Estimating Aircraft Turbine Engine Costs
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Report Number: RM-6384/1-PR
Author(s): Large, J. P.
Corporate Author(s): The RAND Coporation
Date of Publication: 1970-09
Contract: F44620-67-C-0045
DoD Task:
Identifier: AD0738026
AD Number: AD738026
Abstract:
This memorandum presents equations for estimating development and production costs of turbojet and turbofan engines. Thrust is found to be the best single variable for estimating both development and production cost, but using thrust alone the differences between actual and estimated costs are unacceptably large. For development, these differences are greatly reduced by incorporating a second explanatory variable--either speed, absolute altitude, or thrust-to-airflow ratio. No combination of engine characteristics produces an acceptable estimating relationship for production cost when all engines are treated as a single class. When the sample is stratified into three classes on the basis of design requirements, it appears that useful estimating relationships are obtained for each class. A limitation on this approach is that the next generation of engines may compose a fourth class for which no estimating relationship can be derived empirically. For such engines, extrapolation from the curves and data shown here will be necessary.
Author(s): Large, J. P.
Corporate Author(s): The RAND Coporation
Date of Publication: 1970-09
Contract: F44620-67-C-0045
DoD Task:
Identifier: AD0738026
AD Number: AD738026
Abstract:
This memorandum presents equations for estimating development and production costs of turbojet and turbofan engines. Thrust is found to be the best single variable for estimating both development and production cost, but using thrust alone the differences between actual and estimated costs are unacceptably large. For development, these differences are greatly reduced by incorporating a second explanatory variable--either speed, absolute altitude, or thrust-to-airflow ratio. No combination of engine characteristics produces an acceptable estimating relationship for production cost when all engines are treated as a single class. When the sample is stratified into three classes on the basis of design requirements, it appears that useful estimating relationships are obtained for each class. A limitation on this approach is that the next generation of engines may compose a fourth class for which no estimating relationship can be derived empirically. For such engines, extrapolation from the curves and data shown here will be necessary.