13-05-2013, 03:57 PM
PEGASUS ENGINE
PEGASUS ENGINE.pptx (Size: 301.22 KB / Downloads: 56)
Introduction
Pegasus engine was developed by Rolls Royce company
STOVL/VTOL Engine designed to enhance the flight and landing speed of the jet fighters
Designed in late 1960’s the Pegasus engine was first used in British HAWKER P 1127
It was the first turbofan engine to be developed with a zeroth stage
Turbofan Engine
It is mainly a gas turbine engine with a fan at the start
The fan is run with the power supplied by the turbine
The fan is a ducted type fan which accelerates air into the turbine
The main types are single spool, twin spool & triple spool engine
Single spool engine means the whole turbine fan and compressors run on a single shaft
Twin spool engines have two shafts which are connected different compressors and turbine shafts
Another classification is based on bypass ratio as low bypass turbofan and high bypass turbofan engine and also as afterburner turbofan.
Low bypass turbofan is used in places where exhaust velocity must be equal to the plane velocity the bypass ratio being 0.3.
High bypass turbofan engine has a bypass ratio of 1.2 in run time with an ability to reach approx sound speed in travel time with the highest being noted as mach 0.91.
The high bypass turbofan is usually twin spool or higher while low bypass turbofan can be single spool also.
Low Pressure Compressor
Three in number
Have a zeroth stage i.e. the first fan of the low pressure compressor is in front of the frontal bearing. This is the first engine to do so and due to this there are many added advantages like elimination of radial struts and also the icing hazard that it posed also the zeroth stage had an added advantage of due to counter rotation of the spools it reduces the gyroscopic effect and helps stabilisation of the flight much more easily
Low Pressure Turbine
The low pressure turbine is mounted right behind the high pressure turbine and is the last part of the rotary engine.
The turbines job is to increase the output given from the high pressure turbine by taking the pressure energy left within the burnt gas coming from the high pressure turbine
Also another important factor is that the rear vents are connected to the exhaust from the low pressure turbine so it has to derive the energy from the gas without having any effect on the thrust
Thrust Vectoring System
Thrust Vectoring Control or TVC is the ability of a plane or rocket to manipulate the thrust originating from the engine in order to control altitude and angular velocity
This is usually employed in rockets and STOVL/VTOL engines
In Pegasus engine the thrust vectoring is done by using nozzles that can be controlled by the pilot for STOVL/VTOL purposes