JEC COMPOSITES MAGAZINE - Issue #89 - May 2014 - 13

bodywork was simply made
from 2 layers of the same
carbon fibre fabrics. The use
of Airtech vacuum bagging
products made it possible to
save more than 1 kg.

Formula 1 technology
at Formula Student

Fig. 1: The FS.05 racing at Hockenheimring ©FSG, Schindler

Fig. 2: Electric formula in a rainy race in Italy ©CTU CarTech, Klíma

at the end of 2009. Here,
the team used for the first
time Airtech products for
vacuum bagging and general
composites manufacturing.
It took many months for the
team to successfully use the
technology to produce really
efficient composite materials. Why efficient? Because
it really matters how you
process composites during
the manufacturing step.
Basic free curing of composites results in an excessive
amount of resin in the final
cured part. This is only dead
weight with no real impact
on the strength of the final
part. The excess resin can be
eliminated using the vacuum
bagging technology, with

specialized Airtech products
such as vacuum bagging
and release films, sealant
tapes, hoses, valves and
other accessories (Figures
3). The pressure created by
the vacuum induces closer
contact between the layers
and the excess resin flows
out of the structure. This
has two main benefits: lower
weight and higher mechanical properties.
This can be illustrated
comparing the carbon fibre
bodyworks for the third and
fourth models of the Formula Student car. These models
had the same bodywork
shape, but the first one was
produced using free cure
and the second one using
vacuum bagging. All of the

Capitalizing on its growing
experience with carbon fibre
parts, the team set a new
goal: to replace the steel
space frame of the car with
a carbon fibre monocoque.
It was the very first time a
carbon fibre monocoque
was used for a vehicle and,
generally speaking, there
is not much knowledge
available for the design of
structural carbon fibre composites. Therefore, the team
had to do a lot of research
and many material tests
with different layouts and
cores. In the end, the best
mechanical properties were
achieved by ensuring proper
contact between single
layers. Carbon fibre prepregs were used to ensure a
suitable fabric/resin ratio.
The parts were cured at
temperatures up to 125°C.
The force needed to press
the single layers together
was introduced by vacuum
bagging and the whole part,
inside the bag, was placed in
the pressurized chamber of
an autoclave. The high-quality materials and vacuum
bagging materials withstood
the high temperature and
pressure inside the autoclave. This technology is
exactly the same as the one
used for Formula 1 monocoques.
A similar technology was
used for the aerodynamic
wings of the Combustion
No89 May 2014

car. In order to create a down
force, each wing has an area
of approximately 1.2 square
metres. Thanks to high-performance composites, processed using Airtech vacuum
bagging products, the weight
of each wing does not exceed
3 kg.

Hard work that
was worth it
The team competed in four
international competitions
with each of the cars. First
in July 2013 at the Hockenheimring circuit, Germany,
where the Combustion team
obtained very good results
in all the static and dynamic
disciplines. Formula Student
Germany is unofficially
called a world championship
because top teams from
around the world participate
in this event (Figures 5).
CTU CarTech's Combustion
car took 11th place out of 75
competitors.
A premiere Czech competition took place shortly after
the German competition.
Both of the CTU CarTech
cars competed in Czech
Republic's Formula Student
event, which was attended
by 24 teams from around the
globe, including Germany,
the UK, and India. The
Combustion car was favoured in its class and finally
took 2nd place overall. The
Electric car had problems
with its control systems and
was unable to compete in
any of the dynamic disciplines.
Next was the Hungarian
race. Here, all combustion
and electric cars competed
head to head indifferently of

/ jec composites magazine 13
JEC COMPOSITES MAGAZINE - Issue #89 - May 2014

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