REFLECTOR:Lower Winglets- Secondary function.
Tom Martino
reflector@tvbf.org
Sun, 1 Feb 2004 12:38:41 -0700
Thanks Scott ...
I must have misunderstood that post. I thought it was addressing VGs,
Fences and Vortilons. I wasn't sure if it dealt with lower winglets.
Can I hear from those flying without lower winglets? Are there any?
-----Original Message-----
From: Scott Baker [mailto:sbakr@comcast.net]
Sent: Sunday, February 01, 2004 11:56 AM
To: reflector@tvbf.org
Subject: Re: REFLECTOR:Lower Winglets- Seaondary function.
Hello Tom,
You must of missed my January 26th post -
"Personally ... for the big wing ... since I don't envision short field
ops,
I'd go with the vortilons and I'd try the trailing edge fences (out of
curiosity) to see if they make any significant improvement."
Scott B.
----- Original Message -----
From: "Tom Martino" <tmartino@troubleshooter.com>
To: <reflector@tvbf.org>
Sent: Monday, January 26, 2004 2:40 PM
Subject: RE: REFLECTOR: Vortilons
> OK ... I must ask the obvious question of those at the factory (Scott,
Brenden, etc.) ...
> If you were considering what to do on your very own plane ... what
would
you do?
>
> Vortilons? VGs? Fences? All three? One or the other?
>
> I know that you are reluctant to make general recommendations ... but
I am
asking what would YOU do?
----- Original Message -----
From: "Tom Martino" <tmartino@troubleshooter.com>
To: <reflector@tvbf.org>
Sent: Saturday, January 31, 2004 1:45 PM
Subject: RE: REFLECTOR:Lower Winglets- Seaondary function.
> What is the latest thinking? Again I must ask ... what would the guys
> at the factory do on their "personal" V ... lower winglets? Or not?
> And can they be added to the regular tips?
>
>
>
> -----Original Message-----
> From: Chris Martin [mailto:christophercmartin@earthlink.net]
> Sent: Friday, January 30, 2004 4:28 PM
> To: reflector@tvbf.org; reflector@tvbf.org
> Subject: Re: REFLECTOR:Lower Winglets- Seaondary function.
>
> Greg,
>
> That is the very best explanation of the winglet I've ever heard. The
> vectoring of total component lift replicates the vectoring of lift in
a
> dihedral wing. Brilliant, now I understand how it works and I've been
> working on these planes since 1997 and flying them for over 400 hours.
> It's
> the occasional, inspiring, technical wisdom in the reflector that
makes
> the
> entire reflector worth while reading.
>
> Great explanation!
>
> Christopher Martin
> christophercmartin@earthlink.net
> Why Wait? Move to EarthLink.
>
>
> > [Original Message]
> > From: Laurence Coen <lwcoen@hotmail.com>
> > To: <reflector@tvbf.org>
> > Date: 1/30/2004 10:30:52 AM
> > Subject: Re: REFLECTOR:Lower Winglets- Seaondary function.
> >
> > Greg,
> >
> > The thingies on the ends of the main wing were not designed to be
> winglets
> > as a primary function. Their primary function is vertical
> > stabilizer/rudders. The fact that they are on the ends of the main
> wing
> > causes them to act as winglets, albeit poorly designed ones. If you
> > remember the Ercoupe, it had twin rudders on the end of it's
elevator.
> I
> > can't remember anyone calling them "elevatorets". The rudders
always
> wind
> > up on the rear of the aircraft for the same reason the feathers are
on
> the
> > back end of an arrow. The Ercoupe had the big wing in front and the
> little
> > one in back. Ours are built the other way around but the vertical
> > stabilizer/rudder still has to go in the back. Mounting it on the
> > centerline isn't practical so they are out on the ends of the big
wing
> which
> > is where you would mount winglets if you were going to have them.
> Their
> > primary functions are yaw stability, roll stability and yaw control.
> The
> > only one of these that isn't obvious is how they provide roll
> stability.
> > Assuming that you understand how dihedral on an aircraft provides
roll
> > stability by tilting the lift vectors in toward the center line of
the
> > aircraft, you should also understand how the "winglets" work. The
> winglets
> > produces lift in the horizontal plane toward the centerline while
the
> main
> > wing generates lift vertically. If you sum these two vectors, the
> result
> > will be a lift vector tilted toward the centerline of the aircraft,
> just
> > like the wings with dihedral.
> >
> > Are we having fun yet?
> >
> > Larry Coen
> > Std. RG-E
> >
> > ----- Original Message -----
> > From: "Greg Poole" <gpoole@zeta.org.au>
> > To: <reflector@tvbf.org>
> > Sent: Thursday, January 29, 2004 3:41 PM
> > Subject: Fw: REFLECTOR:Lower Winglets
> >
> >
> > > From one of my aircraft designer mates.....
> > >
> > >
> > > Subject: Re: REFLECTOR:Lower Winglets
> > >
> > >
> > > > hi Greg,
> > > > The lower winglet design on the Velocity is more a wingtip skid
> than a
> > > lower
> > > > Whitcombe winglet. The upper winglet design is more somewhere to
> put
> the
> > > > rudder than a Whitcombe winglet.
> > > > An efficient design would have a winglet span of only 20% of the
> main
> > wing
> > > > semi-span with the leading edge of the upper winglet starting at
> the
> > > thickest
> > > > point of the main wing profile and ending behind the main wing
> trailing
> > > edge.
> > > > The winglet is more tapered and sweptback than the original wing
> and
> the
> > > > airfoil section changes the camber forward towards the tip(
> geometric
> > > > washout).
> > > > The lower Whitcombe tip should be 5% of the wing semi-span (from
> > > memory)and
> > > > start before the leading edge of the wing, ending at the
thickest
> point
> > of
> > > > the main wing airfoil section. The upper winglet has the airfoil
> as a
> > bent
> > > up
> > > > version as the main wing whereas the lower winglet is opposite
> with
> the
> > > main
> > > > camber facing the fuselage.
> > > > Modern design also cant the winglet out at 30 degrees to reduce
> the
> > > bending
> > > > moment and pressure area at the winglet root.
> > > > I hope this gives you a bit of an idea as to winglet designs,
> > > > Ray
> > > >
> > > > On Wed, 28 Jan 2004 17:40:13 +1100, Greg Poole wrote
> > > > > Al,
> > > > >
> > > > > Most of the designs of effective lower winglets as appear on
> other
> > > > > aircraft, kick the winglet out at a decent angle (rather than
up
> and
> > > > > down) and have more of a tapered shape - I would love to know
> the
> > > > > reasons why the Velocity is different in this regard...can
> anybody
> > > > > shed any light? ....Could be better visual aesthetics I
suppose.
> > > > >
> > > > > Forever curious!
> > > > >
> > > > > Greg in Sydney.
> > > > > ----- Original Message -----
> > > > > From: Al Gietzen
> > > > > To: reflector@tvbf.org
> > > > > Sent: Wednesday, January 28, 2004 4:59 PM
> > > > > Subject: RE: REFLECTOR:Lower Winglets
> > > > >
> > > > > One notable result of not having the lower winglet is
> increased
> > > > > speed,
> > > > >
> > > > > which doesn't quite jibe with the above discourse?
> > > > >
> > > > > Scott
> > > > >
> > > > > Oh, I think it could. Airfoils producing a force cause
drag.
> The
> > > > > winglets cause drag, but they produce a force we need for
> handling
> > > > > and stability. I'd expect the Velocity lower winglets to
cause
> drag
> > > > > at cruise without much in the way of offsetting benefit.
> Apparently
> > > > > there is some handling benefit at lower speeds.
> > > > >
> > > > > Do you have any with/without data about the increased cruise
> speed?
> > > > >
> > > > > Al
> > > >
> > > >
> > > > --
> > > > ISPDr Internet WebMail (https://www.ispdr.net.au/mail)
> > >
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