Stratospheric Airship Geodesic Frame and Propulsion Control
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Solution Overview
Problem
Stratospheric airships face challenges with low-speed maneuverability, large ground crew and landing strip requirements, susceptibility to damage, and low-frequency vibrations that affect buoyancy and attitude control, particularly in the stratospheric environment.
Innovation Solution
A spherical airship with a geodesic frame and propulsion units positioned at the center of mass plane, utilizing a buoyant gas cell for pressure equilibrium and four propulsion units for enhanced maneuverability and vibration reduction, allowing for efficient buoyancy control and increased safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a non-rigid or semi-rigid airship structure is used, then the construction is simpler and more flexible, but the airship experiences larger low-frequency vibrations and reduced stability
Solution Approach 1:
The patent employs a flexible envelope made of thin film materials that conforms to the geodesic frame structure. This flexible shell provides aerodynamic stability while allowing the rigid geodesic frame to bear the structural loads, thereby reducing vibrations without compromising construction simplicity.
Solution Approach 2:
The airship combines a rigid geodesic frame structure with a flexible envelope material, creating a composite construction system. The rigid frame provides structural stability and vibration reduction, while the flexible envelope maintains aerodynamic shape and allows for simpler construction methods compared to fully rigid structures.
2Ease of operation
If the propulsion system is positioned away from the center of mass, then the control is easier, but the airship experiences increased vibrations and reduced maneuverability at low speeds
Solution Approach 1:
The patent positions the propulsion units asymmetrically relative to the geodesic frame structure, allowing independent control of thrust vectors. This asymmetric arrangement enables precise maneuverability and attitude control while the distributed positioning around the center of mass minimizes vibrations through balanced force distribution.
Solution Approach 2:
The propulsion units are positioned in three-dimensional space around the center of mass rather than in a single plane, enabling control in multiple dimensions. This spatial distribution allows the system to achieve both ease of control through independent thrust vectoring and reduced vibrations through balanced moment distribution.
3Strength
If a rigid hull with geodesic frame is used, then the structural integrity is improved and vibrations are reduced, but the device complexity increases
Solution Approach 1:
The patent employs a geodesic dome structure based on spherical geometry, which provides exceptional structural integrity and vibration resistance. The curved surface distributes stresses evenly throughout the framework, achieving high strength-to-weight ratio while the modular geodesic pattern simplifies construction compared to traditional rigid hull designs.
Solution Approach 2:
The rigid hull is constructed using a segmented geodesic framework composed of standardized triangular elements. This segmentation allows for modular assembly, reducing overall construction complexity while maintaining the structural integrity and vibration reduction benefits of the rigid framework.
4Duration of action of moving object
If the airship is designed for stratospheric operation, then the operational endurance is extended, but the maneuverability at low speed is reduced
Solution Approach 1:
The patent employs dynamically controllable propulsion units with variable thrust vectors that can be independently adjusted. This dynamic control system allows the airship to optimize its performance for both long-endurance stratospheric operations and low-speed maneuvering by adjusting thrust magnitude and direction in real-time based on operational requirements.
Solution Approach 2:
The propulsion system is designed with multi-functional capability, serving both as the primary drive for long-duration stratospheric flight and as a precise control mechanism for low-speed maneuvers. The same propulsion units perform multiple functions across different operational regimes, eliminating the need for separate systems.
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 provides improved stability, reduced low-frequency oscillations, increased safety, and efficient energy use, enabling prolonged operational cycles with minimal ground crew and landing strip needs, while maintaining structural integrity and reducing descent hazards in case of buoyant gas loss.
Implementation Method 1
utilizing a buoyant gas cell for pressure equilibrium
Data Source
AI summary
An autonomous stratospheric unmanned airship with an operating altitude from 5-22 km and with a multi-month operational cycle. Spheroid rigid geodesic frame of constant volume formed by a multitude of struts, with an outer envelope enclosing the frame defining the eigenfrequency spectrum of the airship above 20 Hz, with vibrational amplitudes between 0.1 and 1 cm. Independently controllable electrical propulsion units, attached to the frame in the horizontal plane passing through the center of mass, can change the direction and value of the thrust vector. Buoyancy is controlled with a system integrated inside the geodesic frame including buoyant fluid pressurized tanks, valves for the release of the buoyant fluid through the buoyant fluid conduit into the buoyant gas cell which fills the geodesic frame. Valves at the subsystem support platform enable ambient atmosphere to fill the internal volume of the frame not occupied by the buoyant gas cell.