REFLECTOR: re. XLFG Intake Air (Mark Magee)

[Dave T Nelson]

I take induction air off the top cooling air NACAs.  I also few for many
years using the old style induction air "elbow" mounted underneath the
right wing.  I've never had a filter or alternate air source.  While a
filter would be a really good idea, I think your fine if you take your
induction air off the top NACA.  I've never seen any indication (including
in my oil analysis) that there is a problem.

One comment - you won't get a ram air effect if you take induction air off
a NACA... the NACA purposely slows the air down and let's it expand before
entering the cowling.

Dave

Dave T. Nelson
T/L 553-4327, Voice 507-253-4327, Fax 507-253-3648
Program Director, ISC ECAT NPI & Test Engineering

   1.  XLFG Intake Air (Mark Magee)

----- Message from Mark Magee <edjonesbrady at gmail.com> on Wed, 20 Mar 2013
22:12:40 -0500 -----
                                                           
      To: Velocity Aircraft Owners and Builders list       
          <reflector at tvbf.org>                             
                                                           
 Subject: REFLECTOR: XLFG Intake Air                       
                                                           

All,
My XLFG was built with a NACA scoop where the bottom engine cowl marries to
the fuselage for ram intake air. As I am nearing painting, and did not
build this into the bird, the PO did, I'm considering eliminating the
filtered lower NACA ram-air configuration for scat tubing to a cooling air
NACA scoop topside for simplicity. As well the NACA down low where it is
does catch considerable FOD from the nosewheel, yet is filtered.
I know some folks are running straight unfiltered from a scat tubing
routing from an upper engine cooling NACA with no alternate air. Any
feedback from the group on how well this is working? If I were to make this
change I fear I might lose a slight loss of manifold pressure, but for the
simplicity would be better off overall. The sealing on the airbox to the
lower cowl is problematic.
Thanks in advance for the feedback.
Mark Magee N34XL XLFG

[attachment "N34XL Lower NACA intake.JPG" deleted by Dave T
Nelson/Rochester/IBM] _______________________________________________
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