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NERO Projects Hx Rocket Separation system

The separation system of the H7 and H10 rocket

The separation system between the first and the second stage is one of the critical components of the H7 rocket. This system has to comply with two very different requirements. When the two stages are still connected, it has to be capable of keeping together the over 2 meter tall rocket at an acceleration close to 25 g. When the separation system is operated, it should guarantee that the first and second stage of the rocket are indeed entirely separated, like a cup on a saucer. From these requirements an elegant design has emerged, which complies fully with the requirements.

The working principle of the separation system is given in the schematic drawing below.

The first stage is attached to the second stage with three clamp-like joints. In the drawing below, only one of these three clamps is shown. This clamp is in contact with both stages and has an extension going into the rocket interior through semi-circular holes in both stages. In this method, the second stage is on top of the first stage and the clamp including its extension is able to move freely through the hole.

When the pyrotechnical device in the center of the separation system is activated, the piston, which is initially held in place by a fixation wire, is pushed upward. This motion cuts the fixation wire in two places. Because of this, the clamps and their extension rotate away freely. This action removes the clamp function completely and the first and second stages are detached from each other.

The rocket separation system before and after separation.
 1  Light blue First stage
2 Dark blue Second stage
P Yellow Piston
C Light Green Clamp and extension
B Dark Green Pyro body
F Grey Fixation wire
X Red Pyro charge

Photograph in lateral direction of the rocket before the launch.

Photo in longitudinal direction of the rocket after the launch. You see the separation system without the used shells. The wires cutted by the pyro-bolt are clearly visible.

The separation system as used in the H10.

Download a Virtual Reality Model from the decoupling device from the H10. This system is an enhanced version from the H7 system (zipped EXE file, viewer included).
Blue=new Red=Visited
Cross section of the separation system in lateral direction of the rocket.
Blue=new Red=Visited
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Cross section of the separation system in longitudinal direction of the rocket.