Analysis of the data logging of Saturday's highly successful second run revealed a peak speed of 444mph - a little higher than first estimates, highlighting the difficulties of giving peak speed immediately after a run. The first indication the team have is given by the Air Speed Indicator - or ASI - but at the 2,900ft altitude of the Jafr Desert this reads some 10% lower than actual ground speed. It is only when the data logs are analysed by systems expert Jeremy Bliss that a definite figure can be put on the speed.
Sunday and Monday were service days for the car. A long-term planned installation of the additional rear-wheel dampers was made to assist the control of 'bump-steer' at higher speeds, while the whole car was checked over and a number of minor detail items dealt with.
This morning was yet another early start on the desert. The first arrivals were some new friends from Australia and New Zealand that the team had met in Petra on Saturday's evening out. Before long the team 'Disco's' were arriving to begin preparations for the days planned runs.
Ron Ayers' two run profiles call for a first run to 450mph indicated air speed, followed by a second to 500mph indicated if the first revealed no problems. The first run would also carry a tail stills camera for the famous French photographer Alain Ernoult, working for the project's sponsor, Paris-Match magazine. The two runs would thus give ground speeds of around 500 and 550mph, taking the team well on its way to the Jordan2 objective of achieving over 600mph.
Good teamwork ensured that everything was quickly ready, but a few small delays ensued while Bedouin vehicles were intercepted and kept clear of the tracks by the Badir desert police. Once the tracks were secured, Andy Green in SSC was given permission to roll. Through the mirage the familiar 'rooster tail' rose and the car accelerated, with Andy bringing in first 'Max Mil' power (no reheat), the Min AB (minimum afterburner), the Max AB. Accelerating impressively the car reached some 450mph indicated before air speed indication in the cockpit was lost. Andy didn't notice, being in the throes of lifting off the throttles and releasing his parachute.
The plan had been to test the modified parachute that had been installed in the lower parachute bin. With some of the ribbons cut to counter the instability problems experienced so far, the lower bin was used instead of the untested upper to keep the variables of the test to a minimum. In a rare error, however, Andy released the upper unmodified parachute - which exhibited the same instability as before. Although the objective was not met, the test did prove the previously untested upper hitch.
The SSC came to a stand some half-mile to a mile short of the predicted point - a good sign - where Brian Palmer in the arriving Jaguar Firechase identified the cause of the loss of air-speed indication: the pitot tube on the tip of the nose had worked loose. It may be a relatively small part, but it is an important one if Andy is to judge his speeds correctly.
Fitting a spare pitot is not, unfortunately, the work of moments, but takes bodywork specialist Mike Horne time to bond properly. A second run was therefore not on the cards, so the team towed the car back to the desert pits for the Press Conference and interviews - with speeds increasing rapidly, the world's media have started to arrive in force to film and record progress.
As I write this the car is being checked out and the design team are checking the videos. A spare pitot is being 'dug out' in case it is needed, while the workshop team are checking over their charge.
Aerodynamicist Ron Ayers outlined his thoughts on the run: "The problems experienced today are typical development problems but will not interfere with the run program. We currently plan to achieve about 550mph tomorrow, and if that is successful we will consider a second run at about 580mph."
Keep watching this site for further updates - and if you haven't entered our online Jafr Speed Competition yet, make sure to do so to have a chance of winning a model of ThrustSSC!
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