Description
The Modulus is a core design that works with a number of different options to suit your flying needs. You can choose to fly with or without a payload bay, or to include flexible foam egg protector in the bay. You can also choose the rocket's diameter--BT-70 or BT-80, the motor mount size--24mm or 29mm, and the nose cone style--either ogive, elliptical, or flexible foam elliptical. You can slim the modulus down to fly on C6 motors using the included 24mm 3D printed motor adapter (with the 24mm motor tube), or beef it up to fly on 24mm or 29mm motors. Add the flexible foam nose cone and egg protector, and you can try your hand at flying a raw hen's egg and returning it unbroken. This makes a great rocket kit for middle school or high school students, and it assembles with wood glue or epoxy. Rocketry Works' new 3D printed motor retainers are unique among motor retainers in that they can be secured using either epoxy (like other motor retainers) or simple wood glue! The Rocketry Works motor retainers are outstanding for school or scout projects, because you don't need to worry about making a mess with epoxy!
The default airframe length is 17 inches (not including payload/nose cone), with an option for a 34 inch length. Note that 34 inch airframe length adds to the price to account for increased shipping costs. Make sure you select the nose cone to match the airframe diameter.
Motor and Altitude Matrix
With this many combinations of airframe, it's best to use the simulation files below in Rocksim or Open Rocket to determine the best motor for your configuration. But generally speaking, these altitudes are possible with different motors:
| Motor | 56mm (BT-70) No Payload | 56mm (BT-70) with 60 g Egg | 66mm (BT-80) No Payload | 66mm (BT-80) with 60 g Egg |
| D12-3 | 448 ft (137 m) | 328 ft (100 m) | 250 ft (76 m) | 172 ft (52 m) |
| E20-4 | 1011 ft (308 m) | 880 ft (268 m) | 727 ft (222 m) | 619 ft (188 m) |
| F44-4 | 1189 ft (362 m) | 1100 ft (335 m) | 852 ft (260 m) | 765 ft (233 m) |
| F32-6 | 1538 ft (469 m) | 1450 ft (400 m) | 1222 ft (372 m) | 1154 ft (351 m) |
Parachute Size & Descent Rate Matrix
| Parachute Size | 56mm (BT-70) No Payload | 56mm (BT-70) with 60 g Egg | 66mm (BT-80) No Payload | 66mm (BT-80) with 60 g Egg |
| 15 inch | 22.1 ft/sec (6.7 m/s) | 25.6 ft/sec (7.8 m/s) too fast) | 27.0 ft/sec (8.2 m/s) too fast | 30 ft/sec (9.1 m/s) too fast |
| 18 inch | 18.4 ft/sec (5.6 m/s) | 21.3 ft/sec (6.5 m/s) | 22.5 ft/sec (6.9 m/s) | 25 ft/sec (7.6 m/s) too fast |
| 24 inch | 13.8 ft/sec (4.2 m/s) | 16.0 ft/sec (4.9 m/s) | 16.9 ft/sec (5.15 m/s) | 18.8 ft/sec (5.7 m/s) |
| 30 inch | 11.1 ft/sec (3.4 m/s) | 12.8 ft/sec (3.9 m/s) | 13.5 ft/sec (4.1 m/s) | 15 ft/sec (4.6 m/s) |
Product Documentation
Assembly instructions are available in a presentable slide deck here.
Simulation Files
 |
Design File BT-70 with 24mm MMT |
|
Design File BT-80 with 29mm MMT |
1 Review
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Modulus Rocket Kits (7)
Perfect kit for my class. Specialized fin configurations provided the expected flight dynamics! The laser Etching for the Casas Logo was a nice touch!!
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