The Supersled

Takes Shape

With the help of the carbon fibre experts at

epm:technology the supersled was starting

to come together.

N CHARGE of the supersled project

at epm:technology was Andy Butt, an

engineer with years of experience in

working with carbon fibre and just the man to

explain why it was the stuff we should be using

for our fairing. The answer is that it’s a miracle

material that engineers and designers absolutely

love. If we were to make our fairing for the

supersled out of steel – and most car body

panels are still made from steel – it wouldn’t be

as strong, it wouldn’t be as stiff and it wouldn’t

be as light. Carbon fibre is five times stronger

than steel, twice as stiff and only one third of

the weight. Saving weight might not have been

such an issue when we were putting together

the prototype chassis, but if we now added too

much weight it might work to slow the sled.

I

Carbon fibre’s secret is in the way that it is

made. A carbon fibre product starts off as very

thin strands of carbon – thinner than a human

hair. These are twisted together to form a kind

of yarn, a bit like cotton fibres are spun to make

thread. The big difference is that the carbon

yarn is far tougher stuff and, when it is woven

into a cloth, it is well on the way to becoming

strong enough to be used in the bodywork of

a Formula One car or a jet airliner.

Turning a textile substance that is delivered

to factories and workshops on long rolls into

something stronger than steel is actually

quite simple. A mould is created rather like a

jelly mould, although the mould they use at

244    world’s fastest sled

Above: The carbon fibre has a smooth, shiny, tough

finish when it comes out of the mould.

epm:technology to create the parts for the

supersled is more like a kind of plaster that can

be shaped, drilled or carved very accurately

to achieve the right shape. The mould is

coated with a very thin film of release agent

that will allow the finished carbon-fibre part

to be separated from the mould cleanly and

easily, and then the carbon-fibre cloth is laid

over the mould. The cloth is tucked in to

all of the mould’s nooks and crannies, and

multiple layers of cloth are used to build up the

thickness and strength of the finished part.

In industry, most carbon-fibre cloth is

impregnated with the correct amount of epoxy

resin – which acts like varnish or glue and

will soak into the carbon fibres, binding them

together and then ‘curing’, or hardening. The

alternative is to paint the epoxy resin on to each

layer of the carbon-fibre cloth before curing it.