Martin H. Eastburn wrote:
One way is to use a 55 gallon drum. The lid has two portals. Inlet and
outlet. The outlet goes to the bag system. Between the two you bolt on
or weld - a fence that extends 4-5 times the diameter of the hose.
So the inlet is pulled in and dumps into the can. Lighter stuff continues
on the way to the filter.

I had that, it's like comparing my single engine C182 to a Gulfstream.
Without the can, it was my Beech 23, compared to my C182.

A real cyclone works so much better than a preseperator that it's not
funny. The extra drum on a bag DC eats CFM, so the suction is much reduced.