Specifications for 38mm casings.
Specifications for 38mm bulkheads.
NOZZLE NUMBERS: Every nozzle is engraved with a number indicating the throat size in 64ths of an inch. For example, a #24 nozzle has a 24/64" = 0.375" throat diameter. Isn't that nice? No more guessing what that nozzle in the bottom of your range box is.
| Motor Diameter |
Case Length |
Case Wall | Aprox. Total Impulse |
Liner length |
Max Propellant Length |
ID of casting tube |
Commercial Nozzle throat | Suggested EX Nozzle throat |
Typical Bates Grain Geometry |
| 29 mm | 5.5" | 0.058" | 120 | 3.5" | 3.25" | #13 | Two 1-5/8" long grains with 3/8" cores | ||
| 29 mm | 7" | 0.058" | 180 | 5.12" | 4.88" | #15 | Three 1-5/8" long grains with 3/8" cores | ||
| 29 mm | 8.6" | 0.058" | 240 | 6.75" | 6.35" | #18 | Four 1-5/8" long grains with 3/8" cores | ||
| 29 mm | 11.8" | 0.058" | 360 | 10" | 9.75" | #22 | Six 1-5/8" long grains, four with 3/8" cores and two with 7/16" cores | ||
| 29 mm | 15.1" | 0.058" | 460 | 13.25" | 13" | #25 | Six 1-5/8" long grains, four with 3/8" cores and two with 7/16" cores, plus one 3-1/4" grain with a 7/16" core | ||
| 38 mm | 7" | 0.083" | 240 | 5.063" | 4.6" | 1.21" | #16 | #16 | Two 2" long grains with 1/2" cores |
| 38 mm | 11.5" | 0.083" | 480 | 9.56" | 8.6" | 1.21" | #19 | #22 | Four 2" long grains with 1/2" cores |
| 38 mm | 16" | 0.083" | 740 | 14.063" | 13.6" | 1.21" | #22 | #28 | Two 2" long grains with 9/16" cores and four 2" long grains with 1/2" cores |
| 38 mm | 24.625" | 0.083" | 1200 | 22.625" | 21.75" | 1.21" | #28 | #28 | Six 3.625" long grains with 1/2" cores. (Hold on tight) |
| 54 mm | 10" | 0.095" | 800 | 7.25" | 6.75" | 1.77" | #24 | Two 3.25" long grains with 5/8" cores | |
| 54 mm | 12-7/8" | 0.095" | 1200 | 10.375" | 9.75" | 1.77" | #24 | #29 | Three 3.25" long grains with 5/8" cores |
| 54 mm | 16-1/4" | 0.095" | 1600 | 13.5" | 13" | 1.77" | #33 | Four 3.25" long grains with 5/8" cores | |
| 54 mm | 19-3/8" | 0.095" | 2000 | 16.875" | 16.25" | 1.77" | #29 | #36 | Four 3.25" long grains with 5/8" cores and one 3.25" long grain with 3/4" core |
| 54 mm | 28-5/8" | 0.095" | 2700 | 26" | 25.375" | 1.77" | #42 | #44 | Six 4" long grains with 13/16" cores. |
| 54 mm | 39.25" | 0.095" | 3600 | 36.5" | 36" | 1.8" | #56 | Six 4.5" long grains with 3/4" cores and two 4.5" long grains with 1" cores. | |
| 76 mm | 14.5" | 0.115" | 2400 | 11.5" | 10.75" | 2.55" | #32 | Two 5" long grains with 5/8" cores | |
| 76 mm | 19-5/8" | 0.115" | 3600 | 16.875" | 15.75" | 2.55" | #40 | #40 | Three 5" long grains with 3/4" cores |
| 76 mm | 25" | 0.115" | 4800 | 21.5" | 20.75" | 2.55" | #48 | Four 5" long grains with 7/8" cores | |
| 76 mm | 30-7/8" | 0.115" | 6000 | 27.188" | 25.75" | 2.55" | #52 | #52 | Four 5" long grains with 7/8" cores and one 5" long grain with a 1" core |
| 76 mm | 40-7/8" | 0.115" | 8000 | 37.188" | 35.75" | 2.55" | #56 | #60 | Six 5.75" long grains with 1" cores |
| 98 mm | 18" | 0.188" | 5000 | 13.75" | 12" | 3.25" | #44 | Two 6" long grains with 1.25" cores | |
| 98 mm | 24" | 0.188" | 7500 | 19.75" | 18" | 3.25" | #52 | Three 6" long grains with 1.25" cores | |
| 98 mm | 30" | 0.188" | 10000 | 25.75" | 24" | 3.25" | #60 | Four 6" long grains with 1.25" cores | |
| 98 mm | 40" | 0.188" | 13000 | 36.125" | 35.5" | 3.25" | #64 | #76 | Six 5-5/8" long grains with 1.5" cores |
| 98 mm | 47-7/8" | 0.188" | 16000 | 44.063" | 42.5" | 3.25" | #80 | ||
| 114 mm | 18" | 0.237" | 6000 | 13.75" | 12" | 3.8" | #48 | Two 6" long grains with 1.5" cores | |
| 114 mm | 24" | 0.237" | 9000 | 19.75" | 18" | 3.8" | #60 | Three 6" long grains with 1.5" cores | |
| 114 mm | 30" | 0.237" | 12000 | 25.75" | 24" | 3.8" | #64 | Four 6" long grains with 1.5" cores | |
| 114 mm | 52" | 0.237" | 22000 | 45.75" | 44" | 3.8" | #90 |
O-ring Info
| Motor Size | ID | OD | Width | Dash number |
| 29 mm | 7/8" | 1" | 1/16" | 020 |
| 38 mm | 1-1/8" | 1-3/8" | 1/8" | 215 or 216* |
| 54 mm | 1-5/8" | 1-7/8" | 1/8" | 223 |
| 76 mm | 2-1/2" | 2-3/4" | 1/8" | 230 |
| 98 mm Nozzle | 2-3/4" | 3" | 1/8" | 232 |
| 98 mm | 3-1/4" | 3-1/2" | 1/8" | 236 |
| 114 mm Nozzle | 2-3/4" | 3" | 1/8" | 232 |
| 114 mm | 3-3/4" | 4" | 1/8" | 240 |
| 152 mm | 5" | 5.5" | 1/4" | 429 |
* In 38mm -215 or -216 can be used. The smaller -215 rings are a tight fit and can be difficult to remove from the nozzle. The larger -216 rings are a loose fit and can be harder to push into the case. I choose the size based on the ring material, for Buna-N rings I use -215 and for Silicone rings -216. Your mileage may vary.
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