It was time to see if we could set a world record speed for a gravity racer. The weather was 21ºC in nearby Avignon and the wind on the 2 km road section was light. Feeling buoyant from the previous day’s 81.8 mph and having a number of further changes up our sleeves — we were optimistic.
The weight of the racer before the attempt was 194.5 kg and we added 5.5 litres (5.5 kg) of water to reach the maximum 200 kg weight. This was distributed mainly to the rear of the gravity racer following Guy’s feedback on its driveability. Brake bias was adjusted and the tyres were pumped up to 84 psi. It is important to stress that all of these changes were made incrementally on each run to allow Guy to adjust to the changes in handling and for us to verify what each speed increase was attributed to. Eventually, the optimum set up was achieved and Guy drove the gravity racer into the Guinness World Record book with a speed of 85.6 mph!
The record had been broken and Guy was already looking to the next challenge; to see how fast the gravity racer could go. Thoughts of breaking 90mph were clearly on his mind. Our time on the mountain was also coming to an end so there was not the time to make further incremental changes. A number of further changes were made at once, including adding further weight. The braking and handling had significantly shifted and Guy commented that he probably should have come to a stop after the first bend but it was now or never and what was the worst that could happen…..
Interestingly Guy managed to tame the racer right up until the final straight when he lost control whilst braking and crashed in spectacular style. “That was the best crash of the year!” Guy claimed laughing as he climbed out completed unharmed. The team breathed a huge sigh of relief — the gravity racer’s safety design of steel tubular frame and 5 point safety harness had been tested to its limit, and passed.
Will we be repairing the racer?
No – although the frame appears intact it has now been put under significant stresses and we can no longer be confident in its structural integrity.
Could we have gone faster?
Yes of course! Our gravity racer was conceived, designed and built within 4 months; this in itself is a fantastic achievement. We had some great comments on the blog and thank you for the interest! We do not think our design is perfect and we look forward to seeing the challengers to our world record!