XJet....
You fly model airplanes and you've never heard of Bernoulli?
....no sir....I have never heard of the man....(Bernoulli)....did he invent something
special ? And yes....I have been flying r/c for 35 years, and have NEVER heard
of the man.
As they say on the web page you referenced, "The most consistent pressure
is found where the pipe first reaches its apex in width" and as I said, the pressure will
be greatest at the widest point (where the flow is slowest) -- so Macs and I agree.
The widest point of an "expansion chamber" may provide "the most consistant
pressure"....but in fact, it is the lowest "pressure area" of the pipe. When the exhaust
charge flows into the largest "expansion" of the pipe....the pressure drops.
Yes....the widest point of the pipe has the least pressure....albiet one of the most
"consistent" points. However, the fact of the matter is....when all we need is approx
one and one half pounds of pressure to the fuel tank....
....any....yes, any point along the exhaust pipe will do.
And, while with the Macs pipe it appears that you will get *some* usefl pressure if you tap the stack, there's no guarantee that this will also be the case on other muffler types/designs.
I have a friend who toasted his heli motor after fitting a tap on the exhaust stack. I warned him that this would cause the engine to run excessively lean at high RPMs but he went ahead and did it -- it cost him a piston, ring, liner and head.
This is simple CFD stuff that any first-year colleged student is taught.
What is it you are warning us about, XJet....some evil placements of the pressure
nipple ?
FBD.
