One of the most common questions we get is about the Budweiser Rocket. Designed by Bill Frederick and driven by Stan Barrett, this car is claimed to have broken the Sound Barrier in December 1979. The assertion that Barrett exceeded Mach 1 is often disputed - out on the desert picking up stones from the racetracks, a time when conversation is often at its best, it received some thought.

It is important that we point out that this was not an attempt on the World Land Speed Record, being made in one direction, and achieving its peak speed for a distance of just 50 feet. Speed was calculated from measurements taken with a ground tracking radar system. The WLSR on the other hand requires two runs in opposite directions through a measured mile or kilometre, timed by independent timekeepers using equipment approved by the FIA, the record's governing body.

In the cold December air, the Budweiser Rocket was reported to have reached a peak of 739.666mph, fractionally exceeding Mach 1 at the low temperatures. No sonic boom was heard. The unconventional means of timing the car, as well as the lack of a boom, has caused people to question whether the sound barrier was indeed broken, and it is sad that this has left a question mark in the history books ever since. There is little doubt that the car went fast, nor that Barrett was an exceptionally brave man - for the rear wheels were clearly off the ground at peak speeds - but was it as fast as reported and therefore supersonic?

A sonic boom has been heard - and felt - from ThrustSSC as she has edged close the sound barrier. Richard Meredith-Hardy's incredible aerial photographs show a shockwave developing on the front of the car and stretching out either side for some 150ft. Photos taken from ground level show the effect as well, with a layer of dust lifted alongside the car. On the racetrack the characteristic marks left by ThrustSSC are obliterated as the passage of the shockwave has pulverised the desert surface - indeed it is only by looking along the tracks rather than directly down at them that the wheelmarks can even be found.

Although shockwaves were always expected from ThrustSSC - and the high-speed photographs of the rocket-sled models exhibited several - quite such visual effects never were. We have never seen similar photographs of shockwaves from the Budweiser Rocket, nor have we ever heard reports of a similar effect on the surface of the desert at the Edwards Airforce Base where the car ran. Has anyone got such pictures? If so, we'd love to see them - please let us know at thrust.news@battlement.digital.co.uk.

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