Hi Brian,
Carl's advice is entirely correct. The top of the fuselage is a low
pressure area (think about it....the longitudinal cross section is not
so dissimilar to a wing cross section).
One of the earlier Europa (Mk1) builders did exactly as you are
proposing, NACA vent with eyeballs positioned exactly where you suggest
and found to his dismay that the air flowed efficiently OUT of the vent.
The recommended vent position provides an icy blast to one knee only (my
personal opinion). On my aircraft I have positioned eyeball vents at
face level on the dash, much like a car. You will need to consider how
the ventilation air can exit the cabin in order to provide a proper flow
(a vent at the top of the fuselage near the rear of the cabin maybe?)
There has been much discussion on this matter in the past, suggest you
plough through some of the archived threads.
Nigel
----- Original Message -----
From: Brian Hutchinson
Subject: Date: Sat, 3 Feb 2001 20:35:17 -0000
Hi all,
I've spent nearly 2500 hours on my XS so far, but this
computer wizardry is all new to me, so if it all goes pearshaped please
accept my apologies.
I have been considering the need for extra cooling in the cockpit
and to me, the obvious place is a small NACA duct in the fuselage top,
just behind the front door hinges feeding a couple of the airliner type
eyeball vents. Rainwater could be tubed into the door jamb inboard of
the seal. Then Carl Reynaud suggested that the region above this part
of the fuselage might be a low pressure zone and the air might, in fact,
move out of the cockpit rather than blast in! Has anyone tried this
idea... You could save me a few more hundred hours if it's a bad plot.
Brian Hutchinson
XS 357
Sleaford England
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