Winglets

[Chilli]

Why don't they put them on the rear "wings" of the larger planes?
Was just wondering...

[Antimus]

Saw this on TV once, the winglets only cause problems on the long main wings on the plane, causing drag on the tips because of the cyclone of air they create. It's not a problem on the tail because the wings aren't long enough and the wind drag from the main wings stops any problems like that.

I THINK that's it

[Antimus]

in FACT, after a little reading, winglets are a thing of the past, raked wingtips are the new way of cancelling out the drag from wing tips. Instead of curling up at the ends, they sweep back in a sabre sort of way (the sword, not the car)

edit: not a sabre, they don't curve, damnit, what is it, scimitar? eh, nevermind.

Edited by Antimus on Tuesday 12th October 11:55

[Chilli]

Are you alright mate?!
Actually, I thought the Winglets/Wingtips were there to increase the level of lift, as air cannot escape "over the edge".
Guess I'm talking crap again then!

[Eric Mc]

Chilli said:

Are you alright mate?!
Actually, I thought the Winglets/Wingtips were there to increase the level of lift, as air cannot escape "over the edge".
Guess I'm talking crap again then!

They became more common from the late 1970s, although some advanced designs right back to the 1920s and 30s featured them. The original drawings for what became the Handley Page Victor featured upward sweeping wingtips, and that was back in 1948.

[Simpo Two]

Chilli said:

Why don't they put them on the rear "wings" of the larger planes?

Elevators.

I was getting confused with canard wings there for moment.

[SamHH]

Chilli said:

Are you alright mate?!
Actually, I thought the Winglets/Wingtips were there to increase the level of lift, as air cannot escape "over the edge".
Guess I'm talking crap again then!

I think you are basically correct about their purpose. However, the main purpose of the tailplane is to provide stability and control of pitch, not lift. I suspect that is why winglets would be of little use on the tailplane.

Edited by SamHH on Tuesday 12th October 12:36

[markcp]

My FiL is currently working on the redesign of the winglets for one of the Airbus range (can't remember which one). IIRC they increase lift therefore giving better econmony and better range. However, they add so much additional load to the wing, it means that a large part of the wing needs to be strengthened which adds weight and reduces the fuel load capacity which cancels out the better economy...

More worryingly, if one fell off an Airbus the aircraft would be highly unstable but for some reason Boeing's design can cope with one falling off...

[pushthebutton]

Don't they decrease induced drag due to creating lift by all but eliminating wingtip vortices? I think the result is increased range and decreased fuel burn.

[anonymous-user]

Large winglets retrofitted on 73/75/76 etc save about 1% of fuel per hour. So a 10 hour flight has 10% fuel saving taking into account the extra weight etc.

Most operators are getting them on older aircraft as fuel has become so expensive.

[pushthebutton]

1% of fuel burn.

Edited by pushthebutton on Tuesday 12th October 16:11

[anonymous-user]

doogz said:

el stovey said:

Large winglets retrofitted on 73/75/76 etc save about 1% of fuel per hour. So a 10 hour flight has 10% fuel saving taking into account the extra weight etc.

Most operators are getting them on older aircraft as fuel has become so expensive.

How does that work then?

If you fly non-stop for 100 hours, you save 100% of your fuel?

I don't think the formula can be quite as simple as that.

Clearly the saving is based on NORMAL operating ranges for those aircraft I mentioned compared to non blended winglet 73/75/76s

The figure I quoted is what my airline think they are saving.

Boeing publish their own figures here, with reference to blended winglets.

http://www.boeing.com/commercial/aeromagazine/arti...

[Rum Runner]

A foil looses a lot of lift due to "Tip Losses" turbulence between the meeting of high and low pressure where it gets forced to tip. The winglet reduces these losses by creating a fence on the foil so goes some way to stop the pressure differences meeting each other and cutting down on turbulent flow at the tip and basically gives the foil more lift yet maintaining a shorter wing.
Less turbulance = Better Lift+Less drag. Reynolds numbers...

Remember how the Aussies won the Americas Cup in 1983 with there winged keel..so around a long time in boat world before they started fitting them to Airlines.;)

Edited by Rum Runner on Thursday 14th October 09:41

[Eric Mc]

The Learjet Longhorn had them in 1978/79.

Rutan's light aircraft had them from the mid 70s.

[ninja-lewis]

Simpo Two said:

Chilli said:

Why don't they put them on the rear "wings" of the larger planes?

Elevators.

I was getting confused with canard wings there for moment.

Tailplane or Horizontal Stabiliser - the elevators are only the flappy bits on the trailing edge. Unless of course the whole tailplane moves in which case its a Stabilator.

[Chilli]

ninja-lewis said:

Simpo Two said:

Chilli said:

Why don't they put them on the rear "wings" of the larger planes?

Elevators.

I was getting confused with canard wings there for moment.

Tailplane or Horizontal Stabiliser - the elevators are only the flappy bits on the trailing edge. Unless of course the whole tailplane moves in which case its a Stabilator.

So I guess their job isn't to create lift then?

[SamHH]

Chilli said:

ninja-lewis said:

Simpo Two said:

Chilli said:

Why don't they put them on the rear "wings" of the larger planes?

Elevators.

I was getting confused with canard wings there for moment.

Tailplane or Horizontal Stabiliser - the elevators are only the flappy bits on the trailing edge. Unless of course the whole tailplane moves in which case its a Stabilator.

So I guess their job isn't to create lift then?

The main purpose of the tailplane is to provide stability and control of pitch, not lift.

[ninja-lewis]

Chilli said:

ninja-lewis said:

Simpo Two said:

Chilli said:

Why don't they put them on the rear "wings" of the larger planes?

Elevators.

I was getting confused with canard wings there for moment.

Tailplane or Horizontal Stabiliser - the elevators are only the flappy bits on the trailing edge. Unless of course the whole tailplane moves in which case its a Stabilator.

So I guess their job isn't to create lift then?

Technically they create lift but only a very small amount compared to the wings, which is sufficient due to the distance between the tail and the wings (like a seesaw). Hence they're used to balance the lift provided by the wings, allowing the aircraft to achieve a particular pitch attitude.

[Super Slo Mo]

markcp said:

My FiL is currently working on the redesign of the winglets for one of the Airbus range (can't remember which one). IIRC they increase lift therefore giving better econmony and better range. However, they add so much additional load to the wing, it means that a large part of the wing needs to be strengthened which adds weight and reduces the fuel load capacity which cancels out the better economy...

More worryingly, if one fell off an Airbus the aircraft would be highly unstable but for some reason Boeing's design can cope with one falling off...

I've been on an aircraft with the port wide winglet missing. I'm pretty sure that was an Airbus too, think it was a Thomas Cook flight to Calgary (although could be wrong since I've been on an awful lot of flights since then).

It flew perfectly happily, as far as one could tell from the passenger compartment.

[SlipStream77]

ninja-lewis said:

Simpo Two said:

Chilli said:

Why don't they put them on the rear "wings" of the larger planes?

Elevators.

I was getting confused with canard wings there for moment.

Tailplane or Horizontal Stabiliser - the elevators are only the flappy bits on the trailing edge. Unless of course the whole tailplane moves in which case its a Stabilator.

Unless it carries out the role (no pun intended ) of an aileron as well, in which case it's known as a taileron. x2

Also, they're not winglets but have a look at the tail on the Shuttle carrying 747.

http://en.wikipedia.org/wiki/Shuttle_Carrier_Aircr...