sunrisevalley
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77W And A350XWB-1000

Mon Mar 15, 2010 5:39 pm

I have been going back through the archives trying to find precisely what has been said on comparative payload and range
between the two types. From the Aug.2009 ACAP pages it appears the 77W has a MZFW of ~237.7t at about 5700nm. Assuming an in service weight of 173t the max payload at that range is ~65t. All I can find on the AirBus offering is a max payload of 68.5t at a generic OEW of 145t. No range quoted that I can see. It is not unreasonable to assume that the in service weight would be in the range of 150 to 152t reducing the pay load to ~62t.
Assuming both operate at a similar range at max payload then on the face of it the 77W carries more. But does it?
Assuming 350 passengers for both and the 13-LD3 positions needed for the bags; both offerings are left with 10 pallet positions ( 11.6 m^3) plus bulk ( 17m^3) for a gross of 133m^3. Based on the industry norm for belly cargo of ~150kg/m^3 plus tare max cargo load is ~20t. Add 350-passengers payload and payload is in the 49t range +- for both offerings. Cearly volume limited and substancially less than max payload.
Based on the hypothesis above the ZFW of the 77W is ~222t and the A350XWB-1000 ~ 202t. The 77W has a useable fuel load of 145.5t and the AirBus 120.5t. Expressed as a percentage of ZFW , 77W is 65.5% and the AirBus 70%.
Thus is it reasonable to argue that the -1000 has the potential ability to fly further with the same payload because it has a better useable fuel spread. Of course this is all based on what is known at this point in time on both types. Does some one have better data that would help refine the hypothesis.
 
bvms
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RE: 77W And A350XWB-1000

Mon Jun 27, 2011 9:41 pm

Quoting sunrisevalley (Thread starter):
Thus is it reasonable to argue that the -1000 has the potential ability to fly further with the same payload because it has a better useable fuel spread. Of course this is all based on what is known at this point in time on both types. Does some one have better data that would help refine the hypothesis.

it's looking like Boeing *IS* going to upgrade it-by how much? obviously not enough to eat into it's b747-8I stats.

http://www.flightglobal.com/articles...ls-777-9x.html

http://www.flightglobal.com/articles...-wingspan.html


""What we'll do on the 777 is continue to improve the airplane we have," said Albaugh. "But we also have some major upgrades we could do in the event that we have to respond to a move by the competition."

Boeing vice-president of sales Marlin Dailey said longer-term improvements to the 777, including examining the "up-gauging" or stretching of the fuselage, through the conceptual 777-9X and 777-8X, would be available early in the next decade."

Money is money and 'the big three' gulf airlines translate into BIG money orders for both Airbus and Boeing so they both DO listen quite carefully to their needs, and Boeing stated it wants to keep it's reputation 'as the leading OEM' on the Boeing 777-300er so hence the upgrade, now look to Airbus to also later on announce 'another significant upgrade' to the a350xwb-1000 as a result, and so on and so forth-tit for tat, and the airline companies will (natch) continue to gripe and whine and pit one OEM against the other OEM, and natch, their customers all win better flying comforts at the expense of the airlines (who laugh all the way to the bank!)

http://en.wikipedia.org/wiki/Competi...bus_and_Boeing

Tim Clark did say there was room in Emirates fleet for both types so you can also bet that come Nov 13, 2011 in time for the Dubai Air show-He'll likely order BOTH OEM's planes, and considering the long waiting time for delivery, many airlines DO order both OEM's planes- not only Emirates, it's a well proven strategy that brings profits to the airlines!

Precisely the talk that is starting the pressure on Airbus to up the a350xwb-1000 a step higher then Boeing has announced with it's 7779x etc. 'Touche' to Qatar airways talk, I hope Airbus listens and makes amends of it's a350XWB-1000 even more then it's already done, for it to beat Boeing on the 777-300er (NG) it'll have to work a lot harder then it is.

"Al Baker warned that if Boeing can harvest a 5% fuel burn improvement as part of its 777-300ER improvement effort, "that alone will defeat the -1000 programme".

One leasing company source told Flightglobal: "Boeing will be very happy if Airbus builds the A350-1000 that it is talking about now."

http://www.flightglobal.com/articles...r-upgrade.html

(obviously), this is exactly what I was mentioning about. it's nice to hear Qatar airways and others gripe more- now look to Airbus to announce another "significant upgrade-to the a350xwb-1000" again. 'duh, if that happens (which it likely will) will that be a coincidence or what?'
 
LAXDESI
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RE: 77W And A350XWB-1000

Tue Jun 28, 2011 2:39 am

Going by historical ratios, I expect A350-10 to have a max. payload range of 6,000nm(72% of design range of 8,400 nm).

My model suggests that A350-10 is MTOW limited, and not fuel volume limited at design range. At design range, I expect it to have an unused fuel capacity of nearly 3,000 gallons(fuel capacity is 41,211 gallons). So any future increase in MTOW, or a reduction in OEW, will enable A350-10 to increase design range.

It seems to me that the extra fuel capacity at 350-10 MTOW leaves room for a stretch(A350-11) to have a design range of about 8,000 nm if accompanied by a sufficient bump in MTOW.

Here's what I have come up with based on public data and estimating:

...............................A3510.......................B773ER
MTOW.....................679,000....................775,000 lbs.
MZFW......................485,000...................524,000
OEW........................343,900...................370,000 (OEW for A3510 is my estimate)
MSP.........................141,100...................154,000
Design Range................8,400.....................7,930 nm (passenger only, and zero cargo)
Design Range................6,000.....................5,700 nm (range at max. payload)
Engine Thrust..............97,000...................115,500 lbf
Fuel Capacity..............41,211.....................47,890 gallons

Ratois
OEW/MTOW.....................0.50...........................0.48
OEW/MZFW......................0.71...........................0.71
MZFW/MTOW....................0.71...........................0.67(consistent with lower fuel burn of a newer aircraft)
MTOW/Wingarea............143............................168 (777 has much higher wingloading)
MTOW/Thrust....................3.50...........................3.35 (777 has more powerful engines normalised for MTOW)
 
ferpe
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RE: 77W And A350XWB-1000

Tue Jun 28, 2011 5:23 am

The major difference between the 77W and the 350-1000 is the fuel burn, from Zeke we have the following figures:

- 77W 8100 kg/hr

- 350-1000 "fuel burn of a 333" = 6000 kg/hr

i.e. the 3510 consumes 74% of the 77W. Now pan that out over 15 hours and you have north of 30t fuel burn difference. This is not only cost but a shedload of weight disadvantage.

Look at it another way a 77NG with engines as good as the RR XWB would only need a MTOW of 320t instead of 351t to fly the same payload/range (of course if would need a bit more thrust then 97klbf to move 320t instead of 308t but not a lot).

As said many times here on A.net it is all about the engine fuel burn and less about those advanced aeros or structures.
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parapente
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RE: 77W And A350XWB-1000

Tue Jun 28, 2011 4:52 pm

I believe one other differentiator may be size. The 773er has become the de facto replacement aircraft for the 744 (ok the 380 replaces the 744 as well). It is just so phenominaly fuel efficient compared to the latter.

However what we have seen is..

A smaller aircraft - super range, super fuel burn - but a little bit less capable ie the first iteration of the 351 has been given a rather big rasberry.

A (much) bigger aircraft than the 773er - The 748 is a fair chunk bigger and competes primarily with the 380.Here again (lets be fair now) it has got a fairly big rasberry too.

Now the 351Mk2 has been turned into a Chinese copy in Pax/payload terms of the 733er (but huge fuel savings).

Yet

Al B was not that happy was he? Why?

You see as stated in the articles above and many threads the 773 can grow.Both in width (X10 across) or (re article) take a little stretch.

So if the "new" optimum size is something a little bigger than the 773er then Airbus better watch out. Perhaps that is why there has been so much speculation on the mythical 350-1100.

It is easy to see why Boeing would not want to go this way as it would finish off the 748i. But perhas it is nearly "done" in sales terms already. .If not it would not only be very expensive to build/develop it would kill off one of their own new aircraft.
So perhaps optimum size is key here?
 
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Stitch
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RE: 77W And A350XWB-1000

Tue Jun 28, 2011 6:04 pm

Quoting sunrisevalley (Thread starter):
Thus is it reasonable to argue that the -1000 has the potential ability to fly further with the same payload because it has a better useable fuel spread.

The A350-1000 has the legs on the 777-300ER thanks to both lower OEW and better fuel burn.

However, it appears to be falling short on maximum structural payload and that could be a sticking point with QR.

The latest Boeing ACAP shows a 70t maximum structural payload and a range of 5750nm at MZFW. I've never seen an A350-1000 maximum structural payload number, but if the 69t number is correct, then I don't quite understand why EK notes the 77W can lift 6 tons more payload and QR is complaining the A35J is not as good as the 77W in terms of lift.
 
LAXDESI
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RE: 77W And A350XWB-1000

Tue Jun 28, 2011 6:25 pm

Quoting Stitch (Reply 5):
I've never seen an A350-1000 maximum structural payload number, but if the 69t number is correct, then I don't quite understand why EK notes the 77W can lift 6 tons more payload and QR is complaining the A35J is not as good as the 77W in terms of lift.

Based on some informed discussion at another blog on A350-10 OEW weight at EIS, my estimate for MSP is consistent with 6t difference that EK notes. It was suggested in the blog that A350-10 will be about 11,000 lbs. heavier at EIS. It is not clear how much of this extra weight can be reduced over time.

Quoting LAXDESI (Reply 2):
...............................A3510.......................B773ER
MSP.........................141,100...................154,000
 
ferpe
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RE: 77W And A350XWB-1000

Tue Jun 28, 2011 7:25 pm

A has stated that the MEW increases with 2,4t for a MTOW increase of 10 t. As there is no diff in passanger capacity the furnishings does not change i.e. MEW increase = OEW increase.

Oldareoguy (ex Boeing) has stated that for an increase in MTOW solely with fuel you increase the MEW with 10% of MTOW increase, here we have 24%, this points to an increase in MZFW. How much is difficult to say, as a rule of thumb a payload increase causes a 4 times higher MTOW increase, i.e. in this case we would increase MSP with 2.5t.

Fact is, we have a MTOW increase with 10t, thereof you loose 2.4t to structure, leaves 7.6t. 400nm is 0,85 hours flight time at 6t fuel burn per hour, gives approx 5.1t more fuel for the extra distance. Then you have a 10t heavier A/C to fly those 7900nm until this extended range comes into play, seems this consumes the 2.5t left for the maxPaxnoCargo case.

I would venture a gues that MSP has increases 2.5t and that MZFW 2.4+2.5= approx 5t.

[Edited 2011-06-28 12:35:03]
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astuteman
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RE: 77W And A350XWB-1000

Tue Jun 28, 2011 8:46 pm

Quoting LAXDESI (Reply 2):
Going by historical ratios, I expect A350-10 to have a max. payload range of 6,000nm(72% of design range of 8,400 nm).

I doubt that, even in 308t guise...
Because of its lower fuel burn, it will gain less payload as range falls.
I make the 308 tonner to have a similar payload to the 773ER at 5 700Nm, and gain as range rises...
The "old" 298 tonner fell short by about 6 tonnes at 5 700Nm in my calcs...

Quoting LAXDESI (Reply 2):
My model suggests that A350-10 is MTOW limited, and not fuel volume limited at design range

I've modelled that, too. The trouble is we don't know......

Quoting Stitch (Reply 5):
The latest Boeing ACAP shows a 70t maximum structural payload and a range of 5750nm at MZFW. I've never seen an A350-1000 maximum structural payload number, but if the 69t number is correct, then I don't quite understand why EK notes the 77W can lift 6 tons more payload

See above.
MSP can be the same, and payload at 8 000Nm can be the same.
But if the A350-1000's range/payload chart has a shallower gradient between 8 000Nm and MSP range, between those two points it will have a payload disadvantage, reachinga maximum at the 773ER's MSP range (5 700Nm)

Rgds
 
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zeke
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RE: 77W And A350XWB-1000

Tue Jun 28, 2011 10:45 pm

Quoting LAXDESI (Reply 6):
Based on some informed discussion at another blog

The Aspire Aviation blog is not "informed discussion", he has published so many things that have turned out to be wrong over and over again.

For example in the last few months he has stated that CX has ordered an additional 14 x 77W, and then a matter of weeks later stated that CX has ordered 14 77F and 748Fs, both turned out to be false.

In both cases he stated information was obtained from his sources, his sources are useless as they are never correct, if they even exist. Even a broken watch is correct twice a day.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
LAXDESI
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RE: 77W And A350XWB-1000

Tue Jun 28, 2011 10:51 pm

Quoting astuteman (Reply 8):
Because of its lower fuel burn, it will gain less payload as range falls.

Here's some numbers that perhaps capture your point:
..................................Design Range............MSP Range..........MSP/Design...........MSP
B744ER..........................7,670 nm.................6,200 nm...............0.80..................148,000 lbs
B773ER..........................7,930 nm.................5,700 nm.............. 0.72..................154,000 lbs

Quoting astuteman (Reply 8):
I make the 308 tonner to have a similar payload to the 773ER at 5 700Nm, and gain as range
rises...

Going by the latest design range of 8,400 nm and assuming MSP range of 5,700 nm, here's how A350-10 stacks up:
A350-10..........................8,400 nm.................5,700 nm................0.68.......................(?) lbs

For reference, (MSP/Design) range ratio for A332HGW and B788 are 0.71 and 0.66 respectively. I may need to revise my model to account for a lower MSP range for A350-10 than what I have assumed (6,000 nm) for the latest A350-10 revision.
 
ferpe
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RE: 77W And A350XWB-1000

Wed Jun 29, 2011 10:51 am

Based on the method I described here:

Efficiency Of Modern Cfrp Airliners (by ferpe May 22 2011 in Tech Ops)

I have let my excel sheet do a range-payload diagram of the 3510 vs 77W, enjoy:



The lines are the maxPaxnoCargo ranges. As said before, this is based on a simple excel calc using the basic data that the framers supply (AP guide for 77W), it can be wrong several % for the 350. What one can not see is that to do this work the 77W needs 25% more fuel, however it does this today, tomorrow and yesterday Big grin .

[Edited 2011-06-29 03:54:51]
Non French in France
 
flyAUA
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RE: 77W And A350XWB-1000

Wed Jun 29, 2011 12:26 pm

Quoting parapente (Reply 4):
You see as stated in the articles above and many threads the 773 can grow.

Can the B777 really grow any more than it has already grown so far? I mean, stretching the 772 into a 773ER was already a lot of work. I don't see it getting much bigger. It's not like it's just a matter of whacking on a few frames in front of and a few frames behind the wingbox and voila. A lot of other factors and physical constraints must be taken into account.
Not drinking, also isn't a solution!
 
astuteman
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RE: 77W And A350XWB-1000

Wed Jun 29, 2011 7:31 pm

Quoting ferpe (Reply 11):
I have let my excel sheet do a range-payload diagram of the 3510 vs 77W, enjoy:


Looks remarkably similar to the one I fabricated for the new 308 tonne A350-1000.   

And perhaps shows how the earlier 298 tonne version would come up short in payload (by 5t - 6t) at most ranges between 5 500Nm and 7 500Nm despite having nominally the same pax only range and max structural payload

Rgds
 
ferpe
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RE: 77W And A350XWB-1000

Wed Jun 29, 2011 8:00 pm

Quoting astuteman (Reply 13):
Looks remarkably similar to the one I fabricated for the new 308 tonne A350-1000.


We probably used about the same simple method, I counted back and forward from the given design range with my calculated fuel burns including compensation for 5% range contingency fuel.

As long as one uses a reasonable fuel burn estimate for the section that one subtracts or adds and only works with max MTOW cases the climb profile, varying drag due to lift etc is all included in the OEMs design range calculation.

And as always a diagram says a lot more then words  
Non French in France
 
aspireaviation
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RE: 77W And A350XWB-1000

Thu Jun 30, 2011 5:13 am

Quoting LAXDESI (Reply 10):

Zeke,

Aspire Aviation publishes every post with care and its best understanding at press time.

If you're a Cathay employee, or a CX pilot, you would know that Cathay is going to place an order for 15 747-8F & 777F late July, as included in the internal magazine CX World June issue.

My CX source, which is a CX management, said the CX order for 15 747-8F & 777F would further be delayed to August, potentially coinciding CX's interim results announcement.

This Jul/Aug order would be informative and will be coming soon, how could you say Aspire Aviation as uninformed?
 
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zeke
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RE: 77W And A350XWB-1000

Thu Jun 30, 2011 8:42 am

Quoting aspireaviation (Reply 15):
as included in the internal magazine CX World June issue.

That is not correct, yet another misleading statement. What was said ....

"The Boeing 747-8Fs begin arriving later in the year and CX has already begun to evaluate its freighter requirements for the 2013 to 2018 period.

“We need additional aircraft both for growth and to replace the BCFs leaving the fleet,” says Director Cargo Nick Rhodes. “At this stage all types of freighter aircraft are under study including more 747-8s, the 777F and the A330F.”"

This is not a big secret as “CX World” it is not a confidential publication, and the same has been repeated in the press openly, e.g. the front page of the business section of the SCMP on June 15, 2011, "Cathay targets freighter to meet cargo demand". Not one source has said CX has decided on the best mix, aircraft types, or ordered the aircraft.

Quoting aspireaviation (Reply 15):
how could you say Aspire Aviation as uninformed?

In the past few months Aspire Aviation have said that CX had placed an order for an additional 14 77Ws, and then subsequently 15 freighters were on order. Both claims were false at the time of publication.

As Aspire Aviation never officially obtained from CX confirmation of the claims (and no official confirmation would be forthcoming until the HKEX has been notified), the statement "Aspire Aviation publishes every post with care and its best understanding at press time" is also false.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
aspireaviation
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RE: 77W And A350XWB-1000

Thu Jun 30, 2011 8:59 am

Quoting zeke,reply=16In the past few months Aspire Aviation have said that CX had placed an order for an additional 14 77Ws, and then subsequently 15 freighters were on order. Both claims were false at the time of publication.:

What was also included in the CX World:

"Nick says the study and relevant negotiations with airframe and engine suppliers should be completed by the end of this summer."

My source doesn't just come from Cathay Pacific alone, my Boeing source also confirms that Cathay will order 15 747-8F & 777F one week before the Paris Air Show.

Aspire Aviation said Cathay "may" order the aircraft and we did NOT say Cathay "ordered" 15 747-8F & 777F or 14 777-300ER whatsoever. Your claim is false as well.

Had an official confirmation be needed for every article, then what use is media of?

I have long said before the Paris Air Show that Hong Kong Airlines' A380 deal was being rekindled and this was confirmed.

Focusing on the wrong predictions but neglecting the correct ones is "taken out of context".

I have also noticed your past post, told by my friend, that you said Cathay selected the A350-900 over the 787-9 because the 787-9 could not accommodate CX's economy class seat in a 3-3-3 seat configuration.

This was false and misleading as well. My CX source said the A350-900's larger size suits CX more and Airbus made a compelling offer. Then how could you explain your inaccuracies as well?

Can't you just stop this vicious attack & respect what the media do?
 
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zeke
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RE: 77W And A350XWB-1000

Fri Jul 01, 2011 12:14 am

Quoting aspireaviation (Reply 17):

What was also included in the CX World:

That still does not say

Quoting aspireaviation (Reply 15):
Cathay is going to place an order for 15 747-8F & 777F late July, as included in the internal magazine CX World June issue.

Again, “is going” is not the same as “may”.

Quoting aspireaviation (Reply 17):

Aspire Aviation said Cathay "may" order the aircraft and we did NOT say Cathay "ordered" 15 747-8F & 777F or 14 777-300ER whatsoever. Your claim is false as well.

These are two direct quotes from the site, “will sign” and “is announcing an order” is used, not “may”.

"Meanwhile, Aspire Aviation has learned that Cathay Pacific will sign a contract with Chicago-based airframer Boeing to purchase 14 additional 777-300ERs in May, bringing the total of 777-300ERs on order and operated by Cathay to 60."

"However, Aspire Aviation can exclusively reveal that Cathay Pacific is announcing an order for Boeing 777F and additional 747-8F freighters totalling 14 aircraft at next week’s Paris Airshow, after separate sources from both Chicago-based airframer Boeing and Cathay Pacific confirming the information."

Quoting aspireaviation (Reply 17):

Had an official confirmation be needed for every article, then what use is media of?

Aspire Aviation is a personal blog, it is not any sort of recognised media. Had confirmation been sought, all CX would have confirmed is that a number of different types are under evaluation. You have however stated that CX has confirmed the information, when it would not have.

Quoting aspireaviation (Reply 17):

I have also noticed your past post, told by my friend, that you said Cathay selected the A350-900 over the 787-9 because the 787-9 could not accommodate CX's economy class seat in a 3-3-3 seat configuration.

This was false and misleading as well. My CX source said the A350-900's larger size suits CX more and Airbus made a compelling offer. Then how could you explain your inaccuracies as well?

I did not state the sole reason CX selected the A350 was because the 787 “could not accommodate CX's economy class seat in a 3-3-3 seat configuration“. I am either being misquoted or taken out of context there. I will put those comments back into context.

Being able to provide a consistent cabin product and a consistent level of passenger comfort across various types was a contributing factor as it is not uncommon for our passengers to change types when transiting HKG. CX aim to provide a consistent product to our passengers from ticketing all the way though to the onboard product. The economy product used in the 787/A350 configuration evaluation, and for the proposed 777/A330 cabin configurations is not a product that is currently installed. As you would be aware, CX uses a 9 across configuration in the long hauls 777s, it is not possible to provide a consistent product on a 9 across 787 due to the fuselage width, it is possible 8 across.

I would expect that CX will formally launch a few new cabin products in the next 12 months, and those products will have a consistent level of passenger comfort across the A330/A350/777 long haul aircraft. Some work is also being done to standardise the CX/KA products.

Mr Tyler said: "I am delighted that we have now finalised this milestone deal for Cathay Pacific. The purchase of these new generation aircraft is an important step in our plan to grow our fleet to ensure that we stay at the forefront of the industry. The A350 fits perfectly into our operation. Its passenger capacity, flight range and operating economics are just right to become the backbone of our mid-sized long haul wide-bodied fleet."

http://www.cathaypacific.com/cpa/en_...651b91b210VgnVCM1000000ad21c39____
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar

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