The Vortex/Hurricane story is a heck of a story!
When the early vortex models came out (the red and white ones and the Vortex power in blue and black), they used a high efficiency dust separation cyclone like a Dyson. However, it infringed on Dysons patent and Dyson sued Hoover over the design, meaning they could no longer produce Vortex machines of that design. Hoover scrapped the high efficiency cyclone design and rebadged the machines as "Hurricane" and stuck a low efficiency, direct filter cyclone it. A great shame, as I found the Vortex to be much higher performing than the DC01 and DC03, but it was a complete rip off of the DC01's cyclone