The first Anglo-French M 45 engine has made its maiden run successfully. This event heralds?
The first Anglo-French M 45 engine has made its maiden run successfully. This event heralds the new series of engines on which the French Company SNECMA and the British Company Bristol Siddeley Engines Ltd., are working together.
The firs turn was made at the SNECMA Test Centre at Melun-Villaroche, near Paris. The engine is the version knows as the M 45F. As well as being capable of development as a subsonic civil engine of about 6,500 lb thrust, this version is also valuable as a 'demonstrator' and for gaining experience in co-operation in early design and development work.
Engines of the M 45 family have been designed to power the military Anglo-French variable geometry aircraft, and the German/Dutch VFW 614 civil transport.
It is noteworthy that only 16 months elapsed between the issue of the first drawings and the first run of the complete engine on the test bed. This is a remarkable performance which has been made possible only through close co-operation between SNECMA and Bristol Siddeley, who are sharing equally in the development of this engine. SNECMA has overall control of the project and responsibility for the low-pressure system and the fuel system. Bristol Siddeley is responsible for the high-pressure system.
Before the complete engine was tested at SNECMA rig tests had been carried out both at Villaroche and at Bristol. They were completely satisfactory.
In spite of difficulties with language, distance and systems of units and standards, the components and sub-assemblies designed and manufactured at Bristol were mated up on schedule and without difficulties of tolerances with components designed and manufactured at Villaroche, thus demonstrating the quality of the technical co-operation between the two companies.
It is logical result of the cordial collaboration between Bristol Siddeley and SNECMA in the production of the Olympus 593 for the Concorde.
The two principal significant technical points are:-
1. The low pressure compressors on the military and civil versions benefit fro SNECMA's experience with transonic compressors, both the experimental TS 12 compressor, and the TF 106 engine for the Mirage III V vertical take-off fighter.
2. In order to minimise the overall size and to eliminate icing problems, the shaft supporting the front fan overhangs the main bearings, thus eliminating the need for inlet guide vanes. This arrangement has been proved on the Bristol Siddeley Pegasus vectored thrust turbofan which powers the Hawker Siddeley Kestrel V/STOL aircraft.
Although the M 45 family is based on technological experience already acquired, the M 45 itself is a new type of engine designed to give very low specific fuel consumption at high power levels. This characteristics is of fundamental importance in the economics of short range aircraft and for very advanced military aircraft.
The M 45F is a twin spool turbofan. The low pressure system comprises a three-stage compressor (fan), a two-stage compressor, and a two-stage turbine driving the five compressor stages through the entire high-pressure system.
The high-pressure system comprises a seven-stage compressor, an annular combustion chamber, and a single-stage turbine driving the seven compressor stages.
At the exit from the low-pressure system the primary air is combined with the secondary air which, having passed through the exterior part of the three fan stages, is at the same pressure as the primary flow. The mixture is exhausted through a single nozzle.
The twin rotor assembly turning on the same axis but a different speeds, is supported on five bearings. The combustion chamber is of the annular vaporising type. The blades of the high-pressure turbine are cooled by means of small radial channels within the blades, which are fed with air tapped from the exit of the high-pressure compressor.
The engine has no intake casing nor inlet guide vanes, air entering the engine directly through the rotating blades.
Primary Air: Pressure Ration 14 to 1
Turbine entry temperature approx 1000????C
Secondary Air: Pressure ration 2.15
By-pass ration 1.2
Total Air Mass Flow: 70 kg per second.