Bronwen Jones
PROTOTYPES of puncture-proof tyres just made at a factory in Carletonville mark the beginnings of what is expected to become a multi-million rand industry for South Africa.
The main design project started in 1991, when military users asked the Defence Research and Development Council and Allthane Technologies International, to find a solution to the high cost of tyre punctures.
Together they have devised a polyurethane replacement to pneumatic rubber tyres. While the first designs were smooth, there is now a treaded version, with vane-like spaces all around the rim.
A provisional patent was filed in early 1996, but the fine detail is top secret as attorneys carry out thorough patent searches in Australia, France, Germany, Japan, the United Kingdom and the United States. Then a further R40 000 will be spent to register patents in all those countries.
At the same time, extensive meetings have been held with Chinese scientists and industrialists. John French, project manager of Allthane, said: “The market there is vast. They could use more tyres than we could ever make.”
Tyres are big business for military users and for heavy industry, particularly mining. An insider commented on espionage attempts: “We’ve had people from General and Michelin hanging around, trying to photograph our tests. We had to confiscate a camera from one guy who was just pointing it in our direction and taking pictures on motordrive.”
Spooks should not surprise the military, but Armscor was alarmed when, a mere 17 minutes after a prototype failed at the Gerotek vehicle test facility outside Pretoria, it was mentioned in casual conversation by someone in a head office corridor.
Not only do all those involved want to recoup the R2,4-million development costs, but the potential employment and foreign exchange benefits to South Africa are vast.
Finite element analysis on the tyres was completed at the University of Pretoria in April. This involved immersing the material in oil, stretching and squeezing it at different temperatures to see how it elongates and compresses under different conditions. All this data is then fed into a computer to simulate loads on the material.
By the end of this year, a 35cm wide, 50cm inside diameter, puncture-proof tyre will be for sale. While each one, at about R8 500, will cost twice as much as a conventional military tyre, it is expected to run for some 8 500km, whereas a conventional counterpart would run for 3 000km if it didn’t puncture.
Rooikat Armoured Car tyres can puncture every running 11km, making the tyres contribute more than 10% of the total running cost per kilometre. While these features are common to many military vehicles around the world, the last thing soldiers want to do in a conflict is to have to change a wheel.
Add to that the flammability of rubber and vehicle burnouts are common. Even the heat generated by rubber tyres in normal use helps enemies locate a vehicle by its infra-red signal. And then there is the cost of support vehicles to consider, with their loads of spare wheels and tyres. The new tyres remove all these problems.
Whether the polyurethane tyre will also one day replace ordinary car tyres is not yet up for discussion. But the puncture-proof prototype from Carletonville proves not only that it makes good sense to reinvent the wheel, but that a host of civilian spin-offs from military hardware may doubly justify the existence of the much maligned defence budget.