  The role played by protostellar feedback in clustered star formation is still
a matter of debate. In particular, protostellar outflows have been proposed as
a source of turbulence in cluster-forming clumps, which may provide support
against global collapse for several free-fall times.
  Here, we seek to test the above hypothesis in the case of the well-documented
NGC 2264-C protocluster, byquantifying the amount of turbulence and support
injected in the surrounding medium by protostellar outflows.
  Using the HERA heterodyne array on the IRAM 30m telescope, we carried out an
extensive mapping of NGC 2264-C in the three molecular line transitions
12CO(2-1), 13CO(2-1), and C18O(2-1). We found widespread high-velocity 12CO
emission, testifying to the presence of eleven outflow lobes, closely linked to
the compact millimeter continuum sources previously detected in the
protocluster.
  We carried out a detailed analysis of the dynamical parameters of these
outflows, including a quantitative evaluation of the overall momentum flux
injected in the cluster-forming clump. These dynamical parameters were compared
to the gravitational and turbulent properties of the clump.
  We show that the population of protostellar outflows identified in NGC 2264-C
are likely to contribute a significant fraction of the observed turbulence but
cannot efficiently support the protocluster against global collapse. Gravity
appears to largely dominate the dynamics of the NGC 2264-C clump at the present
time. It is however possible that an increase in the star formation rate during
the further evolution of the protocluster will trigger sufficient outflows to
finally halt the contraction of the cloud.
