Ready for lift-off!

For the manufacture of Ariane 6 rocket components, specialist machine builder Roth Composite Machinery has developed a Filament Winding Plant, designed in close cooperation with customer Avio, a leading manufacturer of space propulsion systems. Avio produces the so-called boosters – the propulsion rockets for Ariane 6 – by using the new Roth machine. It is expected to carry out the transport of satellites for the European Space Agency (ESA) in future.

In modern rockets, fibre solids are used increasingly more often for the lightweight composite casings of the engines and other components and manufactured using either filament winding or prepreg processes. Owing to the lightweight construction, for example, the weight of the booster stages of Ariane 6 can be reduced by up to 35%. As to the operation of the rocket, the expenses per load-ton are thus supposed to be reduced by up to 50%.

Avio and Roth Composite Machinery utilised their common experience from previous Ariane 5 and Vega projects, as well as the technology and application know-how built up for decades in developing the new Filament Winding Plant.

Having a weight of 100 tons, it’s one of the world’s largest plants using Roth Composite Machinery. With a maximum length of 17m and a diameter of 3.6m, the winding mandrel weighs around 120 tons. The plant is equipped with three carriages for three different winding processes – each carriage has a length of 7.4m and is moving up to 90m per minute.

To provide the necessary heat resistance for the boosters, the first carriage is used for winding heat protection tape onto the mandrel in a mould-less composite construction (first layer inside the booster). After tape vulcanisation, the Towpreg winding process is achieved using the second carriage. In this case pre-impregnated bundles of fibres are wound onto the winding reel. Due to the prior separate impregnation of the fibres resulting in Towpregs with a very constant quality, a highly homogeneous composite structure of high-quality is established.

The third carriage is equipped with a fibre delivery head for automated tape laying (ATL). This technology enables the exact laying of the tape resulting in complex geometrical shapes for the attachment parts of the boosters. The trimming of the tape is undertaken via an ultrasonic cutting head. The ATL technology was developed by Avio, together with Roth and a further Italian partner.

Cut and thrust

The boosters of Ariane 6 are about 15m long and have a diameter of up to 3.6m. Depending on payload weight, two or four boosters per rocket are used. They are filled with solid fuel and ensure the enormous thrust when firing the rocket, as well as in the first flight phase in order to reach the thinner air layers as quickly as possible. The booster case is made entirely from carbon fibre and replaces the steel casing of the previous version used on Ariane 5. The boosters must resist high temperatures when the fuel is burned and extreme force loads during the acceleration of the rocket. Components made of fibre composites have ideal mechanic characteristics, such as high tensile strength and high force absorption.

“We belong to the world’s market leaders in the composite technology sector,” states Roth Industries’ chairman, Manfred Roth. “With the Filament Winding Plant manufacturing components for the aerospace industry, we’ve confirmed our claim of being the technology leader.”

www.roth-composite-machinery.com