Partners in production

Andrew Doyle/MUNICH

Eurofighter production is getting under way with the help of advanced manufacturing technologies

Four separate final assembly lines in four different countries, while politically expedient, is not the most efficient means of producing 620 Eurofighters for Germany, Italy, Spain and the UK. But the partner companies are keen to promote the cost savings being achieved as production of the aircraft gathers momentum.

Programme officials point out that final assembly represents only a small proportion of total manufacturing costs, and that there is virtually no duplication in the production of subassemblies that will arrive at each line.

Firm orders are in place for a first tranche of 148 aircraft and 363 Eurojet EJ200 engines (including spares), worth DM14 billion ($7.86 billion). This fixed-price agreement also covers procurement of long-lead items for the planned second tranche of 236 Eurofighters, which will be followed eventually by a third batch of 236.

The umbrella contract signed by the four countries covers a total of 620 aircraft plus 90 options, and workshare is split according to each nation's planned procurement. The UK's commitment to take 232 Eurofighters netted the country 37% of the manufacturing work, while Germany gets 30% for its 180-aircraft purchase. Italy and Spain have taken 19% and 14% respectively, in return for buying 121 and 87 aircraft, respectively.

All manufacturing is single-sourced and is divided as follows:

· British Aerospace - front fuselage, canards, windscreen and canopy, dorsal spine, vertical stabiliser, inboard flaperons and stage one of the aft fuselage;

· DaimlerChrysler Aerospace (Dasa) - central fuselage;

· Alenia - left wing, outboard flaperons and the second and third stages of the aft fuselage;

· CASA - right wing and leading edge slats.

First deliveries are due in 2001, when five instrumented production aircraft will join the seven Eurofighter prototypes in the flight test programme. The first operational deployment is expected the following year.

Dasa began manufacturing its first production parts in May last year. These included major fuselage frames and longerons, produced at the company's Augsburg factory. The first wing attachment frames for the centre fuselage, built by BAe, have also been delivered to Dasa.

"The workshare package is similar to that of the [Panavia] Tornado programme," says Dasa, "so, in Augsburg, we carry out the airframe centre-fuselage assembly and, in Manching, we carry out the equipping of the centre fuselage and the final assembly of the Eurofighters for Germany."

Infrastructure installation

The German firm says it had to start investing in manufacturing infrastructure before the production contracts were signed in late 1998 by the four participating countries, to ensure that first deliveries would take place by 2002.

Manufacturing equipment being installed by Dasa for Eurofighter production includes numerical control (NC) machines, automatic drilling and riveting devices, a paint cabin and non-destructive testing (NDT) facilities. Tooling for major components is also being manufactured, and the mould tool for the carbonfibre composite skin of the centre fuselage is complete.

"When we started with the production investment phase, we planned the aircraft manufacturing concept and, as a result, more than DM100 million-worth of special capital investments are now in the process of installation," says Dasa.

The centre fuselage is constructed in three sections, and production of the aft part began in November. This first section was placed in its assembly jig in December, while the forward centre fuselage parts were placed in the jig at Augsburg on 25 February. The first carbonfibre composite upper-half shell of the centre fuselage, which is 5m long and forms its outer skin, was completed later that month. This is undergoing NDT to ensure that it meets quality requirements.

"We will start equipping the centre fuselage in January and it is our plan to finish the first centre fuselage in September 2000," says Dasa. The first centre fuselage will be transferred to BAe, which is due to roll out the first aircraft in August 2001, two months ahead of the first German-assembled Eurofighter.

The start of Eurofighter production will lead to a slight increase in staff at Dasa, although productivity gains at the company's Airbus Industrie production lines in Hamburg will see some manpower transferred to the military programme, says Dasa.

Increased productivity will be a key difference between the era of Tornado production and that of the Eurofighter, says the company. For example, the centre fuselages for the Tornado were hand-riveted. "Now we have introduced special equipment to do it automatically," says Dasa, adding that this also improves repeatability, and therefore quality.

Another change is the extensive use of CATIA computer-aided design software, which helps to reduce lead times and scrap rates by allowing "virtual prototypes" of parts to be produced. "We have had a very good experience with the introduction of CATIA and the associated NC programming, and the results were very, very impressive for us," says Dasa.

Fewer parts, less cost

The ability to produce large, one-piece, carbonfibre composite parts is also helping to drive down costs by allowing a "significantly reduced number of parts". This reduced parts count should, in turn, improve the reliability of the aircraft itself.

The partner companies have set up a "technical interface" between their design departments, using CATIA, allowing the construction of a digital mock-up. Dasa's virtual centre fuselage, for example, is available online so that the engineers can iron out potential integration problems. "This allows us to prevent snags or mismatches during installation," says Dasa.

Each partner is responsible for quality inspection of their respective subassemblies, regardless of which of the four final assembly lines they are destined for.

BAe started its production phase with completion of the first batch of carbonfibre cockpit sills, and the UK company has begun assembling the front-fuselage cockpit half-sections. The first foreplane spigot frame for the forward fuselage has also been completed.

The company will build its subassemblies along a series of 12 production stations, the first of which has been tooled up. "We have only tooled the stations we require so far - station 12 isn't required until April 2000," says BAe director of Eurofighter production Neil McKay.

A major advance since the days of Tornado production is the introduction of a "flexible floor", says McKay. This is fitted with standardised "jig points", allowing the units to be moved around when required.

"You can change the floor layout much more easily," says McKay. "It's easy for us to meet our reduced lead-time requirements. If we find, for example, that there is a bottleneck and we need to double up the tooling, then we can do that.

"The whole process is quite remarkably different to that of the Tornado - it's built around composites, high-speed machining and superplastic forming. The potential to hit low lead-times is phenomenal," he adds.

Southern partners at work

Some £90 million ($144 million) has been invested in machines, tooling and infrastructure at BAe's Samlesbury site. Construction of the building where forward and aft fuselages will be assembled is complete, and an interchangable y-axis drilling machine has been delivered. This will be used to drill 1,000 rivet holes automatically in each forward fuselage. Also complete is the spigot frame manufacturing cell. Other equipment being installed at the site includes a CNC automatic drill and rivet machine, a "deep slotter" and an electron beam welder.

In Turin, Alenia began series production late last year, delivering longeron brackets to Dasa for installation in the centre fuselage subassembly. "The wing and rear fuselage manufacturing has started," says the Italian company. "The first wing will be delivered to BAe by the beginning of this autumn, together with the first rear fuselage." Tooling of the final assembly line is also under way.

Alenia is investing about L1 billion ($570,000) in new facilities for Eurofighter production, including a final-assembly building located at Caselle, a superplastic forming/diffusion bonding (SPF/DB) press, a clean room and production rigs for ground testing. Also, a carbonfibre manufacturing building has been erected at Foggia.

"The new technologies are improving the production process in terms of cost reduction, quality and reliability of the product and safety for production staff," says Alenia. The rear-fuselage keel, which separates the engines, will be built by Alenia, using SPF/DB technology.

CASA is constructing buildings at Getafe for production of the right wing and final assembly of the Eurofighters destined for the Spanish air force. High-speed milling machines are being installed at the company's production site at Tablada in Seville, and an SPF/DB press is being erected at Cadiz. The latter technology will also be used in the manufacture of the wing slats. Tooling for lower wing skin co-bonding has been tested and qualified by CASA in co-operation with Alenia.

Source: Flight International