Projectile Fins with Interstitial Foam for Launch Pressure Management
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Solution Overview
Problem
Launching finned projectiles from circular cross-section launch tubes or guns is challenging due to the difficulty in accommodating fins, which often results in fin damage from sudden pressure differences during launch, leading to instability and potential breakage.
Innovation Solution
A projectile design featuring a fuselage with fins hingedly coupled to its outer surface and filler material in the spaces between the fins and the fuselage, which deploys after launch to prevent pressure-induced forces from causing fin damage, using lightweight materials like plastics or closed-cell foams to fill these spaces and absorb pressure differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If fins are added to stabilize projectile flight, then flight stability is improved, but fin damage from pressure differences during launch occurs
Solution Approach 1:
The filler material is pre-installed in the spaces between the fins and fuselage before launch. This preliminary action prevents pressure differentials from forming during launch by blocking gas flow paths, thereby protecting the fins from damage while maintaining their stability function.
Solution Approach 2:
The filler material acts as an intermediary substance between the fins and the external environment. It mediates the pressure differential by blocking gas flow, preventing the direct action of high-pressure gas on the fins during launch, thus protecting fin integrity while allowing fins to remain attached.
2Adaptability or versatility
If fins are kept close to fuselage in compact configuration, then launch tube compatibility is improved, but pressure differences can still cause fin damage
Solution Approach 1:
The filler material serves as an intermediary that blocks gas flow paths between the compact fins and the external environment. This prevents pressure differentials from developing even when fins are in compact configuration, protecting fin integrity while maintaining launch tube compatibility.
Solution Approach 2:
The invention extracts the harmful pressure differential effect by introducing filler material that removes the gas flow paths. This separates the fin structure from the harmful pressure environment during launch, allowing compact configuration to be maintained without fin damage.
3Reliability
If filler material is used to prevent pressure-induced fin damage, then fin integrity is improved, but device complexity increases
Solution Approach 1:
The filler material is designed as a simple, inexpensive, disposable component that is easily integrated into the projectile structure. It serves its protective function during launch and then separates harmlessly, providing fin integrity protection without requiring complex mechanisms or expensive materials.
Solution Approach 2:
The filler material is applied locally only in the specific spaces between the fins and fuselage where pressure differentials would cause damage. This localized application provides targeted protection without adding complexity to the entire projectile structure, maintaining simplicity while improving fin integrity.
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 solution effectively stabilizes the projectile by preventing fin damage and ensuring smooth deployment, reducing the risk of mechanical failure and maintaining fin functionality during flight, while also minimizing the impact on launch tube integrity.
Implementation Method 1
filler material in spaces between the fins and the outer surface when the fins are in a compact configuration, close to the outer surface
Data Source
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AI summary
A projectile (10) has filler material (18) placed between an outer surface of its fuselage (12), and fins (14) that are hingedly coupled to the fuselage (12). The filler material (18) fills space (16) that otherwise would be occupied by pressurized gases. Such pressurized gases could cause undesired outward force against the projectile fins (14) during launch of the projectile (10) from a launch tube or gun, such as when pressure outside the fins (14) is suddenly removed, as in when the projectile (10) passes a muzzle brake in the launch tube. The filler material (18) may be any of a variety of lightweight solid materials, such as suitable plastics or closed cell foams. The filler material (18) prevents pressurized gases from entering at least some of the space between the fins (14) and the outer fuselage surface (12). When the fins (14) deploy after the projectile (10) emerges from the launch tube the filler material (18) pieces fall away harmlessly.