News footage of Emirates A380 arrival into JFK
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Have a look at the footage of the landing in Heathrow a couple of years back (by the Airbus test-drivers) servo jacks on the rudder getting a hell of a work out with the standard UK crosswinds...fly-by-wire smoke and mirrors I guess, after 15 years of it I don't give it a second thought anymore, oh well looked impressive.
I'm guessing the CP didn't give that landing to his FO
Dooner
I'm guessing the CP didn't give that landing to his FO
Dooner
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Not specifically related to the rudder, but this is quite interesting:
Redusing the load
While aerodynamic and structural efficiency obviously affect the overall performance of the wing, the weight of the wing is significantly influenced by the loads which the structure must react. To a large degree these loads are generated by aerodynamic forces developed when an aircraft makes a manoeuvre or encounters turbulent air. The A380 is the first commercial aircraft to use a combined Load Alleviation Function (LAF) to minimise the effects of both flying situations. When the aircraft executes a manoeuvre the system is designed to deflect the wing movable surfaces to minimise the loads. In a similar fashion the controls will also deploy when the aircraft encounters turbulence, again with the aim of reducing loads on the wing.
In addition, patented load reduction techniques were developed to enable the fuel system to control the loads actively on the wing in all phases of flight, continuing a tradition started in the UK with Concorde. Typically, Airbus aircraft pump fuel between the wing tanks and tail tank to maintain the centre of gravity in the most advantageous place to minimise the drag of the aircraft in cruise. This happens too on the A380, but here the technique goes one step further.
In the A380 fuel is also pumped from the inner wing tanks to the outer wing tanks after take-off and then in the opposite direction before touchdown, which reduces the “ground-air-ground” fatigue loads on the wing (Figure 1). The combination of these load alleviation techniques saves more than two and a half tonnes of wing weight.
While aerodynamic and structural efficiency obviously affect the overall performance of the wing, the weight of the wing is significantly influenced by the loads which the structure must react. To a large degree these loads are generated by aerodynamic forces developed when an aircraft makes a manoeuvre or encounters turbulent air. The A380 is the first commercial aircraft to use a combined Load Alleviation Function (LAF) to minimise the effects of both flying situations. When the aircraft executes a manoeuvre the system is designed to deflect the wing movable surfaces to minimise the loads. In a similar fashion the controls will also deploy when the aircraft encounters turbulence, again with the aim of reducing loads on the wing.
In addition, patented load reduction techniques were developed to enable the fuel system to control the loads actively on the wing in all phases of flight, continuing a tradition started in the UK with Concorde. Typically, Airbus aircraft pump fuel between the wing tanks and tail tank to maintain the centre of gravity in the most advantageous place to minimise the drag of the aircraft in cruise. This happens too on the A380, but here the technique goes one step further.
In the A380 fuel is also pumped from the inner wing tanks to the outer wing tanks after take-off and then in the opposite direction before touchdown, which reduces the “ground-air-ground” fatigue loads on the wing (Figure 1). The combination of these load alleviation techniques saves more than two and a half tonnes of wing weight.
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I think that because of the relatively 'short' length of this aircraft, you would need rudders the size of barn doors for effective yaw control. Also explains maybe why only the inner two engines have thrust reversers. Assymetric reversing from outer engines might be have too much moment for the rudder to handle. Possible VMCA and VMCG issues.
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Anyway it is all jolly clever stuff and possibly lots to go wrong.....I pray they never loose one due all this clever stuff failing to work as it ages.
I note there is a B777 wreck going cheap at LHR and nobody seems to presently know exactly what caused thoes engines to fail to respond....if they do presently they are not telling.
I note there is a B777 wreck going cheap at LHR and nobody seems to presently know exactly what caused thoes engines to fail to respond....if they do presently they are not telling.
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Originally Posted by Iver
How many more A380s expected to be delivered through the end of the year? How about next year?
For instance, Emirates should have 4 by year end, and aim to start LHR service on Dec 1, so the model parked on the Concorde (or is it Emirates?) roundabout will mean something then.
Last edited by sanjosebaz; 6th Aug 2008 at 02:51.
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Sal-e wrote:
"I think that because of the relatively 'short' length of this aircraft, you would need rudders the size of barn doors for effective yaw control. Also explains maybe why only the inner two engines have thrust reversers. Assymetric reversing from outer engines might be have too much moment for the rudder to handle. Possible VMCA and VMCG issues."
Seems I remember the nos. 1 and 4 reversers were removed solely to reduce weight. Correct me if I'm wrong.
Bigus
"I think that because of the relatively 'short' length of this aircraft, you would need rudders the size of barn doors for effective yaw control. Also explains maybe why only the inner two engines have thrust reversers. Assymetric reversing from outer engines might be have too much moment for the rudder to handle. Possible VMCA and VMCG issues."
Seems I remember the nos. 1 and 4 reversers were removed solely to reduce weight. Correct me if I'm wrong.
Bigus
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That's correct Jet. The original plan was not to have any reversers but Airbus were told to compromise and that is why two engines were fitted. Not sure which authorities were involved though.
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Oh boy...
Guys: The rule is not to post here if you ain't got a clue or if you had too many drinks before you switched on the PC.Have a look at all available youtube footage of 380 landings. The rudder is always very lively. Its a short coupled bird, right?
Airbus never thought about getting rid of all reversers. Not installing them on 1+4 is simply for not digging trenches next to 45m runways.
EDA is alive and well and as I am writing this, Abbas is taking her from LAX to JFK to end the west coast promotional tour.
BTW: Thanks to AA and their elderly and 'maintained by Americans with pride' 757 for screwing up the water curtain arrival in LA. Their elderly bird needed the fire trucks more urgently than us.
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Doubt they would have used the 22L VOR when there is an ILS on that runway.
That wing unloading was most impressive.
Got to watch it take off Monday morning. Nothing spectacular to see from inside the airport, but did make for a nice smile.
That wing unloading was most impressive.
Got to watch it take off Monday morning. Nothing spectacular to see from inside the airport, but did make for a nice smile.
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How about this for another turbulent EK arrival, this time landing in Seychelles.
Follow the link
YouTube - Emirates A330 crosswind landing attempt
Follow the link
YouTube - Emirates A330 crosswind landing attempt
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A380 Rudder Activity
The reason you see a lot of rudder activity on approach (it's the FBW system commanding it not the pilot via the pedals) is that the A380 has different control law in Yaw to previous Airbus'. In very simple terms zero rudder pedal deflection commands zero sideslip (provided there is no engine failure). So the FBW will use the rudder to maintain zero sideslip (measured by 3 sideslip probes just in front of the cockpit windshield).
