free wing

free wing

A wing-design concept in which the angle of attack is relatively constant and the rigging angle of incidence of the wing in relation to the fuselage can vary. This is in contrast to normal aircraft where the rigging angle of incidence is constant, whereas the angle of attack varies by the control input by the pilot. In this concept, the wing is attached to the fuselage by span-wise hinges rather than by fixed bolts, and its angle of attack to airflow is governed by natural aerodynamic forces rather than through a conventional horizontal stabilizer (tailplane) and elevator. Here, pitch control is through elevons on the wing; the elevator on the horizontal stabilizer is used to set the correct fuselage angle of airflow for minimum drag. In this arrangement, the fuselage remains at a constant angle and the wing responds to changes in airflow, such as turbulence, by changing its rigging angle with respect to the fuselage. This results in a very good gust response in turbulence and allows a wider center of gravity range.