Slotted Wingtip Fins for Fixed-Wing Aircraft Stability

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Solution Overview

Problem

Fixed-wing aircraft, particularly drones, face challenges in achieving increased static stability under high lift conditions while minimizing induced and parasitic drag, leading to power wastage and limited flight range, and require long take-off and landing runways with limited payload capacity.

Innovation Solution

The aircraft features slotted fins at its ends, angled between 0° and 45° relative to the vertical, with slots along the leading edge to generate a stabilizing vertical lift component, and a retractable spout or flap to manage drag, along with a vertical tailplane and inclined fins to enhance stability and lift.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the lift is significantly increased using wing blowing techniques, then the lift is improved, but the angle of incidence varies and the horizontal stabilizer can no longer achieve its stabilizing function

Engineering Contradiction:
ImproveliftVSAvoidstatic stability
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The invention introduces vertical fins extending upward from the horizontal wingtips, adding a vertical dimension to the stabilizing structure. These fins with slots generate stabilizing moments in the vertical plane that counteract pitch variations caused by high-lift wing blowing, enabling static stability to be maintained under high lift conditions without compromising the lift enhancement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of energy

If winglets are extended to reduce induced drag, then the induced drag is reduced, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveinduced dragVSAvoidstructural complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The stabilizing function is segmented from the traditional horizontal stabilizer and distributed to vertical fins at each wingtip. Each fin with slots acts as an independent stabilizing element that reduces induced drag while maintaining simplicity in manufacturing and assembly, avoiding the complexity of conventional winglet designs.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If tactical fixed-wing aircraft are used to reduce cost, then the manufacturing cost is reduced, but the take-off and landing runway length increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidtake-off runway length
Core Design Contradiction:
Ease of manufactureVSLength of moving object

Solution Approach 1:

The slot fins pre-condition the airflow at the wingtips before stall occurs, maintaining attached flow and generating stabilizing moments that enable controlled operation at higher angles of incidence. This preliminary aerodynamic preparation allows the aircraft to achieve liftoff and landing at lower speeds, reducing the required runway length while maintaining cost-effective tactical aircraft design.

Inventive Principle:
Principle #10Preliminary action

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 enhances static stability, reduces power wastage, increases flight range, allows for a large payload, and requires shorter take-off and landing runways, while maintaining a compact design.

Implementation Method 1

The slot formed along the leading edge is oriented to circulate a flow of air through this slot from an external face of the fin to an internal face of said fin

Methodology Applied
Scientific EffectAir flow circulation through slots: Bernoulli Effect

Implementation Method 2

The lift of the aircraft is the force perpendicular to the direction of advance of the aircraft which is exerted on it to keep it in flight

Methodology Applied
Scientific EffectAerodynamic lift: Aerofoil

Implementation Method 3

These fins reduce the drag induced by lift, without increasing the wingspan of the aircraft

Methodology Applied
Scientific EffectInduced drag reduction: Vortex Ring

Data Source

PatentEP3365226B1Fixed-wing aircraft with enhanced static stability
Publication Date: 2020.02.12 DANIELSON AIRCRAFT SYST
  • EP3365226B1 patent drawingFigure 1~2
  • EP3365226B1 patent drawingFigure 3~4
  • EP3365226B1 patent drawingFigure 5

AI summary

The invention relates to an aircraft having at least one wing (5) including, at each end thereof, a fin (6) forming an angle of between 0° and 45° relative to the vertical. According to the invention, each fin (6) has a leading edge (7) that includes at least one slot (8) provided along said leading edge (7) and oriented so as to cause an air flow to flow via said leading edge (7) from an outer surface (6a) of the fin (6) to an inner surface (6b).