Jet Engine

Jim Lawson

While work is underway to acquire the jet engine that will be used for the final operational phase of Jetblack we are able to use the engine we currently own for development and testing. 

The jet engine which will propel Jetblack through its developmental stages, a Rolls Royce Avon, is one of two which was used to power a very famous aircraft, the English Electric Canberra. The RNZAF were equipped with the Canberra, so the engine is no stranger to our shores..
The engine was produced by the well known company of engine manufacturers, Rolls-Royce and is called an Avon 206, known in the aircraft industry as an axial-flow, turbo-jet engine. It consists of several stages, whereby incoming air is compressed, fed into the combustion chambers where ignition takes place and the burning gas flow is accelerated onto the turbine blades, which converts some of the energy to provide motive power to drive the rotor and the balance of which reverts to thrust as it exits through the exhaust pipe to atmosphere.
The engine is in no way connected to the wheels of the vehicle, but acts in a similar way, to propel the car forward, as it does in an aircraft, to make it fly. The amount of thrust is measured in pounds force and the Avon 206 engine is capable of producing 11,250 pounds of thrust, it is this energy or force that will propell the vehicle forward - to a speed where the rocket motors are fired.
Installing a jet engine into a “car” is not unlike that of installing one in an aircraft, ventilation is of prime importance. The heat generated, by the engine, can reach as high as 780 degrees centigrade, therefore a source of cooling air, around the engine, has to be available. The jet pipe, (exhaust) has to be shrouded in thermal insulation, also air cooling will take place, through intakes and ducts, as the vehicle picks up speed.
A jet engine relies on a huge amount of air being directed into the primary stage, the compressor; in the Avon's case this is 156 pounds per second at full thrust. This is achieved by creating an air intake, of suitable size and shape, in the front of the vehicle, that will not affect the aerodynamic smoothness of the airflow around the car. An aerodynamicist’s nightmare. Coupled with this, is the need to make provision for extra air the engine requires, when the vehicle is not moving forward. As the vehicle picks up speed, the need for these extra intakes diminishes due to the ram air effect forcing more air into the engine.
Supplying the engine with fuel is not without its problems due to the large amount that an engine of this size uses. Up to 2,000 litres per hour can be consumed and to have one tank big enough to hold that amount , plus some, would make it an impossible task to fit it into the car. Fortunately the car does not require any where near this volume of fuel to run for up to 90 seconds so a tank of only a few hundred litres is necessary. The position of the tanks is also critical for the safety of the driver.  
From the drivers perspective, his workload has to be kept to a minimum, apart from driving the car, he should have no other distractions. So one can see, that all the systems required to keep the car functioning as a unit, will be electronic, telemetric and fail safe. The Avon 206 jet engine, whilst being a very complex piece of machinery, is very simple to install and is only one part of the overall picture in this ambitious and achievable objective, playing its part in a new World Landspeed record.