Conceptual Design Studies of a Mono Tiltrotor

The Mono Tiltrotor (MTR) has been proposed by the Baldwin Technology Company as an innovative VTOL concept that integrates a tilting coaxial rotor, an aerodynamically deployed folding wing, and an efficient cargo handling system. The MTR has been targeted to meet heavy-lift, long-range mission objectives for which there is growing demand from military planners. This thesis describes a series of conceptual design studies aimed at determining the potential value that the MTR concept would possess, if it were to be technically realized. A versatile rotorcraft sizing analysis was developed to perform sizing and weight predictions for conventional single rotor and coaxial helicopters, as well as the MTR concept, based on key input mission and design requirements. This analysis was partly based on historical trends used in the rotorcraft and fixed-wing aircraft industries. These methods were expanded upon to include the capability for sizing the unique MTR concept. As presented, the results of this design analysis include a detailed weight budget of any number of potential aircraft point designs. The sizing methodology was validated against legacy helicopter sizing and component weights data, with good overall agreement. Comparisons, in terms of sizing and potential performance, between the MTR concept and conventional and coaxial helicopters sized to perform the same heavy-lift, long range mission are then presented. Key mission and design trade studies are also detailed, which were performed to study and refine the design concept and analytical methodology. The optimization of two key design points is also presented. These design points include a heavy-lift, long-range (20 ton payload, 1,000 nm range) MTR, and an MTR Scaled Demonstrator (2 ton payload, 700 nm range). Detailed performance studies are reported for each optimized point design. Overall, it was found that the MTR concept, if technically realized, offers unprecedented performance capability in terms of payload, range, and mission versatility. This comes in a very compact package relative to the size of a helicopter that would be required to complete the same mission

Hazards Analysis and Failure Modes and Effects Criticality Analysis (FMECA) of Four Concept Vehicle Propulsion Systems

The primary objective of this research effort is to identify failure modes and hazards associated with the concept vehicles and to perform functional hazard analyses (FHA) and failure modes and effects criticality analyses (FMECA) for each. Boeing also created a Fault Tree Analysis (FTA) for each of the concept vehicles, as the FTA contains the connectivity between systems and is an accepted, top-down method to analyze the safety of an air-vehicle. Conceptual design of notional powertrain configuration for each of four (4) NASA RVLT (Revolutionary Vertical Lift Technology) Concept Vehicles were developed in as much detail as was necessary to support the reliability and safety analysis for this project. Functional block diagrams from each of the conceptual powertrain configurations were created and used to order the FHA, FMECA, and FTA. Hazards were identified and the severity of each were categorized in the FHA for use in a follow-up FMECA. The FTA took inputs from the FMECA and the functional block diagrams to develop the connectivity and develop a quantitative architecture that could be used to perform sensitivity studies, as related to vehicle safety.Guidelines for reliability targets for both the air vehicle and the operation in the UAM (Urban Air Mobility) mission are discussed. An industry literature search was performed in order to assess gaps in existing government regulations and industry specifications. The industry literature search led to air-vehicle and operational reliability discussions, as related to Distributed Electric/Hybrid-Electric Propulsion (DE/HEP) system operating in the UAM role. A discussion of results and recommendations for future work is also provided