ANALYSIS: A400M Grizzly bares all

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As Airbus Military prepares to deliver its first production example to the French air force, Flightglobal puts Europe's new airlift and refuelling asset through its paces

The A400M is Airbus Military's first bespoke product and traces its roots to a European Staff Requirement for a more capable airlifter for the 21st century. In broad terms the type would replace the C160 Transall and Lockheed Martin C-130 Hercules of purchasing countries' air forces. The eight partner nations specified an aircraft that could perform both tactical and strategic airlift roles.

Airbus Military and project partners Turkish Aerospace Industries and Belgium's Flabel realised that in an era of tight budgets, any new aircraft would have to be able to fulfil a number of roles. In addition to transport duties, the A400M would be designed from the outset to provide an aerial refuelling capability. It would be no mere form/fit/function replacement for the C-130; but offer dramatically improved performance and operational capabilities.

The first A400M development aircraft was rolled out from Airbus Military's Seville production facility in Spain on 26 June 2008. The medium transport features the largest Western turboprop engines to date swinging massive eight-bladed scimitar propellers. The first Grizzly, as the five developmental aircraft became nicknamed, was flown on 11 December 2009. Following an extensive developmental programme, Airbus Military is set to deliver the first operational A400M, or Atlas, to the French air force in late June or early July 2013. In advance of the milestone being achieved, Flight International was invited to Toulouse to fly the new-generation product.

HEAVY LIFTING

From an overall size perspective the A400M slots neatly between the C-130J-30 Super Hercules ­and the Boeing C-17. Like both these US airlifters, the business end of the A400M features a flat-floored cargo hold with an aft-mounted ramp.

The A400M can carry a total of nine 463L (88 x 108in) cargo pallets: one more than the C-130J-30 and nine fewer than the C-17. Two variants of the LD7 civil pallet can also be transported, with dimensions of 88 x 125in and 96 x 125in. All three airlifters can be operated with a single loadmaster, working from a dedicated station in the cargo hold.

While palletised cargo capability is one measure of a transport's usefulness, the ability to carry outsized loads has assumed greater importance. Pallets can be loaded on any number of civil freighters and landed at in-theatre logistics bases. Moving armoured fighting vehicles and helicopters for deploying rapid reaction forces demands a voluminous cargo hold. The A400M has demonstrated the ability to load both the NH Industries NH90 and Eurocopter EC725 helicopters with minimal disassembly. Airbus Military is confident it will even be able to load a Boeing CH-47 Chinook heavy-lift helicopter.

In addition to its large cargo hold and respectable 37t maximum payload, the A400M has a unique aerial tanker capability. Several variants of the C-130 can refuel slow-moving aircraft and helicopters from wing-mounted hose and drogue units. This capability has proven to be an effective force multiplier for combat search and rescue operations, as well as special operations missions.

With a top speed of less than Mach 0.58 the C-130J would struggle to refuel tactical jets. The A400M has a top-end calibrated airspeed giving it the ability to refuel fighters, but it will also support helicopters flying as slow as 105kt (194km/h). It comes plumbed for aerial tanking duties, with the option for two wing-mounted pods as well as a ramp centerline-mounted hose and drum unit. Offloaded fuel is from the A400M's normal fuel system, but additional capability can be realised with the installation of optional pallet-mounted cargo hold fuel tanks. These are connected directly to the aircraft's fuel system and controlled by the centralised fuel management system.

In terms of range and payload, compared to the C130-J the A400M excels. At cruise, the Super Hercules has a true airspeed in the region of 348kt, while the A400M can comfortably cruise at 422kt. In general terms the A400M can carry the same payload twice as far, or twice the payload the same distance. Compared to the C-17, which cruises at speeds between M0.74 and M0.77, the more fuel-efficient A400M cruises in the M0.68-0.72 range.

How this plays out in operational terms can be illustrated by France's recent Mali operations. With the A400M, according to Airbus Military chief test pilot Ed Strongman, the French forces could have been deployed more rapidly, and with a dramatic reduction in total air movements.

Assuming staging out of Istres air base in the south of France and arrival in Bamako, Mali, the A400M would require only 5h 30min to transport 31t of cargo. The air force's current Transall would require 10h to deliver only 5t, while a C-130 would need 7h 30min to deliver 13t. "While C-17s were used to deliver outsized cargo and fighting vehicles, it was to Bamako, which was 900km [486nm] from the front lines," says Strongman.

FIRST IMPRESSIONS

Our preview flight was flown out of Toulouse Blagnac, with Strongman acting as the pilot in command. Prior to the flight he introduced me to the A400M and our proposed flight profile with a session in a fixed-base engineering developmental simulator. The preview aircraft, MSN6/F-WWMZ/Grizzly 5, was production-representative, with the exception of some software loadings. The aircraft was configured with an air refuelling receiver probe, but did not have wing-mounted pods installed.

Parked on the ramp at Airbus's Toulouse facility, the A400M looked out of place, surrounded by a large variety and number of civil airliners. While the grey camouflage paint is new, it lacks the shine of a passenger aircraft.

The A400M's appearance screams that this is not your typical Airbus. The high wing, four Europrop International TP400-D6 turboprop engines and fuselage-mounted main landing gear pontoons all say military transport. The general configuration of the A400M is the same as the venerable Hercules.

Closer examination however, reveals an aircraft that is more akin to the C-17. In place of the C-130's straight, highly cambered wing, the A400M has a thin supercritical one with 15˚ of sweep. Instead of a fuselage-mounted horizontal stabiliser and elevator, it has a high-mounted all-moving T-tail. The propeller-driven A400M was built for speed.

I accompanied Airbus test pilot Frank Chapman, second in command for the flight, as he accomplished the pre-flight walk around inspection. The most notable feature of the A400M is its four large 5.33m (17.5ft) diameter propellers. The scimitar shape of the composite blades clearly indicated their direction of rotation. Western turboprops, when viewed from behind, rotate in a clockwise direction.

DOWN BETWEEN THE ENGINES

For the A400M Airbus has developed a unique down-between-the-engines (DBE) scheme for propeller rotation direction. Engines 1 and 3 rotate clockwise, while 2 and 4 have an idler gear installed that gives them an anti-clockwise rotation. This is a marked departure from the typical counter-rotation scheme that has all engines on a wing turning in the same direction.

The DBE configuration produces a more symmetrical flow over the wing, improving lift and handling qualities while allowing for smaller (less drag-inducing) tail surfaces. The symmetric propeller slipstreams also allow for mirror image wing structure and reduced structural weight due to lower wing bending moment loads. Finally, the DBE configuration has a benefit for passengers in the cargo compartment, too. Airbus had planned to install active acoustic dampeners to muffle the sound of the propellers. The DBE configuration has the blade closest to the fuselage travelling upwards, which reduces cargo compartment noise by approximately 1dB.

Other features noted during pre-flight include ventral fins placed near the tail cone to reduce drag. Several aspects of the main landing gear pontoons also caught my eye.

During early flight test activities small lateral oscillations were noted in some flight conditions. Drawing on lessons learned in the development of the Transall, a small fin was placed on the lower (doors closed) aft surface of each gear pontoon. These small surfaces did the trick and the annoying motions stopped.

Located above the aft portion of each main landing gear pontoon is a paratroop door with a cheese grater-style blast deflector forward. The gear pontoon is notched to accommodate the door while providing a flat step for paratrooper exit.

Having been a jumpmaster on and jumped from the C-130 a number of times, I have witnessed paratroopers hitting the fuselage on exit as they got caught in the fuselage's boundary layer/slipstream. While a "vigorous" exit prevents this, the A400M's step located away from the fuselage may make for a smoother exit for static line paratroopers.

Additionally, the DBE symmetrical airflow should ensure equally good separation for sticks (paratroopers) exiting both side doors.