  This work presents swarm parameters of electrons (the bulk drift velocity,
the bulk longitudinal component of the diffusion tensor, and the effective
ionization frequency) in C$_2$H$_n$, with $n =$ 2, 4 and 6, measured in a
scanning drift tube apparatus under time-of-flight conditions over a wide range
of the reduced electric field, 1 Td $\leq\,E/N\,\leq$ 1790 Td (1 Td =
$10^{-21}$ Vm$^2$). The effective steady-state Townsend ionization coefficient
is also derived from the experimental data. A kinetic simulation of the
experimental drift cell allows estimating the uncertainties introduced in the
data acquisition procedure and provides a correction factor to each of the
measured swarm parameters. These parameters are compared to results of previous
experimental studies, as well as to results of various kinetic swarm
calculations: solutions of the electron Boltzmann equation under different
approximations (multiterm and density gradient expansions) and Monte Carlo
simulations. The experimental data are consistent with most of the swarm
parameters obtained in earlier studies. In the case of C$_2$H$_2$, the swarm
calculations show that the thermally excited vibrational population should not
be neglected, in particular, in the fitting of cross sections to swarm results.
