<VV> Mo' Fanz

[Padgett]

> > Perhaps a better question though would be, "Why is there such a pressure
> > build up in the Corvair, around 10" at higher rpms?"

A) all of that comes from one line on the graph on page 24 of the 140 
"Stock Engine Test" labeled "Obs. Plenium Pressure" which in truth does 
show 10 " H2O at 4500 and about 7 at 3500. Frankly the line on the same 
graph "Obs. Cooling Air Flow" which shows about 1300 cfm at 3500 and 1650 
at 4800 to be more important.  Has anyone instrumented the electric fans to 
determine just what the flow rate is ? Until someone does that we are all 
just guessing.

Further, a lot matters on *where* that pressure reading was taken: the air 
is coming off the outer edge of the fan with considerable velocity and to a 
stationary pressure sensor, that would be interpreted as pressure. I really 
cannot tell from the booklet. Remember 27 in H2O = 1 psi so we are talking 
on the order of 1/4 psi at 3500 rpm. Not much and the air is definitely not 
stationary. In fact with an electric fan, the air is being accellerated in 
a straight line - down toward the cyl and block while the air is coming off 
the stock fan is making one right angle turn off the edges and another to 
reach the cylinders.

So can come up with a number of possible reasons that a pressure sensor 
would be correct but not representative and what we care about is flow, not 
pressure.

Anyone have a flowmeter that reads to at least 1500 CFM ?

Padgett