Table 1: Summary of 76 mm test motor geometry parameters.
Fuel Material | Outside Diameter | Port Diameter | Length | Weight |
ABS Ignitor Cap | 6.985 cm (max) 4.762 cm (min) |
2.16 cm | 5.08 cm | 95.5 grams |
Fuel Grain | 6.985 cm | 2.16 cm | 23 cm | 800 grams (ABS) |
Nozzle | Throat Diameter | Exit Diameter | Exit Angle, deg. | Expansion Ratio |
1.087 cm | 2.083 | 12 deg. | 3.7:1 | |
GOX | Injector Diameter: | Feed Pressure | Full Tank Pressure | Full Tank Mass |
Single Port | 0.476 cm‡‡ | 350-500 psig | 2200 psig | 65 grams |
4-Port | 4 × 0.238 cm§§ | " | " | " |
H2O2 | Injector Diameter: | Regulator Feed Pressure Settings | N2 Pressurant Tank Pressure | Full Tank Mass |
1) Single Port | 0.381 cm*** | 350 psig/250 psig | 800-1200 psig | 525 grams |
2) 5-Port | 5 × 0.170 cm††† | " | " | " |
3) Full-Cone | 0.254 cm, 120 deg spray angle‡‡‡ | " | " | " |
4) Hollow-Cone | 0.2286 cm, 120 deg spray angle§§§ | " | " | " |
5) Hollow-Cone | 0.1524, 90 deg spray angle**** | " | " | " |
‡‡Custom built from 1/4" NPT Brass Plug (https://www.mcmaster.com/#50785K221) with drilled 0.476 cm diameter center port.
§§Custom built from 1/4" NPT Brass Plug with 4 × drilled center 0.23 cm diameter ports.
***Custom built from 1/4" NPT Brass Plug with drilled center 0.381 cm diameter center port.
†††Custom built from 1/4" NPT Brass Plug with 5 × drilled 0.170 cm diameter ports.
‡‡‡1/4 NPT Brass full cone injector, 0.1" port, 50o spray angle, McMaster-Car Part No. 32885K101, https://www.mcmaster.com/#32885K101
§§§1/4 NPT Brass hollow cone injector, 0.09" port, 50o spray angle, McMaster-Car Part No. 32825K111, https://www.mcmaster.com/3282k111
****1/4 NPT Brass hollow cone injector, 0.06" port, 00o spray angle, McMaster-Car Part No. 33685K412, https://www.mcmaster.com/#33685K412002E