REFLECTOR:Belly NACA
alventures
reflector@tvbf.org
Sun, 20 Jul 2003 10:45:35 -0700
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Chris;
Both theory and experience indicates the pressures toward the rear of
the fuselage (at about the cowl cut) are fairly well recovered so NACA
scoops can work pretty well. But also note that, in general, NACA
scoops are not recommended for intakes to heat exchangers that tend to
have fairly high air-side pressure drops. Even the authors of the
original papers on the NACA scoop say so. Pressure recovery is not as
high as with a ram scoop, especially far back on the fuselage where the
boundary layer is well developed. So going this route you would want a
radiator design that is relatively thin, and maybe a bit higher fin
spacing.
In sizing the scoop inlet, keep in mind that the rejection temp from our
liquid cooled radiators is lower than the average fin temp of the
aircooled engines, so we need more airflow for the same HP. The size of
the Velocity supplied scoops is likely to be too small.
Al
-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org] On
Behalf Of CBarber
Sent: Saturday, July 19, 2003 5:22 PM
To: Reflector@Tvbf.Org
Subject: REFLECTOR:Belly NACA
As y'all may know, I plan to use a Mazda Rotary on my SE fixed gear.
With
the engine mount I already have, there is ample room to position a full
size
radiator under the engine mount angled facing forward. Unlike the duel
NACA's that need to be split on top of the fuselage and go to each bank
of
cylinder heads for a Lyc/Frank/Cont, I should only need one air source
to
the radiator set up to provide adequate cooling. I have seen this done
with
a NACA scoop installed on the bottom of a Cozy but the under the engine
set
up on another Velo I saw had a "big ol' scoop hanging under the fuselage
(which is not my preference).
Do y'all see a problem with me doing this on my Velocity. I would
appreciate
the groups input as to problems I may encounter or reasons this may be a
bone-head idea. My thoughts as to issues I need to address include:
1) Do NACA's work ok on the bottom of the plane? Yep, start with the
basics. I have read contradictory views on NACA's use. Some seem to
love
them on their Velocity's, some don't.
2) I will need to cut out about 1.5 inches high, by 9-ish inches wide,
hole
from the bottom of the "gear bulkhead" to fit the NACA scoop. I would
reinforce the missing material with some Triax. Should this
reinforcement
be enough? Thoughts?
3) I will need to raise "sump tank" about 1.5 - 2 inches since the NACA
scoop will be where the sump sets. It seems easy enough to elevate the
sump
and rest it on the top of the NACA scoop once it is installed and create
a
solid pedestal for the sump to rest upon. Will the added height effect
the
gravity flow from the main tanks? The pictures I have seen seem to
indicate
this is a non issue as the main tank lines seem more than high enough to
accommodate a slightly elevated sump tank....but photo's can be
deceiving.
4) Of course, before I decided on using the rotary, I already installed
my
two top mounted NACA scoops on my SE. Does anyone have a use for
them....such a supplemental/primary cooling of something such as
accessories
(alternator, potential turbocharger etc) or would I be better off
closing
them back up. Also, if they were closed up, would the airspeed be
potentially increased. Also, I can't imagine a good way to duct the flow
from the top NACA's around the pipes and engine to underneath the engine
and
mount to the bottom mounted radiator....thus necessitating this entire
question. The radiators can be set up in different ways, it is just
under
the engine mount seems clearly the best.
5) Finally, I know I could just "build" the scoop into the bottom of
the
fuselage, but I am inclined to just buy a pre-molded scoop from
Velocity,
Inc. I know technically, there is a right NACA scoop and a left NACA
scoop,
but on the two that came with my kit, I can see VERY little difference.
Anyway, the standard scoops are about 9 inches wide.....how wide are the
scoops on the XL and would the larger XL scoop prove a better choice.
Thanks for your input, considered opinions and time as to what I may be
missing and/or other thoughts.
All the best,
Chris
www.LoneStarVelocity.com
Christopher Barber
Attorney and Counselor at Law
11930 S Sam Houston Pkwy E
Suite 103
Houston, Texas 77089-4755
281-464-LAWS (5297)
"Serving the needs of Senior Texans"
CBarber@TexasAttorney.net
www.TexasAttorney.net
_______________________________________________
To change your email address, visit
http://www.tvbf.org/mailman/listinfo/reflector
Visit the gallery! tvbf:jamaicangoose
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<p class=3DMsoPlainText><font size=3D2 face=3DVerdana><span =
style=3D'font-size:11.0pt;
font-family:Verdana'>Chris;</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DVerdana><span =
style=3D'font-size:11.0pt;
font-family:Verdana'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DVerdana><span =
style=3D'font-size:11.0pt;
font-family:Verdana'>Both theory and experience indicates the pressures =
toward
the rear of the fuselage (at about the cowl cut) are fairly well =
recovered so
NACA scoops can work pretty well. But also note that, in general, =
NACA
scoops are not recommended for intakes to heat exchangers that tend to =
have
fairly high air-side pressure drops. Even the authors of the =
original
papers on the NACA scoop say so. Pressure recovery is not as =
high
as with a ram scoop, especially far back on the fuselage where the =
boundary
layer is well developed. So going this route you would want a =
radiator
design that is relatively thin, and maybe a bit higher fin =
spacing.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DVerdana><span =
style=3D'font-size:11.0pt;
font-family:Verdana'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DVerdana><span =
style=3D'font-size:11.0pt;
font-family:Verdana'>In sizing the scoop inlet, keep in mind that the =
rejection
temp from our liquid cooled radiators is lower than the average fin temp =
of the
aircooled engines, so we need more airflow for the same HP. The =
size of
the Velocity supplied scoops is likely to be too =
small.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DVerdana><span =
style=3D'font-size:11.0pt;
font-family:Verdana'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DVerdana><span =
style=3D'font-size:11.0pt;
font-family:Verdana'>Al</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DVerdana><span =
style=3D'font-size:11.0pt;
font-family:Verdana'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DVerdana><span =
style=3D'font-size:11.0pt;
font-family:Verdana'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>-----Original
Message-----<br>
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org] On =
Behalf Of CBarber<br>
Sent: Saturday, July 19, 2003 5:22 PM<br>
To: Reflector@Tvbf.Org<br>
Subject: REFLECTOR:Belly NACA</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>As
y'all may know, I plan to use a Mazda Rotary on my SE fixed gear. =
With</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>the
engine mount I already have, there is ample room to position a full =
size</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>radiator
under the engine mount angled facing forward. Unlike the =
duel</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>NACA's
that need to be split on top of the fuselage and go to each bank =
of</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>cylinder
heads for a Lyc/Frank/Cont, I should only need one air source =
to</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>the
radiator set up to provide adequate cooling. I have seen this done =
with</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>a
NACA scoop installed on the bottom of a Cozy but the under the engine =
set</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>up
on another Velo I saw had a "big ol' scoop hanging under the =
fuselage</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>(which
is not my preference).</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Do
y'all see a problem with me doing this on my Velocity. I would =
appreciate</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>the
groups input as to problems I may encounter or reasons this may be =
a</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>bone-head
idea. My thoughts as to issues I need to address =
include:</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>1)
Do NACA's work ok on the bottom of the plane? Yep, start with =
the</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>basics.
I have read contradictory views on NACA's use. Some seem to =
love</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>them
on their Velocity's, some don't.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>2)
I will need to cut out about 1.5 inches high, by 9-ish inches wide, =
hole</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>from
the bottom of the "gear bulkhead" to fit the NACA scoop. I =
would</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>reinforce
the missing material with some Triax. Should this =
reinforcement</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>be
enough? Thoughts?</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>3)
I will need to raise "sump tank" about 1.5 - 2 inches since =
the NACA</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>scoop
will be where the sump sets. It seems easy enough to elevate the =
sump</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>and
rest it on the top of the NACA scoop once it is installed and create =
a</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>solid
pedestal for the sump to rest upon. Will the added height effect =
the</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>gravity
flow from the main tanks? The pictures I have seen seem to =
indicate</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>this
is a non issue as the main tank lines seem more than high enough =
to</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>accommodate
a slightly elevated sump tank....but photo's can be =
deceiving.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>4)
Of course, before I decided on using the rotary, I already installed =
my</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>two
top mounted NACA scoops on my SE. Does anyone have a use =
for</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>them....such
a supplemental/primary cooling of something such as =
accessories</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>(alternator,
potential turbocharger etc) or would I be better off =
closing</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>them
back up. Also, if they were closed up, would the airspeed =
be</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>potentially
increased. Also, I can't imagine a good way to duct the =
flow</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>from
the top NACA's around the pipes and engine to underneath the engine =
and</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>mount
to the bottom mounted radiator....thus necessitating this =
entire</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>question.
The radiators can be set up in different ways, it is just =
under</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>the
engine mount seems clearly the best.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>5)
Finally, I know I could just "build" the scoop into the bottom =
of the</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>fuselage,
but I am inclined to just buy a pre-molded scoop from =
Velocity,</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Inc.
I know technically, there is a right NACA scoop and a left NACA =
scoop,</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>but
on the two that came with my kit, I can see VERY little =
difference.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Anyway,
the standard scoops are about 9 inches wide.....how wide are =
the</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>scoops
on the XL and would the larger XL scoop prove a better =
choice.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Thanks
for your input, considered opinions and time as to what I may =
be</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>missing
and/or other thoughts.</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>All
the best,</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Chris</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>www.LoneStarVelocity.com</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Christopher
Barber</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Attorney
and Counselor at Law</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>11930
S Sam Houston Pkwy E</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Suite
103</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Houston,
Texas 77089-4755</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>281-464-LAWS
(5297)</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>"Serving
the needs of Senior Texans"</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>CBarber@TexasAttorney.net</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>www.TexasAttorney.net</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>______________________________________________=
_</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>To
change your email address, visit =
http://www.tvbf.org/mailman/listinfo/reflector</span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'> </span></font></p>
<p class=3DMsoPlainText><font size=3D2 face=3DNimrod><span =
style=3D'font-size:11.0pt'>Visit
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