Race track testing the finished FR-1 roadster sports car.
Race track testing the finished FR-1 roadster sports car.
The carbon fibre epoxy composite monocoque cockpit chassis was ‘out of autoclave’ moulded under vacuum from GMS EP270 epoxy pregreg at only 70°C.
The carbon fibre epoxy composite monocoque cockpit chassis was ‘out of autoclave’ moulded under vacuum from GMS EP270 epoxy pregreg at only 70°C.
The composite monocoque cockpit chassis is approximately 2 m by 1.5 m.
The composite monocoque cockpit chassis is approximately 2 m by 1.5 m.

The two-seater concept car has many innovative engineering and design features. These include a new lightweight carbon fibre composite monocoque cockpit chassis, the first ever built in Australia, which was designed and moulded ‘out of autoclave’ at only 70°C from GMS EP270, an epoxy prepreg with a 200 g/m2 3k twill carbon fibre base fabric.

This carbon/epoxy cockpit chassis, with approximate dimensions of 2 m by 1.5 m, weighs only 80 kg but still provides the high torsional rigidity needed. This has been achieved by design optimisation in the number and orientation of the carbon fibres plies used.

The high mechanical performance of the fabricated chassis laminate has been independently tested, correlated and analysed using FEA analysis, by the Australia Future Fibres Research & Innovation Centre (AFFRIC) at the Deakin University of Melbourne.

The FR-1 project

Unusually, the entire FR-1 concept car project is run by a charitable foundation called ‘AutoHorizon,’ whose aims are to demonstrate the engineering, design and manufacturing expertise available in Australia today and to inspire Australian school and college students to become the engineers and designers of the future.

The FR-1 project has over 90 sponsors including:

  • the Victorian Centre for Advanced Materials Manufacturing (VCAMM);
  • Holden;
  • Boeing Aerostructures Australia;
  • the Automotive Centre of Excellence (ACE) in Melbourne, where the car was built; and
  • GMS Composites, which manufactured and supplied the GMS EP270 carbon fibre prepreg system for the project.

The VCAMM / Autohorizons / Boeing engineering team which has worked on the FR-1 project designed and built the FRP cockpit chassis and the fibreglass mould tooling. They looked at a number of different epoxy prepreg options. GMS EP270 was selected from the onset due to a combination of several critical factors.

Firstly, as the vehicle is a one off, they were looking for a cost efficient low temperature tooling and production process, and in a material which they could obtain in small volumes.

Secondly, they needed a material which, post cured, would provide the required dynamic strength and stiffness properties in the monocoque cockpit chassis needed for a sports car powered by a Holden 6.0 litre V8 with a Ferrari 355 transmission.

GMS EP270 with a carbon fibre fabric fitted the bill perfectly, being a high performance ‘out of autoclave’ epoxy prepreg designed for low temperature moulding under a vacuum at as low as 70°, using fibreglass tooling.

FR-1 has been a fantastic engineering project, bringing together leading automotive designers and material technologies in Australia. We are thrilled to have been involved and to demonstrate the application performance that can be achieved with our low temperature, out of autoclave advanced carbon prepreg system.
Sam Weller, managing director, GMS Composites

GMS Composites has the manufacturing flexibility to supply even small volumes of the GMS EP270 prepreg system in a choice of carbon fibre, aramid or glass fibre reinforcements. In addition to being used for moulded FRP parts, GMS EP270 can also be used in the construction of composite sandwich structures as well as for tooling applications.

Production benefits

Having completed the design and material specification phase and built the mould tooling, the FR-1 project team then used the production expertise of Boeing Aerostructures in Port Melbourne to assist with lay-up, moulding and to fully cure the GMS EP270 carbon fibre prepreg, as well as bonding the chassis using an aerospace grade Araldite® structural adhesive.

Jason Bonar, who has been with Boeing for over 18 years, worked with the AutoHorizon team on the moulding and lay-up of the chassis, which included eight 16 hour cure phases and a final post cure, all done out of autoclave under vacuum at 70°C.

During production, GMS EP270 prepreg offered the benefits of being very easy to work with, conforming accurately to the tight and detailed tool. The finish and integrity of the final product was outstanding.

“With respect to workability and surface finish, I found GMS EP270 prepreg to be on par, if not better, than any other prepregs I have used,” says Bonar.

Out of autoclave

For some years now, in order to drive down capital and operating costs, as well as to gain greater production efficiency and flexibility, many leading OEM and Tier 1 manufacturing companies in the aerospace industry have approved and specified a number of primary and secondary structural composites parts manufactured from an ‘out of autoclave’ composite prepreg material.

Out of autoclave prepregs have the added benefit of simpler and significantly lower tooling costs.

While exact figures are not given out by Boeing Aerostructures, out of autoclave composite part manufacturing costs are estimated to be a factor of four times lower, with tooling costs typically reduced by over 50%. ♦