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Re: RAdiator fans and H2o cooled engine

> From:          Jeff Barnes <jcbarnes@ibm.net>

> A Concept Correction (the way I understand it anyway): with the
> augmentor, the inlet and exhaust areas are ALREADY minimally sized for
> cruise...the exhaust augmentation is what keeps you cool on the ground

Great, as long as there aren't any unforseen drawbacks. But, then, 
that's true for any modification.

> The IO-540 powered XL doesn't have cowl flaps, though Jean Prudhomme has
> a some inlet controls.  I wonder what Alan's got on his 300hp STD.

I was thinking more along the lines of Cessna 206's, DC-3's, Aztecs, 
F-4U's, etc. I can't be positive, but I bet most larger production 
aircraft have variable outlets.

> Except if the variable exit comes out of the fuselage: pusher cowl flaps
> stand greater chance of disturbing flow to the prop, where you'll really
> see a performance loss and a potential health hazard.

Depends to a large extent on how the exit ductwork is done. You could 
have all the ducting and mechanicals inside the cowling. You could 
have some of the exhaust inside the cowling and have a relatively 
small variable opening that's closed and flush when not needed.

David Parrish