The Airbus A350: Thermo/fluid dynamics principles

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The Problem


Hallam Engineering which is a Limited Partnership consultancy firm was approached by Airbus to provide engineering expertise to analyze the A350 and recommended design changes to improve the product or operation. The task includes A350 to be analyzed to assess the current performance and use the information obtained to make an informed suggestion on how it could be improved. The potential impact of the improved operation or cost saving to be included to justify the substantial investment Airbus has made in employing Hallam Engineering Limited Partnership.


The Airbus A350: Thermo/fluid dynamics principles


Flight Physics include the non specific design activities that carry the data used for the detailed design of aircraft components & systems. Inside Flight Physics in Airbus UK there are 3 main areas: loads & aero elastics, aerodynamics, and mass properties.


Aerodynamics has dependability for ensuring the aircraft design meets the aerodynamic flight presentation requirements. Chief activities include design of the wing shape, supplementary in the development of the aircraft configuration and generation of aerodynamic data for use by other disciplines.

Loads &Aero elastics

The loads team concludes the aircraft loads that outcome from most tremendous conditions an aircraft might meet during its lifetime. These loads are used to set minimum level of strength necessary for the structure. Loads work involves applying, developing & validating mathematical models that symbolize the response of aircraft. The team also ensures any new aircraft design will be without charge from divergent or oscillatory aero elastic behavior.

Mass Properties

Mass Properties is accountable for tracking & predicting the weight of the aircraft as the design develops. The overall aim is to make sure that the optimal mass is achieved for every component based on a negotiation between manufacturing capabilities, design limitations, cost & time. To accomplish this aim, Engineers build up, validate & deploy mass prediction tools that are used to predict component weight & on the whole aircraft weight.


Discussion: Problems and recommended design changes


Airbus brings all together the very most recent in aerodynamics, design& advanced technologies in  A350 XWB to provide a 25% step-change in fuel effectiveness compared to its present long-range competitor. Contributing to this performance are Rolls-Royce Trent XWB engines that power the A350 XWB family.

Over 70% of A350 XWB’s weight efficient airframe is made from superior materials, combining 53% of composite structures with titanium & advanced aluminum alloys. The aircraft’s inventive all-new Carbon Fiber Reinforced Plastic (CFRP) fuselage consequences in lower fuel consumption, as well as easy maintenance.

The A350 XWB’s broad fuselage cross-section was considered for an optimal travel experience in all modules of service.  Passengers will take pleasure in more headroom, broad panoramic windows & larger overhead storage space.  With a range of 220 inches from support to armrest, the jetliner’s cabin provides the widest seats in its category, being five inches larger than its adjacent competitor.  additionally to provide the space for supreme premium first class & business solutions, A350 XWB permits for high comfort economy seating in a 9-abreast agreement, with Airbus’ standard 18-inch seat breadth.

Rest areas for flight crew that are used in long range operations – are situated in the fuselage’s crown area, contributing unequalled comfort for devoid of reducing overall returns passenger seating capacity. Cabin crew members will make use of a rest facility in the A350 XWB’s rear fuselage that accommodates 6 to 8 bunks. It has a full height standing area, provided that a comfortable zone that allows crews to prepare & dress more easily.


The high lift system is one of most mechanically complex systems on aircraft.
The system consists of a composite series of mechanical actuators, drive-shafts & linkages that set up the slat & flap systems for take-off & landing.

Due to the possibility to generate roll irregularity that could not be controlled if deflections were dissimilar between left & right hand wings, the systems also consist of a complex detection system to lock the slats & flaps in place if a failure is noticed. The A350 XWB high lift system also includes new technology with the Advanced Drop Hinge Flap (ADHF) system.

A new trailing-edge high-lift system has been accepted with a superior dropped hinge flap, which authorize the gap between trailing edge & flap to be closed with spoiler.

A stub flap is center of attention to simulate air loads formed by pneumatic cylinder being compressed by a hydraulically operated frame.

The Airbus high raise ‘zero’ rig, situated in Bremen (Germany), consists of a complete left hand ‘wing’ with all systems that will be found establish on MSN001. The aircraft structure is not present & is replacing by a steel structure to permit the system to be installed & operated. The right hand wing is replicated by a high technology electro-hydraulic brake system. This test rig is used to carry out many safety tests former to the first flight to make sure safety. A number of tests are performing on this rig that would be too hazardous to perform in flight – purposeful failures of drive or shafts link, for example.

The A350 XWB high raise ‘zero’ has been prepared since late 2011 & was promoted to full MSN001 arrangement with real flaps established in September 2012

The new high-lift flap, which has been unproved by Airbus, is a plunge hinge design& consists of a beam through a rotation point. Elected as the “advanced dropped hinge flap,” it is simpler than a predictable flap & requires less moving parts, resultant in a half tone weight reduction. It is also easier & less costly to maintain.

The main landing gear for -1000 variant of A350 XWB will be provided by Goodrich when Messier-Dowty is providing the main landing gear for smaller A350-900 & -800.
The A350-1000 works at higher design weights than A350-900/-800 & features an all-new, 6-wheel main landing gear evaluate to the 4-wheel design of other A350 models. Airbus commences a call for tender to protect best overall value for A350-1000. After methodical evaluation of competitive bids – covering a broad range of criteria – Goodrich was elected” said Airbus.


Goodrich is to construct the engine nacelle for A350’s GEnx engine, with Airbus providing the composite inlet, which integrate a “zero splice” acoustic inner barrel to offer a new level of fan-noise reduction. Preparations for Trent 1700 nacelle have not been finalized. Contrasting the 787& 747-8 nacelles, the A350 unit does not integrate noise-reducing chevrons. “We dint get a noise advantage from chevrons, & there is an exact fuel consumption punishment, so we have not approve them,” says Hunter.
Airbus is functioning with designers on an all-new cabin for A350, with a mock-up predictable to be revealing in Toulouse later this year. The producer is looking at integrate innovations from t A380, as well as new ideas.
It is a little over 4 years until A350 is due to go in service – in mid-2010 – roughly 24 months after its US rival. Airbus engineers know they must keep approaching to make sure that they can turn its later entrance into an advantage & wring the max. Out of A350’s specification.

The doors are hinged back-to-back in center of fuselage & open only when landing gear are deployed or retracted. Located below each wing, adjoining to fuselage, each landing gear levers inmost for storage under the fuselage. The MLGDs are flat & rectangular apart from a 0.9m broad curved tab that expands from end opposite the pivot to conform to fuselage curvature.

Daher-Socata made decision to design A350 XWB’s MLGD with distort built in to keep the door snug & rattle-free.
Engineers exposed that continually changing air pressures as the aircraft changes altitude & airspeed cause MLGD to change shape. Designers determined where & how these changes occurred & then used that data to optimize design.

After numerous iterations, Daher-Socata designer developed on a final “distorted” design that incorporated an obvious gap of indefinite dimension at the door closure between MLGD edge & landing gear opening in the underside of plane. To match both objectives: to properly stress the door & to meet aerodynamic requirements.


Simulating reality

Advancement in simulation technology are functional to A350 XWB program me – factually from nose to tail.

A validation simulator has been used ever since 2009 to expand how pilots will interrelate with systems in cockpit, whereas two development simulators have been ready from 2011 to confirm a proper incorporation of the airliner’s electronics using real systems.

To make sure a close synchronization that is truly global, the same Airbus teams concerned in its own incorporation testing are working with the universal supplier network to monitor & assist in their test activities.

The “Iron Bird”

Airbus’ systems incorporation test bench is the ideal tool to corroborate characteristics of all system mechanism.

Located inside a shed at Airbus, Toulouse & France’ ground-based systems incorporation test bench – also recognized as “Iron Bird” – provides a significant resource in authenticating the workings the spirit of its next-generation aircraft. With a diversity of vantage points for engineers to review the movements, this skeleton-like installation is a delegate layout of A350 XWB’s systems, electrical network, hydraulic pumps & flight controls, which are cycled to symbolize their operation in airline service.

The “Iron Bird” rig has assisted Airbus identify issues correlated to the incorporation of complex systems that computer testing unaccompanied might not catch. As a result, Airbus has made numerous improvements to A350 XWB’s hardware & software, which have now integrated into the aircraft.

Airbus’ devoted A350 XWB rig has been in use as 2010, well before construction began on the first jetliners.


 Aircraft “0”

Airbus took its in-house testing attitude one step more by linking incorporation simulators with the A350 XWB “Iron Bird” to check aircraft functions.

Throughout this tie-up which replicates a broad range of in-flight situations, Airbus has formed a so-called “Aircraft 0” demonstration of A350 XWB that permit for highly sensible virtual testing.

Other ground test fitting also add to testing – including a fix in Bremen, Germany that fully symbolize the wing’s high-lift moving surfaces, a landing gear test ability in Filton, UK for the authentication of braking & steering functionality, & a platform in Hamburg, Germany that the process of such passenger cabin functions as ventilation & handling of waste water.

Electrical circuits in the jetliner’s forward & centre fuselage sections are experienced in an automated process at Airbus’ Saint-Nazaire facility in France, which formerly evaluated these components by hand. The automated validations considerably reduce the duration of testing, both for the A350 XWB & for other programmers – together with the A400M military airlifter.

The Trent XWB engine takes flight

Airbus’ flying test bed aircraft already have fruitfully evaluated A350 XWB components.

Even previous to the first A350 XWB carry out its maiden takeoff, key elements of aircraft are being put from side to side their paces using Airbus flying test bed aircraft. The most noticeable is Rolls-Royce Trent XWB engine, which has been established on A380 development aircraft for airborne assessment of power plant, its superior nacelle housing & thrust reverser system.

Other Airbus test aircraft – as well as its in-house A320 and A340 – have been particularly fitted & equipped to authenticate A350 XWB components that include landing gear door sensors, cockpit oxygen masks, the digital radio altimeter, the first officer’s seat & more. additionally, tests on A350 XWB sections have been carry out during Beluga transportation flights – authenticates the thermal assumptions made during design process in low temperatures found during flight.

For A350 XWB’s real flight testing, a total of 5 aircraft will be consumed in a 12- month certification campaign, which includes 2 fully outfitted with passenger cabins.

The future takes shape

From nose to tail & wingtip to wingtip, the A350 XWB integrates design features that not only make it imposing to look at, but amazing to fly as well.

As an effect of this approach, 350 XWB will live up to its pledge of shaping future & improving the competence of airline operations on medium- & long-haul flights.


From the first look, it’s clear that Airbus’ next-generation wide body jetliner fit in in the sky.

The A350 XWB’s sleek lines commence at its forward fuselage, with a sleek nose & curved wrap-around cockpit windows that give aircraft a sole sporty look – while also contributing to its outstanding aerodynamic efficiency.

Not only are A350 XWB’s pointed wings pleasing to eye, they are of an higher aerodynamic design that benefits from improvement already proven on A380, while also integrate further improvements urbanized by Airbus engineers.

Optimized for a fast journey speed of Mach 0.85, they improve the A350 XWB’s on the whole operational effectiveness & improve the jetliner’s range.

By removing end-taper that is characteristic on profitable aircraft fuselages,  A350 XWB retains the full side by side seat count in rear, maximizes the soothe for passengers in this section, & provides more operational area for cabin crew in rear galley zone.



Airbus’ A350 XWB establishes that beauty is added than skin-deep.

By assimilating state-of-the-art systems that are robust & efficient, Airbus has convey a new level of intelligence to A350 XWB, while also rising reliability & lowering maintenance requirements.

The use of fully electrical 3-axis flight controls takes this Airbus-pioneered fly-by-wire technology to its next level on A350 XWB, based on millions of hours logged with company’s A320, A380, and A330/A340 & Family aircraft.

Operators will promote from the improved flight safety, reduced pilot workload & reduction of mechanical parts that come with fly-by-wire – all along with operational commonality crossways the product line, Airbus individuality.

The A350 XWB also has an Airbus urbanized fully duplex network backbone that progress data exchange capabilities on board the aircraft, with its 1,000-fold increase in bandwidth behind the transfer of more digital data with fewer boxes & less cables.

This (Avionics Full Duplex Switched Ethernet) AFDX® configuration was first used on A380 & is perfect for demanding in-flight applications, while make simpler data exchange when compared to preceding protocols.

Another A380-proven idea is A350 XWB’s use of two hydraulic circuits, as an alternative of 3 on other jetliners, with repeatedness provided by a dual-channel electro-hydraulic backup system. additionally, the jetliner’s hydraulics will be manage at the high level of  pressure 5,000 psi., which also has been authenticated on A380.

Such increased operating pressure decrease size of pipes, actuators &other system components while also make easy the overall access – leading to improved reliability & maintainability, as well as reducing weight & increasing cost savings.


Built with (CFRP) carbon-fiber reinforced plastic, A350 XWB’s all-new fuselage supports easier maintenance, lower fuel burn & increased resistance to corrosion.

More than 70% of A350 XWB’s airframe is made of advanced materials – take together the best attributes of composites, titanium &advanced aluminum alloys precisely where they are needed.

Most of A350 XWB’s wing is made of lightweight carbon composites, including its upper & lower covers – measuring 32 mts length by six mts breadth, making them largest single aviation parts ever made from carbon fiber.

The wing’s superior structural design, combined with its higher aerodynamics, is a major contributor to jetliner’s 25-% fuel-saving performance.

The intelligent application of modern, high-tech materials is demonstrated by A350 XWB’s nose section, which uses a mixture of 55% aluminum-lithium alloys, 40% composites & 5% titanium.


Less fuel burn and CO2 emissions

The A350 XWB has been premeditated to be competent from gate to gate, which means lower noise & fewer emissions at every stage of journey.

Airbus brings mutually the very latest in aerodynamics, design & advanced technologies in A350 XWB to provide a 25 % step-change in fuel efficiency contrast to its current long-range competitor.

Contributing to this presentation are Rolls-Royce Trent XWB engines that control the A350 XWB Family. As over 70% of A350 XWB’s weight-efficient airframe is made from superior materials, combining 53% of composite structures with fully ecological titanium & advanced aluminum alloys, the aircraft’s inventive all-new(CFRP( Carbon Fiber Reinforced Plastic fuselage also consequences in lower fuel consumption.

Simply put, every tone of fuel saved means more than 3 tones of CO2 evade, &the A350 XWB’s operations make sure margins for both current & future international environmental protection regulations.

Less noise

With operations that are quieter than most recent worldwide requirements, A350 XWB is a good neighbor.

Airbus engineers have developed or enhanced several functionalities that will be presented as standard on A350 XWB.

These embrace the Automatic (NADP) Noise Abatement Departure Procedure), which optimizes the thrust & flight path to reduce the noise above crowded areas.

This means significantly less noise around airports, extenuating noise nuisance in airport surrounds.


Fewer chemicals

The A350 XWB design favors environmentally-friendly materials in produce of aircraft.

The A350 XWB design favors materials that lower environmental footprint of aircraft’s manufacture.

One way of attaining the objective is to substitute the standard chrome-plating process with a thermal spray option. This dry procedure produces a dense metal coating, which gives same properties as chrome plating – including corrosion resistance; wear resistance, low oxide content, low porosity, low stress & high bonding strength to base metal.

As other example, the picture of A350 XWBs in airline colors will use chromate-free primer paint. Additionally, following best practices from auto industry, Airbus will use a new clear coat system that requires less paint & less solvent. This painting procedure also means that less detergent will be needed when wash the aircraft. To decrease the environmental impact of its painting process even additional, Airbus will use, everywhere possible, water-based paint inside the jetliner.

Airbus has formed a bridge between the virtual & real worlds with its A350 XWB Digital Mock-Up, which supply a high-definition representation of aircraft – right down to smallest parts – on computer screens. It also strengthen Airbus’ role as an integrator, & capitalizes on company’s decades of experience from previous programmers.

This very realistic digital version of A350 XWB has factually changed the way aircraft are visualized, as it allows an accurate visualization of where systems are situated during design, how they are put in production & what access is available for preservation during jetliner’s operational lifetime.

By opening this Digital Mock-Up to the 1000s of A350 XWB designers & engineers at Airbus & its key suppliers, the tool provides shared real-time access to a rich database with highly comprehensive information.

Its pragmatism goes even further, enabling airlines to help visualize such aspects as how the passenger cabin will look, to organize ground operations while the aircraft is at an airport gate, & to train their workings – all of which is possible well in front of the A350 XWB’s entry into service.

The onboard systems of Airbus’ A350 XWB were intended with maximum reliability, operability & simplicity in mind.

Many of these systems are consequent from A380, providing the advantages of operational experience & ensuring a high level of maturity from their introduction by airlines.

In 1 example, the jetliner’s hydraulics will be function at a higher pressure level – as is the case on A380 – which decreases the size of pipes, actuators & other system components while also lowering aircraft weight for better performance & more payloads.

(IMA) Integrated modular avionics & (AFDX) multiplexed buses also are resulting from A380, with enriched functionalities – such as remote data concentrators – spread all along the fuselage to decrease wiring length & response time.

Airbus uses solid-state command control technology on A350 XWB, providing a new method of power control management throughout the aircraft that abolish the need for individual circuit breakers in cockpit, cabin & electronics bay.

Built chiefly from carbon composite materials, the wing – which combines aerodynamic enhancements by now validated on A380 with additional improvements developed by Airbus engineers – has been methodically tested in advance with cutting-edge computer technology & in wind tunnels, optimizing it for fast cruise speeds that reduce trip times, perk up overall efficiency & extend aircraft’s range.

By intelligently controlling A350 XWB wing’s moving exterior using on-board computer systems, the wing will be “morphed” while in the air – tailoring it for maximum aerodynamic competence in the various phases of flight.

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