The unique capabilities of the tilt-rotor configuration are generally accepted to provide significant potential when applied to numerous civil and military operations. A vital stage in the development of any tilt-rotor design is the simulation of its basic flying qualities which are essentially defined by the vehicle's response to a range of control inputs and the trim states it adopts. In order to carry out this simulation satisfactorily, an accurate generic mathematical model is required, however, the author is unaware of any existing tilt-rotor simulations which utilise the latest modelling techniques. A generic tilt-rotor simulation model (GTILT) which includes individual blade modelling to describe the behaviour of the rotor has been developed during this research. One of the most significant attributes of individual blade models is that they portray the oscillatory nature of the forces and moments produced by a lifting rotor. The resulting trimmed flight path of the vehicle is periodic rather than steady in nature and consequently existing trimming algorithms, formulated for use with rotor disc representations, are inappropriate when applied to individual blade simulations. A specialised trimming algorithm capable of rapidly trimming rotorcraft simulations to a specified periodic trim state has been developed and incorporated into the GTILT model. Individual blade modelling provides a higher level of fidelity than is possible when using a rotor disc representation but this benefit is obtained at the expense of computational burden. Hence, most sequential computing facilities are unable to provide the performance necessary to make such models practical. In order to reduce computational run-times to an acceptable level GTILT has been parallelised and implemented on a custom designed transputer network. GTILT has been configured using XV-IS data in order to investigate the fidelity of its predicted trim states and vehicle response to a range of control inputs. During the course of this investigation, the trim algorithm is shown to be robust and capable of producing rapid convergence to a wide range of trim states. Longitudinal trims predicted by GTILT are verified against those of the similarly configured Bell C81 for a range of nacelle incidences and good correlation obtained in all cases. A qualitative verification of the trim states adopted in turning flight reveals no anomalies and the results obtained are very encouraging. The dynamic response of the vehicle is demonstrated to be qualitatively valid when a range of control inputs are applied at various nacelle incidences with the behaviour of the vehicle being explicable in all cases.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:442698 |
| Date | January 1993 |
| Creators | McVicar, J. Scott G. |
| Publisher | University of Glasgow |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://theses.gla.ac.uk/4952/ |
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