Thomas Parkes wrote:

Perry:

I appreciate the challenge you face in cooling your oil.  Your pusher
configuration is especially challenging, what with the armpit scoops and
possible pressure ahead of the ducted fan.  One shouldn't necessarilly
conclude, however, that a Mazda oil cooler cannot be made to work when
mounted longitudinally.  Several tractor engine installations have been
moderately successfull with longitudinally mounted coolers.

My Lancair ES has a longitudinal Mazda oil cooler installation.  Its
original  NACA duct inlet was successful up to OATs of 80 degrees F, dispite
the questionable use of a NACA duct for oil coolers, and dispite the fact
that the engine is producing close to 300 HP at 32" MP.  When I recently
modified the scoop into a modified bayonet layout, oil temperatures were
reduced approximately 10 degrees.  I flew today at an OAT of 93 degrees.
Max oil temp briefly reached 220 degrees, then gradually retreated to the
mid 190 range at higher altitudes and 30" MP at 5500 rpm.

Your ducting problems are far more complex than mine, but I would be careful
discarding a reliable Mazda cooler, especially since we know of at least two
aftermarket cooler failures (Chuck Harbert's Velocity) with serious
consequences.  Like you, I'm still experimenting and trying to optimize the
cooler ducting.  Good luck!

Tom Parkes
N44AZ --31.3 hours down, 8.7 to go, but who's counting.

Thanks Tom, I guess I'm just becoming very frustrated with it. Others
such as yourself have made it work, but I don't know  why yet. Under the
conditions you mentioned my oil temp would reach 230 and drop to only
220, and with less than half the HP.


Perry

 
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