REFLECTOR:Belly NACA

[Wayne Owens]

My rear seat is a bench seat  on a 173 FG and I plan to move it a little
higher at the front and forward  and I will have about 8 inches under the
rear seat to accommodate my wide low  radiator. This will move the cg
forward a mite and reduce the ammount of  pregnant guppy belly profile.   It
still will use a scoop though but should look more like a p51 than a torpedo
with a tumor. Present configuration has lots of drag behind the tumor.
See the next CONTACT magazine.
 I will also be able to use  a rear flap ala P51 to reduce drag .
I should  have lots of room under the engine for my water/ oil heat
exchangers.  They are much more effective than  the various air/oil
radiators I tried.
I have a couple of pix of what not to do. I could send to you directly.
Wayne

----- Original Message ----- 
From: "CBarber" <CBarber@texasattorney.net>
To: "Reflector@Tvbf.Org" <reflector@tvbf.org>
Sent: Saturday, July 19, 2003 9:22 PM
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
>
>
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