  Recently it was proposed that ten-dimensional tachyonic string vacua may
serve as starting points for the construction of viable four dimensional
phenomenological string models which are tachyon free. This is achieved by
projecting out the tachyons in the four-dimensional models using projectors
other than the projector which is utilised in the supersymmetric models and
those of the $SO(16)\times SO(16)$ heterotic string. We continue the
exploration of this class of models by developing systematic computerised tools
for their classification, the analysis of their tachyonic and massless spectra,
as well as analysis of their partition functions and vacuum energy. We explore
a randomly generated space of $2\times10^9$ string vacua in this class and find
that tachyon--free models occur with $\sim 5\times 10^{-3}$ probability, and of
those, phenomenologically inclined $SO(10)$ vacua with $a_{00}=N_b^0-N_f^0=0$,
i.e. equal number of fermionic and bosonic massless states, occur with
frequency $\sim 2\times 10^{-6}$. Extracting larger numbers of phenomenological
vacua therefore requires adaptation of fertility conditions that we discuss,
and significantly increase the frequency of tachyon--free models. Our results
suggest that spacetime supersymmetry may not be a necessary ingredient in
phenomenological string models, even at the Planck scale.
