REFLECTOR:Lower Winglets
Greg Poole
reflector@tvbf.org
Tue, 27 Jan 2004 21:01:48 +1100
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Al said; From an aerodynamics standpoint, I don't think adding height to =
the tipsail bears much relation to removing the bottom extension (lower =
winglet). It may add a bit to the yaw stability because of the =
additional inward force, and can add to rudder effectiveness if you also =
lengthen the rudder.
Yes I was trying to understand how height would substitute for the lower =
winglet.=20
And then Al said; One notable feature of the Velocity lower winglet is =
the airfoil is backwards; i.e., the airfoil should be the other way, the =
camber on the outside (Check out Rutan's design, and you'll see that is =
the case). Even as it is, the lower winglet can help stability by =
reducing the 'spill' off the tip enhancing the lift at the tip just a =
bit, and further reducing the vortex. With the camber on the outside it =
would do more than just stop the spill, it 'pushes' the air inboard, =
more effectively eliminating tip vortex, and maybe some other good =
things.
Very interesting ...so Al & Co. .....why does the Velocity lower winglet =
feature the airfoil backwards whereas the Rutan design is said (I took a =
look at Al's second picture and the inner shape of the lower winglet =
actually looks concave - as in an aerofoil - to me...) to be the =
reverse? ...Burt Rutan, where are you when we need you?
Greg in Sydney.
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<DIV><FONT size=3D2>Al said; From an aerodynamics standpoint, I don=92t =
think adding=20
height to the tipsail bears much relation to removing the bottom =
extension=20
(lower winglet). It may add a bit to the yaw stability because of =
the=20
additional inward force, and can add to rudder effectiveness if you also =
lengthen the rudder.<BR><BR></FONT>Yes I was trying to understand how =
height=20
would substitute for the lower winglet. <BR><BR><FONT size=3D2>And then =
Al said;=20
One notable feature of the Velocity lower winglet is the airfoil is =
backwards;=20
i.e., the airfoil should be the other way, the camber on the outside =
(Check out=20
Rutan=92s design, and you=92ll see that is the case). Even as it =
is, the lower=20
winglet can help stability by reducing the =91spill=92 off the tip =
enhancing the=20
lift at the tip just a bit, and further reducing the vortex. With =
the=20
camber on the outside it would do more than just stop the spill, it =
=91pushes=92 the=20
air inboard, more effectively eliminating tip vortex, and maybe some =
other good=20
things.<BR></FONT><BR>Very interesting ...so Al & Co. .....why does =
the=20
Velocity lower winglet feature the airfoil backwards whereas the Rutan =
design is=20
said (I took a look at Al's second picture and the inner shape of the =
lower=20
winglet actually looks concave - as in an aerofoil - to me...) to =
be the=20
reverse? ...Burt Rutan, where are you when we need you?</DIV>
<DIV> </DIV>
<DIV>Greg in Sydney.</DIV>
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