REFLECTOR: XLFG Intake Air

[Geoff Gerhardt]

Mark,

I am running unfiltered air from the top cooling NACA to my intake and it
is working fine for me.  But, I've heard others talk about improved
manifold pressure from a ram air intake.  I wonder if at high altitude
cruise it might be beneficial.  I would think a ram air intake (a scoop
that hangs out into the wind) would be better than a NACA intake for
producing better intake pressures, tho.

I need to make some changes to my cowl and repaint this summer, so I was
going to experiment with a ram air scoop now that I have lots of data on
the NACA cooling intake.  The other change I planned to make was a
rear-exiting exhaust (mine blows straight down).  I understand that can
make the biggest difference (not sure I believe the 10kts I've heard, but
I'd take 5kts).

Geoff

On Wed, Mar 20, 2013 at 11:12 PM, Mark Magee <edjonesbrady at gmail.com> wrote:

> 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
>
> [image: Inline image 1]
>
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