  High-resolution spectroscopic observations of the W UMa-type binary Epsilon
CrA obtained as a time monitoring sequence on four full and four partial nights
within two weeks have been used to derive orbital elements of the system and
discuss the validity of the Lucy model for description of the radial-velocity
data. The observations had more extensive temporal coverage and better quality
than similar time-sequence observations of the contact binary AW UMa. The two
binaries share several physical properties with both showing very similar
deviations from the Lucy model: The primary component is a rapidly-rotating
star almost unaffected by the presence of the secondary component, while the
latter is embedded in a complex gas flow and appears to have its own
rotation-velocity field, in contradiction to the model. The spectroscopic mass
ratio is found to be larger than the one derived from the light-curve analysis,
similarly as in many other W UMa-type binaries, but this discrepancy for
Epsilon CrA is relatively minor suggesting a systematic problem with one of the
observational methods commonly affecting other determinations. The presence of
the complex velocity flows contradicting the solid-body rotation assumption
suggest a necessity of modification to the Lucy model, possibly along the lines
outlined by Stepien (2009) in his concept of the energy transfer between the
binary components.
