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Monday, 1 July 2013

When talking about materials innovation the key codes are A380 - A350: Light weight materials,CFRP's, Al, Ti..Light weight concepts, eco-efficiency,green-design


"The A350 XWB is an all-new design offering a step-change 
in lower seat mile costs requested by the market for its 
next-generation of twin-aisle, long-range jetliners"
according to Airbus Industries' Le Bourget website, ref. below.
Several photos due to Airbus Industries are reproduced below but their is a very large selection
to be found in the reference 1. below

Over 70 per cent of the A350 XWB’s weight-efficient airframe is made from advanced materials, combining 53 per cent of composite structures with titanium and advanced aluminium alloys, the aircraft’s innovative all-new Carbon Fibre Reinforced Plastic (CFRP) fuselage also results in lower fuel consumption

A350 Graphic

KEY DESIGN FEATURES driving this improvement in economic efficiency are:
- the extensive use of lightweight composite materials for lower weight 
and maintenance costs; 
-the implementation of simple, efficient and 
proven systems, including integrated modular avionics; 
-the application of state-of-the-art aerodynamics; and the use of latest-generation engines with the lowest fuel consumption and reduced emissions.

Composites, titanium and advanced aluminium-alloys are applied extensively throughout the A350 XWB’s fuselage, with their use tailored to the best characteristics of these materials. (1) The 53 per cent of composites utilised in the fuselage and wing reduces the need for fatigue-related inspections required on more traditional aluminium jetliners. (2) The composites and titanium also diminish the requirement for corrosion-related maintenance checks on the A350 XWB.
These two factors reduce the new aircraft’s overall fatigue and corrosion maintenance tasks by 60 per cent. 
Construction of the A350 XWB’s fuselage sections is made by assembling four-skin panel sections – two lateral side panels, one at the crown, and another for the belly – onto carbon fibre frames. In contrast to other composite aircraft, this construction technique allows for a tailoring of composite layup thickness to each panel, based on calculations of local fuselage stresses and loads.

The A350 XWB’s onboard systems are designed for maximum reliability, operability and simplicity. They are optimised for two primary criteria: (1) Robustness for ensured reliability and operability; (2) Simplicity for reduced maintenance time and cost.

                                 INFLUENCE OF THE AIRBUS FLAGSHIP -THE A380 
Many of these systems are derived from Airbus’ A380, providing the advantages of operational experience with this 21st century flagship aircraft and ensuring a high level of maturity at the A350’s XWB entry into service. 
(1) Solid-state power control technology on the A350 XWB eliminates the need for individual circuit breakers in the cockpit, cabin and electronics bay – providing a modern method of power control management throughout the aircraft.
(2) The application of variable frequency generators, which were first introduced with the A380, provides more power with less weight and lower maintenance costs, along with increased reliability and time-between-removals.
(3) Another A380-proven concept is the use of two hydraulic circuits (instead of three on other jetliners), with redundancy provided by a dual-channel electro-hydraulic backup system. In addition, A350 XWB’s hydraulics will be operated at the higher pressure level of 5,000 psi., which also is used on the A380. This increased operating pressure reduces the size of pipes, actuators and other system components while also facilitating the overall access – leading to improved reliability and maintainability, as well as reducing weight and increasing cost savings.
Highly efficient wing

The A350 XWB will be a faster, more efficient and quieter aircraft as the result of its advanced wing design – which combines aerodynamic enhancements already validated on the A380 with further improvements developed by Airbus engineers.
(1) Built primarily from carbon composite materials, the wing is optimised through extensive use of computational fluid dynamics and wind tunnel testing for a fast cruise speed of Mach 0.85. This reduces trip times, improves overall efficiency, and extends the aircraft’s range. 

(2) Both scaling & tailoring are permitted: a) Scaling. All three A350 XWB family members share the same wing planform – with a 64.7-metre wingspan, a total area of 442 sq. metres, and high swept leading edge. b)Tailored: In addition the internal wing structure will be scaled to meet the specific requirements of each aircraft variant. 
(3) Innovative concepts applied to the A350 XWB wing’s high-lift devices will reduce noise and drag while also improving the aircraft’s low-speed performance.  NB. One of these innovations is the stream-wise deployment of trailing-edge flaps. On a traditional swept-wing jetliner, the outboard flaps extend at an angle to the airflow. For the A350 XWB, flap deployment is along the direction of flight – resulting in better lift efficiency and improved low-speed performance, while reducing aerodynamic-generated noise. 

(4) Other A350 XWB wing enhancements include;
-4a. the adoption of a drop-hinge mechanism to improve the flap’s deployment kinetics, along with
-4b. the introduction of a downwards movement for the upper wing spoilers to fill the gaps that occur when flaps are extended.
-4c. In addition, the A350 XWB’s flight computer will perform in-flight trimming of the inboard and outboard flaps, creating a variable camber wing that adapts to different flight conditions.

REFERENCE 1. A350 XWB FAMILY:- Technology and Innovation

The A350 XWB has been designed to be eco-efficient from gate to gate ie. lower noise and fewer emissions at every single stage of the journey:

-1. It brings together the very latest in aerodynamics, design and advanced technologies in the A350 XWB to provide a 25 per cent step-change in fuel efficiency compared to its current long-range competitor.

-2. Contributing to this performance are the Rolls-Royce Trent XWB engines that power the A350 XWB Family. 

As over 70 per cent of the A350 XWB’s weight-efficient airframe is made from advanced materials, combining 53 per cent of composite structures with titanium and advanced aluminium alloys, the aircraft’s innovative all-new Carbon Fibre Reinforced Plastic (CFRP) fuselage also results in lower fuel consumption.

Simply put, every tonne of fuel saved means more than 3 tonnes of CO2 avoided, and the A350 XWB’s eco-efficient operation ensured margins for both current and future international environmental protection regulations.

A350XWB Eco-efficient

Less chemicals

The A350 XWB design favours environmentally-friendly materials in the manufacture of the aircraft.
Such as: 
1. Replacing the standard chrome-plating process with a more environmentally-friendly thermal spray alternative. This dry process produces a dense metal coating, which gives the same properties as chrome plating – including wear resistance, corrosion resistance, low oxide content, low stress, low porosity, and high bonding strength to the base metal.

2. The painting of A350 XWB's in airline colours uses an environmentally-friendly, chromate-free primer paint. Also following best practices from the auto industry, Airbus will use a new base coat/clear coat system that requires less paint and less solvent. This eco-efficient painting process also means that less detergent will be needed when washing the aircraft. Inside, the jetliner, Airbus will use, wherever possible, water-based paint – one of the most environmentally-friendly types of paint available.

A350 XWB


Eco-efficiency and recycling


Solar-cells on assembly-line roof

Eco-efficiency, recycling and end-of-life approaches

Eco-efficient, recycling-carbon-composites

Eco-efficient alternative-energy


The first striking feature is the sheer scale of the machine - the diameter of the set of fan blades at the front of the engine is 118 inches (299cm), the largest ever made by the British company and roomy enough to accommodate the fuselage of a Concorde.
The blades themselves, made of titanium, are hollow and strengthened inside by a microscopically small grid construction. GE has opted for fan blades made of composite materials.
The size of the fan enables the engine to suck in enough air to fill a squash court every second, and then squeeze it to the size of a fridge-freezer - what's known as a "compression ratio" of 50 to 1, the highest pressure Rolls-Royce has yet attained.
The larger the flow of air into the engine, and the greater the potential compression, the better the efficiency of the whole process.
When the mix of fuel and air is ignited, the resulting gas reaches an extraordinary temperature of 2,200C - a higher level than has been achieved before - which is meant to maximise the output of each drop of fuel.
The searing heat of 2,200C is in fact 700C hotter than the melting point of the components in the combustion chamber - including the turbine blades that are driven by this fast-expanding gas.
So each blade is drilled with a network of 300 tiny holes about the size of a human hair. This allows cooling air to flow in a thin film over the turbines' surface and act as a form of insulation.
To withstand this exceptional heat - and the massive pressures involved - the 68 turbine blades are made of a nickel-based alloy and are grown in a single crystal to avoid the risk of any internal fissures becoming sources of weakness.
The result is that each blade, driven by the expanding gases, generates as much power as a Formula One car, spinning an internal shaft that drives the massive fan blades at the engine's front.
On average, aircraft engines have become about 1% more fuel-efficient every year for the past two decades.
The claims by Rolls Royce will inevitably be followed by similar assertions by GE when its next engines are unveiled.
Airlines facing rising fuel prices are desperate to reduce costs, and the aviation industry as a whole is also under pressure to minimize its carbon emissions.
But as the latest generations of engines become more efficient, any reductions in greenhouse gases are outweighed by the global growth in air traffic, especially in Asia.
Dr Peter Hollingsworth, lecturer in aerospace engineering at Manchester University, said that basic physics meant that there were likely to be limits to how much more efficiency could be extracted from existing designs.
"It's a real challenge. With aviation growing at the rate it's growing, there's not a whole lot you can do. You can do the 1-2% average so over a number of years you get 20% but even that's a real challenge.
"Now that engines are a lot more efficient, a 20% improvement isn't worth as much as it was, so you're always working with diminishing returns and, at the same time, aviation is growing."
The aviation industry has set itself a target of a 50% reduction in carbon emissions by 2050 compared with 2005 levels - and there's a recognition that that will only be achievable with a revolutionary shift in designs.
Among the ideas being considered are engines that are embedded within the wings and contra-rotating propellers.
Alan Newby, chief engineer for advanced projects at Rolls-Royce, said: "Ultimately, if we're going to make these radical changes then the aircraft will have to starting looking different.

Science-Environment from BBC News, by Science Editor, David Shukman

Advanced technology

The engine will deliver…
  • module weight savings of 15 per cent and aerodynamic efficiency improvements via the use of compressor blisk technology
  • an optimised internal air system which reduces core air demand and reduces fuel burn
  • higher operating temperatures improve fuel burn. Latest generation material technologies so improvement achieved without degrading reliability
  • a combustor with proven reliability and that is cleaner than all current and future emissions targets
  • world-beating levels of performance and noise with reduced operational cost thanks to the latest fan system technologies
  • the highest efficiency turbine system of any Trent engine, which includes a second stage of IP turbine for improved efficiency and greater capability
  • new bearing system, using larger bearings with increased load capability bringing fuel burn benefits
  • most advanced engine health monitoring system for minimised operational disruption
The Trent XWB will be created by using advanced manufacturing techniques to develop a lighter, more capable and efficient engine to meet tomorrow’s operational needs.

Smart design

Intelligent innovation means…
  • maximised revenue earning potential for operators
  • life-cycle cost focus has been at the heart of all design ensuring the best for engine and aircraft performance
  • proven design with 65 million hours of Trent experience by the time the aircraft enters service in 2014

Rolls-Royce Civil Aviation Large Aircraft, The RR-Trent XWB

EngineStatic Thrust (lbf)Basic Engine Weight (lb)Thrust to Weight RatioLength (in)Fan Diameter (in)Entry Into ServiceApplications

Trent XWB-7575,000/79,000???1182014Airbus A350-800 XWB
Trent XWB-8484,000???1182013Airbus A350-900 XWB
Trent XWB-9797,000???1182015Airbus A350-1000 XWB

High Purity Cr sources for Superalloys

Energy for th Future:Phil.Trans.A-Vol. 365, N° 1853 / April 15, 2007, curtesy The Royal Soc. London

Engineered foams and porous materials: Phil Trans A. Vol 364, N° 1838 / 06 curtesy_The R Soc. Lond