Mailing List flyrotary@lancaironline.net Message #30654
From: Ed Anderson <eanderson@carolina.rr.com>
Subject: Re: [FlyRotary] Re: NACA's, Cooling and Sport Aviation Mag..
Date: Sat, 11 Mar 2006 08:05:56 -0500
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
> I suppose even with a streamline-diffuser (84% revocery of pressure).
Question is with what pressure to you start out? Ambient? To what baseline
to you recover the 84%?

The 84% figure was based on the amount of theoretical dynamic pressure recovery (1/2pV^2)  possible based on the air velocity in the air duct.  A lower/higher dynamic pressure would therefore effect how much pressure would be recovered.  High duct velocity results in more skin friction but less tendency for the wall boundary layer to separate - so as aways - a trade off.

Ed


If the differential pressure is low enough - this obviously works fine!
Next question: How can one calculate/computer analyze/test all different
variations efficiently before starting to cut metal (or sticking glasfibers
together....)?

On the particular plane above, also observe the rather "big radius"-nose
compared to other "slicker look"-pointier noses of Eze siblings. The man
says research shows his noseform is the right one until you hit trans-sonic
speeds.....

Anyone knows a source for reports on the difference between NACA-low
pressure cooling systems versus Ram pressure systems? The real interist
thing would of course be the Drag-difference at the same cooling
results.....

Thomas J.


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