Trijet

In three-rayed aircraft (English: Trijets ) typically two of the jet engines are mounted on the side of the rear fuselage or under the wings, the middle engine is fitted with almost all models below the rudder. In the year 2010 there were about 3,200 Trijets in civil and worldwide about 60 in the military field in use, including the single-aisle aircraft Boeing 727, Yakovlev Yak -42 and Tupolev Tu- 154 wide-body DC -10 and MD - 11, and business aircraft the Dassault Falcon family.

• 2.1 S-shaped air inlet
• 2.2 The rear nacelle
• 2.3 Other constructions

Historical Development

This type was very common in medium-haul aircraft and long-range aircraft during the 1970s and 1980s. Early 1960s found the three-beam construction initially use for greater short- and medium-haul aircraft ( Boeing 727, Hawker Siddeley Trident, later Tupolev Tu- 154). With the advent of wide-body aircraft ( the Boeing 747 into service in 1970 ) and larger models were equipped with three engines. Between the beginning of the 1970s ( the appearance of the DC -10) and the early 1980s, the large, three-beam pattern DC-10 and Lockheed TriStar of pay weak long-range were not indispensable and served at the same time especially in the U.S. heavily used short and medium distances. Twin patterns were for crossing oceans at that time, for example, not allowed (see ETOPS) and of three instead of four engines were promised to greater economy. Completed the three-beam pattern initially the gap between the smaller, older four radiators ( mainly DC-8 and Boeing 707 ) and the much larger Boeing 747, they formed with phasing out the smaller four spotlights the " base " of the middle - and long-haul fleets. Mid-80s, however, twin-engine aircraft such as the Boeing 767 had proved so reliable that they received approval for transoceanic applications. This was the reason for the airlines, their getting on in years three-engined widebody aircraft with more modern machines (initially 767, later Airbus A330 and A340 and Boeing 777 ) to replace the two that were almost all rare vierstrahlig. The early 90s as a revision of the DC-10 MD -11 introduced could not establish long-term the market is. During the 1980s, the Boeing 727 disappeared slowly from the short and medium distances.

Three projectors today

Particularly in the Western industrialized countries are today only a few three-engine jets found in passenger service. The most common pattern is still the MD -11, which is still operated by some airlines. The older DC-10 and Boeing 727, however, are almost completely disappeared from European airports and flying in the passenger versions today almost exclusively in the Third World. They were replaced by twin jets. In the air freight sector, however, are still many three burners in use, because after their withdrawal from passenger service many have been DC - 10 and in particular MD-11 converted to freighters. Just the MD-11 comes as quite modern, economical aircraft in this regard, of particular importance. Largest operator dreistrahliger aircraft is today the U.S. cargo carrier Federal Express, which has the largest fleet of Boeing 727 model, DC -10 and MD -11 has worldwide. Even in the military ( cargo, troop transport, aerial refueling ) are also found three-beam pattern (eg KC -10). However, there is now no dreistrahliges passenger aircraft out of production. New models will be built only in the field of business aircraft ( Dassault Falcon 7X Dassault Falcon and 900).

Special construction features

Three engine aircraft generally require the installation of an engine to the longitudinal axis of the aircraft. This raises jet engines at major structural problems than propeller planes, where ( as in the famous Junkers Ju -52), the average engine could be integrated directly into the fuselage nose. In the construction dreistrahliger Airliners two basic concepts for the assembly of the central engine have prevailed essentially:

The S-shaped air inlet

( Engl. referred to as S- duct ) With this design is only the air intake at the front edge of the fin and performs in a substantially S -shaped bend in the rear of the aircraft, where the actual engine is mounted. The outlet of the turbine then usually forms the tail tip. The engine is integrated into the rear end of the hull. This design has particularly strong distribution found and comes with these passenger aircraft used:

• Boeing 727
• Dassault Falcon 50
• Dassault Falcon 900
• Dassault Falcon 7X
• Hawker Siddeley Trident
• Lockheed L -1011 TriStar (the largest ever built with an S-shaped inlet plane )
• Tupolev Tu -154
• Yakovlev Yak -40
• Yakovlev Yak -42

With the exception of the Lockheed TriStar of the S-shaped inlet is always combined with the other two engines on the rear fuselage. Only Lockheed opted for an assembly of the two remaining engines under the wings. One of the TriStar comparable engine assembly Boeing planned in the 1970s for a shortened, three-engine variant of the Boeing 747, which was never realized.

The rear pod

In the rear cable is an engine mount, in which the fin is completely placed on the engine. The middle engine is mounted on the rear fuselage and above the gondola is the vertical stabilizer. This construction was essentially responsible for the wide-body DC -10 and MD -11 American McDonnell Douglas application. The small, three-engined passenger aircraft Britten- Norman Trislander used a similar suspension for a piston engine which drives a propeller.

Other constructions

Future developments

A future production of Trijets in the area of ​​standard -body and wide -body aircraft is very unlikely. Airbus S.A.S. could be though patenting a Trijet construction with the third engine in a nacelle above the fuselage and tail with a double vertical tail in 2008, whether this type is, however, ever produced, is very uncertain.

The business aircraft Falcon 900 and Falcon 7X Dassault Aviation are likely to remain prepared with three jet engines. New developments other manufacturers are not currently announced.

Boeing has also copied 1997 designs for a new Trijet family called MD -XX by merging with McDonnell Douglas in years. This project for such a large and modernized DC-10 with longer range, however, was completed in 1996 provisionally.

Since 2004, Boeing and NASA are experimenting with the Boeing X -48, a 6.4 m long unmanned three-engined experimental aircraft to test the properties of a Blended Wing Body (BWB ), a special form of the flying wing.

The future of the Russian, driven not by kerosene, but hydrogen or natural gas Tupolev Tu-155/156 is unclear.

Classification dreistrahliger aircraft to use, size and production

Note to table: For a quick overview, the types of aircraft in 2012 are highlighted in light blue. The columns can be sorted by clicking on the small arrows in the title bar.