Ez-18x3

Ez3D 18x3: Three 18mm Motor Cluster

• Parts tape together - No glue required
• Uses extended length rail button

After conquering the challenge of the "Ez3D-Mini", take a step up to the world of clusters!

Parts List:

1. Ez3D-18x3-60 Fin Can
2. BT-60 Nose Cone
3. Special 3D printed Motor Retainer Cap
4. Two extended length 1010 Rail Buttons
5. One small sheet metal or wood screw
6. Eighteen (18) inches of BT-60 type body tube
7. Five (5) feet of Kevlar string for Recovery Harness
   • Flight tested on 9KM DWLIFE Black Braided Kevlar Cord (1.3mm, 300 lb) but others may work
8. 18" parachute
9. Tape

Assembly:

1. Attach Rail Buttons to Body Tube
2. Tie Recovery Harness to hole in Fin Can
3. Thread Recovery Harness thru Body Tube
4. Slide Body Tube onto top of Fin Can
5. Tape Fin Can to Body Tube
6. Tie loose end of Recovery Harness to Nose Cone
7. Tie parachute to Recovery Harness near top of Nose Cone

NOTE: Individual printers and filament have different tolerances

- Fit check items before assembly. Options to adjust if necessary:

• Add tape to increase diameter
• Remove material by sanding
• If your printer has a scaling feature, use it to adjust the part size
• Change the dimensions in the FreeCAD file available at https://github.com/Ez3D-Rocketry

Launch Preparation:

1. Insert 1 or 2 squares of recovery wadding into Body Tube
2. Load Recovery Harness and Parachute into Body Tube
3. Place Nose Cone on top of Body Tube - ensure slightly snug fit
4. Load motors into Fin Can
5. Secure Motor Retention Cap onto base of Fin Can with small screws
6. Launch using lots of ignitors or black powder flash pan for reliable simultaneous motor ignition and additional excitement

Recommended motors and expected performance:

• C6-5 or C6-7 (x3) = ~800 ft

Need a Boost?

• Cluster Booster is oversized and will likely require some tape to fit firmly to upper stage
• C6-0 (x3) to B4-6 (x3) = ~800 ft - About the same as single stage with 3 C6s!

IMPORTANT POST FLIGHT NOTES:

• 3D printed material shrinks after cooling down from heat of motor
  • It shrinks even more after suffering the heat of several motors at one time. A PLA fin can will likely last one flight. ABS may last several flights.

Flight Test Info:

2025-01-25 C6-5 (x3), 807 ft (Alt2), Motors could not be removed. Ejection 0.6s before apogee
2025-01-26 C6-5 (x3), 215 g, 776 ft (ALt2), New wider motor tube. Motors removable. Ejection 0.7s before apogee
2025-02-22 C6-5 (x3), 210 g, 835 ft (Alt2), Second use of fin can. Motors could not be removed. Used flash pan ignition. Ejection 0.8s before apogee
2025-08-09 C6-5 (x3), 235 g, 806 ft (Msl Meter), PLA, Tubes warped after flight.
2025-08-09 C6-5 (x3), 215 g, 875 ft (Msl Meter), ABS, Tubes sightly warped after flight but reusable. 7 second delay may have worked better.
2025-10-04 C6-7 (x3), 264 g, 680 ft (Alt2), New motor retainer system. Motors tight.
2025-10-24 C6-0 (x3) to B4-6 (x3), 395 g, 805 ft (Alt1), Staged cluster test. Worked! One motor stuck in upper stage.

2026-07-11 C6-5 (x3), 250g, 757 ft (Msl Meter), 841 ft (AudrelMax). PLA, First Version 2 flight. All motors easily removable.