DASA  MTU

Hanns-Jürgens Lichtfuss

Director Research & Development MTU

            Permettez-moi, Monsieur Dufour, Président directeur général, et Monsieur Bonnet, Vice-Président de Snecma, de vous féliciter à l’occasion de ce 50^e anniversaire de Snecma et des cent ans des moteurs d’aviation français.

            Under the section headline « Engines and Equipment » I have selected the title MTU - A Partner for International Cooperation in Aero Engine Development, Production and Maintenance for my presentation, and during the next 15 minutes I will show you some of the technical contributions MTU has made and is making under its various cooperation programmes.

            First of all, I would like to show our roots and thus also some very early and fundamental relations between France and Germany in this field, or more precisely between SNECMA and Turbomeca on the one hand and MTU on the other hand.

            MTU’s parent company Daimler-Benz has developed the first bypass (u=2,42) engine of the world, the DB109-007 (13,7 kN), and BMW Aero Engine Company was the direct predecessor of MTU (with our main plant site in München-Allach) having been BMW’s piston aero engine facility. Thus, the BMW 003 engine is directly related to MTU. This engine, showing an outstandingly large potential for a very promising technology future, was developed in the early 40s by a team headed by Dr. Hermann Oestrich. Within this team there were also two young engineers, Hans-Georg Münzberg and Otto David, both having just left university and starting their professional career directly with the development of one of the earliest jet engines at all. All three were also members of the « Group O », which was formed just after the war, and they resumed the development of jet engines, first in Rickenbach/Lindau at the Lake of Constance , then in Decize ( Burgundy ) and later on in Villaroche. The whole group had a strong technical influence on SNECMA from the very beginning, as you can clearly see from the comparison of the BMW 003 engine with the first ATAR 101A engine of SNECMA.

            Dr. Münzberg became director research and development of SNECMA in 1961 and David worked under him as head of the turbine department. In 1957, Münzberg became professor for « aero engines » at the Technical University of Berlin, in parallel to his SNECMA duties. And it was in Berlin where I as a young student learnt the fundamentals and some of the secrets of jet engines from Münzberg, who at that time jetted in into the divided city from Paris for the weekend every fortnight with the Air France’s Caravelle, to give his lectures on Fridays and Saturdays and to run the institute on these days and very often also on Sundays. David followed Münzberg to the Berlin chair in 1964 when the former left SNECMA to take over an institute at the Technical University in Munich , and I belonged to the first group of students graduated under David in Berlin .

            After an interruption following the Second World War, on the industrial side, both German companies - Daimler - Benz and BMW - resumed their aero engine development effort and in 1970 they merged to form MTU to start cooperating within the trinational RB199 engine project for the TORNADO combat aircraft.

            Since then MTU has collaborated in many international aero engine programmes for both military and civil applications. In all these cooperations, MTU has played a vital role as a technically competent business partner in development, production and maintenance activities. With the exception of smaller engines, mainly research demonstrators, MTU has not yet been engaged in an engine programme of its own. All programmes were carried out in international cooperation due mainly to economic reasons. The fact that one could build up a virtual engine out of MTU components from different engines, proves our system capability, lays the foundation for our future and clearly shows our ability to cooperate internationally with regard to all types and parts of engines.

            As an actual example of Franco-German collaboration on an aero engine between Turbomeca and MTU, I would like to use the MTR390 turboshaft engine, powering the « Tiger » helicopter, prototypes of which you can see in flight again next week at the « Le Bourget Aero Salon ».

            The development of the MTR390 engine dates back to the year 1976 when Turbomeca and MTU started their collaboration on this engine and as early as in 1978 two identical gas generators were run at Bordes and Munich to reduce the development risk of the MTM380 engine, as it was called at that time. Due to delays in governmental decisions and some changes to the specification, the technical concept of the engine had to be adapted and a new demonstrator was designed and successfully run, which at least in the hot end section was very similar to today’s MTR390 engine, finally launched in 1988. At that time Rolls-Royce also joined the programme on a private basis, and it is one of the first real « fixed-price » contracts within this government business.

            In spite of the small size of the engine and the fixed price development contract, it represents most advanced technology using for example, a reversed flow burner with airblast sprayers, an aerodynamically highly loaded single-stage high-pressure transonic turbine. The small blade size and the high temperature of nearly 1600K calls for a single crystal material blade, incorporating a multipass cooling scheme, whereas the high mechanical and thermal loads of the disc require the use of powder material.

            This new turboshaft engine is being developed for the Franco-German « Tiger » anti-tank and escort/support helicopter programme and is well into the flight testing stage. The engine is also suitable for civil applications, including the new generation of civil medium-sized twin-engine helicopters, and successfully completed qualification tests in late 1994.

            Turbomeca, the second French aero engine company, which very successfully has specialized in engines in the lower power range, looks back on 50 years of Franco-German cooperation. In 1945 a larger group of German engineers, mainly from Daimler-Benz, led by Dr. Nallinger was offered the possibility to restart their work on aero engines at Turbomeca in Peau/Bearn. And again, I found a personal link. Prof. Dr.-Ing. Heinrich Kühl, my first boss during my professional career as head of the DVL (DLR) institute of airbreathing engines in ( Cologne ) Porz-Wahn, was a member of this German group and worked for more than 10 years with Turbomeca.

            The MTR390 programme is far from being the only cooperation of MTU with a French partner. There are links in production between SNECMA and MTU for the CF6 engine family and additionally with Rolls-Royce for the Tyne turboprop powering the Franco-German Transall Airlifter and the Breguet Atlantique marine reconnaissance aircraft.

            Moreover, the LARZAC-04 engine was developed by SNECMA and Turbomeca for the Alpha Jet, also used by the « Luftwaffe ». For production, postdevelopment and overhaul KHD and MTU joined the two French partners holding equal workshares. The first production engines could be completed and supplied to the customer in 1977.

            The LARZAC engine is a two-shaft turbofan in modular component arrangement, featuring a two-stage LP compressor, a four-stage HP compressor followed by an annular combustor, which is fitted with a prevaporizing fuel injection system to keep smoke emissions low. This engine operates with a single turbine stage on each shaft and generates a thrust level of 14kN at a mass flow rate of 27,4 kg/s. More than 1200 units were manufactured until the end of 1983 by the partners involved.

            As an example to illustrate MTU’s involvement in the commercial engine business I would like to use the Pratt&Whitney PW2000 engine programme. As early as 1974 the design effort for the JT10D, as it was labeled at that time, was started together with Rolls-Royce, who later withdrew from the programme.

            The definite PW2037 design leading to hardware in the end, finally was commenced in 1980 and the first engine run on the test bed took place in December 1982, and the first flight was successfully completed on March 14, 1884 . Certification followed on October 25, 1984 and just a few days later first regular flights (5.11.1984) with « Delta Airlines » began. MTU’s responsibility in the engine programme covers the development of the five-stage low-pressure turbine, including the exhaust casing. Due to MTU’s workshare of approximately 10 % at the beginning of the programme, its production share covered only half of the LPT. By increasing the share to 21,2%, MTU’s responsibility was extended and production now also includes the combustion chamber casing and the HP turbine discs. By the end of May 1995, MTU had delivered on the whole more than 830 parts kits to Pratt&Whitney for delivery to the final customer.

            The initial application of the PW2037, the 170 kN class version, was the Boeing B757-200 airplane. A thrust improved version, the 185 kN thrust class PW2040 is used in the B757PF aircraft, and the engine’s military F117-PW-100 version powers the four-engine Mc Donnell Douglas C17 transport aircraft. The PW2337 engine, which differs only slightly from the PW2037, is used to power the four-engine Ilyushin IL96M prototype airplane and has by now completed more than 250 test and demonstration flights, accumulating over 600 flight hours. Certification by the CIS aviation authority and also the FAA is scheduled for December 1996.

            In fact the PW2000 engine family is the first commercial project for which MTU developed the LP turbine. The fuel consumption of modern high bypass ratio jet engines is closely correlated to the efficiency of the low-pressure turbine, because its exchange factor is larger than 1.

            The high efficiency level of MTU’s LP turbines in spite of increased aerodynamic loading is achieved by

            - advanced aerodynamical design methods, and

            - experimental investigations of cascades, turbine rigs and full-scale engine tests.

            In addition to the quasi-3-dimensional standard techniques the MTU aerodynamical design is based on :

            - airfoil design by optimizing boundary layers and transition regimes on the pressure and the suction side, taking also the different engine operating regimes into account

            - distribution of radial loading by considering 3-dimensional effects, and by minimizing the secondary flow losses with respect of the 3-dimensionality.

            As a result MTU airfoils have a strong 3-dimensional character and low overall losses. Special care is also taken in the mechanical design and, even more important, in a well balanced aero-thermo-mechanical design of the MTU LP turbines to

            - enable lightweight structures (disc rim cooling, bolting at the disc),

            - minimize the secondary losses (active clearance control, flow guide).

            Intensive use is made of advanced 3D-Finite-Element-Methods to optimize the components and to achieve structural integrity.

            Meanwhile MTU is applying its turbine know-how not only to the PW2000 engine family but to engines from the whole power range of modern civil power plants for aeronautical propulsion, beginning on the low end with the PW500 and PW300 engines developed in cooperation with Pratt&Whitney Canada and being used for different sizes and ranges of modern business jets, as Cessna’s Bravo and Excel, Raython’s 1000, Learjets 60 and IAI’s Galaxy airplanes.

            Also the newest version, the 100 kN thrust class JT8D-219 of the world’s most widely used commercial jet engine family JT8D, is using MTU’s turbine technology and powers the McDonnell Douglas MD-80 aircraft series. Also the LPT of all versions of IAE’s V2500 engine is designed, produced and maintained by MTU. This engine powers Airbus A319, A320, A321 and all the McDonnell Douglas MD-90 aircraft.

            At the upper end of the power range, MTU is also responsible for the LPT of the PW4000 growth-II engines, the first one of three elephant or monster engines powering the new twin-engine Boeing B-777 aircraft, which has just entered into service with United Airlines on Wednesday this week (07.06.1995) and, even more important, is the first engine ever to get the full ETOPS (180’) bonus already at its first entry into service.

            Apart from all these LP turbine activities for commercial engines, MTU started a major research programme in the mid-eighties with partial funding by the German Ministry of Research and Technology. MTU’s main emphasis was on investigating the application of « ultra high bypass » (UHB) engines or ducted propfans, as they are also called, with bypass ratios in the order of u=20 and the consequences. The prime driver of MTU’s activities was the investigation of all aspects of the « counterrotating integrated shrouded propfan (CRISP). It also provided the basis for a lot of study concepts.

            This technology programme involved a wide spectrum of activities, starting with aerodynamics of fans, compressors, turbines, nacelles and not ending with acoustics, mechanics and integrational aspects. The complete programme is being conducted in close collaboration with a lot of institutions around the world, but of course especially with DLR. A scaled model of the propulsor was investigated in low - and high - speed wind tunnels of DLR at different angles of attack. Two campaigns specifically for acoustic investigations were run in the Dutch-German wind tunnel on the North-East Polder in Holland . Essential spin-offs from this technology programme can certainly be seen in increased knowledge about advanced fans and nacelles. But moreover almost all engine components profited from the technical benefits, not just from an aerodynamical point of view. Additionally, the CRISP programme created a real motivation push throughout the MTU engineering community.

            A little later Pratt&Whitney and FIAT likewise started investigations into UHB engines and associated gear systems, and so quite naturally the three companies joined forces and started a unique « Technology Readiness Programme » for this type of engine. Within this comprehensive programme several quite different engine configurations were studied as well.

            For one of them, today’s most feasible configuration, the « Advanced Ducted Propfan » (ADP), a bench engine demonstrator was built. This ADP features a single-stage variable pitch fan and a gear system driving the low-pressure compressor and turbine spool. The ground demonstrator was built up using an existing PW2000 core, the new propulsor of PW, a new gear system of FIAT, a high-speed transonic LP turbine and a modified PW industrial LP compressor of MTU. The aim was to demonstrate all the predicted performance values and operating characteristics. The first test in Pratt&Whitney’s open air test facility in West Palm Beach in Florida took place on October 28, 1992 . In these full scale engine tests

            - large fuel savings and a low noise level could be verified,

            - the geared fan mechanical integrity was demonstrated, and so was,

            - the engine operability with a hydraulic fan pitch system and 3 variable compression systems.

            In 1993, the ADP was brought from Florida to California, to the NASA Ames Research Center, where aircraft starting and landing conditions with reverse thrust (17% of take-off forward thrust were realized) were simulated in the low-speed tunnel and further acoustic measurements could be successfully completed.

            Now I like to change back from commercial applications to MTU’s latest activity in the field of military engines, the EJ200 engine, an advanced fighter engine which is being developed jointly by MTU, Rolls-Royce, FIAT and ITP to power the Eurofighter 2000. MTU is fully responsible for the whole compression system, i.e., for the highly loaded three-stage fan as well as for the five-stage HP compressor with only the inlet guide vanes being variable.

            Since this engine was described in some detail already yesterday by my Rolls-Royce colleague, I would like to draw your attention mainly to the full authority digital electronic control unit (DECU) which is one of the major engine accessories. After some serious problems had been experienced with this module, jointly developed by four companies in four nations, MTU as System Design Responsibility (SDR) Company took over full responsibility for hardware and software nearly one year ago and achieved flight clearance at the end of last year. The first flight of the engines using this box was successfully completed last Sunday (04.06.1995). MTU is now in the final stage of verification of the production unit, which will meet all requirements of the very stringent specification. The control unit incorporates the most modern technology, as regards the different ASICs used, as well as the design and material of the different platines (printed circuit boards).

            Also with the next engine I would like to direct your attention mainly to an accessory, not yet used in aircraft engines. In the late seventies, MTU and General Electric decided to cooperate in the development of an advanced propulsion system for armoured tracked vehicles and won a competition of the US Army (TACOM) with their LV100 1000 kW tank engine.

            Within this programme MTU is responsible for the development of the variable power turbine, the turbine exit diffusor and the heat exchanger. After leaving the last turbine stage, the exhaust gases, which are still relatively hot, pass through the heat exchanger where a large extent of the residual thermal energy is fed back to the compressed inlet air, so that a considerable amount of fuel energy is saved. The power pack requires minimized matrix dimensions and short interconnecting ducts. Additionally, excellent structural integrity is essential to withstand the thermal cyclic environmental influences by frequent load changes and intensive vibrations and shock loads, in particular. The thermodynamic and hydraulic merits of primary and secondary surface plate structures, such as

            - high thermal efficiency

            - moderate pressure drops, and

            - compact cores

and the thermal and mechanical benefits of a tubular matrix, characterized by

            - resistance to extremely high gas entry temperatures

            - insensitivity to mechanical shock loads, and

            - good thermal shock behaviour

have been integrated into an advanced profile tube heat exchanger concept. So the benefits of both types are combined within this new MTU unit.

            In addition to development and production, MTU is also active in the field of engine repair and overhaul, which MTU has done from the beginning for military engines in Munich . In the late seventies MTU then has founded MTU Maintenance in Langenhagen/Hanover (6.12.1979), a company with approximately 700 employees which is engaged in the repair and overhaul of large commercial turbofan engines and their industrial derivatives.

            The primary objective of this company is the complete refurbishment of different powerplants of Pratt&Whitney, General Electric, IAE and Rolls-Royce (RB211 1984-1986) to support customers worldwide from the Caribbean, the US, Europe, Middle East down to South East Asia, where MTU opened another joint venture overhaul plant in Sha Alam (near Kuala Lumpur) with Malaysian Airlines in 1990. In addition to servicing complete engines, MTU Maintenance overhauls modules and carries out special repairs using the most modern and up-to-date machinery and equipment.

            With the reunification of Germany , MTU took the chance to acquire in 1991 a maintenance company which previously performed engine overhauls for the « Luftstreitkräfte der Nationalen Volksarmee » (East German Airforce). MTU Ludwigsfelde, as it is called now, employs nearly 300 people and is MTU’s repair base for small jet engines, turboshafts and APUs. The repair and overhaul work MTU Ludwigsfelde is expected to carry out mainly includes

            - the repair of T64 helicopter turboshaft engines,

            - the repair of modules from all MTU locations, e.g. gearboxes for civil and military engines, and

            - the inspection and assembly of modules and final assembly of new engines, for instance the LP turbine for the PW300, and the MTU modules for the MTR390 and probably RTM322 engines.

            In addition, MTU formed a 50-50 joint venture with Pratt&Whitney Canada , the Customer Support Center (CSC). The CSC, located also in Ludwigsfelde, offers repair and maintenance services for operators of P&WC engines in Europe , the Middle East and Africa . At the moment these are in particular

            - the PT6A and JT15B turboprop and turbofan engines.

            To integrate its activities into the new P&WC/MTU maintenance concept, the operations of P&WC Aircraft Services (UK) Ltd, which had been engaged in the CSC’s market regions since 1984, were taken over by the CSC in mid 1992.

            Against the background of successful collaborations in the past, we are now on the verge of establishing a new Franco-German or rather European collaboration under the Future Large Aircraft (FLA) turboprop project.

            In April 1994, MTU, SNECMA and FIAT Avio signed an MoU concerning the joint development, production and support of this turboprop designed to generate 6500 to 7500 kW and intended for use for the new, four-engined European military transport aircraft. The engine consortium accordingly submitted a concept based on SNECMA’s existing M88-2 core to the airframe consortium EUROFLAG.

            Essential features of this engine are advanced technology and high reliability, well tried and proven components, accomplished at low overall development costs.

            Featuring low fuel consumption and high power to operate in severe environments, the M138 will enable the FLA to perform tactical missions as well as long logistic missions with high payloads. Being forced to land on commercial airports for humanitarian missions, the FLA with the M138 underneath the wing will comply with the ICAO environmental regulation requirements. MTU’s activities will be focused on the LP-compressor as well as on core components. Currently, the workshares are SNECMA 36.5% and FIAT Avio 27.0%. However, other manufacturers from countries involved in the FLA project are to be offered the opportunity to participate in this engine programme.

            And now at the end, I wish to come back to the very beginning of my presentation and to close the circle. In the auditorium of the Technical University of Berlin there were two other young students listening to Münzberg. One of them was George Karadimas (1957-1964) and the other Jean Hourmouziadis (1958-1965), who also worked from 1965 to 1974 as assistants to David. Hourmouziadis is now head of the turbomachinery departement at MTU, then head of development at BMW/Rolls-Royce and, in October 1994, finally took over the chair founded by Münzberg nearly 40 years ago. As you can see, there exists not only a French-German connection, but a Greek one too, or maybe, we better should say a European connection. We see German and French scientists, engineers and technicians, and Greek ones, too, sitting, learning and working side-by-side, in particular in this heavy weather the aero engine industry has to withstand, at present, for the benefit of both our countries and for all those who fly around the world.

            Mesdames et Messieurs, c’était un grand honneur pour moi de faire ce discours et je vous remercie de votre attention.

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