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Periodic variations of the position angle of the inner jet of the blazar S50716+71 suggest a helical structure for the jet. The geometrical parameters ofa model helical jet are determined. It is shown that, when the trajectories ofthe jet components are non-ballistic, the angle between their velocity vectorsand the line of sight lies in a broader interval than is the case for ballisticmotions of the components, in agreement with available estimates. Thecontradictory results for the apparent speeds of components in the inner andouter jet at epochs 2004 and 2008-2010 can be explained in such a model. Theratio of the apparent speeds in the inner and outer jet is used to derive alower limit for the true speed of the components ($\beta>0.999$) and todetermine the pitch angle of the helical jet ($p=5.5^\circ$). The derivedparameters can give rise to the conditions required to observe high speeds(right to 37$c$) for individual jet components.

Geometrical and Kinematic Parameters of the Jet of the Blazar S5 0716+71 in a Helical-Jet Model