North Central Airlines  Convair 580  N4811C        (c/n  101)

                                    

                                        In 1967 North Central, in common with several other carriers elected to modernize its Convair 440s
                                        to prop-jet status.  This entailed, among other things, the substitution of the radial piston Pratt &
                                        Whitney R-2800-CB16 engines for Allison 501-D13D turboporops delivering some 3750 shp each.
                                        The conversions were done by PacAero in California. (Other Convair 440 conversions had either
                                        Napier Elands, who did the very first turboprop conversion incidentally, or Rolls Royce Dart engines.
                                        These were not as popular in the US as those with the Allison turboprops -  NIH syndrome?).   The
                                        shot above was taken by Bob Garrard at Port Columbus (Ohio) International Airport in May of
                                        1970 and illustrates well a 580 in the original North Central markings.  Later versions of the livery
                                        deleted the gold trim.  Trademark "Herman" now features large on the fin and rudder.