Ejection Seat Stabilization Droguet Chute Drag Reduction

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Solution Overview

Problem

Drogue parachutes often cause collisions between an ejecting seat and an aircraft's tail due to minimal clearance, as they pull the seat aft, leading to increased drag and potential hazards during ejection events, especially with heavier aircrew.

Innovation Solution

A drogue parachute design featuring a mesh or low-resistance structure on one side, configured to reduce drag, with bridles and suspension lines directing this side downward, creating an area of reduced resistance ranging from 64.516 to 2580.64 cm², which helps in stabilizing the ejection seat and preventing collisions by minimizing air resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional drogue parachute is used to decelerate the ejection seat, then the seat can be stabilized for main parachute deployment, but the seat may collide with the aircraft tail due to minimal clearance

Engineering Contradiction:
Improvestabilization of ejection seatVSAvoidcollision with aircraft tail
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The drogue parachute incorporates a low-resistance structure (mesh or opening) on the forward-facing side while maintaining full canopy structure on other sides. This creates localized drag reduction exactly where needed to prevent tail collision, while preserving stabilization function through the remaining canopy structure

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the drag parameter of the drogue parachute by introducing a low-resistance structure that reduces the effective surface area by 20-80%. This parameter modification allows the parachute to provide sufficient deceleration and stabilization while reducing the aft-pulling force that causes tail collision

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a drogue parachute pulls the seat aft to stabilize it, then deployment control is improved, but drag increases causing potential collision with the aircraft tail

Engineering Contradiction:
Improvedeployment controlVSAvoiddrag force
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The low-resistance structure is positioned on the forward-facing side of the drogue parachute, creating localized drag reduction. This allows the parachute to maintain stability and deployment control through the remaining canopy structure while reducing overall drag force that causes tail collision

Inventive Principle:
Principle #3Local quality

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 drogue parachute effectively reduces drag and stabilizes the ejection seat, preventing collisions with the aircraft tail by directing the low-resistance area downward, ensuring safer deployment of the main parachute and reducing the risk of accidents.

Implementation Method 1

the first side comprises a mesh portion configured to reduce drag. The first side also comprises an opening configured to reduce drag

Methodology Applied
Scientific EffectDrag reduction: Drag

Data Source

PatentEP3075659B1Apogee enhancing ejection seat stabilization drogue chute
Publication Date: 2023.03.29 AMI IND INC
  • EP3075659B1 patent drawingFigure 1
  • EP3075659B1 patent drawingFigure 2
  • EP3075659B1 patent drawingFigure 3

AI summary

An aircraft ejection system is provided. The aircraft ejection system may comprise a seat (106), a bridle (108) coupled to the seat, suspension lines (110) coupled to the bridle, and a drogue canopy (120) coupled to the suspension lines. A first side (124) of the drogue canopy may have a lower drag than a second side of the drogue canopy. The first side may comprise a mesh portion and/or an opening to reduce drag. The first side may further include a low-resistance structure (122) with a circular or rectangular geometry. The bridle and the suspension lines may be configured to direct the first side in a predetermined direction, such as downward.