  A toy model for gamma-ray burst-supernovae (GRB-SN) is discussed by
considering the coexistence of baryon poor outflows from black holes (BHs) and
a powerful spin-connection to surrounding disk, giving rise to consistent
calorimetry as described by van Putten (2001a) in a variant of the
Blandford-Znajek process (BZ, 1977). In this model the half-opening angle of
the magnetic flux tube on the horizon is determined by the mapping relation
between the angular coordinate on the BH horizon and the radial coordinate on
the surrounding accretion disk. The GRB is powered by the baryon poor outflows
in the BZ process, and the associated SN is powered by very small fraction of
the spin energy transferred from the BH to the disk in the magnetic coupling
(MC) process. The timescale of the GRB is fitted by the duration of the open
magnetic flux on the horizon. It turns out that the data of several GRB-SNe are
well fitted with our model.
