Abstract : A theoretical and experimental investigation of the lift and moment on an 8/1 ellipsoid of revo lution performing small oscillations in a direc tion normal to the free stream has been carried out. The maximum circulatory lift coefficient measured is 0.035, about half the value obtained in steady flow at the same maximum angle of attack and Reynolds number. Furthermore, a phase lag of 20 degrees in the build-up of the lift was observed. The maximum pitching moment is reduced by 16 percent from the value predicted by potential theory. The circulatory lift was predicted theoretically by calculating the net vorticity discharged into the main body of the fluid from the boundary layer at any instant of time. By means of a generalization of the Kutta-Joukowski theorem, the component of lift caused by a vector circulation on a control surface surrounding the body and its wake was then computed. The total lift is obtained by adding to the circulatory lift two additional components which depend on acceleration and are associated with the 'apparent mass' of the body. (Author)