Three Surface Aircraft - A Concept For Future Transport Aircraft

Kurzfassung

For the design and optimization of a canard for a three surface aircraft (TSA) a preliminary aircraft design code was extended by a higher-order panel method, a transonic data base and a trim routine suitable for a three surface aircraft. Preliminary aim of the canard study was the preliminary design of an optimum canard geometry for the DLR-F11 TSA - wind tunnel model under the design constraints of a realistic aircraft. Based on the conventional design for the wind-tunnel model, the retrofit of the geometrically fixed aircraft with a canard was simulated. With sensitivity studies the influence of basic canard geometry parameters was analyzed. Based on an optimization calculation the best set of geometry parameters which provide minimum fuel weight were determined. The analyses show that a swept back canard in low position located downstream the divergent nose part of the body, with high aspect ratio, low taper ratio and moderate canard span promises optimum performance. In addition, the canard lift of the TSA configuration allows to realize higher cruise lift coefficients for an improved induced drag at transonic speeds without the risk of additional wave drag. However, without the control concept of a free-floating canard, the static margin decreases significantly with the integration of a canard.