straight vanes were the norm for most all automatics, and even wringers.....it was a matter of production, one molded, it had to be pulled out from the die in a straight line.....
at the time, even a Super RotoSwirl could be pulled straight out of a die......
when the Surgilator was created/introduced, it was just as revolutionary for the machine as well as the mechanical die used to make it....
one of the first mechanical die used that separated into three pieces to release the finished product, mainly the wavy vanes, under a normal die, could not be pulled straight out....
I think it comes around as the Picture-of-the-day showing the huge die and the creators showing the unit and finished product....