Filament winding machine

The body tube of our first rocket, PIPE, was made from layers of fiberglass fabric laminated on top of one another. However, the resulting tubes did not have the surface quality we had hoped for. 

That is why, following the PIPE project, we decided to build our own winding machine. Once it has been developed, all that remains is to train the operators, and technical skills are not a primary concern. This is a major advantage, especially for student teams with a high turnover of members.

The machine unwinds a roving—a strip of fiber material—from the roll and impregnates it in an epoxy resin bath. This combination of materials gives the tubes their extreme strength-to-weight ratio. The impregnated roving is then wound onto the mold in a preprogrammed pattern. The precise programming of the winding path allows for the targeted adjustment of the tubes’ material properties.

Using this machine, we can manufacture tubes from a wide variety of fiber composites, such as carbon fiber, glass fiber, and aramid (Kevlar). The tubes can be up to approximately 1.5 meters long and have a diameter of up to about 160 millimeters. These dimensions can be expanded in the future with minor design adjustments.

Decoupler

In order for our planned “ARCHER” rocket to fly in two stages, a separation mechanism is required. Its job is to safely separate the two rocket stages from one another while ensuring that this does not happen too early during the flight.

The basic concept consists of a rotating disc with “cutouts” that, when in the correct position, allow the steps above and below to engage. When the disc is turned, the pins are “locked” and the steps hold together.

The decoupler is controlled by a pneumatic system that ensures reliable activation despite its compact design. For ARCHER, a fully functional decoupler is essential to achieving the mission objectives, which is why this is a key focus of development.

To ensure that the two stages separate properly, they must push away from each other. To achieve this, strong springs are used, and the lower stage will also be able to use air brakes to gradually separate the stages from one another. 

Airbrakes

The airbrakes cause the two stages to separate, allowing the second stage to ignite without burning up the first stage. However, the airbrakes are not only important in the first stage; they also serve an important purpose in the second stage.

Since ARCHER is scheduled to fly in the European Rocketry Challenge, our goal is to reach a predetermined altitude as precisely as possible. By controlling the airbrakes, we can begin braking at exactly the right moment and hit our target altitude.

Rings

To ensure easy access to the individual components, the rocket is divided into separate segments that are connected using standardized rings. The wound body tubes are bonded over a large surface area to the rings to ensure optimal force transmission.

A standardized panel will be installed between the two rings with a plug-in system, to which the other work modules can be attached. The greatest engineering challenge for the rings will be transmitting the enormous forces generated during rocket launch.