OK, I'll try this again. The first page at the hyperlink is the page of
interest. Everything else at that URL is of academic interest only (sorry
about the bad pun - I couldn't help myself). My suggestion was that the air
flow behind the NACA inlet corresponds to the water flow in the photo at the
top of that page and the "vacuum" line from the drum corresponds to the
exhaust duct in the aircraft. To make this work it would be necessary to
dump the flow from the straight line behind the NACA duct overboard
(presumably in a low pressure area).
Just for fun check out the video at the "Show movie" link at the bottom of
the page.
Best regards,
Rob Housman
Europa XS Tri-Gear A070
Airframe complete
Irvine, CA
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com]On Behalf Of Fergus Kyle
Subject: Re: NACA vent placement (was RE: Europa-List: Gel Coat)
| ----- Original Message -----
| From: "qcbccgalley" <cgalley@qcbc.org>
| To: <europa-list@matronics.com>
| Subject: Re: NACA vent placement (was RE: Europa-List: Gel Coat)
| | NACA vents are INlets not outlet vents. They don't work as outlets.
|
| Right. I've noted several mentions of using the vent for evacuating the
| cabin air. The NACA inlet was chosen to operate the engine inlets for the
| F93 version of the Sabre. It is designed to induce intake from high speed
| flow without incurring great drag. . It will do nothing for cabin outlets
or
| any other reverse flow. Might as well cut a hole.
| Ferg
| A064
Europa-List message posted by: "Rob Housman" <RobH@hyperion-ef.com>
| While I must agree with your comments, Ferg, there is a way to use the
NACA
| inlet to do the job, thanks to our old friend Bernoulli. See
| http://hyperphysics.phy-astr.gsu.edu/hbase/fluids/aspir.html for a brief
| description of an aspirator, a device for generating low pressure by using
| higher pressure flow. Many of us are probably familiar (from chem lab)
with
| the scheme shown in the hyperlink where water is used to generate air flow
| into the tee, but the same principle works with compressed air in the
| straight leg of the tee to create a vacuum in the side arm of the tee.
| Clever guy, Bernoulli.
| Best regards, Rob Housman
| Europa XS Tri-Gear A070
Rob et al,
I'll buy that, so I went to the site and saw three choices:
Hyperphysics - to 'Condensed Matter'[the only applicable site]; then
Mechanics - to Pressure to Kinetic Energy; then
to Potential Energy; then
to Bernoulli Equation -
much of which I remember (if not with fondness), but little of which
inspired understanding of how a NACA inlet is sited/configured to extract
cabin air at relative low speed. Perhaps there's a site therein which I
missed.......
There's just the off-chance my comprehension is ready for a cleaning
and polishing, but can you point me to the principle or practicality of
using a NACA inlet design?
Of course this is all E&OE,
Cheers, Ferg.
|