I'd like to jump on this one, Paul, and give my input.
I've been experimenting with many different types of electric fans in the
Rx7 automotive platform for quite some time. I've used Hayden, Permacool,
Vintage Air, and the like. Last October, after shorting out my not-so-old
$170, 16" aftermarket fan (I still have no clue how it happened), I went
hunting around the junkyards. I figured I could find a fan that would be
able to move enough air through the radiator (on a hot Texas summer day)
thinking those same factory fans would have to be good enough for that since
they're sold on factory cars in varying climates and environments. After a
good 1/2 hr of kicking up dirt, looking under the hoods of various junked
cars, I ran across the diamond in the rough -- A 1988 Pontiac Fiero radiator
fan. 5 minutes and $10 later, I had my new test-fan ready to try out as I
headed home for the install. This fan, after studying it, has some
advantages, I think, over some of these aftermarket ones that are common
from Mr. Gasket, Summit, JEGS, and the like. Here's my reasoning:
- As stated before, this fan is equipped on a factory car that's sold to
owners in varying climates and environments (read ambient temperatures). By
way of reasoning, it must be good enough to sustain reasonable (coolant)
operating temperatures whilst the vehicle has a running A/C system, on a
very hot summer day, sitting at idle engine RPM.
- This fan has a skinner and taller blower motor as compared to a common
thread with the aftermarket ones; they all have short, fat, and wide blower
motors, potentially increasing the amount of air drawn through the radiator
per that same space being used by fan blades.
- This fan, unlike aftermarket ones, uses a plastic shroud that shrouds a
greater surface area. Aftermarket fans, like the one in the picture as
posted by Paul, shrouds directly around the fan blades, making the fan (in
my opinion) less efficient.
Of all of the fans I've used, I am by far the most impressed with this $10
junkyard unit. My water temperatures stay much colder (lower 180F's instead
of higher 180F's to low 190F's), they drop more quickly if in the event they
do rise from having sustained engine load, as well as my oil temperatures
staying much lower than they were when I was using a different fan. I'm not
sure of current draw, but it's somewhere inbetween 15A and 20A when running
normally. With the "hand over the fan" test, it's moving a tonne of air;
substantially more than the older fans I used were. This fan also fit
nearly perfectly on my Summit 22" x 19" radiator and does fit perfectly
around the factory radiator used on the 2nd generation Rx7.
I'm not sure how this plays out for you aircraft folk but I'd take a look at
it and consider its merits. Attached are two photos of this fan; one of
them mounted to my Summit radiator as well as one operating on a factory
radiator. This should give you an idea of it. Let me know if you guys
would like any other pictures of the fan. I'm armed with a digital camera
and can take some w/ measurements.
B