The next generation of Tactical Air Transport capability for the RAF is the Airbus A400M 'Atlas'.
The A400M Atlas isn’t a C-17 and (although the visuals are closer) nor is it C-130 - but then it isn’t supposed to be! Atlas is designed and scheduled to replace the C-130J in the tactical air transport and special forces’ support roles and to complement Voyager and C-17 in providing air mobility to the Future Forces.
With the future forces likely to be reliant on bulky, heavy protected mobility vehicles and humanitarian operations looking to deliver relief more quickly to more remote or desolate regions, the Atlas requirement was: ‘to deliver what youcan’t get into a Hercules into landing zones that a C-17 can’t get into’.
Delving into a little technical detail, this article is a gallop through some of key design areas that are needed to meet the challenge
The Business End. As with all air mobility aircraft, one of the most important features of A400M Atlas is the cargo bay. The A400M is capable of carrying up to 37 tonnes of payload with the cargo hold dimensions optimised for carriage of heavy vehicles, helicopters or cargo pallets along the central cargo area and troops seated at either side. For combat operations, Atlas can carry protected vehicles with side armour and top-mounted guns fitted allowing a deploying force to arrive ready to fight. In the humanitarian role, it can deploy a mobile crane or an excavator and large dump truck for clearing earthquake sites.
Treading Softly. Each Atlas main landing gear unit consists of three independent struts with twin wheel and brake assemblies and is designed to operate in rugged terrain and to evenly distribute ground loads into the fuselage structure. Braking is provided through 12 multi-disc carbon brakes units which are at the heart of the aircraft’s impressive short-field performance.
A Level Playing Field? Atlas will often find itself operating from austere or unprepared surfaces and with rudimentary loading vehicles. In these circumstances, the air loadmaster, can manipulate the landing gear to make the aircraft ‘kneel’ and ‘roll’ in order to make load transfers easier and faster. Symmetrical kneeling of the main landing gear legs is used to adjust the height and longitudinal inclination of the cargo hold floor. Asymmetrical rolling can be used to compensate for differences in shock absorber compression, or when the aircraftis parked on uneven ground.
On British Wings. The wings for all 174 Atlas aircraft will be made in Filton near Bristol and benefit from the UK’s position as a global leader in wing design and technology. Advanced 3D computational fluid dynamics has been used to optimise the wing shape, resulting in a low drag design which permits a high cruise speed of Mach 0.72, without compromising low speed performance and handling. But it is not just the shape of the wing which is ‘special’. The wing forms part of about 30% of the Atlas structure which is made of composite materials. This includes the wings’ 19m (62ft) skin panels which are the largest ever produced and, for the first time in history, a main spar which is made from composites. The extensive use of composite material enables Atlas to be much lighter and enhances the aircraft’s performance both in terms of range and payload.
The Driving Force. One of the key elements of the Atlas’s versatility is its all-new, specifically designed three-shaft turboprop engine with iconic scimitar-shaped, eight-bladed propellers. At 11,000 shp, the ‘TP400’ is the most powerful turboprop in production. It allows a wide range of speeds and flight levels and offers extremely efficient fuel consumption. Four of these turboprops allow Atlas to operate at altitudes as high as 37,000 ft at speeds up to Mach 0.72. At the other end of the ‘envelope’, the A400M can safely operate at 110 kt at low level to drop equipment and supplies.
Down Between the Engines? One of the most notable differences between Atlas and other turboprop aircraft is that the two propellers on each wing turn in opposite directions (towards each other). This ‘Down Between the Engines’ counter-rotation produces a more symmetrical airflow over the wing, which improves lift, aircraft handling and stability. As well as allowing a reduction in the structural weight of the wing, the arrangement reduces the adverse yaw in case of an engine failure and gives a 4% increase in the lift at low speed and reduces the level of vibrations and therefore the noise inside the aircraft.
A Fully-Loaded Flight Deck! The Atlas cockpit comes fully loaded with pilot’s ‘toys’. It features Head-up-Dispays(HUD) which provide the pilots with all primary flight information together with eight large interchangeable LCD head-down displays. There is also an Enhanced Vision System (EVS) based on Forward Looking Infra Red (FLIR) technology which, in low visibility conditions can project an image of the environment in front of the aircraft onto the HUD.
RP Defense note : thank you to Think Defence for the information !!