Introduction:  At the Present day scenario the development of new aircraft either it is military or civil aircraft is more complex and competitive due to customers need for high performance and economical product. To design such complex machine within short time frame needs very advance numerical tools for rapid different design iterations.

The main aim of the research work to come up with a simple but robust and sophisticated numerical tool for conceptual aircraft design. To achieve this task knowledge based approach in aircraft design is adopted with the aid of multi disciplinary design optimization technique.

The design and optimization is decided into two levels .1) The using the customer input need and using the previous knowledge gain and base design is created. The aerodynamics performance of the base design is assessed using 3D PM tool which is computationally very fast compare to CFD. 2) Once the aerodynamics characteristics are achived the Aeroelastic performance of the aircraft is assessed using reduced order model(ROM) Aero-elastic tool. The  complete strategy of two level design and optimization is presented in the figure(left) and an aerodynamics model inthe figure below. The Aero-elastic tool is developed using Non linear beam model+3D PM with lose coupling.