While most components of our rocket are built by our own engineers in the D:Dream hall, some components require such high precision that it is not possible for us to make them ourselves. For two of these high-precision components Precimax is helping us by offering their expertise and machinery. Precimax is a Dutch company specialized in CNC milling and lathing. By using the latest in software and machinery, they are able to make parts that would otherwise be simply out of our reach. Specifically, they make two highly critical components of our rocket: the injector plate and the upper skirt collar.
The injector plate is effectively a high-tech showerhead that sprays the liquid oxidizer into the engine. It very precisely lets in the right amount of oxidizer for our engine to burn efficiently and at the same time introduces a swirl. This swirl is needed to sufficiently mix the fuel and oxidizer, and we would lose a huge amount of performance without it. The injector plate is an aluminum plate with many tiny holes in it (only 1.5 mm in diameter), which are all under a slight angle. It also has to keep functioning properly under some of the most extreme circumstances in the engine, with pressures up to 60 bar, and temperatures up to 3000 K.
Injector plate after an engine test, which aside from some scorch marks is still in pristine condition.
The upper skirt collar is an aluminum ring at the top of the tank. It is a part of the flight separation system. Once the rocket reaches the highest point in its flight, the nosecone and recovery bay separate from the oxidizer tank and the engine. If this part isn’t precise or strong enough, something unexpected could happen during separation, which could risk the recovery of our data and payload. It is also one of the pieces that connect the two parts of the rocket before separation.
The upper skirt collar is the aluminum piece at the front of this image. The attachment points are visible too.
Without advanced components like these, we could not achieve our goals as we would be stuck with a bulkier, heavier and less efficient rocket. We are very thankful to Precimax for producing these components for us!
by Daan van Heteren