The RB199 engine was developed by Turbo Union, a company formed in 1969 by Rolls Royce, Motoren und Turbinen Union Daimler Chrysler and FIAT Avio. It was selected to power the Tornado after numerous American engines were discounted.
The RB199 is of turbofan design, i.e. not all of the air entering the intake passes through the combustion section of the engine a proportion of it passes along the exterior of the engine to provide cooling and thrust.
The advantages of this engine are according to Rolls Royce, High thrust to weight ratio, Low cruise specific fuel consumption, Full authority digital electronic control, Single crystal turbine blades, Compact, fully modular construction, On condition maintenance, Growth potential.
|Thrust|| 9,550lb/42.5kn Dry|
|Pressure Ratio||Over 23:1|
|Compressor Stages||3 Low Pressure, |
3 Intermediate Pressure,
6 High Pressure
|Turbine Stages||2 Low Pressure, |
1 Intermediate Pressure,
1 High Pressure
The RB199 engine used technology developed for the commercial RB211. The design allowed the rotating parts of the engine to operate at different speeds allowing each to operate at its optimal speed. The engine design and construction used some of the latest technology available at the time.
The fan was a development of that used on the Pegasus engine and was assembled using a novel technique. The fan blades are electron beam welded which saves weight and reduces vibration. The repair of the fans has been demonstrated by cutting the old or damaged blades from the fan and new blades welded in.
The RB199 engine first took to the air mounted under a Vulcan, during April 1973.
Rolls Royce manufactured a large proportion of the engine, the parts included the inlet, the low pressure casing, the fan, the combustion system, the whole high pressure turbine including the casing and the fuel control system. MTU produced the intermediate and high pressure compressors, the intermediate casing, the gearbox and accessory drive, the bypass duct and outer engine casing, the intermediate pressure turbine, driveshaft and the reversers. FIAT produced the complete low pressure turbine and driveshaft, the exhaust diffuser, the rear jet pipe and variable nozzle.
The engines are effectively linked by their gearboxes which allows either engine to drive all the accessories. The gearboxes are linked via a clutched driveshaft that comes into play when the engines speeds differ by a pre determined amount.
The first production engines were to the -101 standard and were somewhat troublesome. They often failed to reach their designed overhaul times and consequently had to be removed on a regular basis. The -101 engines were de rated by a significant amount on the frontline squadrons and even more so at the Tri National Tornado Training Establishment, TTTE in an effort to reduce the failures. These changes allow the turbine discs to run at cooler temperatures and therefore extend their life.
From Batch 4 all IDS airframes were equipped with the -103 engine which incorporated a number of modifications to improve the efficiency and extend the life of the engine. These modifications included a revised oil system that allowed prolonged negative 'G' manoeuvres and many mechanical improvements. These engines are often used in a de rated condition to extend their life. A number of -101 equipped airframes were upgraded to -103 standard. the -103 engine spawned a further development known as the -103b.
The ADV/F.2/F.3 was initially powered by the -103 engine although this was subsequently replaced with the -104 which offered more thrust and digital control. The -104 utilised a longer jet pipe and the Tornado rear fuselage was modified accordingly to house this engine.
The German Navy subsequently upgraded their ECR airframes with the -105 engine which are similar to the -103 but utilises a higher pressure fan known as a 62b and utilised a DECU manufactured by BGT. These changes resulted in an engine that was more responsive and developed slightly more power than the -103.
In Service Specifications
Batch 4 onwards