Mailing List lml@lancaironline.net Message #35366
From: Marvin Kaye <marv@lancaironline.net>
Subject: Re: Why a Lancair
Date: Sat, 22 Apr 2006 12:25:30 -0400
To: <lml>
Posted for "Mark & Lisa" <marknlisa@hometel.com>:

 Paul,
 
 Can you tell me more about the outer lip of the NACA duct?  Are you
 referring to the aft lip, or the sides?  My understanding is the sides edges
 must be sharp to induce the vortexes that create the airflow into the the
 duct.  Do I have this wrong?
 
 Regards,
 
 Mark Sletten
 Legacy FG N828LM
 http://www.legacyfgbuilder.com
 
 
 
  -----Original Message-----
  From: Paul Lipps [mailto:elippse@sbcglobal.net]
  Sent: Friday, April 21, 2006 20:57
  Subject: Why a Lancair
 
...snip...
 Don't steal cylinder cooling air from the
 upper plenum to feed the oil cooler. Feed it with a separate inlet with a
 diverging duct, then give it a converging duct and outlet pointing to the
 rear; don't just dump it into the area ahead of the firewall. Don't use the
 so-called "NACA" duct unless you understand its pressure recovery vs duct
 flow ratio. It's just one of three of the family of "submerged" ducts. Its
 proper name is divergent curved-wall submerged duct. There is also
 straight-wall divergent submerged duct and a parallel-wall submerged duct.
 Is the outer lip of your NACA duct sharp or is it rounded and shaped like an
 inverted leading edge? If it's sharp, it's wrong!
...snip...

Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster