VS announces plans for non stop Australia-UK service

[KeithMEL]

http://www.virgin-atlantic.com/en/au/b7879.jsp

Info provided is scant and is buried in another announcement about a new plane order (15x787-9s):

We're planning to pioneer non-stop services between Australia and the UK using the cuttind (sic) edge aircraft. Watch this space...

Interesting...

[MAN Flyer]

I believe it's PER-LHR they are looking at. I'll believe it when I see it...

[singaporu_kooku]

Does Boeing 787 can fly non stop from London to Sydney? According to wikipedia (I understand, the info in wiki may not be 100% correct), B787-9 can only fly up to 8500nm, which is around 2000miles short of LHR-SYD. Unless they have non standard configuration.

[MAN Flyer]

(I understand, the info in wiki may not be 100% correct)

I think that's an understatement...

[9V-JKL]

Think you've mixed nm & mi. LHR-SYD is 9,188nm or 10,573mi.
A payload restricted 789 could do LHR-SYD but not SYD-LHR.

[9V-JKL]

I believe it's PER-LHR they are looking at. I'll believe it when I see it...

It is PER-LHR they're considering, see routes on page3 of the factsheet:
http://www.virgin-atlantic.com/tridi...cm6-506204.pdf

[singaporu_kooku]

Think you've mixed nm & mi. LHR-SYD is 9,188nm or 10,573mi.
A payload restricted 789 could do LHR-SYD but not SYD-LHR.

Oops.. My bad.. Thanks for the correction.

[flyboy777]

Virgin said they planned many destinations with the new B789s, but Hawaii & Perth really grabbed the attention. Personally, I feel its just to grab media attention, whereas some of there other listed destionations are more reasonable such as Bangkok & Seattle. I think Virgin will boost other destinations before they do something like LHR-PER. Perhaps more in China & India?

[SQflyergirl]

What happened to 4 engines 4 longhaul and all that spiel?

[McCoy]

That slogan was quietly painted over on all the VS 346s several months ago.. in advance of their statements on improving aircraft efficiency/carbon footprint/nonsense, and their consequent order for 2 engine long-haul aircraft.

[DeltaFlyingProf]

That slogan was quietly painted over on all the VS 346s several months ago.. in advance of their statements on improving aircraft efficiency/carbon footprint/nonsense, and their consequent order for 2 engine long-haul aircraft.

You sound like my students who thought that 4 engines consume twice as much fuel as a 2 engine aircraft. The 2 vs 4 has nothing to do with fuel efficiency (though overall efficiency increases very slightly with the size of the engine, we're talking maybe 1% difference). It has to do with maintenance costs.

[McCoy]

Indeed. I never said 2 engines was more efficient.. in fact you'll see the word "nonsense" in my reply..

[flyboy777]

You sound like my students who thought that 4 engines consume twice as much fuel as a 2 engine aircraft. The 2 vs 4 has nothing to do with fuel efficiency (though overall efficiency increases very slightly with the size of the engine, we're talking maybe 1% difference). It has to do with maintenance costs.

So it has twice as much maintenence costs? A 2 engine aircraft has to be more fuel efficient than a 4 holer. Give a reason why not?

[DeltaFlyingProf]

So it has twice as much maintenence costs? A 2 engine aircraft has to be more fuel efficient than a 4 holer. Give a reason why not?

No it does not have twice as much maintenance cost. But it is higher, you have to examine 4 smaller engines (smaller, thus spare parts are cheaper, hence it is not twice as expensive) instead of 2 large ones. Reliability is slightly lover since now you have one of 4 engines that can have a glitch.

As for why a 2 engine aircraft is not more efficient than a 4 engine one, I have to go into a few technical details:

For a given weight and aircraft, the thrust to be provided is independent of the number of engine. It is actually the weight divided by the lift to drag ratio. The lift to drag ratio is a function almost exclusively of the shape of the aircraft, nothing else. In general, the larger the aircraft, the better it is because the Reynolds number increases.

Now for a given speed, both jet engines, turbo-fans, turbo props or any kind of engine consumption is proportional to the thrust it provides. So if you have 4 engines, each engine has to provide only 1/2 the thrust the engine of the 2 engine aircraft have to produce. So now you have 4 engines consuming each 1/2 of the fuel of the 2 engine aircraft and I will leave it to you as a homework to show that the total fuel consumption is the same.
I expect your copy by tomorrow noon on my desk and will have no mercy in my grading. You get either 100 or 0, no in between!

Where do difference come in in term of fuel burn? Larger engine of the same generation tend to be slightly more efficient (but we are talking at most a 1 or 2% difference in today's engines) and the smaller engine have an area exposed to the air which is more than 1/2 of the large engine. This adds some drag, but again, it is rather small compared to the total drag and may affect the lift to drag ration by at most 1 or 2 percents.

So difference in efficiency total? Maybe 2%. That can be outdone by differences in design. And in fact, because of the weight distribution, the structural weight of the wing of the 4 engine aircraft may be lower because of the stress relief due to having a better weight distribution along the wing... So at the end, maybe 1% difference.

Any more questions?

[simong]

I belive the kids would say pwned....