As observed previously, the Russian approach to development follows an “evolutionary” design philosophy, in which risks are retired early in the development phase of a new aircraft type or variant. Where possible, the retirement of risks is achieved in earlier programs, as demonstrated repeatedly in the development of the T-10 Flanker series of aircraft.
The PAK-FA prototypes displayed in January, 2010, are clearly intended to validate the compatibility of the overall observables shaping with the aerodynamic and structural design needs and clearly so, as the expensive detail RCS flare spot treatments we are accustomed to seeing on US prototypes are absent. The rationale for this is simple - why expend valuable but scarce development resources if aerodynamic / structural load testing shows that major changes are required to shaping of important design elements? For Western contractors, where the imperative is to extract the maximum of development funding from the customer, and make early cancellation of a program difficult, the highest risk approach will nearly always be sought by senior management. An excellent case study of the latter is the extremely high level of “concurrency risk”, reported by the General Accounting Office, in the F-35 Joint Strike Fighter program.
