Pratt & Whitney JT8D
The Pratt & Whitney JT8D engine is a twin-shaft engine with a two-stage fan made by the US engine manufacturer Pratt & Whitney .
In the course of the production cycle around 11,800 copies have been produced in 8 different versions. Currently (March 2016) around 2,400 of these engines are still in service. The service began in 1964 on a Boeing 727-100 , then the Boeing 737-100 / -200 and DC-9 were added. As the last variant, the JT8D in the revised version JT8D-200 was used on the McDonnell Douglas MD-80 . With an afterburner developed by Volvo Flygmotor , the engine was also used as the RM8B in the Saab 37 Viggen fighter aircraft from 1967 .
The JT8D was an early turbofan engine with a by today's standards very low bypass ratio of 1: 1. At that time, this was a very high value, but it caused a very high noise level by today's standards, so that aircraft such as the DC-9, Boeing 727 or Boeing 737-200 are no longer allowed to fly to many countries without retrofitted silencers ( hush kits ). The more modern variant JT8D-200 developed for the McDonnell Douglas has a new, larger fan, which increased the bypass flow ratio to 1.7: 1, which is also low by today's standards. This comparatively minor change in the engine led to a significant reduction in the noise level, which was sufficient to be able to use the MD-80 to this day. Nevertheless, the noise level is significantly higher than with the Boeing 737s (from the 300 series) equipped with more modern engines and the Airbus A320.
Since the JT8D was the only engine for these aircraft models, it was for a long time the best-selling civil jet engine in the world. This changed in the 1980s because Pratt & Whitney failed to develop a modern successor to the JT8D. Instead, Pratt & Whitney had left it to offer only the comparatively slightly modified version JT8D-200. Therefore, both the next generation of the Boeing 737 from the 737-300 and the newly released Airbus A320 were equipped with the more modern CFM-56 engines from CFMI, the A320 also with the V2500 engine from International Aero Engines (IAE) , which due to their significantly higher bypass flow ratios had a significantly lower noise level and lower fuel consumption. Only the McDonnell Douglas MD-80 continued to sell well with this engine until the 1990s, despite higher noise levels, but here too, McDonnell Douglas decided to use the IAE-V2500 engine for the successor model MD-90. As Pratt & Whitney is part of the IAE consortium , it has not completely lost its market position in the field of these standard fuselage aircraft. With the PW6000 engine offered for the Airbus A318 , Pratt & Whitney succeeded, albeit to a modest extent, in offering another engine for this market segment. With the orders for the development of the geared turbofan PW1000G for the Mitsubishi Regional Jet (MRJ), Airbus A220 , Irkut MS-21 and A320neo aircraft , Pratt & Whitney was finally able to return to this market segment.
Technical specifications
- Type: twin - shaft turbofan engine
- Dimensions:
- Length: 3,914 mm
- Fan diameter: 1,249 mm
- Weight: 2,048 kg
- Power:
- Max. Thrust: 96.5 kN
- Air flow: 225 kg / s
- Sidestream ratio: 1.74: 1
- Pressure ratio: 21: 1
Web links
Individual evidence
- ↑ Pratt & Whitney: JT8D ENGINE (PDF).