Inlet Vane Control for VTOL Ducted Fan Yaw and Side Force

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

VTOL aircraft face challenges in stability and control due to the complexity, weight, and cost of traditional collective and cyclic control methods, particularly in creating rotational moments without unwanted side forces.

Innovation Solution

A ducted fan vehicle design with vanes mounted across the inlet end of the duct, which are pivotally or non-pivotally operational, to produce desired side forces and rotational moments, combined with vanes at the exit end for enhanced control forces and moments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If vanes are mounted at the exit section of the duct to create rotational moments, then control moments are generated, but unwanted side forces are created that cause counter-productive vehicle acceleration

Engineering Contradiction:

Improverotational momentVSAvoidunwanted side force

Core Design Contradiction:

ForceVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the conventional arrangement by mounting vanes at the inlet end of the duct instead of the exit section. This reversal changes the flow interaction geometry so that when vanes are deflected, they generate rotational moments about the vehicle's longitudinal axis while the resulting side forces act through or near the center of gravity, minimizing counter-productive acceleration. The inverted positioning fundamentally alters the force moment arm relationships.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent applies local quality by positioning control vanes specifically at the inlet end of the duct where the airflow first enters, rather than uniformly distributing control surfaces along the duct. This localized placement at the inlet creates a specific flow deflection pattern that generates desired yaw moments while the vanes' orientation and positioning ensure side forces are minimized or directed through the center of gravity.

Inventive Principle:

Principle #3Local quality

2Device complexity

If collective control is used to change the angle of all blades simultaneously, then control is simplified, but the ability to generate precise rotational moments is reduced

Engineering Contradiction:

Improvecontrol mechanismVSAvoidrotational moment

Core Design Contradiction:

Device complexityVSForce

Solution Approach 1:

The patent introduces an intermediary control mechanism - the inlet vanes - that mediates between the simple collective pitch control system and the need for precise rotational moments. Instead of modifying complex blade pitch mechanisms to achieve yaw control, the inlet vanves serve as a separate, simpler control element that directly generates rotational moments through their deflection in the incoming airflow, while the main rotor continues its simple collective pitch operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If ducts are made slightly divergent with larger exit area, then efficiency is increased and power per unit lift is reduced, but the ability to generate control forces is limited

Engineering Contradiction:

Improvepower per unit liftVSAvoidcontrol capability

Core Design Contradiction:

Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The patent segments the control function from the propulsion function. The duct maintains its optimized divergent shape for efficient propulsion (reducing power per unit lift), while separate inlet vanes are introduced specifically for control functions. This segmentation allows the duct geometry to be optimized for energy efficiency without compromising control capability, as the vanes provide the necessary control authority independently of the duct's aerodynamic shape.

Inventive Principle:

Principle #1Segmentation

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

This configuration allows for effective control of VTOL aircraft, enabling desired movements such as forward, aft, left, and right translation, as well as yaw, pitch, and roll, while minimizing counterproductive side forces.

Implementation Method 1

a propeller rotatably mounted within the duct about the longitudinal axis of the duct to force an ambient fluid through from its inlet at the upper end of the duct through its exit at the lower end of the duct, and thereby to produce an upward lift force applied to the vehicle

Methodology Applied

Scientific EffectPropeller thrust: Impeller

Implementation Method 2

a plurality of spaced vanes mounted to and across the inlet end of the duct about pivotal axes perpendicular to the longitudinal axis of the duct and selectively operational to produce a desired horizontal control force in addition to the lift force applied to the vehicle

Methodology Applied

Scientific EffectAerodynamic force: Aerofoil

Data Source

PatentUS7717368B2Apparatus for generating horizontal forces in aerial vehicles and related method

Publication Date: 2010.05.18 URBAN AERONAUTICS

AI summary

A vehicle, comprising: a vehicle frame; a duct carried by the vehicle frame with the longitudinal axis of the duct perpendicular to the longitudinal axis of the vehicle frame; a propeller rotatably mounted within the duct about the longitudinal axis of the duct to force an ambient fluid through from an inlet at the upper end of the duct through an exit at the lower end of the duct, and thereby produce an upward lift force applied to the vehicle; a first plurality of substantially parallel, spaced vanes non-pivotally mounted across at least the inlet end of the duct; and fluidic means for affecting the ambient fluid flow around the vanes to generate horizontal force components to the lift force applied to the vehicle.