A rotorcraft with slung-load model was built.Slung-load model with six freedoms was used to simulate the flight process with slung-load.It is assumed that the external slung-load is suspended in a single-point.Trim calculation of the helicopter with slung-load model was conducted and compared with the reference values.Stability of helicopter with slung-load was analyzed in forward flight

and the change of stability was compared when some parameters were adjusted.At last

the dynamic response to the step inputs of the longitudinal

lateral and pedal controls was analyzed in forward flight simulation.