Mailing List flyrotary@lancaironline.net Message #27089
From: rijakits <rijakits@cwpanama.net>
Subject: Re: [FlyRotary] flyrotary NACA scoops
Date: Thu, 20 Oct 2005 19:22:03 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Okay,
 
here is the site with the modified NACA-ducts:
 
Check: "Oil Flow Test on NACA inlet" and "Cylinderhead  Cooling  Trials"
 
Keep in mind, this is a aircooled engine - less pressure delta, but higher flow.
 
Reading superficially through the mentioned NACA-report: http://naca.larc.nasa.gov/reports/1951/naca-tn-2323/
(not taking any formulas...) it is iteresting that the report also mentions the flow-fences you see on the marcborom site - they cost efficiency.
No mention of the corner-guides.....
What I read out of the report is that NACA works - for a specific situation, if specifically developed for it. As soon as there developes some backpressure you will get some costly drag. It seems this is not a solution for big speed-spread.
The report seems (maybe not....)  to give some indication on how to use the formulas to develope a proper duct for specific situations, but it looks like a lot of maths.
 
Thomas J.
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