Coming from experimental APCP motors, LD and myself were ready for a new rocketry project and had been considering designing and building a liquid bipropellant ETHALOX engine for some time. However, with no prior experience in liquid propellants, this represented a significant step up from the relatively easy solid rocket motors we had been making.
During the pandemic in 2020-21 it became clear that in order to get a new design fin bracket machined I was getting too dependent on external factors. Hence the decision was made to become self-sufficient with the conversion of a manual HBM BF 25 / G0704 mill/drill into a full blown DIY CNC milling machine.
After a great boost, the BOOSTAR-TWO / GIGA IV two stage rocket flew to a disappointing 8+km as the 2nd stage motor experienced a catastrophic anomaly upon delayed ignition at the LRE summer 2021. Please click here for the full launch report.
See text under photos for a detailed description.
On 24.09.2020 we tested to see whether the BOOSTAR-TWO and the GIGA IV would fit together in the launch rail and to prevent unpleasant integration surprises at the LRE. Espcially orientation of equipment and launch buttons are critical. All went well and within the hour the BOOSTAR-TWO / GIGA IV were erected and lowered from
Place eye bolt for shock cord 45° to head end igniter body. Place shock cord above eye bolt as the drogue fabric could get squeezed tight between eye bolt and d-shackle.
Lessons learned: Don’t take this route again using the M10 threaded section as a basis for concentricity. If going to machine on lathe, start with concentric mold before laminating / machining. Don’t rely on staightness M10 threaded section which can get close but slightly off straight M10 threaded section will result in a significant
One of the design changes for the GIGA IV is a common bulkhead to join the previously central avionics bay of GIGA I-III (in control of recovery) with the updated nose cone electronics (camera and GPS tracker). With this modification there is no longer space for a separate main parachute compartment as can be expected
The GIGA III was built completely from aluminium but heavy like a tank. That is probably the reason why it was so successful recovering from non-flight-critical failures. In order to shave some weight for the from the total rocket mass of the GIGA IV it was decided to replace the aluminium tubes with fiberglass (FG)
The amateur, experimental, two stage, BOOSTAR-ONE / GIGA III rocket reached near space and was safely receoved at the LRE 2019 spring launch hosted by the kind people of the PTR. Please stay tuned for more info.