Protecting the world’s first Supersonic Car

Filters that move faster than sound

Pall's latest filtration solution not only debuted with a bang, but also with a sonic boom. On October 15, 1997, Andy Green became the first man to drive faster than the speed of sound, thanks in part to the crucial hydraulic system in his car, protected by Pall filtration.

On that dusty day in the Black Rock Desert in Nevada, USA, Green, a 35-year-old fighter pilot with the UK Royal Air Force, strapped on a twin-engine jet designed for supersonic speeds, but which was never intended to fly. Before the day was over, Green and his car, the Thrust SSC (Super Sonic Car), owned the prestigious World Landspeed Record, with an official speed of 763.035 mph (1,228 kph), or Mach 1.020. This result shattered the 14-year-old record of 633.468 mph (1.019 kph) set by Green's boss and Thrust team leader, Richard Noble, and allowed Green to claim the title as the first man to ever officially drive faster than the speed of sound. This amazing achievement came 50 years and one day after Chuck Yeager's historic supersonic flight.

It Takes a Lot of Drive to Break the World Landspeed Record

It would be difficult to find a more exciting and technically challenging form of motor racing than the World Landspeed Record (WLR). But the rules that govern it are surprisingly simple. The car must make two passes over a measured mile (1.6 km) within 60 minutes, and the average speed of the two passes yields the official result. Another rule is that the vehicle must have four or more wheels, with steering provided by two of those wheels. Other than that, there are no design restrictions.

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Innovation Can't Take a Back Seat

The Thrust SSC uses an innovative design that takes full advantage of the WLR's lack of restrictions. The 10-ton car's most notable features are its twin layout Rolls-Royce Spey 202/205 afterburning turbofan engines. These modified aircraft engines generate the 110.000 horsepower needed to propel the car through the sound barrier. The Rolls-Royce engines were chosen for their design stability, and because they could be positioned such that 60% of their weight rested on the car's front wheels. This would help keep the Thrust SSC, a twin-engine jet car, from becoming airborne.

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Driving Reigns in the Desert

The extremely high speeds that are inherent in pursuing the World Landspeed Record, coupled with the unevenness of the course's surface of compacted desert sand, make controlling the car's stability a crucial and difficult problem to solve. Thrust SSC uses a hydraulic active ride suspension system that is similar to those developed for Formula 1 racing cars. Active suspension dynamically adjusts the displacement of the rear suspension, helping to keep the vehicle on the ground. Because this hydraulically operated system had to operate with perfect reliability despite the demanding desert environment, the Thrust SSC team chose Pall as its filtration partner.

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This Racing Team Needed a Partner That Could Perform with the Best

Pall has worked with all Formula 1 design teams for many years, so it is not surprising that the Thrust SSC team approached us. To ensure the best possible protection, we first examined dust from the Black Rock Desert, where the WLR attempt is held. This examination, conducted by Pall's Scientific and Laboratory Services, established that approximately 85% of the test sample contained dust particles smaller than five microns. Particles of this size can be particularly damaging to the components in the fluid systems of cars, and can lead to excessive and rapid component wear, inefficient operation, and possibly a premature total system failure. At Mach speeds, failure puts lives in jeopardy.

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Active Suspension Struts its Stuff

The active suspension system adjusts the relative angle of the car with respect to the ground, to help maintain stability at any speed. It does this with the help of high-performance servo valves. These valves are very sensitive to particulate contamination in the hydraulic oil. To protect it, the suspension system was first flushed using Pall high-efficiency one-micron filters, to rapidly remove contamination introduced during assembly of the system, before it was filled with pre-filtered hydraulic fluid. Next, fluid samples were taken to determine when the fluid cleanliness had stabilized. Finally, the running filters and servo valves were fitted.

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Filtration Ensured Nothing Would Break But the Record

Thrust SSC uses four Pall 9021-Series non-bypass pressure-line filter assemblies, with a filtration rating of 3 micrometers (ß3=200). Each assembly also incorporates an indicator, to help the team rapidly determine when a filter is blocked and a replacement is required. Before and even during the run for the record, hydraulic fluid cleanliness levels were monitored to ensure that they were maintained at the required cleanliness level. And throughout the testing, live runs, and record-setting attempts, the Pall filters performed faultlessly -- and therefore, so did the suspension system.

We at Pall are proud of our involvement in this exciting project, and wish to extend our congratulations to Richard Noble, Andy Green and the entire Thrust SSC team.

As the consecutive World Landspeed Record holders and members of the first team to send a car through the sound barrier, we obviously think you've pulled a fast one.

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