After ThrustSSC's run on Monday Andy Green reported that the handling and ride of the car were better than last year - indeed on the in-car video he reported that the suspension handled well over the bumps in the desert. Closer study of the videos and car revealed a different story, however - the videos apparently showed sharp deflections of the steering rear wheels as the car travelled over the bumps, while the amount of 'play' in the rear wheels seemed to have increased when they were checked back at the Aireshelta. The car's data logging appeared to contradict the video - the LVDTs on the steering quadrants showed minimal deflection of the steering arms relative to the linkage.
The design team met to discuss the results - and decided that further study was warranted. This would mean that Tuesday's planned run or runs would be postponed until at least today (Wednesday). Two facts needed to be established - was there really more movement in the linkages, or was it an optical effect caused by the wide camera angle and sideways movement of the wheel as it rose over the bumps?
The first was assessed by measuring the degree of play in the system, which was soon found to be within Glynne Bowsher's design tolerances. The second was established by watching the camera view as the rear wheel was jacked and lowered. The conclusion was that the deflections seen were a combination of the wheel's arc of movement and the engineering tolerances - meaning that there was no contradiction with the logged data. The only concern remaining was that the wheel deflections were sudden ones, so the decision was taken to re-fit the wheel damping that had been installed in 1996 before the desert flooded and to repeat the profile of Monday's run to check out the modification. The dampers had been left off for the first run to avoid disguising the effect of the winter's changes to the suspension geometry.
That job was underway yesterday when the dust storm struck the camp (please read "Weather To Run Or Hide?" for more details) and work was delayed while everyone took shelter. Nick Dove's workshop team worked late into the evening to make up the lost time - putting their suppers well back into the evening's rest time. That rest would be much needed with another 0330 alarm call for a run.
Nick's team were back in action early - fitting the Spax shock absorbers to the new brackets. Adam Northcote-Wright had his 'other hat' on and was fitting a camera to record the trailing rear wheel with bodywork specialist Mike Horne. By 0900hrs this morning ThrustSSC was prepared and in position at Mile 6 facing south. 'Pegasus' - the microlight - buzzed overhead while the BBC crew watched from opposite Mile 6.5. Howard Stapleton from Tomorrow's World had joined Bill Grist's crew for a couple of days and to prepare his report for airing on the program next Wednesday.
The start routine has become almost commonplace now - after all, this was ThrustSSC's 26th run. The Palouste started, followed by the car's twin Speys, and all the attendant vehicles withdrew. The engine pitch could be clearly heard nearly a mile away as it rose to a roar and ThrustSSC rolled forward, gently at first, then with ever increasing purpose. A mile down the track the car came to a stop on rolling resistance alone - Andy Green needed to apply no brakes, succeeding in acquiring more valuable data for Ron Ayers to use when deciding his Run Profiles.
One minor problem had been experienced - the 24-volt supply in the car failed at around 50mph, cutting Andy Green's intercom and warning lights. Unable to tell if there was any problem, particularly a fire in the car, Andy stopped accelerating at 100mph rather than the planned 125. The South Team called 'safe' for him and went into action. The television crew rushed to get their pictures of Andy climbing out and the video tapes being recovered for analysis by the Design Team. The recovery team brought up their Supacat and towing dolly and lifted the rear of the car for returning to the Aireshelta. The new silver cover - provided by Merlo who loan the massive 6-ton capacity handler to the team - was fitted to the front to keep down the absorption of heat by the car. Interviews were completed and the car towed back to 'Stonehenge' - the desert pits.
Back in the Pit Station the videos revealed good results - the wheel's were much more stable over the bumps and the suspension's ability to absorb them was excellent. The car checked out well, as did both telemetry and data logging. The 'all clear' was given to progress to higher speeds.
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