One week, one part. The nozzle retainer will hold the full graphite nozzle in place. It is a variation on the simplest form of a retaining ring as used earlier on the KILO 6G motor. The variation consists of:
- the nozzle retainer has a divergent section where it lengthens the actual divergent section of the graphite nozzle thereby increasing Isp.
- Secondly the nozzle retainer acts as a boattail and has the same OD as the casing. The 15° boattail – simple chosen to match the divergent angle – will help to reduce drag and, since the GIGA is designed as “sustainer ready”, will help keeping the rocket aligned. When used as a sustainer I’m planning a none binding taper in the interstage coupler. This will perfectly center the rocket on the booster and eliminating any radial movement. Down side of this design are the blind holes required for the M5 threads which are tedious to make.