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The need for speed

The Bloodhound SSC project, a supersonic car that is designed not only to go faster than the speed of sound (supersonic), but to over 1 000mph (1 600km/h), has suffered yet further setbacks as the project struggles against financial and environmental pressures.

Citing “short-term cash flow problems,” and flooding of the Hakskeen Pan in the Northern Cape province of South Africa where the record attempt will take place, Bloodhound SSC project director and former World Land Speed Record holder Richard Noble is confident 2017 is the year of milestones for the Bloodhound SSC.

Certain circumstances may have put a dent in the schedule, but the upside, says the vast team working on Bloodhound SSC, is that it provides additional time for engineers to generate more power from the car in the event that the final build structure is heavier than expected.

“It’s frustrating, I know; and the team are disappointed but we’re resilient and we’re going to make this happen,” Bloodhound director Richard Noble told BBC News. “The money is coming in but it doesn’t always match our planning and fit with the times when we need it.”

“While this is undoubtedly good news there is inevitably a time delay between pledges of support, contracts being signed and cash arriving. Anyone who runs their own business will be familiar with this and the need to be pragmatic when planning.”

“However, temporary delays do not change our direction of travel! 2017 will be a milestone year for The Bloodhound Project and we are determined to be out in South Africa, challenging records, next year.”

According to an official press release: “Hakskeen Pan flooded in January [2017] and then again [in March]. Allowing for similar events next year, and building in time to make final preparations to the track, we expect our advance party to deploy to the Kalahari in [mid] 2018.”

Not only is the project aimed at going faster that any other land-based vehicle has before, but it is also to assist in inspiring the next generation of scientists and engineers, which is the overall objective of the project. The current record stands at 1 228km/h – Mach 1.02 – and was set by Andy Green in Thrust SSC in 1997. Green will drive the Bloodhound SSC car. Prior to that, the record was a speed of 1014km/h, achieved by Richard Noble in Thrust 2 in 1983.

Bloodhound SSC is approximately 13.4 metres long and weighs 7.5 tons. The design is a mix of car and aircraft technology, with the front section being a carbon fibre monocoque (like a racing car) and the back portion being a metallic framework and panels (like an aircraft). The two front wheels sit within the body and two rear wheels are mounted externally within wheel fairings.

It will be powered by both a jet engine and a rocket, which together will produce more than 135 000 horsepower – the equivalent of more than six times the power of all the Formula 1 cars on a starting grid put together. Over 110 man years of effort have been invested in the design, build and manufacture of Bloodhound SSC.

Design
Bloodhound SSC is, without doubt, the most complicated car ever built. When finished, it will comprise over 3 500 parts (and 22 500 rivets), of which many have been designed and manufactured uniquely for this car. Consequently, Bloodhound is a very difficult car to describe in detail.

Bloodhound SSC is a hybrid construction because there are different requirements for the two ends of the car. The front section of the car (which consists broadly of the nose and the cockpit) is primarily made of carbon fibre composite while the rear section is made from metal. Each part of the structure presents its own challenges in terms of design and manufacturing.

Forward structure
The front section of the car consists of a carbon fibre monocoque, similar in concept to a Formula 1 tub. This provides Andy Green, the driver, with a very secure, rigid safety cell. It is also the most efficient way to form the complex curved design of the car in front of the cockpit and main jet engine intake.

The monocoque needs to take the aerodynamic load (air pressure) of up to 10 tons per square metre. As a result, it has taken more than 10 000 hours to design and manufacture.

It is made from five different types of carbon fibre weave and two different resins. Sandwiched between the layers of carbon fibre are three different thicknesses of aluminium honeycomb core (8, 12 and 20mm), which provide additional strength. At its thickest point the monocoque comprises 13 individual layers but is just 25mm in cross section. Overall the monocoque weighs 200kg.

The monocoque bolts directly to the metallic rear chassis.

As a safety check, projectiles have been shot at the ballistic panels that will go on the side of the monocoque to ensure Green will be fully protected from stones or other debris hitting the car at high speed.

Rear structure
The rear of the car is a metallic structure that’s been constructed separately as upper and lower halves.

Upper chassis
The upper chassis houses the Eurojet EJ200 engine and the intake duct, and above this sits the fin. This half of the chassis is a ‘rib and stringer’ construction, similar to that used in the aerospace industry. The ribs are machined from aluminium billet and the stringers that run the length of the structure are made from titanium. The outer skin is also titanium in order to reduce the weight at the rear of the car but keep it stiff.

The titanium skin was both glued and riveted on to the ribs – a process that used 11 500 aerospace rivets. It was then ‘cooked’ in a giant autoclave (effectively a huge pressure cooker) at the National Composite Centre to ‘cure’ the glue, in a process that saw the temperature raised by 5°C per minute, then baked at 175°C for one hour and allowed to cool overnight. Using both glue and rivets makes the upper chassis doubly strong, as either would be strong enough on its own.

Lower chassis
The lower part of the rear structure houses the auxiliary power unit, the jet fuel tank and the rocket system. It is made of a series of aluminium frames and bulkheads that are skinned in steel, using around 4 000 rivets to hold it together.

The furthest back portion of the lower structure forms the ‘rear subframe’. The rear suspension is mounted on this, together with the rocket thrust ring – which transfers the thrust of the rocket into the chassis – and the parachute cans and attachment.

Underside
The underside of the front of the car – the monocoque – is titanium, while the floor of the rear of the car is made of steel plate. Both materials were chosen to prevent the bottom of the car from being worn through by the desert silt.

Hakskeen Pan
The Northern Cape team (all 300 of them) have removed over 16 000 tons of stones, by hand. All of this adds to the roughness and irregularity of our supposedly ‘flat’ desert surface.

The task set for the team was to scan the whole 20 kilometre long by 500 metre wide track surface, measuring the elevation (height) in each square metre, to an accuracy of 10mm or less. That’s 10 million precision measured points, just for the main track surface (the safety zones either side were also scanned, which doubled the task). It’s fairly easy to measure one point accurately, or even several (surveyors do it all the time), but 10 million points spread over 10 million square metres? That was not practical until now.

Bloodhound SSC has two parachutes as part of its braking system. They can be deployed at speeds up to 650mph. With a thrust to weight ratio 9:1, it will cover a mile in just 3.6 seconds.

For more information visit www.bloodhoundssc.com

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