You are right. It had just one "pipe". So soon they forget - and it was only back in 1949, too. I rode it up the Arroyo Seca Parkway with my friend who was "rich" and had a Motobecane. The Parkway was the first freeway in the US, and is now called the Pasadena Freeway. I think the Whizzer ran 35mph, which was way too fast for the rear wheel bicycle brake.