Based on the screw theory

some basic design principles of six-component thrust stand were described to ensure its effectiveness. This proved that it was improper mathematically to predict the vector thrust by multiplying the inverse static mapping matrix with the reading of sensors

and only three forces and three moments of the vector thrust can be obtained

but the action point cannot be accurately positioned. In order to find the action point

an experimental method denoted as circular deflection method was proposed

at least three tests about thrusts of same axial angle and different direction angles were needed.Finally

the validity of the proposed method was verified by examples. The numerical result showed that the weights of the engine and the floating frame seriously affected the positioning of action point

so the gravity influence must be eliminated before using this method.