1225. The Use of System Level Cost Estimating Relationships to Establish Initial Design to Cost Targets for Rotorcraft, Fixed Wing and Hybrid Aircraft

Paper

Abstract

Aircraft design groups have for some time had methods to obtain total aircraft weight by determining the weights for each of the systems on a system by system basis. A comparable capability for estimating costs on a system by system basis has not been available until recently. This paper provides a complete set of system level cost estimating relationships (CERs) for transport aircraft. These CERs estimate cost as a function of system weight. A companion set of weight estimating relationships has been developed which enables cost to be estimated based on performance characteristics as well. A similar set of CERs is also provided for helicopter systems – these are not complete, however, as they exclude manufacturer costs associated with assembly and check-out. A discussion of how transport aircraft and helicopter CERs could be used jointly to estimate the cost of hybrid aircraft (e.g., tilt rotor) is also included.
The CERs are provided in a Design to Cost (DTC) framework (Why, When and How) and key factors related to their development and use are also discussed. The principal point made in this paper is that, by using a disaggregated set of equations to estimate cost at the systems level, reasonably accurate preliminary cost estimates may be achieved. These estimates may serve directly as initial DTC targets. Also, adjustments may be made to estimates obtained for selected systems to estimate the production cost impact of alternative designs or manufacturing technologies. The relative ease by which estimates may be made with these equations, the flexibility they provide by being disaggregated and the accuracy of their estimates make them unique and useful tools for establishing initial DTC targets.