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