This study is aimed at development of a theoretical model by combining modified non-ideal adiabatic model and dynamic analyses in order to predict the dynamic behavior of a 1-kW class beta-type Stirling engine with rhombic drive mechanism during starting. All friction losses caused by piston rings, bearings, and seals are taken into consideration. The total torque can be expressed in a closed-form relation by including the effects of the inertia force, the gravity force, the pressure force and the friction forces. The transient variations of instantaneous angular velocity under different operating conditions are simulated. The variations of the engine speed, the shaft power, and the mechanical efficiency of the engine under time-varying output torque are also described. The results also indicate that engine has a minimum and a maximum operating speed, and a minimum initial speed for starting. A prototype engine is built and tested for validation of the present model. Experiments on the transient behavior of the prototype engine during starting and under time-varying operating conditions are conducted. The numerical predictions by the present model closely agree with the experiments. And the maximum power generated by the engine is 1358 W at 1313 rpm in the test. (C) 2018 Elsevier Ltd. All rights reserved.