based tools are used for blade pitch adjustment, then the ease of operation is maintained, but loss of time increases due to the time-consuming tuning process

Engineering Contradiction:

Improveblade tuning speedVSAvoidtime for tuning all blades

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical adjustment with automated optical measurement and control systems. The optical system rapidly captures blade position data, and computer-controlled mechanisms automatically adjust blade pitches, eliminating time-consuming manual operations and enabling faster tuning of multiple blades.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements self-measuring and self-adjusting capabilities where the optical measurement system automatically detects blade pitch deviations and the control system autonomously makes corrections. This reduces the need for continuous manual intervention and accelerates the overall tuning process.

Inventive Principle:

Principle #25Self-service

3Reliability

If contact-based shoes are placed against the blade suction face for measurement, then the ease of operation is improved, but reliability deteriorates due to subjective errors and mechanical wear

Engineering Contradiction:

Improvemeasurement reliabilityVSAvoidoperation simplicity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces mechanical contact measurement with optical non-contact measurement. Laser transducers and optical sensors detect blade positions and orientations through light reflection or direct measurement without physical contact, eliminating shoes, mechanical wear, and subjective reading errors while maintaining operational simplicity through automated detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 tool achieves improved precision and reduced time for tuning propeller blades, ensuring accuracy better than ±0.1 degree and up to ±0.05 degree, enhancing the reliability of wind-tunnel test results and maintaining symmetry in aircraft models.

Implementation Method 1

optical means, such as laser transducers, to determine the pitch of propeller blades with ±0.05 degree precision by measuring distances on the suction face

Methodology Applied

Scientific EffectLaser: Laser

Data Source

PatentUS8605272B2Tool, tool set and method of setting the pitch of the blades of a model propeller

Publication Date: 2013.12.10 AIRBUS OPERATIONS (SAS)

AI summary

A tool for tuning the pitch of blades on a model propeller with pivoting blades, the tool comprising a mount for the model propeller and a calculation module. The mount allows the propeller to be positioned such that the axis of the propeller coincides with a fixed reference axis of the mount and to place each blade of the propeller, successively, in a measurement position. The calculation module determines the angle between a chord of a blade in the measurement position and a fixed reference plane of the tool, the fixed reference plane being orthogonal to the fixed reference axis, based on optical sightings by the calculation model on a suction face of the blade in the measurement position.