Hans,

   I think you missed Michael's point.

   It isn't the volume of air that's at issue, but rather
where that air has to go.  A direct-air cooled engine needs
the air to travel in intimate contact with the cylinder
fins - filling the entire engine compartment.  An indirect-
air cooled system allows the airstream to be confined to a ductwork where there are no flamable liquids or gasses,
making it far easier to isolate the engine compartment from
sources of fresh air.

Regards,
Dale R.
    
> From: Hans Conser <conserreceipts@earthlink.net>
> Date: 2005/08/26 Fri AM 10:29:50 EDT
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Subject: [FlyRotary] Re: Fire extinguishers
>
>
> On Aug 26, 2005, at 12:55 AM, Michael Burke wrote:
>
>>...
>>     The point I'm making is this. The rotary is NOT air cooled, (directly
>> anyway)therefore we can take a different approach in designing the cowl. We
>> do not need a large volume of air blasting into the cowl, because the the
>> radiators can be set up so that they are ducted from the outside seperately.
>> ...
>>
>
> Actually liquid cooled engines need a great volume of air than air
> cooled engines.  This is because the temperature differential (Delta T)
> of the aircooled engine is much greater.  In other words it takes less
> air to cool 400 degree cooling fins vs 220 degree coolant.
>
> Hans Conser
>
>
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