Classical trajectory calculations have been performed on experimentally determined intermolecular potentials for He-O-2, He-CO, and He-CO2 in order to simulate the collisional formation of rotationally aligned molecular distributions in a supersonic expansion. These calculations verify that multiple collisions between the light "diluent" gas and heavier "seed" rotor molecules result in a distribution of rotor molecules with negative alignment (a(2) < 0), i.e., a preference for j perpendicular to the expansion axis. These rotational alignment effects are found to be robustly insensitive to collision energy and qualitatively similar for all three collision systems, thereby providing a useful basis for comparison with experimental studies. The asymptotic alignment is observed to depend strongly on the angular momentum, increasing monotonically with j. When analyzed on a collision-by-collision basis, this j dependence can be traced to gyroscopic stability, i.e., higher j states are classically more resistant to the collisional loss of alignment. In addition, collisional formation of the alignment is found to reflect comparable contributions from both elastic (m(j)-changing) and inelastic (j-changing) collisions. Finally, the calculations indicate that molecules with j aligned parallel to the expansion axis are correlated with faster average velocities than molecules with j perpendicular to the axis, which is consistent with the He+CO experimental studies of Harich and Wodtke [J. Chem. Phys. 107, 5983 (1997)], as well as the He+N-2(+) drift tube studies of Anthony [J. Chem. Phys. 106, 5413 (1997)].