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
Quote:
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.
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.
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
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.
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.
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?
Re: 787 May Be 20K lbs Overweight, Could Cut Range by 1300NM
Man, and I thought I need to go on a diet :shock:
