[en] Highlights: • Rhombic drive and crank drive mechanisms of a beta type engine were compared. • Nodal analysis method was used to compare engines having different drive mechanism. • Maximum specific power was 1410 W/L for rhombic-drive engine. • Heat transfer coefficient was determined as 475 W/m"2K for rhombic-drive engine. • Rhombic drive provided higher efficiency because of its better kinematic behaviours. - Abstract: In this study, the effect of rhombic drive and crank drive mechanisms on the performance of a beta-type Stirling engine was investigated by nodal analysis. Kinematic and thermodynamic relations for both drive mechanisms were introduced and a Fortran code was written for the solution. Piston strokes, cylinder and displacer diameters, hot and cold end temperatures, regenerator volumes and heat transfer surface areas were taken equal for both engines with two different drive mechanisms. In the analysis, air was used as the working gas. Engine power and efficiency were compared for different charge pressure values, working gas mass values, heat transfer coefficients and hot end temperatures. Maximum specific engine power was 1410 W/L for the engine with rhombic drive mechanism and 1200 W/L for the engine with crank drive mechanism at 4 bars of charge pressure and 500 W/m"2K heat transfer coefficient. Rhombic drive mechanism was relatively advantageous at low working gas mass values and high hot end temperatures. In comparison with the engine having rhombic drive mechanism, the relatively poor kinematic behaviour of the engine having crank drive mechanism caused lower engine efficiency and performance. Heat transfer coefficient was also predicted by using an experimental pressure trace.