The science behind what aims to be the fastest vehicle of all time

The world record bid again teams Andy, the current record holder and first man to drive a supersonic vehicle on land with Head of the Design Team and former world record holder Richard Noble. It is aiming to develop the first land speed vehicle that breaks the 1,000 mph barrier and will have its design underpinned through world-class research from some of the UK's top laboratories.

The scientists at the UK's National Physical Laboratory (NPL) have worked with the Atomic Weapons Establishment (AWE) and Fluid Gravity Engineering (FGE) to advise the world-record bid team on two of the most high-risk aspects of the world record attempt – wheel and rocket designs.

The wheels are arguably the most important design feature for the vehicle. To reach 1,000 mph they need to be able to rotate at 10,500 rpm without being damaged by the surface or any stones that they run over. They also need to be as light as possible to minimise steering and suspension forces, absorb all of the weight, down force loads and stresses and distribute this pressure without causing damage to the vehicle or the surface.

To make sure that none of these issues were a risk NPL spent the last year examining every aspect of the wheel design. Its materials experts researched the choice of metals and composites that could be used in the design, providing reports on titanium and aluminium alloys, and metal composites. This will help to advise the team on what materials are most compatible to the wheel size, brake and suspension requirements. NPL also worked with AWE and FGE in considering the effect that shockwaves would have on the wheel design, and advised on the best way to manufacture the wheels.

After advising on wheel designs, NPL and FGE then needed to examine how to provide the thrust and power to ensure that the wheels could rotate fast enough and sustain their speed – by thoroughly understanding the rocket design. The vehicle will have the first ever mixed powerplant of a hybrid rocket motor and a jet engine that is currently used on the Eurofighter Typhoon. It uses cutting edge jet technology to provide the initial thrust and the novel rocket impulse to achieve the 1,000 mph target.

As this is a totally new vehicle powerplant concept, NPL and FGE needed to develop a modelling tool to understand the hybrid combustion process and simulate the internal motor ballistics. This could then provide data for the design team to compare to their own tests done with 6 inch rocket firings and enable considerable developments to the basic hybrid design. This will help to optimise the injector design, oxidiser streams into the fuel grain, radiation transfer, regression rates and rocket motor exhaust. NPL also provided advice on the type of materials to be used in the rocket design, how high temperatures would affect them, what the best material would be for rocket nozzles and how all of these should be produced.

Brian Chapman, Project Leader for NPL, said:

"When you're travelling at 1,000 mph you don't want to be worrying about your motor holding out or whether your tyres are up to it. That's why NPL – with FGE and AWE – have spent the last year looking at every eventuality for both the wheel and the rocket motor designs. We have been closely examining the effect that materials properties will have on the rocket performance, the size and weight the wheels need to be to sustain the speed, and environmental effects such as a high speed impact with a small piece of debris could have. We're confident that our work will help to ensure that Richard and Andy are able to safely oversee another successful world record attempt for the UK, and go faster than ever before."

Richard Noble, Project Director of The BLOODHOUND Project, said:

"On behalf of The BLOODHOUND Team, I would like to thank NPL, FGE, AWE and the MOD for undertaking this valuable work which has underpinned the rest of the early research for BLOODHOUND SSC and given us the confidence to proceed. With the help of experts like these we are sure that our world record attempt can be a success, and inspire the next generation of scientists and engineers in the UK."

The analysis is now being assessed by the BLOODHOUND design team and the Ministry of Defence as the funding organisation.
http://www.npl.co.uk