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Thread: 787 May Be 20K lbs Overweight, Could Cut Range by 1300NM

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    Moderator Matt Molnar's Avatar
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    787 May Be 20K lbs Overweight, Could Cut Range by 1300NM

    FlightBlogger just posted some analysis of the 787's weight issues.

    http://www.flightglobal.com/blogs/fligh ... mined.html
    Bernstein Research says ZA100 will be 8% overweight with a 10-15% shortfall in range.

    Let's take a look at what that might mean for aircraft performance:

    * Boeing targeted a Spec Operating Empty Weight of 252,500 lbs for a 787-8 and maximum empty weight of 191,000 lbs at firm configuration, according to the Airbus assessment. 8% over puts the weight between 15,280 and 20,200 lbs over target.

    * The figure of 20,200 lbs correlates closely to the Airbus Dossier, which cites 21,050 lbs of LN1 maximum empty weight growth since firm configuration. Airbus cited Boeing documents in this estimate. LN1 would be significantly heavier as a result of the significant instrumentation and associated wiring installed for the flight test campaign.

    * Using this data (15-20K lbs) against the 1% SFC shortfall in Trent 1000 Build 4A engines, the PianoX performance analysis puts the 787-8 EIS range between 6,490 and 6,756 NM. (Up to 15% off of 7,650 NM)

    * However, Bernstein estimates the performance of the 787 "will translate into a range near 6,900 nm., well below the promised 7,700-8,200 nm. range." (10% off off 7,700 NM and 15% off of 8,200 NM)

    * Overall, using these various calculations, 787 range projections of overweight performance vary from 6,490 NM up to 6,900 NM.

    * Great Circle Mapper comparison of 6,490 NM v. 6,900 NM v. 7,650 NM v 8,200 NM from Tokyo's Narita Airport for rough range performance of launch customer ANA's 787s.
    Ladies and gentlemen, this is your captain speaking. We have a small problem.
    All four engines have stopped. We are doing our damnedest to get them under control.
    I trust you are not in too much distress. —Captain Eric Moody, British Airways Flight 9

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    Re: 787 May Be 20K lbs Overweight, Could Cut Range by 1300NM

    A 10 to 15% shortfall in range is huge...Boeing better pray this is not the case or it could mean tens of millions in compensation for contract violations.

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    Re: 787 May Be 20K lbs Overweight, Could Cut Range by 1300NM

    Quote Originally Posted by T-Bird76
    A 10 to 15% shortfall in range is huge...Boeing better pray this is not the case or it could mean tens of millions in compensation for contract violations.
    issued Friday by New York-based Bernstein Research that also suggest a 10%-15% range shortfall for early delivery aircraft.

    It is not uncommon for the early aircraft to not meet performance specs...

    http://www.atwonline.com/news/story.html?storyID=16495
    The problem with socialism is that you eventually,
    run out of other people’s money.
    ” - Margaret Thatcher

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    Moderator Matt Molnar's Avatar
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    Re: 787 May Be 20K lbs Overweight, Could Cut Range by 1300NM

    According to the article, Boeing pays United $500 per pound per year for their launch delivery 777s. If the 787 delivery contracts were the same, that would add up to $1 million a year for a 20,000lb overweight 787.

    As a commenter on the article points out, if you center the Great Circle Mapper on JFK, service to JNB, BOM, BKK and HKG would be out of the question with these ranges.
    Ladies and gentlemen, this is your captain speaking. We have a small problem.
    All four engines have stopped. We are doing our damnedest to get them under control.
    I trust you are not in too much distress. —Captain Eric Moody, British Airways Flight 9

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    Moderator Matt Molnar's Avatar
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    Re: 787 May Be 20K lbs Overweight, Could Cut Range by 1300NM

    Another point to consider: in many aircraft programs, a lot of weight savings is found by changing conventional materials to composites. Can't do that here...most of the plane is already composites.
    Ladies and gentlemen, this is your captain speaking. We have a small problem.
    All four engines have stopped. We are doing our damnedest to get them under control.
    I trust you are not in too much distress. —Captain Eric Moody, British Airways Flight 9

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    Moderator mirrodie's Avatar
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    Re: 787 May Be 20K lbs Overweight, Could Cut Range by 1300NM

    MOst of hte body is composite, but how about internal? seats, galleys, etc?
    And I, I took the path less traveled by
    and that has made all the difference......yet...
    I have a feeling a handle of people are going to be very interested in what I post in the near future.

    http://www.jetphotos.net/showphotos.php?userid=187

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    Senior Member moose135's Avatar
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    Re: 787 May Be 20K lbs Overweight, Could Cut Range by 1300NM

    Man, and I thought I need to go on a diet :shock:

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