The reveal of Geely as Bloodhound’s main sponsor has reignited interest in the 1000mph record attempt.
The backing means Richard Noble, Andy Green and the rest of the team will once again hold the world’s attention at Hakskeen Pan, South Africa with a daring and accomplished feat of British ingenuity.
Geely is the largest privately-owned automotive company in China, owns Volvo Group and also makes black London taxis. The company is providing enough money to clear the project’s debts and pay for its ongoing costs.
Bloodhound's first 800mph record attempt will take place during October next year. A second run to take the car to 1,000mph is planned to take place during 2018.
Bloodhound's project director Richard Noble, says:. “We’re not quite there yet, but people now understand that Bloodhound is going to happen,”
“Geely brings financial resources to bear, will share the technology and take Bloodhound’s message to a vast global audience.”
Tests with the rocket engine and mono propellant are planned for next June, followed by a low-speed run in Newquay during the summer. For the second, 1,000mph run in 2018, the single rocket fuelled by a mono propellant has to be replaced with a cluster of three hybrid-fuel rockets so the Bloodhound car can reach the higher speeds.
October 2017’s record attempt will be 20 years to the month that its predecessor, Thrust SSC, set the existing land speed record of 763.035mph. That 1997 record is longest standing record in the history of land speed records.
Although everyone’s focus is naturally on whether the car will reach the required speeds, there is an inordinate amount of impressive engineering going on to support reaching this target. There are lots of examples of the depth of UK engineering expertise and capability within the sub-component parts of the Bloodhound car.
Precision manufacture and assembly
The manufacture and assembly of the car requires the level of precision that is normally only reserved for jet fighters. The company that is supplying the measurement equipment to Bloodhound also works with defence firm BAE Systems to to make the Eurofighter Typhoon fighter aircraft.
Bloodhound’s engineers and technicians are using the latest 3D laser scanning and measurement equipment to not only verify that components, sub-assemblies and body parts are manufactured to the correct size, but also that everything is assembled to within an accuracy of the width of a human hair, 0.05mm.
Jon Kimber, product line specialist at Hexagon Manufacturing Intelligence, says: “This level of accuracy is essential to reaching 1000mph and coping with the speeds, aerodynamic forces, and loads. The technology simply wasn’t available to do this with the Thrust cars.
“The real key is to have that high level of accuracy and precision alignment all over the car, all the individual components and parts. We even measured Andy Green to produce the seat. Without this precision measurement, the car couldn’t run.”
The fin is the hardest working that has ever been built on any vehicle, adds Kimber. Just 1mm out when it is fitted onto the body of the vehicle would create massive turning moments that could be disastrous for the record attempt.
Hexagon has supplied a Leica laser tracker for measuring Bloodhound. The measurement system uses a combination of a tripod-mounted camera, lasers, reflector targets and hand held devices to obtain highly precise measurement data using horizontal and vertical angles and distance.
All of the parts of the components of the car are measured, point by point, to build up a 3D point cloud, which can then be verified against the 3D CAD designs using software.
The same system will be used when the car is reassembled after being transported, first for the trial runs and then for the final run in South Africa. Embedded targets on the car and a 20 point auto-measure software routine will ensure parts are reassembled precisely relative to each other.
“It’s not the only check, but you want as many checks as possible when running a 1000mph car,” says Kimble.
Hexagon’s involvement in the project underpins the entire project, from the initial production of the car to the final run. As well as being involved in such an inspiring project, Kimble says the company has received lots of tangible benefits from its participation.
“We do a lot of commercially-sensitive work, and its great to be able to use an open and free IP to help promote the company’s capabilities,” he says. “It’s also opened a lot of doors and reinforced our existing relationships.”
Braking system
Just as important as the car’s assembly is the slowing down after the run, not least to the car’s driver Andy Green, who says, “getting to 1000 mph is optional, slowing down afterwards is compulsory!”
The braking system has three main systems: air brakes, parachutes and wheel brakes.
Detailed design and engineering experience has paid dividends with the parachute system. Marlow Ropes, which has been making rope at its East Sussex factory since 1807, is supplying the ropes that will connect the parachute to the Bloodhound car. This seemingly simple job presents a difficult engineering challenge.
Paul Dyer, technical manager at Marlow Ropes says: “The job of the rope isn’t just slowing the car down. It also needs to mitigate the impact of the deceleration from the parachute. When the parachute explodes out of the can at 800mph it picks up kinetic energy before it deploys. It’s that energy that has to be dissipated.
“We are designing around a 130kN, 13 ton shock load and a steady state deceleration of around 90kN, 9 tons of force.”
Each of the ropes will be around 10m long, 32cm in diameter and weigh around 15kg. The ropes will be made of nylon, which Dyer says still represents the “state-of-the-art” for energy dissipation. However the ropes will also feature a length of fabric called Technora, a Kevlar-like material. This piece of fabric will be put in at the end of the ropes near the attachment points of the car.
The section of Technora is a redundant safety measure. If the parachute deploys above the speeds of 800mph, the shock load would be more than the attachment point could take. The weak link of fabric will tear, ensuring the entire back section of the car isn’t torn away by the force of the parachute deploying. Technora is being used because of its resistance to heat – the attachment points are mounted near the rear of Bloodhound’s rocket engine, where the temperature could reach up to 6000 °C.
Dyer expects the specification of the rope to change after the test runs: “There are some considerable unknowns around when the parachute deploys. When the runs happen the system will be tweaked and the size may be lowered,” he says Dyer.
Fuelling
Just as vital is supplying the fuel to Bloodhound’s engines. The fuel system contains three tanks, a main jet tank and two auxiliary tanks. There is also a very small petrol tank to power the APU engine for the htp pump.
The fuel tanks are being supplied by Advanced Fuel Systems, which supplies similar tanks to the motorsport sector, including Formula 1. The main fuel tank for Bloodhound is not a metal box, but a “bag” manufactured from a strong, flexible composite made of nylon and polyurethane. The bag can deform if an accident occurs to allow the fuel to be moved away from the accident, but remains contained.
The outer structure is made of the composite, and is manufactured by using a process similar to a wet layup process, allowing the company to form it to a more tailored shape and get a more optimised fit. Bloodhound’s acceleration will create 2.5G, pushing all the fuel to the back of the tank. Similarly to the ropes, the most challenging aspect is what happens when the car starts decelerating.
Jonathan Tubb, managing director of Advanced Fuel Systems, says: “At the end of the measured mile, during the deceleration process, the jet engine still needs to be running because it’s consuming a huge amount of air at the front of the car. If it wasn’t running, the air would be stalling against the compressor, spilling out of the front of the intake. The car would become unstable.”
Inside the tank the 3G created by the deceleration will affect the position of the fuel, effectively tilting it upwards 72 degrees. In order to ensure that the fuel is at a point in the tank where it can be used, engineers have devised a system consisting of a series of louvres inside it, which holds the hold the fuel in place.
“It seems simple, but actually it’s quite complex. The fuel moves backwards under gravity because of acceleration, as that becomes deceleration the gravity acting on the louvre closes the slats, pushing the remaining small amount of fuel forward that is trapped.
“We start with 550 litres of fuel. About the time its decelerating there might only be 60 litres of fuel left, but its vital that it can still be picked up. With our pump system it can be.”
Engineers have used a combination of simulation, CFD and practical tests to develop the tank. Most of it has now been built and they are currently looking at the leakage in the louvres and ways to optimally fill the tank.
Advanced Fuel Systems, also supplied the fuel system for Thrust SSC. Tubb says: “The material density for a similar strength is less this time and the louvre system is significantly more complex. But the packaging has also been a real challenge, it’s a huge car, you’d think there is plenty of room, but it’s incredibly tight in there.”
Tubb agrees that there have been tangible benefits for his company. “We get brand awareness and the project has this wider appeal, which is great,” he says. “Engineers everywhere love it and want to know more about it, and we can tell everyone about our role, which for us is actually quite rare. It opens a lot of doors and gives us a lot of credibility.”