Putting the brakes on Bloodhound’s land speed record attempt

Drawing on its vast experience in brake technology, AP Racing is helping put a stop to the vehicle aiming to reach 1000mph in 2016, by providing bespoke brake systems.

Bringing the vehicle safely to a stop after breaking the Land Speed Record is a challenge. The team behind Bloodhound SSC turned to AP Racing in order to work out how to stop the jet and rocket-powered vehicle. AP Racing’s experience with other world record attempts, and its history of innovation, proved valuable insight.

Providing the last link in the chain, AP Racing’s contribution will handle the final stage of braking Bloodhound SSC after the vehicle’s air brakes have been deployed.

Initially the team looked at using off-the-shelf brake components for the record attempt but they quickly realised that a new solution would be required. Drawing on the engineering behind aircraft brake systems and data from Rejected Take Off (RTO) scenarios, the team mapped out the requirements with the Bloodhound team.

Providing different brake systems for both the initial runway testing in the UK and the high-speed runs in the South African desert, AP Racing have selected the materials best suited to each run: taking into account speed, centrifugal force and operating temperature. Cooling was one prime consideration: the vehicle cannot afford air cooling as this would increase aerodynamic drag.

“The two scenarios under which Bloodhound SSC will run present very different operating parameters,” explained Richard Bass, chief engineer brakes of AP Racing. “The trial runs will actually require the braking system to slow the vehicle from a higher speed, but for the record attempts the brake components have to withstand far harsher conditions.”

For the trial runs in the UK, braking will be provided by two AP Racing systems, on the front and rear, both employing carbon/carbon disc brakes. These will slow the vehicle from a maximum 235mph as the car completes its assessment and shakedown runs.

However, for the high-speed runs only the front brakes will be employed using steel brake discs. Designed to withstand the high centrifugal forces generated, they can rotate at 10,000rpm without disintegrating and will take over once Bloodhound SSC’s air brakes have been deployed. These brakes handle the last stage of the vehicle’s deceleration, from 160mph to a complete stop.

An extra complexity was that, as part of the rules covering an LSR attempt, the vehicle has to make the two timed runs within 60 minutes. This meant that all components had to work flawlessly for the two runs, as there would be no time to affect repairs. The engineers also had to allow for an emergency situation, where the brake system could be engaged, at a higher speed, if the other braking systems malfunctioned for any reason.

As part of its work on Bloodhound SSC, AP Racing also produced the two front suspension uprights for the vehicle. In order to keep the frontal area of the car as small as possible, and so more aerodynamic, each front brake caliper is half built into the front upright. This solution allows the suspension and brake package to be as narrow as possible and help deliver the car’s narrow front track. Despite the condensed design each upright, made from solid aluminium, weighs over 21kg, and together both can withstand 30 tonnes of peak suspension load, as the car breaks its 1000mph target.