The effect of adding a vertical jet to a 76-deg delta wing was investigated experimentally and theoretically in terms of the resulting longitudinal aerodynamic characteristics. A small-scale wind-tunnel experiment served for the investigation, and a simplified vortex lattice model was constructed to simulate the first-order effects of this complex flowfield. The major benefits of this combined approach over the use of more developed computer schemes lies in the relative ease in tailoring the mathematical model to a new problem. Results of both the wind-tunnel experiment and the theoretical model showed measurable lift loss due to the ejector jet throughout the whole angle-of-attack range, which will intensify at lower flight speeds.