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Boeing Posts Updated 787 Characteristics  
User currently offlineaerobee From United States of America, joined Dec 2011, 3 posts, RR: 0
Posted (2 years 7 months 1 week 13 hours ago) and read 17596 times:

I was browsing Boeing's website today and noticed that an updated airport compatibility brochure had been posted. It contains some interesting information that I do not remember seeing previously.

Among other things, the brochure includes a full table of airplane weights as well as takeoff and landing runway lengths. The date on the brochure is December 2011 so I assume everything listed is very current.

A few observations:
For a MTOW of 228.4 tonnes, a spec OEW of 111.5 tonnes is listed. I believe that there was some discussion previously about the base (excluding overweight) OEW that Boeing was targeting. Maybe someone knowledgeable can give an idea of what payload-range would be expected from a 787 with a 228.4t MTOW and 111.5 OEW.

With "high-thrust engines" the takeoff field length for the 787 appears to be less than 9000ft. This should be good news for airports such as SAN that may have the potential for new long-haul service but lack long runways.

The document can be found at http://www.boeing.com/commercial/airports/787.html and the numbers I am quoting come from the "airplane description" and "airplane performance" sections.

Long time a.net lurker and first time poster so I hope you all enjoy!

(Added following comment)
Mods: I am just getting the hang of things, so if this discussion would be better in CivilAv or an existing 787 thread, I would appreciate it if you could move it there.

[Edited 2011-12-23 23:31:57]

49 replies: All unread, showing first 25:
 
User currently offlineredrooster3 From United States of America, joined Oct 2010, 229 posts, RR: 2
Reply 1, posted (2 years 7 months 1 week 12 hours ago) and read 17570 times:

Quoting aerobee (Thread starter):
With "high-thrust engines" the takeoff field length for the 787 appears to be less than 9000ft. This should be good news for airports such as SAN that may have the potential for new long-haul service but lack long runways.

Please God, may we see some 787's here at SAN!!!!!!!!!!!!



The only thing you should change about a woman is her last name.
User currently offlinedxing From , joined Dec 1969, posts, RR:
Reply 2, posted (2 years 7 months 1 week 1 hour ago) and read 17294 times:

Quoting aerobee (Thread starter):
Maybe someone knowledgeable can give an idea of what payload-range would be expected from a 787 with a 228.4t MTOW and 111.5 OEW.

That will really depend on the fuel load necessary for the trip. Max payload is 94,000 pounds in the spec sheet but could obviously be chewed up by having to carry more fuel for distance. Long haul flights on twins are usually unable to carry the max payload available on the chart. And welcome to posting.


User currently onlineStitch From United States of America, joined Jul 2005, 30580 posts, RR: 84
Reply 3, posted (2 years 7 months 6 days 23 hours ago) and read 17241 times:
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Quoting aerobee (Thread starter):
For a MTOW of 228.4 tonnes, a spec OEW of 111.5 tonnes is listed.

The September 2007 ACAP (which is the earliest I have) showed an OEW of 114,532kg, so OEW is down by 3000kg.

The configuration is the same at 224 in three classes or 375 in one class, so it doesn't look like Boeing is trying to use a lower-density configuration to skew the OEW. The Exit Limit is lower now, too: 381 versus 440.


User currently offlineaerobee From United States of America, joined Dec 2011, 3 posts, RR: 0
Reply 4, posted (2 years 7 months 6 days 23 hours ago) and read 17215 times:

Stitch, does the ACAP that you have list a MTOW of 228.4 tonnes or the lower value floated earlier that I believe was 484klb?

It is promising if the listed OEW has dropped while the MTOW has increased. The performance should be good for operators once the weight goals are achieved.


User currently offlinesunrisevalley From Canada, joined Jul 2004, 4865 posts, RR: 5
Reply 5, posted (2 years 7 months 6 days 21 hours ago) and read 17166 times:

Stitch, do you believe these are the L/N 90 planned values. I question whether these are the L/N 20 and later values.

User currently onlineStitch From United States of America, joined Jul 2005, 30580 posts, RR: 84
Reply 6, posted (2 years 7 months 5 days 23 hours ago) and read 16786 times:
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Quoting aerobee (Reply 4):
Stitch, does the ACAP that you have list a MTOW of 228.4 tonnes or the lower value floated earlier that I believe was 484klb?

MTOW in September 2007 was still 219,534 kg / 484,000 lbs.


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 7, posted (2 years 7 months 5 days 22 hours ago) and read 16757 times:

The figures in the table in section 2 does not add up in a number of places, strange.

The MZFW is ......161t
The MSP is ..........43t
Gives a OEW of ..118t

Now the OEW is speced at 111.5t?? Should mean the MSP is 48.5t.

Further the MSP of the RR bird is 200lb more then the GE but they have the same MZFW and OEW??????????????

I think we will see a new corrected version soon.

Anyway, if the 111.5t OEW is correct B has increased the MTOW with 9t and lowered the OEW with 4t, not bad    , think I should like to know how they managed that.

With a standard Operators items weight of 63kg/pax they now have an MEW of 111.5-14.1= 96.4t. They have taken 5t out of this figure compared to what A claimed.

I am surprised B gives out a non correct document after such a long wait.

The only plausible conclusion on can draw out of todays numbers are that the MZFW and MSP are correct and that the OEW is a non thought through political figure put there by someone that should have know better.

[Edited 2011-12-25 15:06:51]


Non French in France
User currently onlineStitch From United States of America, joined Jul 2005, 30580 posts, RR: 84
Reply 8, posted (2 years 7 months 5 days 20 hours ago) and read 16667 times:
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Quoting ferpe (Reply 7):
I am surprised B gives out a non correct document after such a long wait.

It appears Boeing is not assuming the plane at MZFW is also at MSP.

For the September 2007 ACAP, MZFW is given as 156,490kg and OEW as 114,532kg so the payload would be 41,958kg.

However, MSP was given as 45,359kg.


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 9, posted (2 years 7 months 5 days 14 hours ago) and read 16558 times:

Quoting Stitch (Reply 8):
For the September 2007 ACAP, MZFW is given as 156,490kg and OEW as 114,532kg so the payload would be 41,958kg.

However, MSP was given as 45,359kg.

Now I am totally confused   . It seems the 787 contains some black material and it ain't CFRP    . The normal law that the diff between MZFW and OEW or DOW is your max structural load seems not to apply    , woodoo or total confusion at work    .

Actually a 111,5t OEW and 42t MSP would make sense for the 219t model and the 114,5t OEW and 45,3t MSP for the 228t model but the way B is presenting things now I can't explain, total mystery    .



Non French in France
User currently offlineastuteman From United Kingdom, joined Jan 2005, 9977 posts, RR: 96
Reply 10, posted (2 years 7 months 5 days 12 hours ago) and read 16500 times:
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Quoting ferpe (Reply 7):
The figures in the table in section 2 does not add up in a number of places, strange.

The MZFW is ......161t
The MSP is ..........43t
Gives a OEW of ..118t

Now the OEW is speced at 111.5t?? Should mean the MSP is 48.5t.

You can find the same thing in some of the Airbus ACAPs where there is a several tonne difference between the listed OEW, and that which is inferred by the max structural payload.

e.g, Airbus list the OEW of the A380 as 270t and MSP as 91t, for the 361t OEW on page 1 of section 2 of the ACAP. However, the range/payload chart in section 3 maxes out at "only" 84t, implying a 277t "OEW".

The only sensible explanation I've ever been able to derive is a difference between a "very basic OEW", and a "passenger ready weight", which might include for example, catering weights, or fresh water weight etc.

Otherwise, I'm as lost as you.

Rgds


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 11, posted (2 years 7 months 5 days 12 hours ago) and read 16492 times:

Quoting astuteman (Reply 10):
Airbus list the OEW of the A380 as 270t and MSP as 91t, for the 361t OEW on page 1 of section 2 of the ACAP. However, the range/payload chart in section 3 maxes out at "only" 84t, implying a 277t "OEW"

Sure, but to Airbus credit the table values does add up, the diff between the MZFW and the OEW = MSP for all weight variants listed. Then they present 1 chart for performance for all WV and both engines (they do list different OEW and MSP per engine as well, all nice and tidy) and then they let you understand that for a real case you better add 7t to reach something which has to do with flying the piece (like catering, newspapers for 525 pax etc which adds up to the DOW).

This all is plausible and explainable, the total dysfunctional display of figures from Boeing is not I am afraid    . For the 788 a DOW addition of 6,5t for 224 pax does not jive with me, further any DOW adds has to be counted within the MSP (Max Structural Payload= everything that goes into the tube, be it pilots, stewardesses,life-vests, toilet paper or catering) nor does the history of the figures presented, it smells deliberately tweaked figures.

I guess B can have taken the OEW from a 1 class cabin and the MSP for a std 3 class one, the ACAP does not positively state that the OEW is for the 3 class cabin. With such tircks they can earn themselves bragging rights in the war of words that B and A seems to have started on the 737MAX vs 320neo side, sad if it shall now spread to the DA side.

To be fair, A is not clean either, they presented a payload-range diagram at Dubai Air show that showed 35J vs 77W with an arbitrarily choosen OEW for the 77W of 173t instead of the published 168t. Guess what the 35J had better payload at all points of the diagram    , I will stick with my own diagram until I can explain those extra 5t for the 77W.

Sigh, I guess we are in for a BS period between A and B  ashamed  .

[Edited 2011-12-26 01:13:09]


Non French in France
User currently onlineStitch From United States of America, joined Jul 2005, 30580 posts, RR: 84
Reply 12, posted (2 years 7 months 5 days 7 hours ago) and read 16355 times:
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Well these are just general guidelines, and meant for airport planning, not mission planning. So as a PR tool, they're not very effective since only us propeller-heads look at them.  

We just need an Air India pilot to smuggle out the internal FCOM for their A330-200 and 787-8, allowing us to do a direct comparison.  


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 13, posted (2 years 7 months 5 days 4 hours ago) and read 16286 times:

Quoting Stitch (Reply 12):
We just need an Air India pilot to smuggle out the internal FCOM for their A330-200 and 787-8, allowing us to do a direct comparison.

Great idea    , you are our elected mission manager    . I will chip in my weekly allowance into our bribe-pool, it will move us forward with 20$    .

[Edited 2011-12-26 07:50:18]


Non French in France
User currently offlineaircellist From Canada, joined Oct 2004, 1711 posts, RR: 8
Reply 14, posted (2 years 7 months 4 days 22 hours ago) and read 16137 times:

Quoting ferpe (Reply 13):
Quoting Stitch (Reply 12):
We just need an Air India pilot to smuggle out the internal FCOM for their A330-200 and 787-8, allowing us to do a direct comparison.

Great idea , you are our elected mission manager . I will chip in my weekly allowance into our bribe-pool, it will move us forward with 20$ .

Love it! Ready to add five canadian dollars!


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 15, posted (2 years 7 months 3 days ago) and read 15612 times:

FWIW, my calculations based on fuselage and wing area suggest that B788 should be about 8,000 lbs. lighter than A332(257,588 lbs./ 117 tonnes) if it were made of similar material.

Assuming additional weight savings due to higher use of composites, it may be possible that a fully mature B788 could reach a spec. weight of 111.5t(245,800 lbs.).


User currently offlinesunrisevalley From Canada, joined Jul 2004, 4865 posts, RR: 5
Reply 16, posted (2 years 7 months 2 days 23 hours ago) and read 15563 times:

Quoting LAXDESI (Reply 15):
Assuming additional weight savings due to higher use of composites, it may be possible that a fully mature B788 could reach a spec. weight of 111.5t(245,800 lbs.).

so do you agree with me that these are post LN 90 values? It rather suggests something in the future since there is no load/range table provided.


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 17, posted (2 years 7 months 2 days 22 hours ago) and read 15542 times:

Quoting sunrisevalley (Reply 16):
so do you agree with me that these are post LN 90 values? It rather suggests something in the future since there is no load/range table provided.

They would then definately be LN90 or later frames.

Thanks LAXDESI, I agree, a mature and well built 50% CFRP frame would be about 4t lighter then a 332 so 111.5 would be fully plausible were it not for the weight history of the 788.

IMO the 788 program did not have the tools when they started the program to do an optimized frame, they discovered that when the structural problemsstarted to appear. These showed them that their tools lack capability to predict close to reality. The furious pace of the program (which was never stopped to think and rethink, this is the key, they just hasted on even more stressed by every problem that delayed them) never let the technicians the time to tune their tools. Thus you have to add margins in your designs and they are only 3-5% overweight at LN90 IMO, a 3-5% margin is really small in a structural design if you are unsure of your tools accuracy. But is is what the CFRP would gain you and they lost the weight advantage of it. They still have all the other advantges.

Please observe that this does not make the frame unsafe, just only 97% optimal, it is just a bit over-strong on the safe side.

So while they would have been at an honest 111.5t if they would have taken their time to do a proper job, I don't believe they are there with the 788. The 789 is the first frame when they had the time to tune everything to the level they usually are, at 99% optimisation   .


But that is just my opinion, lets see what reality tells us in due time  .



Non French in France
User currently offlineaerobee From United States of America, joined Dec 2011, 3 posts, RR: 0
Reply 18, posted (2 years 7 months 2 days 22 hours ago) and read 15538 times:

Quoting LAXDESI (Reply 15):
Assuming additional weight savings due to higher use of composites, it may be possible that a fully mature B788 could reach a spec. weight of 111.5t(245,800 lbs.).

LAXDESI,

If we assume that this is the mature target OEW, what range would be expected with a typical passenger payload and the listed MTOW of 228.4t?


User currently offlinesunrisevalley From Canada, joined Jul 2004, 4865 posts, RR: 5
Reply 19, posted (2 years 7 months 2 days 20 hours ago) and read 15475 times:

Quoting aerobee (Reply 18):
If we assume that this is the mature target OEW, what range would be expected with a typical passenger payload and the listed MTOW of 228.4t?

I ran through Piano X a 787 with MTOW = 227.930t; OEW =111.50t add on for DOW 4.50t and 224 passengers. The output gave a range of 8353 nm. At OEW and no allowance for DOW add on the range was 8912nm.


User currently onlineStitch From United States of America, joined Jul 2005, 30580 posts, RR: 84
Reply 20, posted (2 years 7 months 2 days 20 hours ago) and read 15467 times:
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Boeing updates their APACs over time to reflect improvements in structures, engines and such. I would think these specs are more representative of an LN20 frame than an LN90 one for that reason, but Boeing might have just decided to go with whatever "plan data" was since the first couple of score of airframes are going to see even more variation than usual between frames due to the varying levels of re-work needed.

They may be holding off the Payload-Range charts until they receive final certification from the FAA and can chew through all the data for the GEnx model.


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 21, posted (2 years 7 months 2 days 19 hours ago) and read 15459 times:

Quoting ferpe (Reply 17):
So while they would have been at an honest 111.5t if they would have taken their time to do a proper job, I don't believe they are there with the 788. The 789 is the first frame when they had the time to tune everything to the level they usually are, at 99% optimisation

You raise many valid points, and if you are correct then B788 may never reach a spec. OEW of 111.5t(245,800 lbs.)

Quoting aerobee (Reply 18):
Quoting LAXDESI (Reply 15):Assuming additional weight savings due to higher use of composites, it may be possible that a fully mature B788 could reach a spec. weight of 111.5t(245,800 lbs.).
LAXDESI,

If we assume that this is the mature target OEW, what range would be expected with a typical passenger payload and the listed MTOW of 228.4t?

If the B788 could slim down to 111.5t OEW, then at typical 242 marketing passenger load it should have a design range of 8,600nm(using pianoX template adjusted for weight).

B788 at A332(HGW) weight of 257,588 lbs. will have a design range of 8,000nm, which is 750nm higher than that of A332..

If a fully mature B788 were to be lighter than A332 by at least 5,000lbs, it should have a design range of around 8,300nm(242 passengers in marketing configuration) as per pianoX template.

B788 is not fuel volume limited at design range, so any decrease in OEW or increase in MTOW over time will boost the design range and/or payload.


User currently offlinesunrisevalley From Canada, joined Jul 2004, 4865 posts, RR: 5
Reply 22, posted (2 years 7 months 2 days 19 hours ago) and read 15454 times:

Quoting LAXDESI (Reply 21):
then at typical 242 marketing passenger load

LAXDESI.... I think you have a typo here. I believe it should read 224.


User currently offlinesunrisevalley From Canada, joined Jul 2004, 4865 posts, RR: 5
Reply 23, posted (2 years 7 months 2 days 19 hours ago) and read 15448 times:

Piano X , based on the inputs used in post 19 shows capacity of 28, 36 and 41t payload respectively over 7400, 6500 and 6000nm . All TOW's were close to max.
So the operator who wants to fly NYC- HKG can do it with max passenger load and ~6t of cargo.


User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 24, posted (2 years 7 months 2 days 15 hours ago) and read 15378 times:

Quoting sunrisevalley (Reply 22):
Quoting LAXDESI (Reply 21):
then at typical 242 marketing passenger load

LAXDESI.... I think you have a typo here. I believe it should read 224.

224 is low...that would be very spacious 3-class long haul. ANA's 2-class medium-range interior is 264 for comparison.

Tom.


User currently onlineStitch From United States of America, joined Jul 2005, 30580 posts, RR: 84
Reply 25, posted (2 years 7 months 2 days 7 hours ago) and read 15673 times:
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Quoting tdscanuck (Reply 24):
224 is low...that would be very spacious 3-class long haul.

NH is planning on only 158 in two classes (46C + 112Y) for their international config per reports from FlightGlobal.


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 26, posted (2 years 7 months 2 days 4 hours ago) and read 15583 times:

As per your PianoX runs above you will see that you end up with much better payload range figures then Boeings offcial ones of 210 pax+bags @210lb the range is given as 8200nm. At 250pax+bags 7650nm. Now I don't think B would understate the 788 payload-range capability, they have this pretty clear by now for a frame that is to spec (ie over LN90) and engines that are to spec. So when putting in 111.5t in PianoX one can clearly see that this is not what they had in mind for a 224 Pax frame and cabin (with such a low count this is a long-haul multiclass cabin, ie rather heavy).

I stay with my opinion, this OEW is a political figure dictated by some senior manager and is for a light cabin of some sort. That B did not change the MSP to match is a bit of a mystery. IMO the MSP is the more credible figure as it gives the RR engine as 100lb lighter which the Trents normally are and the DOW that it gives matches with everything else we know and with PianoX simulations.

[Edited 2011-12-29 08:54:52]


Non French in France
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 27, posted (2 years 7 months 2 days 3 hours ago) and read 16045 times:

Quoting Stitch (Reply 25):
Quoting tdscanuck (Reply 24):
224 is low...that would be very spacious 3-class long haul.

NH is planning on only 158 in two classes (46C + 112Y) for their international config per reports from FlightGlobal.

ANA's international long-haul is 3.5 abreast in business class according to their promo video...this causes an absurdly low seat density. I'm not sure it's fair to make that typical.

Tom.


User currently onlineStitch From United States of America, joined Jul 2005, 30580 posts, RR: 84
Reply 28, posted (2 years 7 months 2 days 2 hours ago) and read 15975 times:
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Quoting tdscanuck (Reply 27):
ANA's international long-haul is 3.5 abreast in business class according to their promo video...this causes an absurdly low seat density. I'm not sure it's fair to make that typical.

Probably not. It makes even their "Inspiration of Japan" 77Ws look crowded, and those are very spacious.  

UA is looking at 219 and QF at 258.


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 29, posted (2 years 7 months 11 hours ago) and read 15564 times:

Quoting tdscanuck (Reply 27):
ANA's international long-haul is 3.5 abreast in business class according to their promo video...this causes an absurdly low seat density. I'm not sure it's fair to make that typical.

I don't want to seem overly negative but could that very low seat count have something to do with the payload-range of these early crafts? Does ANA have routes in mind that would tax the present capability of pre LN90 frames?



Non French in France
User currently onlineStitch From United States of America, joined Jul 2005, 30580 posts, RR: 84
Reply 30, posted (2 years 7 months 5 hours ago) and read 15482 times:
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Quoting ferpe (Reply 29):
I don't want to seem overly negative but could that very low seat count have something to do with the payload-range of these early crafts?

I would expect not, to be honest. NRT-FRA should be easily doable even for LN009, much less LN031, 041 and 042.

NH seems to have identified the number of people who will fly their airline exclusively and pay whatever price NH asks and are configuring their planes appropriately. So even though their CASM in these low-density configurations is high, so are their fares, so they can get the RASM they need to make the flights profitable.


User currently offlinesunrisevalley From Canada, joined Jul 2004, 4865 posts, RR: 5
Reply 31, posted (2 years 7 months 4 hours ago) and read 15439 times:

Quoting ferpe (Reply 29):
I don't want to seem overly negative but could that very low seat count have something to do with the payload-range of these early crafts? Does ANA have routes in mind that would tax the present capability of pre LN90 frames?

Assuming they are using 118t OEW plus 4.5t to bring them up to DOW , a max volume limited load of 33.5t ; they can do 12hrs 40min which puts NRT-LHR just inside the barrier. It also allows NRT- ORD/JFK/IAD eastbound. There would be a payload hit westbound but that might not matter too much if the westbound cargo market is less robust.
A 111.5t OEW ( post LN90) plus 4.5t for DOW would improve the range by 800nm which would make westbound JFK/IAD-NRT possible at the above payload based on timetable times.


User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 32, posted (2 years 7 months ago) and read 15447 times:

Quoting ferpe (Reply 29):
I don't want to seem overly negative but could that very low seat count have something to do with the payload-range of these early crafts?

Not really. ANA is so far below the design seatcount that it's not a payload limit...the overweight status of the early frames isn't equivalent to nearly that many people.

Quoting ferpe (Reply 29):
Does ANA have routes in mind that would tax the present capability of pre LN90 frames?

Not that they're talking about...they could be keeping secrets but we won't know until they announce.

Tom.


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 33, posted (2 years 6 months 1 week 3 days 1 hour ago) and read 14346 times:

Quoting ferpe (Reply 7):
The figures in the table in section 2 does not add up in a number of places, strange.
Quoting ferpe (Reply 7):
I think we will see a new corrected version soon.

So Boeing have taken the confused ACAP for the 787 of the air as predicted    .

Now lets see what comes back   , more confusion    or something plausible which will jive with the history of the ACAPs for the 787 where the OEW have tracked between 50 and 51% of MTOW all the time  Wow! ?



Non French in France
User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 34, posted (2 years 5 months 1 day 14 hours ago) and read 12470 times:

Quoting ferpe (Reply 33):
ACAPs for the 787 where the OEW have tracked between 50 and 51% of MTOW all the time

Now one month later Boeing have reinstated the old March 2011 Brochure stating the ACAP is under revision (there has been a dead link for a month now instead of this brochure). I am sorry to see that the 787 public documents seems to have the same production problems as the frame, a month to react to the fact that a document is taken of the air seems rather long.

So given this pace it will take some time before an updated and hopefully more plausible document comes back. For the record I will put down the published MTOW and OEW that I know Boeing have made for the 787-8:


........................MTOW kg.....................OEW kg...................OEW/MTOW %
2005-09............215910........................108499............................50.3
2007-09............219534........................114532............................52.2
2011-11............227930........................111493............................48.9


It should be commented that what can be gleaned from the spec figures for the comparable A350 gives a OEW to MTOW ratio of about -800 51%, -900 50,5% and -1000 49.5%. Such a series makes sense, certain items are fixed size for all members of the family and as your frame grows their fraction of the empty weight shrinks.

The series of OEW/MTOW fractions for the 787-8 is very erratic and I don't know how to make sense of them. The initial value seems OK as a target spec, the middle seems to reflect their deepest despair over their overweight before upping the MTOW to compensate but the final value makes no sense at all, no CFRP frame goes below 49.5% for a ULH frame. It seems to be an error, anything between 50 and 51% as a target spec for over LN90 frames for this smallest member of the 787 family seems plausible.



Non French in France
User currently offlineRuscoe From Australia, joined Aug 1999, 1542 posts, RR: 2
Reply 35, posted (2 years 4 months 1 week 5 days 19 hours ago) and read 11403 times:

Seriously do you think Boeing is deliberatly establishing a moving target, for Airbus?

I actually doubt it because Airbus would know the actual figures I am sure, but a thought none the less.

Ruscoe


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 36, posted (2 years 4 months 1 week 5 days 4 hours ago) and read 11219 times:

Quoting Ruscoe (Reply 35):
Seriously do you think Boeing is deliberatly establishing a moving target, for Airbus?

I don't think so, I think they put in the OEW for a 1 class cabin to get a figure close to the Wikipedia one, reading the ACAP carefully it is not stated the OEW is for a 3 class cabin.

Now why they would go away from the practise of a 3 class cabin to gain some bragging rights I don't understand, even less how they can miss to adjust the MSP accordingly. The MSP indicates an OEW some 6.5t higher, actually the weight difference from a 1 class to a 3 class cabin. Go figure.



Non French in France
User currently onlineStitch From United States of America, joined Jul 2005, 30580 posts, RR: 84
Reply 37, posted (2 years 4 months 1 week 5 days 3 hours ago) and read 11220 times:
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Quoting ferpe (Reply 36):
I don't think so, I think they put in the OEW for a 1 class cabin to get a figure close to the Wikipedia one, reading the ACAP carefully it is not stated the OEW is for a 3 class cabin.

Boeing doesn't use the single class Exit Limit for any other OEW that I can see, so it would be unusual for them to do so here. And even if they did, what does it matter? Airlines don't use the ACAP, airports do. So not like Boeing needs to artificially reduce the OEW of the 787 to win orders.  


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 38, posted (1 year 10 months 3 weeks 2 days 12 hours ago) and read 9623 times:

As per sunrisevallys post in the thread on how the 787 ended weighing more the planned there is new info from Aspire aviation re the MEW of production 787-8 . So if one summarizes what Aspire has gleaned:

Aspire 787 data
MEW.............lb....................kg
Target......221.000...........100.244
LN01.......242.500...........109.996
LN07.......234.500...........106.367
LN20.......229.800...........104.236
LN90.......221.000...........100.244

In addition they gave the projected weight for the 787-10 in a 323pax variant as 263.452lb or 119.500kg.

If one looks at these figures the target MEW fits somewhat with the 2008 weight table that Airbus made public, at Aug 2008 the target MEW for a 248pax 2 class variant was given as 101.2t. Given that the seats are included in a Boeing MEW one have to figure out what cabin config the Aspire data should relate to, I would guess the B ACAP postulated 224 pax 3 class variant. So we have a 24 pax diff for 1t of weight difference between a 224 3 class MEW and a 248 2 class one, makes an average seat weight for the difference of 42kg, a bit high espcially as we go from 3 class to 2 class cabin.

I would rather think B has seen the 789 project enables them to be more aggressive with the mature MEW for the 788. So if we assume the Aspire figure of 100.2t MEW is correct, what spec (show room) OEW does that give us for a 3 class 224 pax frame and how does that compare with the given 111.5t. The difference number as an average per taken pax form a fully furnished cabin + emergency equipment, crew with their docs and bags etc would be interesting to pinpoint given Boeing MEW to OEW rules which are different to Airbus (where the figure seem to be around 63kg).

Anyone have and idea?



Non French in France
User currently offlinesunrisevalley From Canada, joined Jul 2004, 4865 posts, RR: 5
Reply 39, posted (1 year 10 months 3 weeks 1 day 20 hours ago) and read 9315 times:

Quoting ferpe (Reply 38):
the target MEW for a 248pax 2 class variant was given as 101.2t.

I don't see such a variant in Boeing ACAPS. On 2.4.1 Dec 2011 they show a 3-class 187 seat and a 3-class 224-seat.
On 2.4.2 they show a 2-class 227-seat and a 2-class 291- seat. On 2..4.1 July 2012 they show a 3-class 242-seat.
So I believe the starting point is 3-class 224-seat at 100.2t MEW.


Below is a link to a Lissys document that includes their list of the various components and their mass to arrive at a MEW figure for a 224 passenger configuration. Now he shows 107.06t but in furnishings ( no details ) he has 19t or ~85kg per seat. If this unit was adjusted to the Airbus unit of 63kg the 107.06t would drop to 102.13t which is getting very close to the 100.2 put forward by Aspire. This would put the weight at 88t before seating of 224 @63kg.
The mass for the fuselage group is given as 20.37t for 183.5 ft. Straight line based on 20' increases in fuselage length gives 22.6t for the 789 ( + 2.23t) and 24.8t ( plus 4.43t) for the 787-10. No doubt the relationship is not straight line but the increase in mass for strengthening is probably less than half a tonne. However Aspire puts the 787-10 at 119.5t , if 323 seats at 63kg are deducted this puts the weight before seats at ~105t some 17t more than the 788. This seems quite a jump.
Thoughts anybody?


http://www.lissys.demon.co.uk/samp1/index.html


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 40, posted (1 year 10 months 3 weeks 1 day 1 hour ago) and read 9013 times:

I just want to say the 63kg is not only seats, it includes all the items that differ between and Airbus MEW and OEW ie:

- seat

- galleys, toilets

- emergency equipment

. regalementary flight crew with baggage and documentation

This is all averaged then with the number of seats as divisor. How much is a "showroom" seat then. There are some old post that give them as:

- economy class typical 15kg

- business class typical 60kg

- First class, 100-150kg


So how much of the Boeing MEW could be the seats? Some time ago I made this table:

................................../seat......A350-9 787-8 787-9
Total seating...............................314.........242.........280
Economy longrange ...15............250.........182.........214
Business longrange ...60..............50...........44...........50
First longrange .........125..............14...........16...........16
Seat weight..............................8500.......7370 .......8210
Average seat weight:...................27,1........30,5.........29,3

I think we should test with 30kg/seat average and see if that makes sense.



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User currently offlinesunrisevalley From Canada, joined Jul 2004, 4865 posts, RR: 5
Reply 41, posted (1 year 10 months 3 weeks 23 hours ago) and read 8969 times:

Quoting sunrisevalley (Reply 39):
if 323 seats at 63kg are deducted this puts the weight before seats at ~105t some 17t more than the 788.

I have some bad math. here . 105t should read 99t giving a 11t spread between the 788 and 787-10. This seems possible.


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 42, posted (1 year 10 months 3 weeks 18 hours ago) and read 8846 times:

I have used the 30kg to reach a Boeing definition MEW less the seats, you end up at 93480 kg. If you then add 63kg for 224 seats your OEW should be 107.6t, 4t below the figure of the latest ACAP with an OEW in.

This makes you think what MEW we have here, I suspect that it all goes from the Airbus table and that had an Airbus definition. The reason is; that was an internal document which was used to track the 787 program and to show to customers the competitive situation between the 332/358 and the 787, it would make no sense for the Airbus table not to use the same definition as Airbus figures. In such a case there would have been at least a footnote spelling out the different MEW methods.

So if we use the usual 63kg with the Aspire MEW we have:

224 3 class aircraft: 100.2 + 224*0.063 = 114.3t

242 3 class aircraft: 100.2 + 242*0.063 = 115.5t

These 2 figures makes a lot of sense to me, I have indications that the OEW of a mature 788 is not to far from 116t for a 240 seat 788.



Non French in France
User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 43, posted (1 year 10 months 3 weeks 17 hours ago) and read 8854 times:

So if the 788 figures makes sense the 787-10 does not, 119.5t is way to much. In the Airbus 787 lessons learned the 789 tracks the 788 with a 7.2 weight add. This makes sense, with a 280 pax cabin one does then add up at 124.6t spec OEW for a 280 pax 3 class show room 789, something that fits very well with a reasonable OEW/MTOW ratio.

The 787-10 would end up at a whopping 19.4t heavier then a 788. No way this can be true, the 789 adds 7t for 40 seats/10 frames and a hike of 23t in MTOW and 20t in MZFW, the 7810 only adds another 40 pax/10 frames and 10t to the MZFW (nothing to the MTOW). This adds less then an additional 7t to the MEW, ie less then 114t MEW. I have every reason to believe a 787-10 323 pax showroom OEW should be in the region of 132t and the MEW somewhere around 112t.



Non French in France
User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 44, posted (1 year 10 months 3 weeks 15 hours ago) and read 8815 times:

Airbus call their definition of MEW MWE (Manufacturers Weight Empty), I think we might use this way of writing it to denote we actually refer to the Airbus defintion (which is the empty aircraft before any cabin amenities get fitted like gallies, toilets, seats, IFE, emergency equipment, rest compartmetns (not included in a later spec or showroom OEW anyway) and what have you.

If one assumes Aspire have got the info from B I think at best they might have a crossup between these definitions, ie the 788 MEW is really a MWE and the 787-10 is a Boeing definition MEW (I will use MEW from now on to denote a B definition figure). Lets do a reality check on the 787-10 figure:

MEW 119.5 + 323*0.033 = 130t.

It seems to make sense, my average B adder to come from MEW to spec OEW spread between 33 and 35kg, lets use 35kg and we and up at some 131t which would be OK IMO.

So I guess this could be the trail: Aspire B sources only gives them deltas for the MEW figures. Aspire adds these to the Airbus lessons learned MWE which goes between 109t down to 100t for mature frames. Then they get a real MEW figure for the 787-10 and voila the confusion is complete.



Non French in France
User currently offlinesunrisevalley From Canada, joined Jul 2004, 4865 posts, RR: 5
Reply 45, posted (1 year 10 months 3 weeks 3 hours ago) and read 8770 times:

Ferpe,

A particularly insightful analysis. Good work on unravelling the MEW and MWE conundrum! I believe the OEW's that you have put forward are worth adopting until more is revealed by B.
Thanks!


User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 46, posted (1 year 7 months 1 week 4 days ago) and read 6679 times:

So now Boeing have published the ACAP that we have been waiting for since December last year. It shows that my assumption that everything was fine with the ACAP except that someone put in an "optimistic" OEW in the last minute was correct, the new ACAP has a correct list of weights (with one tiny fault on the RR engine side ) that track the previous one with one improvement, the frame is now some 700kg lighter, well done Boeing    . This despite them now listing the OEW as 117.7t for a 242 seat mixed config, previously it was over 118t for a 224 config. Here the table:



It is commendable that B did state the OEW and a real one at that, with that the payload range chart also makes sense, here it is:

http://i298.photobucket.com/albums/mm262/ferpe_bucket/788ACAP102012PRchart_zpsef440fea.jpg



Non French in France
User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 47, posted (1 year 7 months 1 week 3 days 23 hours ago) and read 6626 times:

Here how my model tracked the OEM chart in the end, I have put in the correct OEW but made no other changes:

http://i298.photobucket.com/albums/mm262/ferpe_bucket/788modelvsACAP102012PRchart_zps2fb22d16.jpg



Non French in France
User currently offlineferpe From France, joined Nov 2010, 2800 posts, RR: 59
Reply 48, posted (1 year 7 months 1 week 10 hours ago) and read 5829 times:

The posting of my models 788 chart was done in a naive moment of joy and pride that I wasn't more of in range    , then gradually sanity came back    . No wonder I tracked close to the truth, I had used the 788 as my development frame as there was the complete PianoX data on Lissys website http://www.lissys.demon.co.uk/samp1/index.html and then the 788 model in PianoX itselves. I used it extensively to check and tune my aerodynamic parameters, therefore what is really interesting is how far of is PianoXs model?

Not far at all, here the Nov 2011 PianoX 788 release vs Bs chart. I have adjusted it on 2 counts, I put in the correct final spec OEW (117.7t vs 120.8t) and adjusted the fuel burn to fully mature engines (-3.3%), Lissys said in the release notes it was representative of the early 228t 788. I also adjusted PianoX and my model for a B change in fuel capacity (126903l dec 2011 and 126206l in latest ACAP) So here the curves:

http://i298.photobucket.com/albums/mm262/ferpe_bucket/PR788ModelPianoXandOEMchart_zps8cab135c.jpg

As can be seen the Piano model tracks almost 100%, mine is of by some 1-2%. My TSFC is now about 2% higher then Pianos (0.536 vs 0.523) so that might be the parameter I have to change go get full tracking but it can also be that 0.53 is the correct fuel figure and airframe drag is a tick better then Pianos prediction, B have recently said the 788 is aero wise a bit better then they hoped for.



Non French in France
User currently onlineJoeCanuck From Canada, joined Dec 2005, 5405 posts, RR: 30
Reply 49, posted (1 year 7 months 6 days 16 hours ago) and read 5521 times:

Quoting ferpe (Reply 48):

Gee...couldn't you get any closer...? An electron microscope could pick up that gap easy...



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