No, the system is not limited by the narrowest pipe. It's not a "weakest
link" analogy. The reason is that the speed of the air will vary
inversely to the area of the duct. So the 4 inch restriction will just
accelerate the air. There is some (small) loss with restrictions, mostly
because it is easy to accelerate flow efficiently but hard to slow it
down.

Others have properly noted the fact that while large ducts can pass a
lot of air, the speed of the air drops so that dust can settle out in
the pipe.

Greg


Fly-by-Night CC wrote:
In article , "George" george@least
wrote:


Not an engineer, but imagine the optimum transport pipe is probably ~5".
Force/unit area calcs show 6" less than half the four.


Perhaps someone can point out the error of my thinking on this subject...

The system can only flow as much as the smallest port in the factory
design. Take my Jet 1.5hp for example, what I'm getting at is that the
port and hose from the blower housing to the bag hanging ring is, I
believe, 5" diameter. To my thinking whatever size of the system outside
of the factory setup is limited by this 5" - in other words, one can't
fully draw 6" of main trunk air before the blower through a 5" hose
after the blower - therefore the appropriate size of the main trunk
should be no larger than 5" - or whatever the size of the smallest port
in the manufactured assembly.

Wadya think?