Subject: [FlyRotary] Re: Radiator ducting

 

john wrote:

 

> Finn;  I measured the inlets on the Lopresti, pipers at Oshkosh and

> the inlets were 5 1/4".  JohnD

 

You guys might want to keep in mind that for the same hp the aircooled engine can generally get by with less air flow because the average fin temp may be close to 100 degrees hotter than we can run our coolant radiators; even though our radiators make more efficient use of the surface area. 

 

The typical 200 hp water cooled system might take about 60 – 65 sq. in. of intake area for cooling on a 90F day.  That Piper has about 42 sq. in. for what is likely a 250hp engine.

 

Al