Flapping Ground-Effect Wingtip for Rough-Sea Clearance Control
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Solution Overview
Problem
Current ground effect aircraft either require excessive size or are limited to specific operational conditions, failing to combine efficient cruise at high altitudes with take-off and landing on rough seas and surface effect operation without excessive size.
Innovation Solution
The aircraft employs rotating outboard wing segments that move in a 'flapping' motion relative to inboard segments, controlled by sensors detecting wave height, to reduce drag and adapt to varying water conditions, with each segment comprising at least 8% of the wing span and using mechanical actuators for movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the aircraft uses a large wingspan to reduce lift-induced drag and achieve efficient ground effect cruise, then cruise efficiency is improved, but the aircraft size becomes excessive and cannot operate on rough seas
Solution Approach 1:
The wing is divided into inboard and outboard segments that can move independently. The outboard segments are segmented further into multiple sections that can flap relative to each other, allowing the wing to adapt its effective span to operational conditions.
Solution Approach 2:
The outboard wing segments are made dynamically movable through flapping joints that allow rotation relative to the inboard segments. This dynamic configuration enables the wing span to change from extended (for efficient cruise) to retracted (for rough sea operations).
2Loss of energy
If the aircraft uses a fixed large wingspan for ground effect cruise, then drag is reduced, but the aircraft cannot safely take-off and land on rough seas
Solution Approach 1:
The wing configuration transitions from static to dynamic, allowing the outboard segments to flap up and down. During rough sea operations, segments can be positioned to reduce span and improve safety, while in calm conditions they extend for efficient cruise.
Solution Approach 2:
The effective wingspan parameter is changed dynamically based on operational conditions. Sensors detect wave height and automatically adjust the wing configuration, changing the span parameter to optimize performance for current conditions.
3Adaptability or versatility
If the aircraft reduces wingspan to operate on rough seas, then operational flexibility is improved, but lift-induced drag increases and ground effect cruise efficiency decreases
Solution Approach 1:
The segmented wing design allows only the outboard portions to be retracted while maintaining the inboard wing structure. This selective segmentation enables span reduction for rough sea operations without compromising the core lifting surface needed for efficient cruise.
4Reliability
If the aircraft uses a spring-mounted outer wing segment to allow compliance during wave collisions, then reliability is improved, but the wing sweep changes when segments move up and down
Solution Approach 1:
The wing is segmented into independent sections that can move vertically without affecting the overall wing sweep. Each segment is mounted on springs that allow compliance with wave collisions while maintaining proper aerodynamic alignment.
Solution Approach 2:
The spring-mounted segments provide dynamic compliance with wave conditions while the segment design ensures that vertical movement does not alter the sweep angle, maintaining consistent aerodynamic characteristics.
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 solution allows for efficient cruise at high altitudes, take-off and landing on rough seas, and surface effect operation without excessive size, enhancing operational flexibility and reducing drag by dynamically adjusting wing geometry in response to wave conditions.
Implementation Method 1
drag of an aircraft flying over a water surface is reduced due to ground effect
Data Source
AI summary
An up-down flapping wingtip is provided for a ground effect vehicle. The wingtip is positionable at an anhedral angle to control the wingtip clearance from ground. Variable wingtip clearance reduces the risk of damage due to collision with the ground or water, thereby permitting more efficient flight at lower altitude with an equivalent safety. The wingtip is positioned by a wingtip flap and an actuator. The wingtip anhedral angle is controlled by a flight control system. A sensor is included for determining whether an object lies in the path of the wingtip. The sensor communicates with the flight control system in order to vary the flapping angle of the wingtip to increase clearance from the ground or water, thus avoiding impact with the object. The wingtip anhedral angle is reduced to increase the wingspan for flight out of ground effect.