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• Parametric Studies 
Piano includes a facility for running parametric studies and plotting the results. Any two of the major design parameters can be varied to produce a matrix of outputs. This is saved as a text file using tab-delimited format and can be read by other software such as spreadsheets for further post-processing. Parametric studies are equivalent to running multiple point designs automatically. Piano will consider the effects on all major characteristics such as weight, range and field lengths, and lets you cross-plot the results to visually determine the most promising design regions and local parameter sensitivities. An important study is the traditional preliminary sizing exercise which involves varying the wing area and engine thrust whilst iterating to keep the design range constant.
• Numerical Optimisation
Piano's Multivariable Optimisation feature is a powerful technique that can suggest promising or nominally optimum parameter combinations. Basic aircraft sizing parameters such as the wing area, thrust, aspect ratio, sweepback, etc can be varied freely between upper and lower bounds. The target, or 'objective function' to be minimised may be the aircraft mass, the fuel burn, the DOC (Direct Operating Cost) or some weighted combination of these. The optimisation process will be subject to design constraints specified by the user such as the maximum permissible takeoff/landing field lengths, required range or other performance requirements. Piano's numerical optimization techniques are robust and based on the Nelder-Mead sequential simplex method modified to cater for inequality constraints.
Home | Back to Features | Next (Flight Manoeuvres)
Piano's Multivariable Optimisation feature is a powerful technique that can suggest promising or nominally optimum parameter combinations. Basic aircraft sizing parameters such as the wing area, thrust, aspect ratio, sweepback, etc can be varied freely between upper and lower bounds. The target, or 'objective function' to be minimised may be the aircraft mass, the fuel burn, the DOC (Direct Operating Cost) or some weighted combination of these. The optimisation process will be subject to design constraints specified by the user such as the maximum permissible takeoff/landing field lengths, required range or other performance requirements. Piano's numerical optimization techniques are robust and based on the Nelder-Mead sequential simplex method modified to cater for inequality constraints.