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mintxwb
Posts: 49
Joined: Sat Jun 15, 2019 7:34 pm

Re: 787 vs A350 range

Sun Jun 16, 2019 5:01 pm

ITSTours wrote:
Your "source" only comes from someone else's not-a-clear memory.....
It is not a source.
Also the original SQ thread someone mentions 32t. Why do you conveniently ignore that?


I said "plus 25t is consistent with the DL data point", why do you conveniently ignore that?

In which thread and which post 32t was mentioned? Don't make stuff up.
 
ITSTours
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Re: 787 vs A350 range

Sun Jun 16, 2019 5:03 pm

mintxwb wrote:
ITSTours wrote:
?
Second, JFK-MNL is 15 to 16 hours, https://www.flightradar24.com/data/flights/pr127, please show me how "280t 359 lifts 36t payload for 17 hours" is a conservative statement.


When the headwind is not strong it is 15 hours 30 minutes. Probably arrived with a lot of fuel reserves.
When the headwind is strong it is 16 hours and 56 minutes, on air.

You got flightradar24 so please look at May 27 and 28 data.
 
ITSTours
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Re: 787 vs A350 range

Sun Jun 16, 2019 5:04 pm

mintxwb wrote:
ITSTours wrote:
Your "source" only comes from someone else's not-a-clear memory.....
It is not a source.
Also the original SQ thread someone mentions 32t. Why do you conveniently ignore that?


I said "plus 25t is consistent with the DL data point", why do you conveniently ignore that?

In which thread and which post 32t was mentioned? Don't make stuff up.


1. Because it is not a source? Consistency only gets provided by crosscheck from multiple sources.

2. Your. Own. Link.
 
mintxwb
Posts: 49
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Re: 787 vs A350 range

Sun Jun 16, 2019 5:24 pm

ITSTours wrote:

2. Your. Own. Link.


Ok, In that link someone made up that 32t number by counting arbitrary amount reserve fuel as payload without any justification.
 
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zeke
Posts: 13910
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Re: 787 vs A350 range

Sun Jun 16, 2019 5:34 pm

mintxwb wrote:

Ok, In that link someone made up that 32t number by counting arbitrary amount reserve fuel as payload without any justification.


Counting excess reserve fuel is justified, that comes back to the fuel policy point I mentioned earlier. SQ on their first SIN-JFK flight on the A350 planned to have over 10 tonnes on arrival, meaning they could have held BOS, when they could have held EWR and taken 5 tonnes more payload.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
h1fl1er
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Re: 787 vs A350 range

Sun Jun 16, 2019 7:54 pm

zeke wrote:
315 passengers, was the design payload at the 268 tonne W/V and promised to 7750 nm, Airbus exceeded that objective. (Please note Airbus increased their design payload subsequently from 315 pax to 325 pax, and increased the range it would carry).

It will take a full cabin, that is what the performance software shows.

You will see above the performance software is saying 8100 nm in still wind conditions will take 17:05, that means the flight xwb565 was referring to 17:02 was basically 8100 nm air miles, i.e. the flight was into headwinds. It is a representative example of the A350 flying the design payload, the design range.


i'm sorry but a claim that the 359 can do 8100nm with a full cabin and real world dow at 268t is simply not credible

not even vaguely so. not even in the realm of remotely credible.

if it were true, the ulr would never have been sold to anyone and would not be flown on any route and nobody would have bought anything larger than a 268t as it would cover any and all routes comfortably. you'd have 12 more tons to 280 which would push the 359/280 to what, zeke, 8800 nm? even airbus does not claim this

airbus design payload from your performance software is bogus. please stop doing this. you know better.

the ulr would not even have needed to have been built if we accepted your claims. and never would have been.

in addition, a 17hr flight does not cover 8100nm still air.

or else there are numerous flights right now listed at substantially lower ranges that you are contending are 8100nm flights including qf9, ua101, multiple sq flights, akl-dxb, and so forth.

did you forget to include takeoff and landing? zeke you are a pilot you know better than this

zeke wrote:
Counting excess reserve fuel is justified, that comes back to the fuel policy point I mentioned earlier. SQ on their first SIN-JFK flight on the A350 planned to have over 10 tonnes on arrival, meaning they could have held BOS, when they could have held EWR and taken 5 tonnes more payload.


I agree absolutely justified. problem is I already dealt with this when flip made the 9700 claim for ulr on the other thread. he actually said 9600 using the excess reserves plus the extra mtow headroom. and I noted correctly that he didn't account ofr weight penalty of increased fuel and that it should be mid 9300s. aka about one hour shy of spec. so he called me a troll lol.

it's sin ewr btw not kennedy
Last edited by h1fl1er on Sun Jun 16, 2019 8:11 pm, edited 1 time in total.
 
h1fl1er
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:05 pm

Eyad89 wrote:
1. SQ31 SFO-SIN, TOW 271t, payload 25t, 16 hours https://www.airliners.net/forum/viewtopic.php?t=1408737

nothing in that thread indicates a payload of 25t on that flight. Do we know for sure that it had zero cargo?

SQ generates 9% of its revenue from belly cargo.


know what else, nothing in that thread says SQ was carrying 253 passengers either!

in fact, when someone posted the LFs for these flights, SQ was averaging barely over 200 for a full quarter. someone inferred 25 based on full cabin which sq wasn't doing.

the 25t payload performance was consistent with that which seen on other sq flights inc ulr and the other flights.

in review the delta flight cited had cargo and psngr count both listed along with fuel, tow and the other stuff. you cannot shoehorn that inot the performance claims made by anet.

you can take that delta route and swap cargo for fuel..you had 25t to play with and it did like 5763nm going east. 25t gives 4.2 hr, or at 488kt 2085nm. at 275t. 7848 with 230ish ppl. bump it from 275.4 to 280 you don't get maybe a half hour of more range, around 8100 even 230ish ppl.

a real flight. but here we hear that at 268 this plane goes 8100 with 325. cmon guys please stop.
 
mintxwb
Posts: 49
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:15 pm

h1fl1er wrote:
i'm sorry but a claim that the 359 can do 8100nm with a full cabin and real world dow at 268t is simply not credible

not even vaguely so. not even in the realm of remotely credible.

if it were true, the ulr would never have been sold to anyone and would not be flown on any route and nobody would have bought anything larger than a 268t as it would cover any and all routes comfortably. you'd have 12 more tons to 280 which would push the 359/280 to what, zeke, 8800 nm? even airbus does not claim this

airbus design payload from your performance software is bogus. please stop doing this. you know better.

the ulr would not even have needed to have been built if we accepted your claims. and never would have been.

in addition, a 17hr flight does not cover 8100nm still air.

or else there are numerous flights right now listed at substantially lower ranges that you are contending are 8100nm flights including qf9, ua101, multiple sq flights, akl-dxb, and so forth.

did you forget to include takeoff and landing? zeke you are a pilot you know better than this


If as zeke said, the discrepancy between [email protected], 30t payload over 17 hours and [email protected], 25t payload over 16 hours can be explained by various factors like "ISA variations, tropopause variations, loading variations, directions, not get the ideal levels exactly as want them, calorific value of fuel varies, aircraft run into and collect insects, paint imperfections and scratches, dents, worn seals, company fuel policy etc etc", doesn't that show how inaccurate Airbus' range number is? I understand the advertised range numbers to the general public are not the same as the numbers provided to airlines, but still, they are misleading. Shouldn't the "brochure" range number reflect, even roughly, reality to some degree? If no airline whatsoever can achieve 8100 nmi in real world, why bother publish that. Shouldn't Airbus just adjust their number like what Boeing did, to somewhat more faithfully reflect actual cabin configs used by airlines? Saying A350-900 has 7500 nmi range won't hurt its sale. It is still a very capable aircraft!

If we adjust airbus range by 500-600 nmi, everything makes sense!

A350-900 (325 seats)
@268t ~6500 nmi
@280t ~7500 nmi

A350-1000 (366 seats)
@316t ~7800 nmi
@319t ~8000 nmi

Boeing 787-9 (290 seats)
@254t ~7600 nmi
@260t ~8000 nmi

Boeing 787-10 (330 seats)
@254t ~6400 nmi
@260t ~6800 nmi
Last edited by mintxwb on Sun Jun 16, 2019 8:33 pm, edited 2 times in total.
 
flipdewaf
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787 vs A350 range

Sun Jun 16, 2019 8:24 pm

h1fl1er wrote:
zeke wrote:
315 passengers, was the design payload at the 268 tonne W/V and promised to 7750 nm, Airbus exceeded that objective. (Please note Airbus increased their design payload subsequently from 315 pax to 325 pax, and increased the range it would carry).

It will take a full cabin, that is what the performance software shows.

You will see above the performance software is saying 8100 nm in still wind conditions will take 17:05, that means the flight xwb565 was referring to 17:02 was basically 8100 nm air miles, i.e. the flight was into headwinds. It is a representative example of the A350 flying the design payload, the design range.


i'm sorry but a claim that the 359 can do 8100nm with a full cabin and real world dow at 268t is simply not credible

not even vaguely so. not even in the realm of remotely credible.
dint say it twice, show why it isn’t credible.
h1fl1er wrote:
if it were true, the ulr would never have been sold to anyone and would not be flown on any route and nobody would have bought anything larger than a 268t as it would cover any and all routes comfortably. you'd have 12 more tons to 280 which would push the 359/280 to what, zeke, 8800 nm? even airbus does not claim this
the ULR is more about tank capacity, as it stands the sq flights would come up against volume limits on sq21.
h1fl1er wrote:

airbus design payload from your performance software is bogus. please stop doing this. you know better.
thats s bold claim, tell us how you know?
h1fl1er wrote:
the ulr would not even have needed to have been built if we accepted your claims. and never would have been.
as above, fuel volume limitations
h1fl1er wrote:

in addition, a 17hr flight does not cover 8100nm still air.
17 x 488kts (M0.85) is 8296nm.
h1fl1er wrote:

or else there are numerous flights right now listed at substantially lower ranges that you are contending are 8100nm flights including qf9, ua101, multiple sq flights, akl-dxb, and so forth.
yes, the frequently do go over 8000nm still air range.
h1fl1er wrote:

did you forget to include takeoff and landing? zeke you are a pilot you know better than this
[email protected] takes 16hrs 36mins thus giving 29 mins ‘give’ over the climb and descent being slower ( also likely the part at fl350).

Fred



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mintxwb
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:31 pm

flipdewaf wrote:
dint say it twice, show why it isn’t credible.


It doesn't agree with real flights.

flipdewaf wrote:
as above, fuel volume limitations


Agree with you on the fuel volume. But if 268t can do 8100 still air SQ doesn't need to certify their A359ULR as 280t MTOW.
 
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Stitch
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:32 pm

mintxwb wrote:
I understand the advertised range numbers to the general public are not the same as the numbers provided to airlines, but still, they are misleading.


Considering the general public are not buying these products, what does it matter to them if the numbers are "misleading"?


mintxwb wrote:
Shouldn't the "brochure" range number reflect, even roughly, reality to some degree?


Well there is no one "reality" as each airline and aviation oversight agency has their own particular "reality" as it applies to their operations / requirements.

We all should not forget that the ACAP stands for Airplane Characteristics for Airport Planning. It is designed to assist airports in planning their fields for operations by that type of airplane and the thing an airport cares about least is how far the damn thing will fly. I honestly don't know why Airbus and Boeing bother putting a Payload-Range chart in the ACAPs.


mintxwb wrote:
If no airline whatsoever can achieve 8100 nmi in real world, why bother publish that.


Except of course an airline can achieve 8100 nautical miles real world in an A350-900, just not at maximum structural payload (which is not what the "brochure range" given is even close to).


mintxwb wrote:
Shouldn't Airbus just adjust their number like what Boeing did, to somewhat more faithfully reflect actual cabin configs used by airlines?


When it comes to widebody airplane families, Airbus has reflected actual cabin configurations used by airlines far, far longer than Boeing has. In fact, Boeing's 747, 767 and 777 ACAPs still reflect their OEM cabin configuration based on what airlines were using in the late 1980s (with the caveat that Boeing has added a 777-300ER seating configuration with present-day values). And as much shade has been thrown at Boeing for that, it was meant to show the general size difference between frames across a standardized metric (it was just that the metric was two decades out of date).


mintxwb wrote:
Saying A350-900 has 7500 nmi range won't hurt its sale. It is still a very capable aircraft!


Saying the A350-900 has 75 nautical mile range would not hurt its sales since no airline goes off the "brochure range" when evaluating models and no OEM would ever use "brochure range" as part of their response to an RFP.
 
flipdewaf
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Joined: Thu Jul 20, 2006 6:28 am

787 vs A350 range

Sun Jun 16, 2019 8:33 pm

mintxwb wrote:
Boeing 787-9 (236seats)
@254t ~7600 nmi
@260t ~8000 nmi

Fixed it for you!



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mintxwb
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:36 pm

flipdewaf wrote:
mintxwb wrote:
Boeing 787-9 (236seats)
@254t ~7600 nmi
@260t ~8000 nmi

Fixed it for you!


You forgot to fix this:

A350-900 (253 seats)
@268t ~6500 nmi
@280t ~7500 nmi
 
mintxwb
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:42 pm

Stitch wrote:
Considering the general public are not buying these products, what does it matter to them if the numbers are "misleading"?


So what is exactly the problem of saying "Airbus' range is 1 hour or so too optimistic"? It's not like I am suing Airbus for not achieving the range.

Stitch wrote:
Well there is no one "reality" as each airline and aviation oversight agency has their own particular "reality" as it applies to their operations / requirements.

We all should not forget that the ACAP stands for Airplane Characteristics for Airport Planning. It is designed to assist airports in planning their fields for operations by that type of airplane and the thing an airport cares about least is how far the damn thing will fly. I honestly don't know why Airbus and Boeing bother putting a Payload-Range chart in the ACAPs.


The reality is some airlines operate A350 in real world, the range we see from real flights are not even close to 8100nmi.



Stitch wrote:
Except of course an airline can achieve 8100 nautical miles real world in an A350-900, just not at maximum structural payload (which is not what the "brochure range" given is even close to).


No body ever said at maximum structural payload or MZFW. We are talking about a full cabin, 320 or so passengers for A359. I have no doubt a ferry flight can do 10000 nmi, but why is that relevant?
 
h1fl1er
Posts: 121
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:43 pm

flipdewaf wrote:
h1fl1er wrote:
zeke wrote:
315 passengers, was the design payload at the 268 tonne W/V and promised to 7750 nm, Airbus exceeded that objective. (Please note Airbus increased their design payload subsequently from 315 pax to 325 pax, and increased the range it would carry).

It will take a full cabin, that is what the performance software shows.

You will see above the performance software is saying 8100 nm in still wind conditions will take 17:05, that means the flight xwb565 was referring to 17:02 was basically 8100 nm air miles, i.e. the flight was into headwinds. It is a representative example of the A350 flying the design payload, the design range.


i'm sorry but a claim that the 359 can do 8100nm with a full cabin and real world dow at 268t is simply not credible
not even vaguely so. not even in the realm of remotely credible.
dint say it twice, show why it isn’t credible.


I just did didn't I?

so if the 359/268 can go 8100...wow. that's 14t heavier than the 789 yet it can fly 32.5t 500nm further? magical performance

at 268 a range of 8100 means 8800 at 280t

even airbus doesn't claims this

onus on you to provide evidence

please point to real flight with this performance. actual load sheets, actual flight computer

bc the flights shown from delta and sing are showing performance nowhere near this and neither are any others, fred, inc your ULR flight that did ewr sin at 272t with half this number of passengers. I mean, my god why did sq buy the ulr if the 268 could literaly fly this route with around 260 ppl according to these numbers zeke is giving us? you take 6.5t of pax and swap it for fuel you have over 8600nm of range. at 268t. I find it exceedingly odd that the ulr needed 267t (minused out the extra 5 reserve) to do the route with 100 less people.

must be a lot of insects or something

cannot take anyone seriously arguing that the 268t 359 can go 8100 full. the 280 going that far full was a stretch but you guys have jumped the shark here
Last edited by h1fl1er on Sun Jun 16, 2019 8:50 pm, edited 1 time in total.
 
mintxwb
Posts: 49
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:47 pm

h1fl1er wrote:
I mean, my god why did sq buy the ulr if the 268 could literaly fly this route with around 260 ppl according to these numbers zeke is giving us? you take 6.5t of pax and swap it for fuel you have over 8500nm of range. at 268t. I find it exceedingly odd that the ulr needed 267t (the extra 5 reserve) to do the route with 100 less people.


If what fred and zeke said were true, "ULR" fuel volume is indeed needed, but "ULR" weight, 280t, is not needed.
 
h1fl1er
Posts: 121
Joined: Thu Jun 06, 2019 5:58 pm

Re: 787 vs A350 range

Sun Jun 16, 2019 8:47 pm

flipdewaf wrote:
mintxwb wrote:
Boeing 787-9 (236seats)
@254t ~7600 nmi
@260t ~8000 nmi

Fixed it for you!



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????

flip, the 236 seat 789 goes 7800+ on lhr leg for qants and it's takin off light apparently from what was posted on anet

according also to info these flights are relatively high lf

ua101 is longer actually and ual has 250 seats. dunno the lfs
 
User avatar
Stitch
Posts: 26346
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:50 pm

mintxwb wrote:
Agree with you (flipdewaf) on the fuel volume. But if 268t can do 8100 still air SQ doesn't need to certify their A359ULR as 280t MTOW.


Except SIN-LAX is not flown in "still air". And this means that the actual distance flown will be greater than the 7,621 nautical miles (nm) of the direct Great Circle route between both cities.

SQ also doesn't just operate SIN-LAX. They also operate SIN-EWR. And the direct Great Circle distance between them is 8285nm so the real distance will be even farther. So SQ needs a frame that can handle both SIN-LAX and SIN-EWR and they will want enough headroom in terms of operating weights to account for their specific airline regulations as related to diversion and hold fuel as well as seasonal variables in weather and the impact it has on the actual distance flown.

We know from an actual flight plan that at least one SIN-EWR flight had a Trip Fuel value of ~111,500kg, which is more than the ~108,000kg fuel capacity of an A350-900. So regardless of the MTOW, the flight could not physically load enough fuel for the trip if it had been operated by an A350-900. The only option (within the A350 family) was the A350-900ULR, even if the full 129,500kg of fuel capacity was not needed. And even though that flight went out at a TOW of 273,000kg, that doesn't mean that some flights might need even more fuel - and therefore more TOW to accommodate it.
 
h1fl1er
Posts: 121
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:55 pm

Stitch wrote:
mintxwb wrote:
Agree with you (flipdewaf) on the fuel volume. But if 268t can do 8100 still air SQ doesn't need to certify their A359ULR as 280t MTOW.


Except SIN-LAX is not flown in "still air". And this means that the actual distance flown will be greater than the 7,621 nautical miles (nm) of the direct Great Circle route between both cities.


dude, they claimed 268t 359 can do 8100nm with full cabin. way more than enough to do lax sin

SQ also doesn't just operate SIN-LAX. They also operate SIN-EWR. And the direct Great Circle distance between them is 8285nm so the real distance will be even farther. So SQ needs a frame that can handle both SIN-LAX and SIN-EWR and they will want enough headroom in terms of operating weights to account for their specific airline regulations as related to diversion and hold fuel as well as seasonal variables in weather and the impact it has on the actual distance flown.
.


268 has more than enough headroom in zeke spec. 8100 with 320 ppl. no need for ulr. url is same as acts but a very clever way
 
mintxwb
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Re: 787 vs A350 range

Sun Jun 16, 2019 8:57 pm

Stitch wrote:

Except SIN-LAX is not flown in "still air". And this means that the actual distance flown will be greater than the 7,621 nautical miles (nm) of the direct Great Circle route between both cities.

SQ also doesn't just operate SIN-LAX. They also operate SIN-EWR. And the direct Great Circle distance between them is 8285nm so the real distance will be even farther. So SQ needs a frame that can handle both SIN-LAX and SIN-EWR and they will want enough headroom in terms of operating weights to account for their specific airline regulations as related to diversion and hold fuel as well as seasonal variables in weather and the impact it has on the actual distance flown.

We know from an actual flight plan that at least one SIN-EWR flight had a Trip Fuel value of ~111,500kg, which is more than the ~108,000kg fuel capacity of an A350-900. So regardless of the MTOW, the flight could not physically load enough fuel for the trip if it had been operated by an A350-900. The only option (within the A350 family) was the A350-900ULR, even if the full 129,500kg of fuel capacity was not needed. And even though that flight went out at a TOW of 273,000kg, that doesn't mean that some flights might need even more fuel - and therefore more TOW to accommodate it.


I think most of what you said is true but you still didn't explain why 280t is needed for SIN-EWR if 268t can do 30t over 17 hours. For SQ ULR flights the payload is only 16t. I already granted you the fuel volume increase is needed. But swap 14t payload for fuel, that is 19 hours of flight time, more than enough for SIN-EWR or vice versa.
 
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Stitch
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Re: 787 vs A350 range

Sun Jun 16, 2019 9:08 pm

mintxwb wrote:
So what is exactly the problem of saying "Airbus' range is 1 hour or so too optimistic"? It's not like I am suing Airbus for not achieving the range.


In general, nothing.

But you're focus of it is disrupting what was a very informative and researched post about the respective real-world real-airline configuration ranges of the 787 and A350 with partisan argumentative bias that does nothing to contribute to that informative and researched narrative and instead risks the entire thread being closed down for "consistent low quality posting" (to use the formal moderation term) thereby depriving those us who were reading and/or participating in it for said informative and researched narrative and not "OEM fanboyism".


mintxwb wrote:
The reality is some airlines operate A350 in real world, the range we see from real flights are not even close to 8100nmi.


And that would be because none of those flights are carrying only passengers who each weigh 90-100kg and have exactly 20kg of baggage - which are just some of the assumptions used to generate that "8100nm" range figure.

The EPA says my 2017 Hyundai Sonata Limited 2.0T should get 31 miles per gallon on the highway, and yet when I drive 150+ miles on said highway, the on-board trip computer says I get closer to 33 miles per gallon. And the EPA says I should get 22 MPG in the city, when said trip computer shows closer to 19-20.

And yet I am not going on Hyundai Owners Forums arguing that Hyundai and the EPA are lying about their city and highway MPG numbers. I recognize that my real-world driving situation is different from the assumptions made to generate the EPA's numbers.


mintxwb wrote:
No body ever said at maximum structural payload or MZFW. We are talking about a full cabin, 320 or so passengers for A359. I have no doubt a ferry flight can do 10000 nmi, but why is that relevant?


It isn't.

And neither is it relevant as to whether an A359 with 320 or so passengers that each weigh 90kg and each loading 20kg of baggage in the hold can fly 8100nm.
Last edited by Stitch on Sun Jun 16, 2019 9:19 pm, edited 1 time in total.
 
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Stitch
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Re: 787 vs A350 range

Sun Jun 16, 2019 9:19 pm

mintxwb wrote:
I think most of what you said is true but you still didn't explain why 280t is needed for SIN-EWR if 268t can do 30t over 17 hours.


I provided an actual flight plan flown by SQ from Singapore to Newark which showed the block fuel loaded was more than the physical volume of an A350-900 - at any TOW - could hold. So the only way a 268,000kg A350-900 could have flown that trip that day was if it had fuel barrels in the cargo hold containing 3500kg of Jet-A with hoses and pumps connected to the fuel tanks. And considering the flight needed 273,000kg of TOW that day to lift that frame, well even if it had those extra fuel barrels, it still would have been 5,000kg short.



mintxwb wrote:
For SQ ULR flights the payload is only 16t. I already granted you the fuel volume increase is needed. But swap 14t payload for fuel, that is 19 hours of flight time, more than enough for SIN-EWR or vice versa.


If operated by an A350-900, SIN-EWR would not be fuel weight limited, but fuel volume limited. Using Airbus values, the 111,400kg of block fuel is equal to 142,000 liters. The fuel volume capacity of the A350-900 is 138,000 liters. So the A350-900 cannot physically carry that fuel load regardless of how much weight it has available to lift fuel. You can trade all the payload weight you want for fuel weight - it will still come up 3100kg short due to a lack of physical volume in the fuel tanks.

The A350-900ULR has a fuel volume of 156,000 liters, so it can carry that extra 4000 liters (and then some). Since SQ only needs to carry another 4000 liters (3100kg) of fuel, it can depart with a TOW of 273,000kg - 7,000kg below the maximum rating of 280,000kg.
 
flipdewaf
Posts: 2859
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Re: 787 vs A350 range

Sun Jun 16, 2019 9:20 pm

h1fl1er wrote:
flipdewaf wrote:
mintxwb wrote:
Boeing 787-9 (236seats)
@254t ~7600 nmi
@260t ~8000 nmi

Fixed it for you!



Sent from my iPhone using Tapatalk



????

flip, the 236 seat 789 goes 7800+ on lhr leg for qants and it's takin off light apparently from what was posted on anet

according also to info these flights are relatively high lf

ua101 is longer actually and ual has 250 seats. dunno the lfs

Qf9 also uses a cruise-climb profile over the Indian Ocean which is a nice fuel saving technique not generally available.

Fred


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mintxwb
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Re: 787 vs A350 range

Sun Jun 16, 2019 9:36 pm

Stitch wrote:
I provided an actual flight plan flown by SQ from Singapore to Newark which showed the block fuel loaded was more than the physical volume of an A350-900 - at any TOW - could hold. So the only way a 268,000kg A350-900 could have flown that trip that day was if it had fuel barrels in the cargo hold containing 3500kg of Jet-A with hoses and pumps connected to the fuel tanks. And considering the flight needed 273,000kg of TOW that day to lift that frame, well even if it had those extra fuel barrels, it still would have been 5,000kg short.


I am not sure why you are arguing with me while we are in agreement...I already said fuel volume mod is required for SQ to do EWR to/from SIN. My point is the very fact that the flight needed 273 TOW proves how far from reality zeke's claim is. He said a full cabin A350 @ 268t can do 8100 nmi still air. This is not something you called as "informative and researched". It should not be unchallenged.

Stitch wrote:
It isn't.

And neither is it relevant as to whether an A359 with 320 or so passengers that each weigh 90kg and each loading 20kg of baggage in the hold can fly 8100nm.


While isn't the title of this thread "787 vs A350 range"? To do a fair comparison we need the same assumption for both planes right? We can't discuss range when Airbus uses "320 or so passengers that each weigh 90kg and each loading 20kg of baggage in the hold " while Boeing uses assumptions closer to real airlines' operation.
 
Mrakula
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Re: 787 vs A350 range

Sun Jun 16, 2019 9:36 pm

h1fl1er wrote:
Stitch wrote:
mintxwb wrote:
Agree with you (flipdewaf) on the fuel volume. But if 268t can do 8100 still air SQ doesn't need to certify their A359ULR as 280t MTOW.


Except SIN-LAX is not flown in "still air". And this means that the actual distance flown will be greater than the 7,621 nautical miles (nm) of the direct Great Circle route between both cities.


dude, they claimed 268t 359 can do 8100nm with full cabin. way more than enough to do lax sin


You ignore real world enviroment. Distance flown are not geat circle distances! Look at flight times. That indicates what distance aircraft have to travel. Lax-sin coul be sometimes more then 18h flight! That is why UA drop the route because 787 in bad weather cannot load enought fuel to carry profitable payload. Even ewr-sin is not on edge of A359ULR performace most of the time but I found flight which was 18:55h but evarege flight time is 17:31h.

For example innaugural flight SQ21 EWR-SIN TOW 277.3T fuel 111.3T reserve fuel 8.5T total distance 9538 nm. 173 on board inc. crew. But ZFW 166T which is 9T more than PER-LHR innaugural flight.

https://airwaysmag.com/special-flights/ ... -airlines/

And another example:

https://mobile.twitter.com/FATIIIAviati ... 6842812137
 
flipdewaf
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Re: 787 vs A350 range

Sun Jun 16, 2019 9:38 pm

h1fl1er wrote:
Stitch wrote:
mintxwb wrote:
Agree with you (flipdewaf) on the fuel volume. But if 268t can do 8100 still air SQ doesn't need to certify their A359ULR as 280t MTOW.


Except SIN-LAX is not flown in "still air". And this means that the actual distance flown will be greater than the 7,621 nautical miles (nm) of the direct Great Circle route between both cities.


dude, they claimed 268t 359 can do 8100nm with full cabin. way more than enough to do lax sin
yes, under they OEM flight dispatch rules, which, as Zeke has pointed out many many many times but you appear not to want to read it understand are very different to how airlines actually operate but yet Boeing seem to operate to similar standards (go figure). As far as I know both airbus and Boeing use nil wind and 30 mins hold without added criterion for ETOPS or depressurisation diversions, there are places in the world where you can operate flights like this so it is not so stupid to do this for your marketing material. However, in the realms of big airlines doing the rules (which have to be agreed by the local certificating authority) then QF probably have some of the least conservative and they have 70mins fuel required with no alternate.

So yes, the A359 can do it with a full cabin but SQ don’t want to. Zeke has shown that it can. If someone who operates the actual aircraft you are questioning and posts everything from the performance software that they are alllwed to show due to NDA an you still don’t want to believe it then I’m afraid it’s all nonsense because what’s the point in flying ULH when the ice wall at the edge of the world gets in the way!


h1fl1er wrote:
SQ also doesn't just operate SIN-LAX. They also operate SIN-EWR. And the direct Great Circle distance between them is 8285nm so the real distance will be even farther. So SQ needs a frame that can handle both SIN-LAX and SIN-EWR and they will want enough headroom in terms of operating weights to account for their specific airline regulations as related to diversion and hold fuel as well as seasonal variables in weather and the impact it has on the actual distance flown.
.


268 has more than enough headroom in zeke spec. 8100 with 320 ppl. no need for ulr. url is same as acts but a very clever way


Right, ULR isn’t really that different. That’s why it’s good! Change the plumbing and front cargo hold and it’s right back to standard and no risk.

Fred


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Stitch
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Re: 787 vs A350 range

Sun Jun 16, 2019 9:48 pm

mintxwb wrote:
To do a fair comparison we need the same assumption for both planes right? We can't discuss range when Airbus uses "320 or so passengers that each weigh 90kg and each loading 20kg of baggage in the hold " while Boeing uses assumptions closer to real airlines' operation.


I believe Airbus uses ICAO figures for calculating passenger weights in their "brochure ranges" and that figure is 90kg per the latest values I could find with a quick web search.

I believe Boeing uses FAA figures for calculating passenger weights in their "brochure ranges" and that figure is 91kg per the latest values I could find with a quick web search.

So I would not consider a 1% difference "closer to real airlines' operation".

And considering I believe some airline staff on this thread have said their airline uses a value of 100kg for a passenger's weight (which likely includes their carry-on luggage), then one could argue that both Airbus and Boeing are under-representing their passenger weights by 10% in their "brochure range" calculations.


mintxwb wrote:
To do a fair comparison we need the same assumption for both planes right?


And flipdewaf has been doing that in his calculations throughout this thread by applying a common payload value to each frame. He's also using assumptions that much more closely mirror those used by airlines than either Airbus or Boeing do in their "brochure ranges".



And frankly, this thread was humming along nicely until this whole side-discussion about "brochure range accuracy" was brought in which has done nothing but pollute it. I've tried to stay out of it due to not wanting to add to said pollution, and I'm jumping out again because, IMO, all these posts (mine included) should be deleted by the moderators for "low quality / off-topic" to allow the original discussion I an others were enjoying to continue without this side-show.

:white: :wave:
 
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Re: 787 vs A350 range

Sun Jun 16, 2019 10:02 pm

Stitch wrote:
mintxwb wrote:
To do a fair comparison we need the same assumption for both planes right?


And flipdewaf has been doing that in his calculations throughout this thread by applying a common payload value to each frame. He's also using assumptions that much more closely mirror those used by airlines than either Airbus or Boeing do in their "brochure ranges".

Thanks, wrong thread though. My models were in the Qantas sunrise thread. This thread has much more, this has real data from real performance databases based on what real aircraft are actually doing in the reality of real life.

The best thing I find is to keep arguing till the world sees them for the reality Deniers they are.

Fred



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Stitch
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Re: 787 vs A350 range

Sun Jun 16, 2019 10:11 pm

flipdewaf wrote:
Thanks, wrong thread though. My models were in the Qantas sunrise thread. This thread has much more, this has real data from real performance databases based on what real aircraft are actually doing in the reality of real life.


My mistake.

Unfortunately, that thread is being polluted, as well.


flipdewaf wrote:
The best thing I find is to keep arguing till the world sees them for the reality Deniers they are.


Oh we all see that clearly - both in this thread and the Project Sunrise one.

My fear is that there will come a point when the moderators decide the pollution is too great and the threads need to be locked. I've enjoyed the reasoned discussions we were having in both before the...sideshows...appeared and would find it a shame for the community if that discussion was ended.
 
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Re: 787 vs A350 range

Sun Jun 16, 2019 10:43 pm

Stitch wrote:
I believe Airbus uses ICAO figures for calculating passenger weights in their "brochure ranges" and that figure is 90kg per the latest values I could find with a quick web search.

I believe Boeing uses FAA figures for calculating passenger weights in their "brochure ranges" and that figure is 91kg per the latest values I could find with a quick web search.


Airbus use the EASA pax and baggage weight of 95 kg, Boeing use 210 lb., 95.272 kg. 272 grams difference.

Stitch wrote:

Except SIN-LAX is not flown in "still air". And this means that the actual distance flown will be greater than the 7,621 nautical miles (nm) of the direct Great Circle route between both cities.



The example I provided was SFO-HKG is 6000 nm great circle, 6300 nm along ATC airways, and 7000 nm air nautical miles, what the aircraft flies along those ATC routes due to headwinds.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
ITSTours
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Re: 787 vs A350 range

Sun Jun 16, 2019 11:14 pm

I still find the merits of the discussion for the information Zeke, flipdewaf, Stitch and other people provide. Thank you all for your patience.
Sometimes I see some of you guys disagreeing with each other but that doesn't mean any of you are being unreasonable.
 
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Re: 787 vs A350 range

Sun Jun 16, 2019 11:35 pm

The problem is clearly not how much each passenger weight in the assumptions. The problem is actual DOW used by full-service airlines is about 6t higher than what Airbus assumes, as h1fl1er pointed out multiple times. This 6t is the reason why Airbus range is about 1 hour or so too optimistic. In ACAP P/R chart, add 6t to whatever payload, you get a pretty good idea of what is the actual range.
Last edited by mintxwb on Sun Jun 16, 2019 11:50 pm, edited 1 time in total.
 
h1fl1er
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Re: 787 vs A350 range

Sun Jun 16, 2019 11:43 pm

mintxwb wrote:
While isn't the title of this thread "787 vs A350 range"? To do a fair comparison we need the same assumption for both planes right? We can't discuss range when Airbus uses "320 or so passengers that each weigh 90kg and each loading 20kg of baggage in the hold " while Boeing uses assumptions closer to real airlines' operation.


we can as long as the airbus always has superior range, superior economics, superior performance, superior everything

even to the point of 8100 nm with 325psngr in a 268t plane, something that until today I didn't think anyone would ever try to claim. at 280 it was far fetched enough, but at 268??

if this plane had this performance, it and not the 789 would be flying per lhr right now. and sfo sin, lax sin, ewr sin, akl ord, akl jfk, iah syd, iah mel, jfk syd, jfk mel, and so many other routes that I cannot even name them all. there would be no other widebody sold.

bc the 280t version of it would have at least 8800nm range with 320 people. this is so incredibly high that it would literally be flying sunrise already. sq is seriously burning money flying a ulr at 267t and 160 pax - which for reasons that remain utterly inexplicable, needs 160 less passengers swapped for fuel in ULR form to go slightly more distance than the zeke-spec 359/268. i'm boggled as to why they didn't just grab a 268t and remove an hour worth of passengers to go from 8100 to 8600 and just do ewr-sin in that plane. they would have 100 more pax aboard. why is sq throwing money away like this? an ACT in the hold would have been so much cheaper. it's 100 people not on that flight. or even better, a 359/275 which would likely have enough range to do the route with 325.

and the K is even bigger and carries more fuel, meaning its range is probably 9500. with 366! you heard it here.

I only joined and posted on this topic because I saw people repeatedly using erroneous information in range discussions. for that I was set on by all sides, called a troll and a sockpuppet, and now a previous poster on this thread wants it shut down.
 
mintxwb
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Re: 787 vs A350 range

Sun Jun 16, 2019 11:55 pm

h1fl1er wrote:
we can as long as the airbus always has superior range, superior economics, superior performance, superior everything


right... the quality of posts is determined by how superior airbus is

h1fl1er wrote:
maybe he means with 325 little people. or 325 plastic army men. but not actual people flown by an actual airline


or maybe he means a plane with no catering, or no seats

h1fl1er wrote:
if this plane had this performance, it and not the 789 would be flying per lhr right now. and sfo sin, lax sin, ewr sin, akl ord, akl jfk, iah syd, iah mel, jfk syd, jfk mel, and so many other routes that I cannot even name them all. there would be no other widebody sold.


And now they will deflect the discussion to fleet commonality so on and so forth...
 
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Pellegrine
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Re: 787 vs A350 range

Mon Jun 17, 2019 12:05 am

mintxwb wrote:
You forgot to fix this:

A350-900 (253 seats)
@268t ~6500 nmi
@280t ~7500 nmi


These A359 numbers are too low by a lot. A 275t A359 should be able to fly 8,100nm at about 31 tonnes payload. 277t and 280t should fly further at that payload.
oh boy, here we go!!!
 
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Re: 787 vs A350 range

Mon Jun 17, 2019 12:06 am

Pellegrine wrote:
mintxwb wrote:
You forgot to fix this:

A350-900 (253 seats)
@268t ~6500 nmi
@280t ~7500 nmi


These A359 numbers are too low by a lot. A 275t A359 should be able to fly 8,100nm at about 31 tonnes payload. 277t and 280t should fly further at that payload.


That was sarcasm... These number are for 325 passengers. See the post I posted earlier.

Well in reality we see 275t fly 13 hours at 48 tonnes payload, or 271t fly 16.5 hours at 25t payload.
 
mintxwb
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Re: 787 vs A350 range

Mon Jun 17, 2019 1:19 am

zeke wrote:

Please read my posts above, I stated 315 pax to 8100 nm. The reason I did this was when the baseline aircraft was announced it was 315 passengers in 3 class configuration. Some time back Airbus revised this to be 325 pax in a 2 class configuration to 8100 nm. The 8100 nm figures were about before the 280 tonne MTOW. In their latest update they are now saying 325 passengers in a 3 class configuration.

To make it simple for you the OEW at 315 pax 3 class is lower than the 325 in two class, and that is lower than 325 in 3 class. So Airbus has been progressively increasing the OEW, and design payload (315 pax is 29925 kg, 325 pax is 30875 kg). That’s a 3% improvement in payload over the same range with an OEW increase gone from 315 three class, to 325 two class, to 325 three class.


If I remember correctly when the MTOW of A359 was 268t, the Airbus range was 7700 or something, definitely not 8100. Do you mean 3-class 315 pax @268t and 3-class 325 pax @280t both have range of 8100? 12 t TOW difference seems to be very high for 10 more people.
 
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Re: 787 vs A350 range

Mon Jun 17, 2019 2:04 am

h1fl1er wrote:

the 25t payload performance was consistent with that which seen on other sq flights inc ulr and the other flights.



Didn't you forget something?

You assumed that plane had no cargo (hence 25t payload), and you assumed this 25t payload is the limit for that range. Didn't you forget that this SQ flight had a TOW of only 271t? They could have added 5 more tons of payload before hitting MTOW, and thus bringing it to 30t of payload.

Another thing, that plane had a reserve fuel of 7.4t, which might be reduced further say to 5t. This allows it to carry 2.4t more paylaod, which brings it up to 32.4t of payload.

You assumed the plane had no cargo, let's break it down:

TOW: 271t
Fuel carried: 103.7t
pax: 25t

This leaves a DOW of 142.3t, which is pretty high based on what we have seen from at least 5 different A350 operators.


I stand by what I said, this plane must have carried some cargo, and the payload in that flight could have been at least 34-35t.

One more thing, this frame doesn't have the 2% fuel burn improvement. A newer SQ A359 could IMO easily hit that number, if not more.
Last edited by Eyad89 on Mon Jun 17, 2019 2:29 am, edited 1 time in total.
 
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Re: 787 vs A350 range

Mon Jun 17, 2019 2:24 am

I tried to add actual math to my last post for zeke but I was unable to edit so I will redo here and try to use proper spelling and punctuation

Fred's own numbers inaugural SQ EWR-SIN. 272t. 160 pax. esad estimated 8500nm. 5t excess reserves which I will deduct in the exercise despite the fact that ULH airlines are mostly using more than a 5t reserve which is relevant to ultimate range. we will assume they go with 5t only like the shorter haulers.

at 272t we can swap payload for range in a linear manner on the mtow-limited portion of the PR chart. swap 5t excess fuel for 50 pax. I will assume 100kg per for the sake of simplicity. We are now at 267t, 210pax, 8500nm esad.

Remove 400nm of range. Swap in a linear manner for more payload. 400/488 = .82 hours. at 5.85t/hr this is 4.8t (acaps suggests 4t). Call this 48 pax. We are now at 267t, 258 pax, 8100nm. This is our pax count for our ULR at 8100nm swapping the excess fuel and excess distance for pax.

We require 6.7t of pax to get to 325. We lose range in a linear manner. Using Airbus ACAPS from their website (search airbus acaps, click a350 link pdf, section 3.2.0), we see that for each 10t additional payload, the A359 loses 1000nm or so in range. So we lose 670nm range for the extra pax. This puts us at 273.7t and 7430nm and 325 pax.

We have now 6.3 additional tons of fuel to add to make 280t MTOW. This will not net us even an hour due to weight penalty. You can swap payload for range in a linear manner but you cannot add fuel for range in a linear manner. Carrying additional fuel adds a penalty. Maybe we assume this is penalty is 2t. So we have 4.3t additional fuel. At 5.85t/hr and 488kts this is 359nm. 325pax/280t/7789nm. By all means round it up to 7800nm. Or round it down to 7700.

You cannot get more "factsy" than this. This is linear y=mx+b algebra combined with actual flight data provided by Fred which is not in dispute.
Last edited by h1fl1er on Mon Jun 17, 2019 2:39 am, edited 1 time in total.
 
mintxwb
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Re: 787 vs A350 range

Mon Jun 17, 2019 2:30 am

Eyad89 wrote:
You assumed that plane had no cargo (hence 25t payload), and you assumed this 25t payload is the limit for that range. Didn't you forget that this SQ flight had a TOW of only 271t? They could have added 5 more tons of payload before hitting MTOW, and thus bringing it to 30t of payload.


Who said they can't have 30t payload when hitting MTOW? Again, 280t TOW, 30t cargo on 16.5 hour sector seems to be reasonable. That is about 1 hour less than 8100 nm still air brochure range. As h1fl1er said, the LF is not 100%, assuming 25t payload is already being optimistic. On average there are only 200 pax on board.

Eyad89 wrote:
Another thing, that plane had a reserve fuel of 7.4t, which might be reduced further say to 5t. This allows it to carry 2.4t more paylaod, which brings it up to 32.4t of payload.


Certainly, they could even reduce further to zero, right? They need that much of reserve fuel because that is their fuel policy, and they can't violate it.

Eyad89 wrote:
TOW: 271t
Fuel carried: 103.7t
pax: 25t

This leaves a DOW of 142.3t, which is pretty high based on what we have seen from at least 5 different A350 operators.



zeke has explained multiple times before, the DOW is not the same as OEW. OEW is about 136t, and DOW is higher than that. 142.3t DOW is very reasonable.
 
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Re: 787 vs A350 range

Mon Jun 17, 2019 2:37 am

h1fl1er wrote:
I tried to add actual math to my last post for zeke but I was unable to edit so I will redo here and try to use proper spelling and punctuation

Fred's own numbers inaugural SQ EWR-SIN. 272t. 160 pax. esad estimated 8500nm. 5t excess reserves which I will deduct in the exercise despite the fact that ULH airlines are mostly using more than a 5t reserve which is relevant to ultimate range. we will assume they go with 5t only like the shorter haulers.

at 272t we can swap payload for range in a linear manner on the mtow-limited portion of the PR chart. swap 5t excess fuel for 50 pax. I will assume 100kg per for the sake of simplicity. We are now at 267t, 210pax, 8500nm esad.

Remove 400nm of range. Swap in a linear manner for more payload. 400/488 = .82 hours. at 5.85t/hr this is 4.8t. Call this 48 pax. We are now at 267t, 258 pax, 8100nm.

We require 6.7t of pax to get to 325. We lose range in a linear manner. Using Airbus ACAPS from their website (search airbus acaps, click a350 link pdf, section 3.2.0), we see that for each 10t additional payload, the A359 loses 1000nm or so in range. So we lose 670nm range for the extra pax. This puts us at 273.7t and 7430nm and 325 pax.

We have now 6.3 additional tons of fuel to add to make 280t MTOW. This will not net us even an hour due to weight penalty. You can swap payload for range in a linear manner but you cannot add fuel for range in a linear manner. Carrying additional fuel adds a penalty. Maybe we assume this is penalty is 2t. So we have 4.3t additional fuel. At 5.85t/hr and 488kts this is 359nm. 325pax/280t/7789nm. By all means round it up to 7800nm. Or round it down to 7700.

You cannot get more "factsy" than this. This is linear y=mx+b algebra combined with actual flight data provided by Fred which is not in dispute.


Very informative, thanks!
 
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Re: 787 vs A350 range

Mon Jun 17, 2019 2:44 am

Stitch wrote:
And frankly, this thread was humming along nicely until this whole side-discussion about "brochure range accuracy" was brought in which has done nothing but pollute it. I've tried to stay out of it due to not wanting to add to said pollution, and I'm jumping out again because, IMO, all these posts (mine included) should be deleted by the moderators for "low quality / off-topic" to allow the original discussion I an others were enjoying to continue without this side-show.

:white: :wave:


Unfortunately that's what A.net is all about. Mostly Boeing fanboys (since Americans are the most populous on this site) drowning out any reasonable conversation about Airbus. This has been the modus operandi since I joined this site over a decade ago.
oh boy, here we go!!!
 
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zeke
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Re: 787 vs A350 range

Mon Jun 17, 2019 3:24 am

mintxwb wrote:
So zeke, you know the AIrbus range doesn't take into account DOW. You know with your real DOW @280t can't do full cabin, be it 325 pax or 315 pax, over 8100nm still air, let alone @268t. Please stop talking about ranges at Airbus marketing configuration. It is meaningless. No airlines operate Airbus marketing configuration; no airlines provide zero catering over long haul.


It does, take for example the A350-900 as they publish a payload of 54 tonnes when MZFW limited.

Image

Image

MZFW is 195700 for WV010 (the 280 MTOW version), minus 54 tonnes payload leave a DOW of 141.7 tonnes. Spec OEW 135132 kg, note the maximum payload is 60528 kg, and they show around 54 tonnes at MZFW in the range payload curve, the 6568 kg difference takes into account catering etc.

Image

Now show me where Boeing provides such data to the public to make the assertion that Airbus numbers are unrealistic.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
 
ITSTours
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Re: 787 vs A350 range

Mon Jun 17, 2019 3:56 am

Trolling aside, I think it is interesting to look at the PR127 JFK-MNL flight data, as it is currently the longest scheduled A359 non-ULR flight (besides occasional swaps on LAX-SIN route).

The great circle distance for this route is 7400 NM.

For one case on May 27:
https://www.flightradar24.com/data/flig ... 7#20a985e2
https://flightaware.com/live/flight/PAL ... /KJFK/RPLL ),

Although the route is close to GCD (7574 NM), the on-air flight duration was 16:56. Almost 17 hours.
This is obviously because the plane met a very strong headwind; the ground speed was 380kts at one point. (I don't have FR24 paid access to the true airspeed data)
As PAL has not required a technical fuel stop or declared fuel emergency since they started this route,
the evidence is sufficient to conclude that 278t MTOW A359 with 35.6-37.1t payload (2018 US BTS data) can fly up to 17 hours.

Sometimes PAL flies the other side of the ocean, on April 23th for example.
https://flightaware.com/live/flight/PAL ... /KJFK/RPLL
https://www.flightradar24.com/data/flig ... 7#2041888e

Although the actual route becomes longer at 7919 NM, the tailwind seemed strong (ground speed above 600kts)
and the flight time was only 15:49. Less than 16 hours.

When the route can be flown under 16 hours because of the wind, then PAL of course takes that route instead. It would definitely save fuels.
But sometimes the headwind is inevitable and they have to fly 17 hours. And Airbus A350-900 278t version can do this with 36-37t payload. Without a planned/emergency fuel stop.

Case closed...
 
mintxwb
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Re: 787 vs A350 range

Mon Jun 17, 2019 4:13 am

ITSTours wrote:
Trolling aside, I think it is interesting to look at the PR127 JFK-MNL flight data, as it is currently the longest scheduled A359 non-ULR flight (besides occasional swaps on LAX-SIN route).

The great circle distance for this route is 7400 NM.

For one case on May 27:
https://www.flightradar24.com/data/flig ... 7#20a985e2
https://flightaware.com/live/flight/PAL ... /KJFK/RPLL ),

Although the route is close to GCD (7574 NM), the on-air flight duration was 16:56. Almost 17 hours.
This is obviously because the plane met a very strong headwind; the ground speed was 380kts at one point. (I don't have FR24 paid access to the true airspeed data)
As PAL has not required a technical fuel stop or declared fuel emergency since they started this route,
the evidence is sufficient to conclude that 278t MTOW A359 with 35.6-37.1t payload (2018 US BTS data) can fly up to 17 hours.


Your reasoning is flawed. 17 hours is the maximum, normally it's about 15 hour. The payload you cite, 35.6-47.1t, is average. You can only conclude average payload with average flight time, not average payload with the max flight time. It is likely that when flight time is 17 hours due to the headwind, the payload on that day is significantly less.
 
ITSTours
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Re: 787 vs A350 range

Mon Jun 17, 2019 4:18 am

mintxwb wrote:
ITSTours wrote:
Trolling aside, I think it is interesting to look at the PR127 JFK-MNL flight data, as it is currently the longest scheduled A359 non-ULR flight (besides occasional swaps on LAX-SIN route).

The great circle distance for this route is 7400 NM.

For one case on May 27:
https://www.flightradar24.com/data/flig ... 7#20a985e2
https://flightaware.com/live/flight/PAL ... /KJFK/RPLL ),

Although the route is close to GCD (7574 NM), the on-air flight duration was 16:56. Almost 17 hours.
This is obviously because the plane met a very strong headwind; the ground speed was 380kts at one point. (I don't have FR24 paid access to the true airspeed data)
As PAL has not required a technical fuel stop or declared fuel emergency since they started this route,
the evidence is sufficient to conclude that 278t MTOW A359 with 35.6-37.1t payload (2018 US BTS data) can fly up to 17 hours.


Your reasoning is flawed. 17 hours is the maximum, normally it's about 15 hour. The payload you cite, 35.6-47.1t, is average. You can only conclude average payload with average flight time, not average payload with the max flight time. It is likely that when flight time is 17 hours due to the headwind, the payload on that day is significantly less.


December average load factor is 92%, and you cannot reduce people's weight. Thus the payload stays quite stable.
 
mintxwb
Posts: 49
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Re: 787 vs A350 range

Mon Jun 17, 2019 5:33 am

ITSTours wrote:

December average load factor is 92%, and you cannot reduce people's weight. Thus the payload stays quite stable.


Not sure if I understand correctly. I assume the 35.6-37.1t payload includes cargo? PR only has 295 seats. Again, on average payload is 35.6t, but what about the days when it takes 17 hours in the air? Is it possible that when headwind strong they have to cut cargo?

zeke wrote:
MZFW is 195700 for WV010 (the 280 MTOW version), minus 54 tonnes payload leave a DOW of 141.7 tonnes. Spec OEW 135132 kg, note the maximum payload is 60528 kg, and they show around 54 tonnes at MZFW in the range payload curve, the 6568 kg difference takes into account catering etc.


And the DOW you flew is not higher than 141.7 tonnes on long-haul missions? When you use your software to produce 325 seats, 268t, 8100nm, what is the DOW you use, the same as 141.7t?
 
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zeke
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Re: 787 vs A350 range

Mon Jun 17, 2019 6:17 am

mintxwb wrote:
And the DOW you flew is not higher than 141.7 tonnes on long-haul missions? When you use your software to produce 325 seats, 268t, 8100nm, what is the DOW you use, the same as 141.7t?


We would have over a dozen different DOW configurations on the A350 depending on the sector, the DOW is not directly presented to us in the cockpit, just the ZFW. For me to work out the DOW I would need to lookup the configuration for the flight and add that to the basic weight.

I have already corrected someone earlier on this to say it was 315 seats not 325. That was the 268 tonne 3 class configuration.

This is not my software, it is the certified software loaded on the aircraft. It is used for real world performance calculations from takeoff to landing.

I am not going to say the DOW, as previously stated the fuel burn is confidential information. If I told you the DOW you know the fuel fraction, ie TOW-DOW.

All I will confirm it does not need the full 268 tonnes to do it, there is an additional margin for fuel reserves.
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flipdewaf
Posts: 2859
Joined: Thu Jul 20, 2006 6:28 am

Re: 787 vs A350 range

Mon Jun 17, 2019 6:46 am

zeke wrote:
mintxwb wrote:
And the DOW you flew is not higher than 141.7 tonnes on long-haul missions? When you use your software to produce 325 seats, 268t, 8100nm, what is the DOW you use, the same as 141.7t?


We would have over a dozen different DOW configurations on the A350 depending on the sector, the DOW is not directly presented to us in the cockpit, just the ZFW. For me to work out the DOW I would need to lookup the configuration for the flight and add that to the basic weight.

I have already corrected someone earlier on this to say it was 315 seats not 325. That was the 268 tonne 3 class configuration.

This is not my software, it is the certified software loaded on the aircraft. It is used for real world performance calculations from takeoff to landing.

I am not going to say the DOW, as previously stated the fuel burn is confidential information. If I told you the DOW you know the fuel fraction, ie TOW-DOW.

All I will confirm it does not need the full 268 tonnes to do it, there is an additional margin for fuel reserves.

Is it possible to ‘fudge’ the numbers such that DOW + payload in the performance software = DOW (141.7t) + payload (29.925t) to get 171.625t if both? Am I skirting on the edges of what your company will sack you for?

Fred


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zeke
Posts: 13910
Joined: Thu Dec 14, 2006 1:42 pm

Re: 787 vs A350 range

Mon Jun 17, 2019 7:13 am

flipdewaf wrote:
Is it possible to ‘fudge’ the numbers such that DOW + payload in the performance software = DOW (141.7t) + payload (29.925t) to get 171.625t if both? Am I skirting on the edges of what your company will sack you for?


The input screen starts with the initial weight and distance and then calculates the trip fuel.
Human rights lawyers are "ambulance chasers of the very worst kind.'" - Sky News
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