Title:
Topology for Modular Reconfigurable Unmanned Rotorcraft
Topology for Modular Reconfigurable Unmanned Rotorcraft
Author(s)
Davis, Joseph
Advisor(s)
Costello, Mark
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Abstract
Traditional air mobility capability development consists of defining a set of requirements and subsequently designing an aircraft that satisfies these requirements. The performance requirements must consider worst case operating conditions and peak performance capabilities of speed, range, payload, etc. These requirements typically demand robust aircraft solutions that are inefficient and expensive to operate during nominal missions when peak performance is not required. Once designed, the overall structure or topology of the aircraft is fixed. That is, the aircraft has certain fixed physical dimensions, number of rotors, number of engines, etc. It is not possible to vary the topology of the machine. The diversity of missions that can be performed and the operational capability of the aircraft is specified by the performance characteristics of this single aircraft. The fundamental unit of capability lies at the aircraft level.
This research takes a different approach where a core set of components (fuselages, rotors, nacelles, power plants, wings, structural beams, and hub connectors) define the fundamental units or modules of the air mobility system. The modules are designed so that they can be quickly connected to other modules to create a vast array of aircraft configurations with widely varying performance capabilities and operating costs. The configurations range from simple and inexpensive fixed pitch quadcopters to high-speed tilt rotors to expansive multi-rotor configurations designed to efficiently transport a wide variety of payloads. This concept is explored for autonomous mission spectrums with nominal payloads around 500 lbs and nominal ranges of 500 nautical miles. When peak performance is required, rotorcraft configurations may be assembled with payload capacities over 3500 lbs, ranges over 2800 km, and max continuous airspeeds as high as 250 KTAS at sea level.
Results indicate that for mission spectrums with large variance in speed requirements and large differences between nominal and maximum payloads, the operational cost per lb-km is significantly reduced using a modular and reconfigurable rotorcraft topology since cargo delivery requirements can be better matched to an air vehicle system. The cost benefit is most evident when the distribution of missions is skewed toward the nominal sizing mission with occasional needs for higher maximum levels of performance.
Finally, a modular and reconfigurable rotorcraft topology enables assembly of very robust rotorcraft configurations with high levels of redundancy that are resilient against in-flight failures of major components such as engines and rotor systems. Most of the configurations presented in this research have multiple engines with the largest configurations having up to eight engines. Hence, the failure of any one engine would not typically result in catastrophic aircraft failure and in most cases would not even require mission abort. Additionally, for configurations with six or more rotor systems, continued flight is possible following a failure of a rotor systems.
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Date Issued
2023-04-25
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Text
Resource Subtype
Dissertation