World’s First Supersonic Car

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 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.

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.

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. 

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. 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.