Wedge Frame Fuselage Tailstrike Angle Enhancement

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Solution Overview

Problem

Aircrafts face the challenge of reduced tailstrike angle when stretched, leading to potential tailstrikes during takeoff and landing, which can result in costly delays and revenue loss, and existing solutions require extensive modifications or additional weight, especially for aircraft without fly-by-wire systems.

Innovation Solution

A wedge frame with non-parallel faceplanes is installed between sections of the fuselage to increase the tailstrike angle, allowing for a larger payload without modifying the landing gear or adding weight, by tilting the aft constant section upward relative to the forward and middle sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the fuselage is stretched to increase passenger and cargo capacity, then the revenue potential increases, but the tailstrike angle is reduced

Engineering Contradiction:
Improvepassenger and cargo capacityVSAvoidtailstrike angle
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The fuselage is divided into multiple constant sections that can be independently configured. By inserting additional constant sections between the middle and aft bodies, the fuselage length is increased without affecting the tailstrike angle, as each section maintains the required geometric relationship

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different geometric configurations to different parts of the fuselage. The aft constant section is specifically designed with non-parallel faceplanes that converge toward the aft, creating a localized geometric feature that enhances the tailstrike angle independently of the overall fuselage length

Inventive Principle:
Principle #3Local quality

2Reliability

If existing solutions like longer main landing gear or tilting bogies are used to prevent tailstrikes, then the tailstrike prevention capability improves, but the device complexity and modification requirements increase

Engineering Contradiction:
Improvetailstrike preventionVSAvoidlanding gear modification
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The solution extracts the tailstrike prevention function from the landing gear system and relocates it to the fuselage structure itself. By modifying the aft constant section geometry, the tailstrike angle enhancement is achieved independently of the landing gear configuration

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary structural element - the aft constant section with non-parallel faceplanes - that mediates between the fuselage and the ground contact. This intermediary geometry provides the tailstrike angle enhancement without requiring direct modifications to the landing gear or tail assembly

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If physical tailskids are added to mitigate tailstrike damage, then the protection capability improves, but the aircraft weight increases

Engineering Contradiction:
Improvetailstrike protectionVSAvoidaircraft weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent provides beforehand cushioning by pre-configuring the aft constant section geometry to enhance the tailstrike angle. This preventive geometric configuration reduces the likelihood of tailstrike occurrence before it happens, eliminating the need for reactive protective devices like tailskids

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP3031711B1Aircraft frame for tailstrike angle enhancement
Publication Date: 2019.05.08 THE BOEING CO
  • EP3031711B1 patent drawingFigure 1
  • EP3031711B1 patent drawingFigure 2A
  • EP3031711B1 patent drawingFigure 2B

AI summary

A wedge frame (201) for an aircraft that provides tailstrike angle enhancement. The wedge frame (201) has converging, non-parallel faceplanes that tilt a rear portion (114) of the aircraft fuselage upward in order to prevent or reduce risk of the tail of the aircraft striking the ground during takeoff and landing. A method to prevent or reduce risk of the rear portion of an aircraft from striking the ground during takeoff and landing by using a wedge frame (201) having converging, non-parallel faceplanes to tilt upward the rear portion (114) of the aircraft.