Beochien est arrivé trop tard.
Pas de polémique, Bluesky. Mieux vaut regarder les faits, et attacher de l'importance aux faits, et non pas aux avis infondés, ou à une lecture sélective (même si abondante).bluesky a écrit:Bonsoir,
Avez vous lu les échanges de Viking et Sevrien sur Aeroweb ? Vous dites n'avoir aucun parti pris ! Laissez moi rire un bon coup. Ce forum a été créé par un parti pris. Il ne faudrait surtout qu'il y ait des membres qui osent confronter Sevrien, le messager de la parole divine. Et ce sont ces mêmes personnes qui ont crié à la liberté expression lors du renvoi de Sevrien d'Aeroweb.
Bonjour, bien sûr Rasta' !Rasta' a écrit:Une toute dernière précision avant de clore ce débat:
ce forum n'est pas davantage celui de Rasta, de Sevrien que de quiconque. Toutes les contributions sont les bienvenues à condition de ne pas entrer dans les polémiques stériles.
Airbus in investigating a backup flight control system that provides transport aircraft control by transferring fuel between separate tanks in the left and right wings for roll control and between belly and tail tanks for pitch control.
Such a system, detailed in a US patent application submitted 2 April, would be transparent to the pilot, with traditional controls sending inputs to a computer that would command the fuel flow using pumps.
"In the event of total failure of the aerodynamic surfaces, the transfer of fuel enables the control of the aircraft to be maintained in order to attempt a landing or splash-down even if one or more jet engines have just gone out of operation," the airframer says in the application.
The pictures below, from the patent application, shows how transfer of fuel would effectively shift the centre of gravity of the aircraft rearward and forward in the top picture to produce pitch, or side to side to produce or roll motion in the bottom picture. Airbus notes that combined pitch and roll maneuvers can also be accomplished.
Airbus on composites, some weight savings haven’t eventuated, but….
November 4, 2009 – 5:37 pm, by Ben Sandilands
Airbus chief operating officer customers, John Leahy shared some interesting thoughts about advanced composite structures in airliners in Sydney this morning.
But at the outset, he made it clear he wasn’t offering a judgement on whether they were better or worse than the use of aluminium alloys, nor announcing a metal A350 XWB or launching into a detailed critique of the Boeing experience with the 787 Dreamliner project.
In relation to their use in the thin large scale structure of new designs, Leahy said :
“Composites technology in those applications has not in general been getting quite the weight savings that everyone had hoped for, however this may well reflect the limitations of current engineering thinking or trying to use composites in a closely similar manner to alloys, where new design approaches could ultimately realise their claimed potential.”
The Airbus A350 would hopefully avoid some of the issues that had arisen for Boeing’s 787, partly because on current indications it might follow it by two years.
The A350 test fuselage sections at Hamburg demonstrated a more conventional approach to design and construction, where composites were used in the floor, and the underlying ribs to which composite fuselage panels were attached.
This was easy to supervise for quality control in construction, and very easy for the airlines to support and maintain in terms of access and processes that offered many similarities to those used on existing fleet.
The Boeing use of large single piece composite sections was more challenging to manufacture and check, and was in his opinion ‘a bridge too far’.
Leahy did not directly respond when asked if Airbus was evaluating whether the more extensive use of composites in designs was going to deliver a worthwhile improvement over using the best alloys .
However he said Airbus was continually examining alternative materials, regardless of whether they were composite in nature or incorporated exotic alloys in its pursuit of weight savings in general in its designs.
He repeated, “We are always looking at all options to save weight including exotic metals.”
In 2004 and 2005 in presentations on the original Airbus proposal for an A350 family which would compete with the Boeing Dreamliner Leahy argued that the benefits it claimed for the high plastic content airliner could be delivered with more certainty and less cost by upgrading the A330 platform with new generation engines and a more evolutionary approach to composites.
In that campaign, which was swamped by orders for the 787, Airbus emphasised its leadership in composites, having gradually introduced them to its line up since the early ’80s, and argued that the Boeing plans were inappropriate as applied to the large sections of carbon barrel fuselages.
Leahy’s words today could fuel speculation that Airbus is at the very least ‘refining’ its approach to composites in the A350 XWB, or proceeding on the basis that it was confident of making them work much better in its design than appears to have been the case so far in the Dreamliner.
Which of course, is how Airbus would like to play it. The largest use of composite components in any airliner yet to fly is in the A380, notably in its central wing box area and wings. If it is working on a ’surprise’ revision of anything in the A350 XWB, it certainly wasn’t going to announce it in Sydney this morning.
Could microwaves cure a composite problem?
Posted by Billburwrite at 11/4/2009 4:40 AM CST
It looks like microwave oven technology has found another use – thanks to its ability to heat objects and liquids from the inside outwards. According to Ray Grainger, Senior Technical Director and Chief Technologist at GKN Aerospace, it’s proving to be a very effective way to cure carbon composite structures. He said recent test results suggest that microwave-curing bonds the fibre layers better than autoclave curing, increasing internal integration and resulting in a stronger product.
Grainger said the microwave process simply requires uncured composite to be placed on a tool or in a mould and sealed in a vacuum before being ‘cooked’ by microwaves – a process which takes around two hours, compared to the 12-hour curing cycles of today’s autoclaves.
A further advantage is that microwaves can be focused to cure selected sections of a structure, enabling large composite structures to be made in several parts. Each component can be made and cured, while the sections where they join can be left uncured. Once these components are assembled however, the joints are cured separately, bonding the elements together as a complete structure. If further tests validate these results, microwave-cured composite will likely become the industry standard.
This is timely technology for GKN Aerospace, as it’s already committed to a £180 million investment to manufacture composite components for the Airbus A350 at two newly acquired facilities near Filton.
(CercleFinance.com) - EADS Innovation Works, la branche de recherche et
développement (R&D) d'EADS, annonce avoir été récompensée par JEC
Group, une organisation chargée de promouvoir les matériaux composites.
La filiale d'EADS précise avoir reçu deux récompenses, la première portant
sur une technologie de tressage non directionnelle pour la production
de cadres composites d'avions et la seconde sur l'assemblage de
structures aéronautiques composites à partir d'adhésifs structurels.
les technologies, développées au sein du centre Airbus Composite Technology
à Stade (Allemagne) sont en train d'être évaluées pour une éventuelle
utilisation au sein de l'A350 XWB.