A two-dimensional (2D) dynamical model based on Langevin equations was applied to study the fission dynamics of the compound nuclei 228U produced in 19F 209Bi reactions at intermediate excitation energies. The distance between the centers of masses of the future fission fragments was used as the first dimension and the projection of the total spin of the compound nucleus onto the symmetry axis, K, was considered as the second dimension in Langevin dynamical calculations. The magnitude of postsaddle friction strength was inferred by fitting measured data on the average pre-scission
neutron multiplicity for 228U. It was shown that the results of calculations are in good agreement with the experimental data by using values of the post-saddle friction equal to 6–8 × 1021 s?1.