Surface radiators for water cooled engines

On 7 Jul 2003 12:43:45 -0700, (Jay) wrote:

A car radiator, while being
small and available, is also exceedingly draggy, which is why its not
an optimal choice choice for a fast airplane. The auto radiator is
designed for different conditions mainly:
1) High disipation at low air flow speeds
2) Clean air entering front surface (Reynolds number less than 10,000)
2) Drag not an issue

An aircraft/cowl-surface scenario doesn't have the condition of high
power output and low airflow and thustly should not besigned for this
condition. Even on the climb out, while the IAS may be low, the prop
wash is turbulent and higher in velocity than the speed of the vehicle
itself.

Regards

Right, auto radiators don't work that well in airplanes for a number
of reasons. That's why you don't see many of them in airplanes. But
if you have the room to install them and can slow the air that passes
through them enough, they do work.

A lot of people who need a liquid heat exchanger go to the companies
that build them for the racing scene, or use something more compact,
like an air conditioning evaporator core. Those aren't optimal either
because they tend to have a dense fin spacing which makes passing the
air through them problematic.

But there are several firms in the US that build heat exchangers
designed for the speeds airplanes encounter and can be custom built to
your specifications. This pretty much solves the problem. If you do
your homework correctly and give them the proper specifications, and
plan your ducting properly, your engine will cool properly.

Corky Scott