REFLECTOR: FW: Wing root fairings

Tue Aug 14 12:13:21 CDT 2007

This may have been touched on by others, but a small radius is less
efficient but a large radius will show compression and tension stress
cracks since our birds are quite flexible the paint will crack then
peel.  My radius at the wing and strake to fuselage is the contour of my
index finger (gloved)and I have stress cracks in the paint where the
spar comes through the fuselage.  The spar flexes as it leaves the RG
box and lay ups attaching it to the firewall.  Alan Shaw would be one
expert on air flow and he loves the Blended wing (see Atlantica).
Rene'

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Douglas Holub
Sent: Tuesday, August 14, 2007 10:33 AM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: FW: Wing root fairings

It would be interesting to know what curve radius gives the least 
aerodynamic drag. Sounds like a great science fair project. I just
looked at 
the fairings on some fast planes and did it about the same. (E.g., some
WWII 
Japanese fighter planes and Jack Northrop's Vega. [Picture attached.])

I think that a fast Rutan canard has a lot more potential for
interference 
drag than a Cessna 172 does. A high wing or low wing airplane only has
one 
side of the wing-fuselage intersection with 90 degree angles. A mid-wing

airplane has both top and bottom. Plus, strakes are more than twice as
wide 
as normal wings are. And, everything else being equal, a plane going 184
mph 
has twice the wind resistance as a plane going 130 mph. Another reason
why 
we probably haven't often seen radii on metal planes is that it's harder
to 
do in metal than it is in fiberglass.

Doug Holub

----- Original Message ----- 
From: "gpoole" <gpoole at zeta.org.au>
To: "'Velocity Aircraft Owners and Builders list'" <reflector at tvbf.org>
Sent: Tuesday, August 14, 2007 12:54 AM
Subject: Re: REFLECTOR: FW: Wing root fairings

> Surely here has to be a "break even" between adding extra airframe
profile
> to the relative airflow vs reducing intersection drag.....do we have
any
> aerodynamicists in our midst?
>
> Greg in Sydney
>
>
>
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
On
> Behalf Of lawrence epstein
> Sent: Tuesday, 14 August 2007 10:41 AM
> To: reflector at tvbf.org
> Subject: Re: REFLECTOR: FW: Wing root fairings
>
> I was talking about the fuselage-strake intersection (i said
fuselage-wing
> in error).
> It might be interesting if we could make a removable fillet and take
> measurements on an already flying  velocity.
>
>
> What you are describing below is really a "blended wing" such as can
be
> found on Alan Shaw's "Atlantica". Blended wings have very low drag
> coefficients.
>
> Larry E.
>
>>From: Hiroo Umeno <humeno at microsoft.com>
>>Reply-To: Velocity Aircraft Owners and Builders list
<reflector at tvbf.org>
>>To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>>Subject: Re: REFLECTOR: FW: Wing root fairings
>>Date: Mon, 13 Aug 2007 17:06:14 -0700
>>
>>Very interesting...  How much difference does eliminating these
>>intersections make in reducing drag?
>>
>>Taking it even further, how about fuselage-strake intersections?
Would
>>flattening that out have any effect in reducing drag?  Think of much
>>thicker, continuously curved baggage area (perhaps slanted, curved
side
>>rear windows)?  It would almost seem one could imagine an airframe
where
>>the roof and floor line transitions into wing-root without any sharp 
>>turns.
>
>>  That would also increase the interior volume as well, right?
>>
>>Or do such modification count against you since it reduces the
effective
>>"wing-shaped" strake area by extending the fuselage area out-ward?
>>
>>(Maybe I am inhaling too much "experimental" gas)...
>>
>>Hiroo
>>
>>From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
On
>>Behalf Of Tony Babb
>>Sent: Monday, August 13, 2007 4:14 PM
>>To: 'Velocity Aircraft Owners and Builders list'
>>Subject: Re: REFLECTOR: FW: Wing root fairings
>>
>>Has anyone done similar with the canard/doghouse and fuselage 
>>intersection?
>
>>I have a removable doghouse and am pondering how to create a fillet
and
>>round out the angle without having a sharp edge- or is  a rounded edge
>>better than nothing?
>>
>>Tony
>>SEFG
>>62% done, 78% to go
>>www.alejandra.net/velocity<http://www.alejandra.net/velocity>
>>-----Original Message-----
>>From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]
On
>>Behalf Of Douglas Holub
>>Sent: Monday, August 13, 2007 2:57 PM
>>To: Velocity Aircraft Owners and Builders list
>>Subject: Re: REFLECTOR: FW: Wing root fairings
>>I don't. I'm trying to eliminate all 90 degree intersections. Here's a
>>picture of my upper and lower wing-winglet intersections. I used pour
foam
>>to build up the area, then shaped it with sandpaper glued to a 6" PVC 
>>pipe,
>
>>then covered it with two plies of bid.
>>
>>Doug Holub
>>----- Original Message -----
>>From: Lawrence J. Epstein, MD<mailto:ljepstein at hotmail.com>
>>To: reflector at tvbf.org<mailto:reflector at tvbf.org>
>>Sent: Monday, August 13, 2007 2:16 PM
>>Subject: REFLECTOR: FW: Wing root fairings
>>
>>
>>Does anyone see any downside to fairing/filling the bottom
wing-fuselage
>>joint in an effort to reduce drag?
>>
>>Larry Epstein
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