Force and torque generation mechanisms for an unconventional tandem ducted fan aircraft are investigated. Numerical techniques are implemented to obtain quasi-steady thrust, numerical integration of nonlinear equations of motion and trim iteration process, respectively. The comprehensive nonlinear model is derived and simplified to linear approximations at different flight conditions for stability and input-output controllability analysis. Specifically, modal analysis is performed for the vehicle at hover and forward flight. Quantitative input-output controllability analysis is then applied to our plant to find out the fundamental controller-independent limitations and capture what performance can be expected.