> O Randall, Imparter of Great Knowledge, please explain to this unworthy Old
> Airplane and TR3 Guy how putting an electric fan in front or behind the
> radiator would make a difference in how much air would flow through the
> radiator? Or did you arrive at this knowledge empirically?
>
> Isn't it rather like putting a resistor in an electric circuit in front of,
> or behind, the load? The flow would decrease just the same?
Let's see if I can echo the explanation given to me by my high school physics
teacher ...
The critical difference is that electrons have no mass (well, not enough to
worry about anyway) and hence go around corners better. Air has inertia,
meaning it does not like to go around corners, and slows down when it does.
Once the air has been deflected by hitting the fan blades, it is turbulent and
moving at an angle relative to the radiator openings.
However, once the air has been through the radiator, it becomes turbulent
anyway. So upsetting the flow at that point makes less difference.
Or I could be all wet on this ... I just know I've seen evidence of this on my
Stag and so I believe the effect is real. Of course that means I'm going to
have trouble when I get the original AC condensor & it's fans fitted, since they
are configured as pushers. Just have to figure out how to keep it cool even
with the reduced airflow. I'm thinking a "chin" spoiler is the way to go ...
BTW, not all cars originally had puller fans ... my 1970 Audi 100LS for example
had a belt-driven pusher fan from the factory. And a tendency to run hot at
freeway speeds. In 1971, Audi switched to an electric puller.
Randall
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