Boeing 787 (partie 1)

Jeannot a écrit:Le problème électique expliqué (enfin...)

[url=http://www.flightglobal.com/blogs/flightblogger/2009/04/the-road-to-787-first-flight---6.html

For ETOPS performance, Boeing is seeking to offer 333min clearance at entry into service, with 207min as a back-up.

Boeing's 787 customers face delivery delays of up to an additional six months, according to a report issued Friday by New York-based Bernstein Research that also suggest a 10%-15% range shortfall for early delivery aircraft.

The May 1 client report, a wrapup after Boeing's 787 certification briefing on April 29 (ATWOnline, April 30), is Bernstein's sixth reassessment of 787 production and forecasts that the manufacturer will not reach its target production rate of 10 aircraft per month until mid-2013, six months later than the latest target (ATWOnline, Feb. 9).

Bernstein warned that it is "not comfortable with assuming that [Boeing] will achieve its goal of making first delivery in Q1 2010 to All Nippon Airways, and even less comfortable assuming a production rate of 10 per month by the end of 2012," and has thus "stretched the time from first flight to the target production rate by an additional six months, with production rates reaching six per month at the end of 2012 and reaching 10 per month in mid-2013."

At its April 29 briefing, Boeing reiterated its plan to fly the 787 by June 30.

The report also expressed concern about the effect on production rates of the redesign required to address weight issues. Bernstein said it understands from customer and supplier discussions that the first production 787s are likely to be roughly 8% overweight, with range 10%-15% less than promised. "That will translate into a range near 6,900 nm., well below the promised 7,700-8,200 nm. range," it claimed.

"These values are worse than for most development programs and suggest that substantial redesign work will be necessary. . .but the Tier 1 suppliers have not yet validated their production capacities with the new production technology, and if substantial redesign is needed to reduce weight, it will further complicate a rapid increase in delivery rates," the report added.

In more bad news Bernstein cast doubt on the ambitious certification timeline for the 787, which it termed "challenging." It warned that the program involves substantial changes in materials, systems and manufacturing technology, creating many opportunities for surprises to emerge during the test program. "There will also be the challenge of getting all six aircraft ready for testing as planned," it said.

Boeing was unable to respond to the report by publication deadline. by Geoffrey Thomas

• 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 analysis6,490 and 6,756 NM. (Up to 15% off of 7,650 NM) puts the 787-8 EIS range between
  
• 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.
  
  Boeing plans to conduct a final weighing of Airplane Seven once final assembly is completed later this year.
  
  Attendons donc le N° 7 pour voir.
  
  http://www.flightglobal.com/blogs/flightblogger/2009/05/analysis-787-8-weight-examined.html
  

Jeannot a écrit:Très chère Gaia

Je n'ai nullement envie de jouer au plus fin avec vous ni encore moins de polémiquer. Dans ma petite cervelle d'étourneau je pensais (et utilisant l'imparfait, je continue à penser) que le fait d'avoir une couleur différente pour ses propos et une autre pour les citations pouvait être utile à la compréhension.

Il me semble maintenant que vous ne partagiez pas ce point de vue. C'est dommage ! Je vais donc obtempérer pour éviter tout quiproquo.

Titre du document en gras

Le contenu de l'article éventuellement enrichi par des soulignements, des italiques et des gras modéremment il va de soi pour ne pas nuire à la lisibilité.