X-Mozilla-Keys:                                                                                 

Paul wrote:

What do you think the of the increased turbulence idea?

Jeff Spitzer wrote:
IMO, there is no benefit from increased turbulence except packaging. Any
significant angle will certainly cause separation from the leading edges
of the fins which will increase pressure drop.  I would much rather have
the increased airflow than the turbulence given the same pressure drop.
Look closely at a good rad and you will see little notches and 
waves in the fins to control mixing and turbulence. These have resulted 
from much theory  and testing and don't need and turbulence 
help from you :-)

Tracy Crook wrote:

I agree with Jeff.  Given the design of any decent compact air-cooled
heat exchanger, the airflow is going to be turbulent as soon as it enters the
core, no matter what the angle of the  radiator.  Another point to note is
that according to the K&W book, airspeed through the core should be on the
order of .1 of inlet speed.  This would be about 20 mph for an RV-4 (at top
speed).  In other words, the pressure recovery has already taken place by
the time air reaches the core and velocity is low (assuming a good diffuser
design)  .  This being the case, there is probably no big loss in pressure
by having the core at an angle to the inlet airstream, ergo, that's why many
of them seem to work pretty good that way.

Tracy Crook
http://www.rotaryaviation.com

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