In the first of a series of interviews, MechanicalDesignOnline speaks to Ben Evans, aerodynamicist for the BLOODHOUND supersonic car.

These days, designing a car is reasonably straightforward, but design one to go 1,000mph and it is fair to say that you will have a few issues on your hands. These are what Dr. Ben Evans is facing as he undertakes the CFD work for the BLOODHOUND SSC.

Evans, a 27 year-old senior research assistant at Swansea University's Civil and Computation Research Centre, had only just completed a PhD. in CFD when Richard Noble and Ron Ayres approached him to work on the BLOODHOUND SSC.

"Swansea University had done the CFD work for Noble's second record breaking car, ThrustSSC and Ayres, the chief of aerodynamics, was looking for someone to undertake research and join the BLOODHOUND's design team. I guess I was in the right place at the right time... not bad for my first real job out of university," Evans told MechanicalDesignOnline. "But I am struggling to think if I will be able to top it in a subsequent career."

Having written his own CFD software package for his PhD, Evans knew what he was doing and he was probably in the best place to do it. Swansea University is seen by many as the home of CFD, with its in-house software, FLITE, supplying many of the methods and calculation used by most of the world's commercial CFD packages. "Techniques developed in FLITE are used by many leading aerospace companies, including BAE Systems and Airbus," Evan explains. "The beauty of the programme is that it gives me the ability to tweak the algorithms for bespoke applications, and they don't get much more bespoke than this!"

One of the primary issues that Evans faces is the combination of elevated Mach numbers and ground particulates. "When you design an aircraft, the effects of dust and sand are not really top of the list for airflow issues," he explains. "You would be hard pressed to find an off-the-shelf package that allows you to analyse this, which is why FLITE is so useful. But even this is not straightforward.

"The university's geography department is working hard to find us a suitable track on which to run the car. South Africa is top of the list, with a sand track, but we also have to think about salt basins just in case. These calculations are so important that we have a person working full time on the different types of particulates and what effect they will have on the aerodynamics." The other issue that Evans faces is wheels. Most aircraft don't need wheels much above 200mph, so once again FLITE has been tailored to address these concerns. Evans also has to consider the fact that, at 10,000rpm, the 90mm wheels will be experiencing 50,000G, but that is another story.

When asked about working with Ron Ayres, Evans is full of praise. "50 years experience of rockets and missiles, including the car's namesake the Bloodhound surface to air missile developed in the 1950s, gives Ron an invaluable insight into this car's development. When Ron has a hunch, we more often than not run with them, after all, it is fair to say that he is right 95% of the time."

The car's design work is taking place at the University of the West of England, in Bristol, where UG models are created and then sent over as IGES files to Evans at Swansea. "The first thing we have to do is run them through CADFix," he explains. "Initially we had big problems get seamless data between the CAD and CFD packages, but CADFix has been very useful as it cleans up the design, especially in the higher resolutions that we need. The company has allowed us to write software that outputs data in our format and we are currently undertaking a project with them that is using the BLOODHOUND as a demonstrator." Evans is able to take an IGES file, run it through CADFix and set it up to run simulations in under a day, when he can then spend another day of runtime looking at variables such as speed and yaw angles.

"In the nicest possible way, this whole idea scares me witless," he exclaims. "This car is design to go zero to 1,000mph and back to zero in less than 90 seconds, covering the measured mile in less than three seconds." It is for this reason that his calculations have to be right on the nail.

When asked the most obvious question: "How does it stay on the ground?" Evans has a well-rehearsed answer. "The biggest challenge over the 0 to 1.4 Mach range is keeping the vertical forces trimmed and within a safe band. Too much and you will have designed the world's fastest plough; too little and it leaves the ground." Everything has an aerodynamic force – Evans and the design team have to balance the aerodynamics of the sleek and slender body with the stability provided by a wider wheel base.

"From an engineering point of view we can build it, but the big question is can we finance it? I have great faith in Richard Noble and his money making efforts," Evans concludes. "If all goes to plan we should see BLOODHOUND SSC taking to a runway in Bristol in the Spring of 2010 to undertake that first of many tests. After that, it will out to some exotic location to really start the proper speed testing." With an estimated test run speed of 800mph, it might even be breaking to world record by simply limbering up!

Keep an eye out on the near future as we speak to Evans again and give you a fascinating insight into a truly unique project.

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