Toller wrote:

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"Toller" wrote in message
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I am looking into buying a cyclone and have narrowed it down to 2.
One fan curve is almost flat, while the second is much higher at low
static pressures and much lower at high static pressures.
The second vender says the sharply sloping curve is more appropriate, as
15' of 4" hose hooked to a jointer will be about 4" of static pressure.
Based on what I have read in the past, I would have expected it to be more
like 8 or 9", and the flat curve is much better there. So, the superior
unit depends on how much static pressure I will be seeing.
Can anyone point me to documentation on this?

and got a static pressure of 9.4" for 15' of 4" hose, but that thing
is confusing, so I might not have been doing it right...

Depends on whether you're talking flex hose or straight wall pipe/hose.
4" sounds about right for smooth wall, 8-9" for flex hose of that length.

Unless you have a fixed path and distance, it'll vary anyway as you move
the hose. If it is fixed location, I'd recommend ditching the flex hose
for anything except the shortest run possible as connection, maybe.

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