Message-ID: <00b301c3af79$3dad7f70$8200a8c0@Jarrett>
From: "JJ JOHNSON" <JJJOHNSON@ACCESSCOMM.CA>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-2752640@logan.com>
Subject: Re: [FlyRotary] Re: Core vs Radistor was Re: [FlyRotary] radiator
Date: Thu, 20 Nov 2003 09:16:13 -0600
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Jim, by diffusers do you mean the pic showing the little alum. angle's that
are [ look like anyway] bonded to the fuse  ~12" ahead of the inlet?  They
look like vortex generators?  I was curious as to what the side 'rails' are
that are located on each side of the inlet ramp to the duct.  If nothing
else they sure look cool. I think one of the major problems w/ the Naca
ducts used in this application is that they should still be placed in an
area of high pressure. I my humble opinion, right behind the thickest part
of the fuse isn't really a high pressure location. However having said
that..  I'm not sure where else he could have put them unless he had wanted
to do alot of ducting. I think that's why he put those little VG's where
they are. It would appear that he was having problems w/ airflow velocity
[boundary layer thickness] and by adding the vg's he re-energized or speed
up/thinned down the boundary layer and improved the airflow into his ducts.
I've seen several pictures of Long-Ez's w/ very large Naca ducts on the
bottom of the fuse, which in my mind would be a higher area of pressure that
on top at least, unless I'm missing something.

My two bits

Jarrett


----- Original Message ----- 
From: "james coffman" <jimcoffmanus@yahoo.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Thursday, November 20, 2003 12:08 AM
Subject: [FlyRotary] Re: Core vs Radistor was Re: [FlyRotary] radiator


> Watch out for naca ducting for cooling. they have a
> reputation for not working.  Having said that, look at
> an article in this months Sport Aviation. I forgot the
> plane type, but using the naca duct on an IO-540.  It
> completely failed in several positions until he added
> difusers (sp) in front. Now works fine. There are
> pictures. Interesting! Jim Coffman