Pyrotechnic Wheel Acceleration for Short-Runway Aircraft Takeoff
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Solution Overview
Problem
Existing aircraft wheel drive systems are unable to efficiently accelerate aircraft to takeoff speeds, particularly for heavier aircraft, and are not suitable for operation from limited runways such as ship decks or improvised airfields.
Innovation Solution
Aircraft-mounted wheel acceleration systems utilizing pyrotechnic cartridge-powered rotary propulsion units, which generate expanding gases to drive an impeller that delivers high torque and power to the wheels, reducing takeoff distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If known electric wheel drive systems are used, then the system is suitable for taxiing applications, but the system cannot deliver sufficient torque and power output to accelerate aircraft to takeoff speeds
Solution Approach 1:
The patent extracts the pyrotechnic propulsion unit as a separate, dedicated component for takeoff acceleration, independent from the electric drive system used for taxiing. This allows the taxiing system to remain lightweight while the pyrotechnic system provides the necessary high power output for takeoff without being a permanent weight burden on the aircraft.
Solution Approach 2:
The patent changes the operational parameters by using pyrotechnic combustion to generate high-temperature expanding gases that drive the impeller. This chemical energy conversion provides a temporary but intense power burst suitable for takeoff acceleration, contrasting with the continuous but lower-power electric motor operation.
2Productivity
If pyrotechnic cartridge-powered rotary propulsion units are added to accelerate aircraft, then takeoff distance is reduced, but system complexity increases
Solution Approach 1:
The patent merges the pyrotechnic power generation unit with the rotary propulsion unit into an integrated assembly that mounts directly to the wheel. This combination eliminates the need for separate power transmission systems and reduces overall system complexity despite adding takeoff acceleration capability.
Solution Approach 2:
The patent uses pneumatic principles by channeling expanding gases from pyrotechnic combustion through a turbine or expansion vane motor to directly drive the wheel. This pneumatic power transmission method is more direct and simpler than mechanical gear systems or electric motor conversions, reducing system complexity.
3Speed
If existing wheel drive systems are used for aircraft with low engine thrust and high mass, then the aircraft can operate, but the takeoff distance becomes excessively long
Solution Approach 1:
The patent applies preliminary action by using the pyrotechnic-powered rotary propulsion unit to accelerate the aircraft to a higher initial speed before the main engines reach full thrust capability. This preliminary acceleration reduces the remaining distance needed for takeoff, allowing aircraft with low engine thrust to achieve takeoff from shorter runways.
Solution Approach 2:
The patent employs periodic action by using the pyrotechnic cartridge as a temporary, time-limited power source that provides intense acceleration during the critical initial phase of takeoff roll, then is discarded or deactivated, allowing the aircraft to complete takeoff using its main engines alone.
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 systems provide sufficient power density to accelerate military aircraft to takeoff speeds without excessive flying weight, enabling operation from limited runways and reducing takeoff distance.
Implementation Method 1
a pyrotechnic unit configured to generate expanding gases by combusting a propellant
Implementation Method 2
The rotary propulsion unit is pneumatically coupled to the pyrotechnic unit. The rotary propulsion unit includes an impeller configured to be driven by the expanding gases
Data Source
AI summary
Wheel acceleration systems are disclosed that provide a motive force to at least one wheel of an aircraft, in order to accelerate the aircraft to takeoff speed with the assistance of main engine thrust. The wheel acceleration system includes a pyrotechnic unit configured to generate expanding gases by combusting a propellant, and a rotary propulsion unit pneumatically coupled to the pyrotechnic unit. The rotary propulsion unit includes an impeller configured to be driven by the expanding gases and to deliver torque to the wheel.