The objective of this proposal is to demonstrate the feasibility of producing an integrated starting model for gas turbine engines using a new physics-based combustion dynamics model that accurately simulates flow interactions among the compressor, combustor, and turbine. Replacing conventionally costly guess-and-test techniques, this new process for starting system analysis, design, and optimization promises a new generation of predictive capability that will allow system engineers to design engines with higher fidelity and eliminate the need for multiple iterations and testing cycles found in current industry practice. EcoPro Technologies' physics-based starting model is built from an innovative solution algorithm which solves the 1-D speed-dependent conservation equations of mass, momentum, and energy for each starting system component. From this integrated algorithmic model, we will be able to achieve predictive capabilities for the most vital engine dynamics, including starting/transient instabilities of combustor flameout, compressor surge and over-temperature shutdowns. Our integrated design tool allows for complex starting simulations, thus enabling successful engine design and modeling with rapid determination of sensitivities with respect to all engine design variables and constraints. This empowers engineers to choose optimized design directions without violating constraints and make appropriate design changes to engines prior to costly manufacturing and testing.