A380 question

[Hai Perso Coyone?]

The only thing that can do that flight is the Boeing 777-200LR

[Alonso]

Does this -- http://seattlepi.nwsource.com/business/ ... tas11.html -- means that the triple 7 can? What about the a340-500 or -642

[PlutonianEmpire]

Another question: why is there no GE engine option? Surely it'd be only fitting that the worlds largest airliner be fitted with the GE-90 engines, the worlds largest jet engine?

[Nexus]

Another question: why is there no GE engine option? Surely it'd be only fitting that the worlds largest airliner be fitted with the GE-90 engines, the worlds largest jet engine?

GE90 design is not suitable for quads.
It s too heavy and packs too much power.

Simply put, the A380 dont need the excessive thrust and certainly can live without the additional weight.

[PlutonianEmpire]

Wouldn't the additional power offset the additional weight?

[Woodlouse2002]

Wouldn't the additional power offset the additional weight?

It doesn't need it. And what would be the point?

[Nexus]

Wouldn't the additional power offset the additional weight?

Additional power means additional fuel consumption to cope with the added weight... And you can't increase the volume of the fueltanks.
Congrats, you have just reduced the range of the A380.
I'm sure the airlines enjoy that.  :)

Also, read Woodlouse's reply. Pretty much sums it up.

[PlutonianEmpire]

Stupid me. I thought it would increase the range. *bangs head on wall*

[Nexus]

Stupid me. I thought it would increase the range. *bangs head on wall*

More powerful engines doesnt necessary equal increased range. I bet that four GE90's will consume considerably more amount of fuel than the current engines available for the A380.

Also throw in the jet engines need for high RPMs to be effective, you soon realize that this can not be done. If you'd keep four GE90's at 90% in cruise, you'd exceed MMO

[chornedsnorkack]

Actually, GE-90 or its Rolls-Royce equivalent should be pretty comfortable to power a A380-sized trijet.

So would you like to fly a doubledecker trijet? And would you prefer to mount a GE90 in the tailcone with S-duct, like Tristar, ot above tail like DC-10 and MD-11?

[Nexus]

An A380 tri-jet, now that is interesting  :)

For design purposes I'd put an S-duct.

The A380-800 is a rather chubby aircraft and would not like to lose some of the rudder surface that has to be sacrificed in order to give way to a straight duct (

[PlutonianEmpire]

Actually, GE-90 or its Rolls-Royce equivalent should be pretty comfortable to power a A380-sized trijet.

So would you like to fly a doubledecker trijet? And would you prefer to mount a GE90 in the tailcone with S-duct, like Tristar, ot above tail like DC-10 and MD-11?

Heck yeah!

I'd choose the S-duct style.

[chornedsnorkack]

More powerful engines doesnt necessary equal increased range. I bet that four GE90's will consume considerably more amount of fuel than the current engines available for the A380.

Also throw in the jet engines need for high RPMs to be effective, you soon realize that this can not be done. If you'd keep four GE90's at 90% in cruise, you'd exceed MMO

Er, why MMO?

If you add power to a plane then I do not think it increases range... see Virgin Atlantic GlobalFlyer, which is deliberately underpowered.

What adding power does do:

Your takeoff roll gets shorter (assuming the rotation speed is unchanged). But the braking distance in a rejected takeoff is not getting any shorter.

Initial climb gradient gets steeper - more excess power, easier to clear terrain ahead, less time to reach a given flight level.

Cruise altitudes increase - after all, a plane climbs until the engines derate to equal drag...

Landing roll is not getting any shorter. However, the gradients of go-around get better.

So... there was recently a 747 that landed in Rand Airport. 1500 m runway, and it is hot and high! Can A380 do the same?

[Nexus]

I was talking about the cruise phase.
Any jet engine likes to run at high rpms, or else the relationship between fuel burn and thrust produced will be worse.

SO...if you run all four GR90s on high RPMs the aircraft will likely exceed the barberpole, since the aircraft is greatly overpowered .

The cruise altitude will increase, but due to regulations the A380 might not be able to fly higher unless the environmental system is re-designed (On most jets it is not the structural strenght that limits the operating ceiling, but the pressurization system)

And I never did say the A380 would gain range, I was saying it will LOSE range with four GE90's  :)

[chornedsnorkack]

[quote]I was talking about the cruise phase.
Any jet engine likes to run at high rpms, or else the relationship between fuel burn and thrust produced will be worse.

SO...if you run all four GR90s on high RPMs the aircraft will likely exceed the barberpole, since the aircraft is greatly overpowered .

The cruise altitude will increase, but due to regulations the A380 might not be able to fly higher unless the environmental system is re-designed (On most jets it is not the structural strenght that limits the operating ceiling, but the pressurization system)

And I never did say the A380 would gain range, I was saying it will LOSE range with four GE90's