Making a 1,000 mph car and breaking the world speed record was always going to be a challenge, but walking around the car, so close to finished, reveals how difficult it really has been.
Originally, the body of the car was going to be made in two main sections and assembled in Bristol. The front, carbon fibre half, was to be manufactured by the Advanced Composites Group and the back, titanium half was going to be made by aerospace company Hampson Industries.
Changes in commercial circumstances meant that some initial commitments could not be kept, and a greater amount of the development and construction has had to take place at Bloodhound’s base, located on an industrial estate at Avonmouth, Bristol. The change in manufacturing is typical fare for such an ambitious project that involves more than 300 partners, most supplying parts and work in kind.
Bloodhound has cost £16 million since it was launched almost eight years ago. It needs another £7 million to achieve its goal – breaking the world land speed record at the Hakskeen Pan, South Africa next year. It may seem a large amount of money, but as Bloodhound’s chief engineer Mark Chapman points out, the Bloodhound team has got this far with a fraction of the budget and resources of similar projects in motor racing or aerospace.
“This is a jet fighter glued onto a race car with a spaceship on the back of it. Each of those would have huge teams to do. With the budget and team size we’ve had, it’s incredible what we’ve achieved so far,” says Chapman. “I’m confident that this is the most advanced, most researched vehicle there is.
Some of the engineering challenges the small team has solved include the aerodynamics of keeping Bloodhound on the ground and installing the EJ200 engine. The vehicle will travel 200 mph faster than the Typhoon jet fighter the EJ200 engine powers at altitude – getting the air intake to work and managing the extra dynamic pressure going into it are all tough engineering problems.
Walking around the car, which is a masterpiece in itself and very exciting to be around, Chapman says it is 95% designed and 90% structurally complete. What’s also impressive when up close is the craftsmanship apparent in the vehicle – the nuts and bolts and precision engineering.
Inside the cockpit where Squadron Leader Andy Green will sit and steer the car through the sound barrier the only things left to install are some dials being supplied Rolex. Up that close to the first car in the world that will travel 1,000 mph gives a sense of closeness to history in the making.
There is additively manufactured parts in the vehicles, but an English wheel, rivets and glue have also been used.
“Artisans have built this car with paddles and hammers and rivet guns. It’s a riveted metal structure. We use new technology where we have to, we don’t use it for the sake of it.”
The main draw when viewing the vehicle is the EJ200 jet engine, which is fuelled by 500 litres of fuel and can propel the car to transonic speeds of around 600mph on its own. The rocket, which sits in the bottom section of the car then kicks in, pushing the car past 1,000mph.
The position of the rocket and jet engine in the car is an example of one of the design changes implemented to the car over the years. The car also originally had air intakes on each of its sides, was longer and had front operated disc brakes. Over the years, the design and development plan has evolved, as further studies and computer simulations have been conducted, and as the commercial situations of partner companies involved in the project has changed.
There are lots of further tweaks yet to be made to Bloodhound’s design and configuration during its testing and trialling. Chapman acknowledges that this will be the most challenging part of the project – the “second half” of the “engineering adventure” that is part of developing the world’s fastest car. “There is a whole area of finding out if the car works as we thought it would,” says Chapman.
The major challenge during the test phase of the project will be the rapid and accurate analysis of the masses of data that running Bloodhound will produce. Each of the 400 sensors on board the car – accelerometers, strain gauges and thermocouples for example, will be recorded at a rate of 500 times a second – imagine hundreds of lines and columns of a spreadsheet endlessly updating at an incredible rate.
Bloodhound’s engineers need to find out where and when pressure sensors mounted on the car leave the boundaries expected according to the computer simulations and studies that have already been conducted. “There will gigabytes of data coming off this car. We don’t have the time to trawl through that. So, particularly with the aerodynamics, we have software that will compare in real time the sensor readings off the car, with what the prediction is.”
The team has devised a graphical representation of the data on a computer model, or “virtual twin” of the car. When the sensor goes out of boundary it goes green and then red, so adjustments can be prepared and made to the vehicle. Engineers may find that predictions about the sonic shockwave expected when the car breaks the sound barrier are incorrect and the computer model needs to be adjusted.
“We’ll validate the models that we already have,” says Chapman. “Computationally we know what things like the chassis stiffness and the wheel hub frequencies are. But there’s nothing like running it. We may need different spring rates, we might want to change how we use down force to affect the vehicle’s stability.
“There are a lot of things that we know we don’t know. Like how the wheels are going to interact with the desert. We can only test that by getting out there and running the car. There is no existing data for that.”
The front and back fins of the car can be moved to aerodynamically balance the car. Suspension rates and dampening rates can also be changed. The biggest possible change could be accommodating a new larger rocket into the car, which changes the rear suspension.
The rocket is one of the biggest possible changes between the “Year One” version of Bloodhound, used for the trials, and the “Year Two” version, which will run in the world record attempt. Such radical changes to the design, so late in a project, would fill most engineers with apprehension to the say the least. But Chapman insists his team is ready for the challenge of completing this last 5% of the design. “It’s not a failure of the team to not know. “A lot of the core team are ex Thrust SSC.
“We’ve identified what we don’t know and have a very robust plan about how to get that data. It’s almost trying to convince the more corporate people that it’s OK not to know.”
“There are parts, like the wheel fairings, that don’t need to be on the car when we do the low speed testing, so we might as well wait for as long as possible before you put them on.
So close to 100% designed and constructed must be frustrating, but Bloodhound engineers have been designing and building the car bit by bit for eight years now. The last 10% won’t be finished until just before the team goes to South Africa. “It’s just in time design, as well as just in time manufacturing,” says Chapman.