MoKa777 wrote:

Zeke, if you know all of this and did the math, why did you even ask the question you did in reply 34?

My understanding of the ULR was it was to share the -1000 wing, gear, and MTOW. It was subsequently suggested this is no longer the case.

zeke wrote:

MoKa777 wrote:

Zeke, if you know all of this and did the math, why did you even ask the question you did in reply 34?

My understanding of the ULR was it was to share the -1000 wing, gear, and MTOW. It was subsequently suggested this is no longer the case.

That's what I heard too...

zeke wrote:

MoKa777 wrote:

Zeke, if you know all of this and did the math, why did you even ask the question you did in reply 34?

My understanding of the ULR was it was to share the -1000 wing, gear, and MTOW. It was subsequently suggested this is no longer the case.

I honestly wish Airbus went through with that plan.

MoKa777 wrote:

zeke wrote:

My understanding of the ULR was it was to share the -1000 wing, gear, and MTOW.

I honestly wish Airbus went through with that plan.

muscle plane.
could it still work for a freighter?
essentially the 778X solution. ( or previously the A345 )

The nimble footed ULR imho shows more elegance.
( and perfectly leverages the tech advance Airbus made.
How much of those further 25t MTOW ( 280 to 305) would have been gobbled up
by additional structure? )

zeke wrote:

I ran some numbers on the Airbus performance database, off the current 16 it will takeoff with 255.5 tonnes dry and 245.0 wet. Off a dry runway 16 it will do PEK with 315 pax and 9.1 tonnes of payload, flight time of 12.43 (assumed 6000 air nautical miles).

I ran the landing distance calculations, the A350-900 will be able to land on 16 at MLW in 5418 ft.

So I dont put too much value into the report.

I wonder what dimensions you have assumed for the existing runway? RWY34 is the shortest as I understand with a TORA of 1921m and upslope of 0.29%, and both runways have an LDA of 1815m.

http://www.aip.net.nz/pdf/NZWN_AD2.pdf Table 2.13

Is that what you have based your numbers on?

Wet performance is probably the issue due to tail height affecting minimum control speeds.

What part of 16 did you not see in the quoted text mentioned three times ?

MoKa777 wrote:

Zeke, if you know all of this and did the math, why did you even ask the question you did in reply 34?

There is no question in reply 34. Just a statement.

zeke wrote:

What part of 16 did you not see in the quoted text mentioned three times ?

Doesnt actually matter - RWY16 is only 25m longer anyway with a 29% downslope so wouldnt expect a material difference over RWY34 apart from the possible impact of obstacles.

Remember airlines will be assessing on the worst performing runway so would be doing their calcs on RWY34 at WLG.

a7ala wrote:

Doesnt actually matter - RWY16 is only 25m longer anyway with a 29% downslope so wouldnt expect a material difference over RWY34 apart from the possible impact of obstacles.

If you "wouldn't expect a material difference over RWY34", what was the point of your previous post ?

zeke wrote:

a7ala wrote:

Doesnt actually matter - RWY16 is only 25m longer anyway with a 29% downslope so wouldnt expect a material difference over RWY34 apart from the possible impact of obstacles.

If you "wouldn't expect a material difference over RWY34", what was the point of your previous post ?

I was trying to reconcile the difference between your original results (which says the existing runway is fine) and the report for the extension you quoted (which says it isnt), and was asking what you assumed in your calcs for existing runway length etc. and whether your landing results are for dry or wet.

MoKa777 wrote:

I honestly wish Airbus went through with that plan.

Probably wiser that they didn't.

They now have something that can probably fly further than that would've (same fuel capacity, lighter weight), versus having to go head to head with the 778 in mission profile in a market that's not all that large to begin with.

Though no one other than SQ has shown much interest in the A359ULR, who knows... maybe and the 778 could eventually generate the a similar relationship that the A332/77E once had: route opener + route grower.

zeke wrote:

If you have a two 1 sq meter boards, hammer 200 nails on one, and 400 nails in the other, turn them upside down and stand on each one in turn. Both exert the same pressure on the 1 sq.m of ground below them when you stand on them, despite one having double the number of nails as the other.

At a gross level that is correct, but assuming that each nail head is the same surface area, the contact load/pressure for each nail in the 200 nails configuration twice the value of of the 400 nail configuration. So while the 400 nail configuration doesn't pierce the surface, the 200 nail configuration might.

FrmrKSEngr wrote:

At a gross level that is correct, but assuming that each nail head is the same surface area, the contact load/pressure for each nail in the 200 nails configuration twice the value of of the 400 nail configuration. So while the 400 nail configuration doesn't pierce the surface, the 200 nail configuration might.

As long as the nails stick in the board the pressure is the same.
You distribute the same nn kg over the 1sqm.

What potentially changes is the number of nails pressing in your soles.
But, channeling Laurence of Arabia: the trick is to not show that it hurts

WIederling wrote:

FrmrKSEngr wrote:

At a gross level that is correct, but assuming that each nail head is the same surface area, the contact load/pressure for each nail in the 200 nails configuration twice the value of of the 400 nail configuration. So while the 400 nail configuration doesn't pierce the surface, the 200 nail configuration might.

As long as the nails stick in the board the pressure is the same.
You distribute the same nn kg over the 1sqm.

What potentially changes is the number of nails pressing in your soles.
But, channeling Laurence of Arabia: the trick is to not show that it hurts

I guess it depends on which side of the board the nails are on. I was assuming the nails were contacting the tarmac (200 or 400 small points of contact) with the board on top. Assuming that the surface area of 400 nail heads is 40% of the board, and 100kg is placed on the board then the contact pressure at each nail head is 100kg/sqm X 1/40% = 250 kg/sqm. Going down to 200 nails of the same size, the contact area would be reduced by another 50%, for a total 20% contact area relative to the flat board, so the contact pressure would be 500 kg/sqm at each nail head.

FrmrKSEngr wrote:

WIederling wrote:

FrmrKSEngr wrote:

At a gross level that is correct, but assuming that each nail head is the same surface area, the contact load/pressure for each nail in the 200 nails configuration twice the value of of the 400 nail configuration. So while the 400 nail configuration doesn't pierce the surface, the 200 nail configuration might.

As long as the nails stick in the board the pressure is the same.
You distribute the same nn kg over the 1sqm.

What potentially changes is the number of nails pressing in your soles.
But, channeling Laurence of Arabia: the trick is to not show that it hurts

I guess it depends on which side of the board the nails are on. I was assuming the nails were contacting the tarmac (200 or 400 small points of contact) with the board on top. Assuming that the surface area of 400 nail heads is 40% of the board, and 100kg is placed on the board then the contact pressure at each nail head is 100kg/sqm X 1/40% = 250 kg/sqm. Going down to 200 nails of the same size, the contact area would be reduced by another 50%, for a total 20% contact area relative to the flat board, so the contact pressure would be 500 kg/sqm at each nail head.

this is the original experiment from Zeke:
"If you have two 1 sq meter boards,
hammer 200 nails on one, and 400 nails in the other,
turn them upside down and stand on each one in turn."

200 or 400 nails into one square meter of plywood or particle board.
Turn upside down.
Then stand on it.

If the nails are evenly distributed your feet/soles will stand on about
twice as many nails on the 400 mails/sqm as on the 200nails/sqm

Your weight will invariable be distributed over 1sqm ( assuming the boards are ideally stiff.)

I used the analogy to highlight the effect of the bearing strength of the surface to accept a given pressure. If you have nails or tyres on a hard surface the bearing strength is such that they will not sink into the surface, on a soft surface like sand they will just sink. When we look at tyres, be it on cars or aircraft on a hard surface, we look at the amount of pressure under the tyre is even regardless of the tread pattern. The tread pattern is like the nail analogy.

In pavement design it is the soil mechanics under the surface is the key for long term durability, not the surface, A firm surface with an uncompacted subgrade may last a few aircraft movements, however long term it will fail. A good pavement can have its surface layer stripped and replaced many times over, this is often what is done on runways every few years.

"If you have two 1 sq meter boards,
hammer 200 nails on one, and 400 nails in the other,
turn them upside down and stand on each one in turn."

So, I drive nails into the boards. The nails are on top, the boards is on the bottom (It would be tough to drive the nails up). The board is in contact with the ground, the nails are sticking up.

Turn the board upside down - now the board is on top, and the nails are on the bottom. 200 and 400 points of contact.

Now step on board and your weight is distributed to the nails in contact with the ground.

As Zeke pointed out in his latest post, if the ground is "soft", the nails will pierce the ground until board contacts the surface and distributes the load and stops you from sinking. The problem is what is soft? All probably agree sand is soft, Concrete is generally Hard, asphalt is in between, especially on a hot day.

Just bringing up an old thread.

With the 359 arriving more regularly for SQ. Is it possible for this bird to operate out of WLG for the short hop? The product upgrade would be welcomed by travellers and potentially help with yields as the lower Y class seating would be a better fit. Is there sufficient premium demand for 42j though... W would sell well ex CBR but could impact on J bookings.
Alternatively could we see the 772ers displaced from BNE be put on the capital express?

qantas747 wrote:

Just bringing up an old thread.

With the 359 arriving more regularly for SQ. Is it possible for this bird to operate out of WLG for the short hop?

easy, plus 15t Cargo or so.


best regards
Thomas

...meanwhile I'm still in the market for a definitive answer on whether an SQ359 could do WLN-SIN non-stop with full pax. Zeke's numbers in the earlier discussion seemed to indicate it would be easily do-able. But the Astral report said there were issues on for both take-off and landing. What's the answer? Is the runway extension project based on faulty technical analysis on the 359? Can anyone from SQ give us a view now they have experience of operating the 777 into WLN?

This question is back in the news. Wellington Airport has announced that Airbus is bringing a 359 to Wellington for landing and take-off performance. Here's the press release: https://www.wellingtonairport.co.nz/new ... n-airport/

Key paras:

"The testing will show the different combinations of loads and distance an A350 can reach off Wellington’s runway. This trial is about determining future performance for Wellington as more of these aircraft enter the fleet in the Asia-Pacific.”

“There is a worldwide trend among airlines to use direct, otherwise known as point-to-point, fuel efficient aircraft with seating capacity matched to demand. This enables efficient, sustainable routes to be opened up to cater for the ever growing demand in air travel, especially in the Asia-Pacific region which is one of the fastest growing in the World.”

There's been comment on the NZ thread that SQ are known to be thinking of switching their current trans-Tasman service from 77E to 359. But reading between the lines, the language in the airport statement sounds as if there's much more at stake than ability to do the short hop from Canberra/Melbourne. Zeke upthread argued that, according to the Airbus performance database, the 359 ought to be able to do Beijing from the current runway with full pax...

Yet the Astra report said the 359 couldn't operate into Wellington at all on a wet runway. Seems strange. We still lack any technical insights into why there might be a landing/take-off issue specific to the 359 in Wellington or other short runways (ie why would its short-field performance be so much worse than a 77E or 789 or A330)? Wing loading too low? Spoiler performance? Rudder authority issue? Braking system issues? Any clues?

http://www.youtube.com/watch?v=-glBWoazjEg

The a359 coming to a full stop in 10 seconds on a wet wellington runway...

tealnz wrote:

Yet the Astra report said the 359 couldn't operate into Wellington at all on a wet runway. Seems strange.

Because Boeing paid for it? I asked the author at the time about the how and why and got
a pretty impolite and forceful brush off.

ap305 wrote:

http://www.youtube.com/watch?v=-glBWoazjEg

The a359 coming to a full stop in 10 seconds on a wet wellington runway...

That's just show-offery masquerading as a technical trial...(which is the whole idea really when selling aircraft, no disrespect intended!)

I recall seeing the 77W doing similar at AKL although it looks much cooler in WLG.

ap305 wrote:

http://www.youtube.com/watch?v=-glBWoazjEg
The a359 coming to a full stop in 10 seconds on a wet wellington runway...

Impressive.
Does anyone in the business know how Airbus/Boeing would normally structure a short field trial of this sort? The Wellington airport release said they were hoping for light winds and some really wet conditions. Would they then try landings at different weights? (Will this be one of the airframes full of water tanks to allow operation at various weights?) Any chance the results will be publicised other than through ACAP amendments? Or do we just wait for SQ to announce launch of the non-stop?

The data has already been published, this is just validation of the certified performance data.

zeke wrote:

The data has already been published, this is just validation of the certified performance data.

... in which case the mystery around the Astra analysis deepens

tealnz wrote:

zeke wrote:

The data has already been published, this is just validation of the certified performance data.

... in which case the mystery around the Astra analysis deepens

see post #73

only in those "icky" cases have I experienced such answers.
In all other cases my requests got a reasonable answer, rarely they vanished in the bithole.( i.e. ignored )

No, A350 does not have a short runway problem.

This could be Zeke trying to make that first taxi exit

https://www.youtube.com/watch?v=rqSTVWw7twU

Not 10 seconds like the other video but no less impressive for that much mass and momemtum to be brought to a halt.

Video kind of reminds me of my landings at AUS on 17R trying to make the G taxiway.

william wrote:

No, A350 does not have a short runway problem.

We might get a definitive answer at the end of the week if the test crew file a flight plan for Wellington-Hong Kong non-stop.

That should not be a problem, HKG is putting on some not so nice weather at the moment.

tealnz wrote:

;)

william wrote:

No, A350 does not have a short runway problem.

We might get a definitive answer at the end of the week if the test crew file a flight plan for Wellington-Hong Kong non-stop.

Looking on FlightRadar it has now left WLG. Last flight was CHC-KUL. Probably heading back home now.

Hopefully we'll find out soon what the results were.

ZaphodHarkonnen wrote:

tealnz wrote:

;)

william wrote:

No, A350 does not have a short runway problem.

We might get a definitive answer at the end of the week if the test crew file a flight plan for Wellington-Hong Kong non-stop.

Looking on FlightRadar it has now left WLG. Last flight was CHC-KUL. Probably heading back home now.

Hopefully we'll find out soon what the results were.

So if WLG/HKG wasn't meant to be a problem, why did it route CHC/KUL ?

jupiter2 wrote:

So if WLG/HKG wasn't meant to be a problem, why did it route CHC/KUL ?

No idea, maybe they had something to show Air Asia and Malaysian. Hong Kong Airlines and Cathay are are already familiar with the A350 and how it can be used to operate to NZ.

zeke wrote:

77west wrote:

Surely the A359 already has the largest weight for a 4 - 4 gear arrangement? On the 280t it will be 35t per wheel!!.

Let's not get facts in the way of a good story

Thank you for the interesting chart.

It is interesting where the FB numbers vary a lot compared to the RB. Does FB stand for flexible base and RB stand for rigid base? It would make sense that a flexible pavement & base would have slightly more contact area and spread the load out more.

Tires, shock absorption, etc all come into play with such testing and represents the maximum wheel load occurring within the design envelope. These would be at a standard runway, runways and taxiways that are rougher or wavy would need to adjust their strength allowances.

zeke wrote:

jupiter2 wrote:

So if WLG/HKG wasn't meant to be a problem, why did it route CHC/KUL ?

No idea, maybe they had something to show Air Asia and Malaysian. Hong Kong Airlines and Cathay are are already familiar with the A350 and how it can be used to operate to NZ.

More of a question why it departed out of CHC instead of direct out of WLG, if WLG/HKG shouldn't have been a problem. Suppose Airbus had there reasons.

jupiter2 wrote:

More of a question why it departed out of CHC instead of direct out of WLG, if WLG/HKG shouldn't have been a problem. Suppose Airbus had there reasons.

No idea why it went to CHC, maybe RNP AR testing. The performance database already showed the A350 could operate in and out of WLG, we already know that. Not sure what a WLG HKG flight would prove.

zeke wrote:

jupiter2 wrote:

More of a question why it departed out of CHC instead of direct out of WLG, if WLG/HKG shouldn't have been a problem. Suppose Airbus had there reasons.

No idea why it went to CHC, maybe RNP AR testing. The performance database already showed the A350 could operate in and out of WLG, we already know that. Not sure what a WLG HKG flight would prove.

Well if the whole trip was showing that the aircraft was more than capable of handling WLG (which I can't see any reason to doubt and as you say, the database says it shoud be able to do it) you would assume that the publicity of it doing WLG/HKG non stop would've taken away any lingering doubts about it being capable of the route. Doubtful such a route would happen anyway, WLG/SIN would seem more likely and that's not going to happen in the foreseeable future.

Just seems odd to fly the aircraft 20000 kms to show it off at a specific airport and then not do something claimed it can do from said airport. Surely there are 6000 ft runways in Europe that could've been used to replicate WLG conditions and save a lot of expense in the process.

jupiter2 wrote:

zeke wrote:

jupiter2 wrote:

So if WLG/HKG wasn't meant to be a problem, why did it route CHC/KUL ?

No idea, maybe they had something to show Air Asia and Malaysian. Hong Kong Airlines and Cathay are are already familiar with the A350 and how it can be used to operate to NZ.

More of a question why it departed out of CHC instead of direct out of WLG, if WLG/HKG shouldn't have been a problem. Suppose Airbus had there reasons.

This was really a "Hmmmm" moment for us. The A350 is a great airplane, but maybe not as good as Airbus would hope us believe. I get that Wellington is a tricky airport and the conditions on the day may have prevented Airbus from doing what they had intended.

It spent sevel days there flying in and out, it was not just one landing and departure.

zeke wrote:

It spent sevel days there flying in and out, it was not just one landing and departure.

We get that and that is was suppose to do departures and landings at different weights to simulate operations. It still leaves the question though, that the obvious point of the whole exercise was to show it could operate medium to long distance flights out of WLG, but when it came to leave, it departed from a longer runway in CHC.

As I said before, it just seems to defeat the whole purpose of the demonstration, WLG/KUL should have been easy.

jupiter2 wrote:

zeke wrote:

It spent sevel days there flying in and out, it was not just one landing and departure.

We get that and that is was suppose to do departures and landings at different weights to simulate operations. It still leaves the question though, that the obvious point of the whole exercise was to show it could operate medium to long distance flights out of WLG, but when it came to leave, it departed from a longer runway in CHC.

As I said before, it just seems to defeat the whole purpose of the demonstration, WLG/KUL should have been easy.

I wouldn't read too much into that.

They probably gathered a mass of data and want to analyse it all before making changes to standard operating procedures. So I think it would make perfect sense for them to run under normal rules unless they're explicitly doing test flights.

ZaphodHarkonnen wrote:

I wouldn't read too much into that.

Would have to agree, what they were doing there was validating data. They were not flight testing to establish a new baseline.

When flight testing performance data they don’t takeoff at MTOW and do a 12 hr flight, they keep doing takeoffs and landings at different weights and CG positions.

I don’t know why they went to CHC, possibly they had a potential customer crew fly a short sector to get a feel of the operation. We were given a similar opportunity on a regional flights when the A350 visited.