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EUROFIGHTER SERIAL PRODUCTION AT DASA

The Eurofighter manufacturers may have the contract for serial production under their belts but, with fixed prices and penalty clauses, it is far from plain sailing. Unless production is efficient, profits will be modest. In Germany, Dasa is responsible for the mid section of the fuselage, which is being assembled in its long-established Augsburg plant.

The first tranche of Eurofighter full production of 148 aircraft will produce DM14 billion ($18.5 billion) of revenue for the participating countries. The total 620 aircraft for the consortium countries Germany, the United Kingdom, Italy and Spain plus the hoped-for export orders will come to many times more and will ensure that the factories are fully utilised until well after 2010.

But the era in which big military orders were extremely lucrative in terms of profits is a thing of the past. For Dasa, Alenia, BAE Systems and CASA the immediate imperative is therefore to maximise the efficiency of production of the high-tech fighter. Old habits had to be cast aside, and catchwords like competence centres, integrated product teams, lean manufacturing processes, short build-times and just-in-time delivery of components are uppermost in the minds of the production specialists.

The international workshare arrangement, under which each country is guaranteed a share commensurate to the quantity it is order, is a complicating factor, which required some components to be re-assigned to partners which had not been involved in their original development. The UK in particular has been allocated some extra parts such as the vertical tail.

As well as systems responsibility for the flight control system, hydraulics, landing gear, lighting and the Attack and Identification subsystem together with final assembly of 128 aircraft, Dasa is also responsible for production of the mid section of the fuselage. In the company's view this is one of the most difficult tasks as a huge number of components and a large amount of fuel have to be accommodated in this central subassembly in which space is extremely confined. Moreover it is this part of the aircraft on which the wing forces act.

Despite the exacting requirements, 72% of the 6.55 m long subassembly, which weighs 1470 kg, is made of aluminium. Carbon fibre parts comprise 16.5% of the weight, titanium only 2% and steel a mere 0.5%.

Over 50% of the approximately 3,500 structural parts are being produced in Dasa's Augsburg-Haunstetten plant, with additional work distributed around the company's factories in northern Germany. Many of the components attain their complex form using powerful numerically controlled milling machines. A typical example is the "X7150 above" bulkhead. Starting from a 850kg, 1.95m x 1.20m x 0.13m aluminium plate, all that is left after machining is 16kg, corresponding to a machining rate of 98%.

With the exception of section 3, which is being made in Bremen, the components are also assembled in Augsburg. To ensure an assembly sequence that is technically optimised and minimises costs, the Dasa engineers have gone for flexible docks, organisation of the technicians into teams and use of the latest numerically controlled machines.

In the hall where Tornado mid sections were once made, six assembly docks and seven assembly stations were therefore built, along with three rooms for seal testing, three paint cabins and an area for machining the carbon fibre skin supplied from Stade.

Two of the smaller docks are devoted to assembly of the extremely complicated air intake with its movable lips, while in another dock section 2B is joined to section 3. The remaining three docks are used to assemble sections 1 and 2A.

The work is performed by teams of between six and 18 persons. At their disposal they have a movable drilling and riveting machine from Brötje, which, according to Dasa, is one of the best in the world. Its distinguishing feature is its small head which enables it to reach almost all of the complex geometrically-shaped areas, for example, in the air intake.

Three identical stations are provided for joining together the two subassemblies (1 + 2A / 3 + 2B). Here the huge carbon fibre skin is finally mounted and its shape is checked to ensure the subassemblies will mate together precisely. If necessary, small compensation pads are affixed. As experience is gained, the dimensions of the parts will be optimised.

The next stage is the numerically controlled drilling and milling centre, which drills around 3,500 rivet holes in the skin and substructure. The holes on the underside are later drilled here as well. The actual riveting work takes place on Station 3, of which there are two, where a considerable amount of manual work is called for. The upper side of the fuselage (the spine) supplied by BAE Systems is then attached here.

The next stage is one of the three working areas for sealing the tank and performing the seal test before the air intake is mounted on Station 5. To facilitate access, the mid section is rotated into a vertical position for this purpose. The points of separation on the front and back sides of the now completed subassembly must now be finished to prepare the way for assembly of the cockpit section and tail. The holes for the wing fitting bolts are drilled to extremely narrow tolerances, following which bushings are inserted.

Once the access panels and covers have been mounted and surface protection has been applied, the mid section is then ready to dispatch to Manching. There it is fitted out and wired, which takes around 40 working days. Under the workshare agreement, Dasa is supplying 69 items of equipment, Alenia 146, BAE Systems 125 and CASA 12. These so-called "spec items" include cylinders, pumps, probes, sensors, valves, actuators, relays, switches and much more besides.

Assembly of the first production mid-section structure took Dasa around 11 months in Augsburg, from 25 February 1999 to 20 January 2000. This year a total of nine units are to be delivered, for example on 11 March, 19 May, 28 August and 21 September. The plan is to successively reduce the throughput time, as the objective is to build a complete Eurofighter in just 18 months.

This is significantly shorter than it used to take to build a Tornado. To achieve this reduced build-time, the partner companies invested considerably in modernising their production plant. For example, Dasa has invested DM 100 million ($46.5 million), BAE Systems #100 million (DM330 million/$153 million, some of which was financed by the customer) and Alenia is said to have invested 300 billion lire. There are no specific figures available for CASA, but they too have procured some new machinery and built a new final assembly hall.

Even if the components for the first production aircraft are already taking shape, that does not mean that the companies are not still on the lookout for further opportunities to make savings. For example, in the Augsburg factory, Dasa is trying out a laser beam welding process which would be used to attach stiffenings to the air intake ducts. A substantial component was manufactured at the end of 1999 and this will now undergo extensive load testing in Ottobrunn until 2002.

From page 72 of FLUG REVUE 7/2000