  We present first results of the scale setting for QCD with Nf=3+1 dynamical
quarks on the lattice. We use a recently proposed massive renormalization
scheme with a non-perturbatively determined clover coefficient. To relate the
bare coupling of the simulations to a lattice spacing in fm, we measure the
flow scale t0 in lattice units at a mass point with degenerate light quark
masses and a physical charm quark mass, where its value in physical units is
known. We discuss the setup, tuning procedure, simulation parameters and
measurement results for ensembles with three different volumes and present a
charmonium spectrum.
