On 6th June 2014, the BLOODHOUND Team passed a huge milestone, five years in the making. They successfully completed a spin test of the first of the supersonic machine’s four wheels.
The test, carried out at Rolls-Royce’s test facility in Derby, saw the wheel successfully spun to 10,429 revolutions per minute. That’s 174 times per second!
Test results were satisfyingly similar to the predictions that the BLOODHOUND Engineers had calculated using their Hyperworks computer simulation software, from the Team’s partner, Altair. The expansion of the wheel’s 902.6mm diameter by 1.6mm was as expected, as was its “dishing” caused by the variation in expansion rates between the aerospace grade aluminium (Al 7037) that the wheel is made from and its steel hub. Design tweaks earlier in the process ensured that these deflections would fall within acceptable parameters. Vibration frequencies were also “pretty damned close” to those predicted, according to BLOODHOUND’s Lead Stress Analyst, Roland Dennison.
The only variable that caused concern was the wheel’s increase in temperature during the test. The test rig is normally operated in a vacuum, when Rolls-Royce use it to test their jet engine fans and turbines, but the BLOODHOUND Engineers wanted to expose the wheel to the sort of environment that it will see when racing across the Hakskeen Pan in South Africa. At one point, the friction of the air against the surface of the wheel saw its temperature rise at an alarming 1˚C per second, which peaked at 96˚C. At 150˚C, the structural integrity of the aluminium starts to be compromised, while at around 200˚C, it is irreparably affected.
The Team, therefore, decided to shorten the cycle of acceleration and deceleration, to better simulate the conditions that the wheel would see during a land-speed record attempt. This did the trick, ensuring that temperatures were kept within acceptable levels.
The empirical data collected during the test will now be used to fine-tune the computer simulations, delivering a more optimum wheel design, as the BLOODHOUND Engineering Team push on with the development of the World’s fastest car.
Huge thanks go to the following partners and sponsors:
- Castle Precision Engineering for the wheel machining and for being the awesome syndicate leader
- Lockheed Martin for their design expertise
- Innoval Technology for material expertise
- Altair Engineering for their Hyperworks FEA software
- Siemens PLM for the Unigraphics design software
- INTEL for the design environment equipment.
- Alimex for the original desert test wheels to validate Brian's design
- Skip and his team for enabling the South African wheel tests
- Trimet - for the pure liquid Ali material
- Otto Fuchs for the casting and forging
- Wheel Dynamic Balancing Ltd for the Balancing operations
- Metal Improvement Company for the shot peening
- Micro Epsilon for providing the spin test sensors
- AMFIN for the anodising
- Metalweb for the plate material
- Rolls-Royce for the spin test resource and design expertise
- Bampton Packaging for their fantastic bespoke boxes at every stage of the wheel programme
- Arthur Spriggs & Sons for transporting the wheel materials and the wheels all over the UK and Europe.
- All World Freight for shipping the desert test wheels to and from South Africa