glidepath73
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Winglets On Elevator?

Tue Jun 07, 2005 10:39 pm

Hi all,

I just thought about the possibility to add winglets on the horizontal stabilizer.
I think at least for (over)longhaul airliners, it would lead to a reduced fuel burn, since the same might happen as on the wings.

What do you guys think about? Was this tested before in windchannel tests?
Are there some guys from aerodynamic engineering, which could let us know more about it?

Regards,
Patrick
Aviation! That rocks...
 
777DadandJr
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RE: Winglets On Elevator?

Tue Jun 07, 2005 10:57 pm

I asked the same question a while back. Check out here:
Winglets On Tail? (by 777DadandJr Mar 31 2005 in Tech Ops)

Russ
My glass is neither 1/2 empty nor 1/2 full, rather, the glass itself is twice as big as it should be.
 
glidepath73
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RE: Winglets On Elevator?

Tue Jun 07, 2005 11:07 pm

Russ,
thanks for the link. Didn't see that one.  Smile
I think though, there still some questions left, especially regarding longhaul aircrafts.
Aviation! That rocks...
 
glacote
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RE: Winglets On Elevator?

Wed Jun 08, 2005 9:14 pm

A properly designed wing is always better without winglets. You put winglets whenever:
- you want to update an existing wing profile without going through a complete revamp
- you have geometrical constraints (e.g. 80m for the A380)

Thus you could try to add winglets on an outdated elevator but the cost savings vs a full revamp and the expected gains are not worth it - you either rebuild a whole new elevator or you do nothing at all.
 
glidepath73
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RE: Winglets On Elevator?

Thu Jun 09, 2005 12:52 am

Glacote, thanks a lot for the information.

Was in your opinion the 330/340 wing not properly designed?


Regards,
Patrick
Aviation! That rocks...
 
HiFi
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RE: Winglets On Elevator?

Thu Jun 09, 2005 2:54 am

The horizontal stabilizer produces much less lift than the wing, probably not enough to be winglet-worthy.
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fly727
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RE: Winglets On Elevator?

Thu Jun 09, 2005 3:09 am

Although not winglets per-se these two examples use to enhance lateral stability these devices in the horizontal stabilizers:


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RM  Smile
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aeroweanie
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RE: Winglets On Elevator?

Thu Jun 09, 2005 6:05 am

Quoting Glacote (Reply 3):
A properly designed wing is always better without winglets. You put winglets whenever:
- you want to update an existing wing profile without going through a complete revamp
- you have geometrical constraints (e.g. 80m for the A380)

Wrong!!! Winglets are just nonplanar span extensions. Any wing will benefit from a span extension.
 
ConcordeBoy
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RE: Winglets On Elevator?

Thu Jun 09, 2005 6:19 am

Quoting Glacote (Reply 3):
A properly designed wing is always better without winglets.



Quoting AeroWeanie (Reply 7):
Any wing will benefit from a span extension.

...neither one of these (sweeping) statements are true in all cases-- there are too many other factors to consider.
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DfwRevolution
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RE: Winglets On Elevator?

Thu Jun 09, 2005 6:27 am

Quoting Glidepath73 (Reply 4):
Was in your opinion the 330/340 wing not properly designed?

Airbus designed the A330/A340 without winglets, but implemented them during an extensive redefinition when IAE dropped the ball big time with the IAE SuperFan engine. Airbus was counting on the SuperFan to meet their performance goals, and when the only engine available was the CFM56-5, they needed enhancing features to avoid missing their targets.

Winglets went on.
 
AsstChiefMark
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RE: Winglets On Elevator?

Thu Jun 09, 2005 6:41 am

Certain 747's have them.  Wink


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glidepath73
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RE: Winglets On Elevator?

Thu Jun 09, 2005 7:32 am

Hi guys,
thanks a lot for your opinions.
Lets say we add winglets at the stabilizer of a 772LR or a 345. Would the a/c need more fuel, same, or less for about the same distance? (Weight shouldn't be that much, since we have composites)

Regards,
Patrick
Aviation! That rocks...
 
SATL382G
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RE: Winglets On Elevator?

Thu Jun 09, 2005 9:42 am

Quoting HiFi (Reply 5):
The horizontal stabilizer produces much less lift than the wing, probably not enough to be winglet-worthy.

Horizontal stabilizers don't produce lift, they produce down force.
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abbs380
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RE: Winglets On Elevator?

Thu Jun 09, 2005 5:45 pm

AsstChief Mark, Your pic is a 747 Shuttle carrier. I think these are actually extra vertical stabilizers which are out of the wake of the shuttle when its being carried. I dont think they are intended as a performance enhancement, just extra stability.
 
keta
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RE: Winglets On Elevator?

Thu Jun 09, 2005 5:59 pm

Quoting AeroWeanie (Reply 7):
Wrong!!! Winglets are just nonplanar span extensions. Any wing will benefit from a span extension.

That's what I was going to say  Wink

Quoting SATL382G (Reply 12):
Horizontal stabilizers don't produce lift, they produce down force.

That's like saying that they produce negative lift, the effect is the same.

Quoting Glidepath73 (Reply 11):
Lets say we add winglets at the stabilizer of a 772LR or a 345. Would the a/c need more fuel, same, or less for about the same distance? (Weight shouldn't be that much, since we have composites)

Depending on the aircraft's CG, speed, weight, altitude... the stabilizers produce lift, negative lift or no lift at all. What kind of winglets would you put? On the wings, the lift is always an upwards force, but on the stabilizers it can be downwards. Kind of tough to design a winglet that would benefit in both cases. Maybe wingtip fences could do that?
I'm not sure, but I'm afraid the vortex created are small, since the aerodynamic force is not very big. The weight is a thing you always have to take into account. I guess the aerodynamic savings would not be sufficient to justify the increase on weight.
Where there's a will, there's a way
 
HiFi
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RE: Winglets On Elevator?

Fri Jun 10, 2005 1:24 am

Quoting AsstChiefMark (Reply 10):
Certain 747's have them

I guess that's more related to stability than aerodynamics...

Quoting Keta (Reply 14):
Quoting SATL382G (Reply 12):
Horizontal stabilizers don't produce lift, they produce down force.

That's like saying that they produce negative lift, the effect is the same.

thanks.
no commercial potential
 
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Jetlagged
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RE: Winglets On Elevator?

Fri Jun 10, 2005 2:02 am

The best way to reduce the drag of the horizontal stabiliser is to have it produce as little lift (and so induced drag) as possible. The less lift is produced, the less a winglet will help.

Endplate fins used to be used a lot in aircraft design, in the search for better efficiency. In the days before winglets, endplates were known to reduce induced drag, but usually their weight and form drag overcame any real advantage.


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Apart from the endplate effect, part of the idea was to put the fin in the propwash to improve the rudder effectiveness (as with the Lodestar above). Not such a good idea with a jet  Smile
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