I'd received a couple of questions about how I constructed the drum in the dyson model, you often see similar things in machine gun barrels and so on. So here is a step by step guide.

 

I then take the above poly object, shift drag it, and make as many copies as I'll require for the final tube, the wider the tube the more copies you'll need. I join all of these separate poly objects into one single poly object and weld the vertices together, maintaining the pattern.
Then I apply the bend modifier to this shape, using the settings shown in the above image.

All thats left to do now is to weld the vertices where the ends of the now bent shape meet and to apply a turbosmooth and a shell modifier to create the desired thickness. I hope you find this useful. Cheers

Hugh.

I then select the vertices subobject and weld the vertices of the separate elements into the pattern shown above.
After that I then delete the centre circle polygons,so you should now have a plane with 9 holes within it.
I select the border subobject and marquee select all the elements, I then switch from the move tool to the scale tool and shift extrude out the borders until the edges of the borders of the circles meet.

So first off I create a spline ngon with 8 sides, I shift drag it across to make 3 spaced copies, I connect all those shapes into one spline object, I then shift drag that spline object down to create 2 further copies leaving a 3*3 layout of circular splines. I attatch all of these into one spline, and convert them into an editable poly.