Ez-185

• 3D printed parts for a rocket that flies on A thru C motors
• Parts tape together - No glue required!

Tall thin structures (like rockets) can be a challenge to print. Ez3D Rocketry designs use 3D printing for the short, complex parts such as fin cans and nose cones while incorporating commercial cardboard body tubes as airframes.

Additional information and other designs available at https://github.com/Ez3D-Rocketry

###Parts List:

1. Ez3D-1850-4 Fin Can
2. BT50 Nose Cone
3. 18mm Retainer Cap
   • Print out the multiple sizes (No scaling, +3%, +5%), These account for different printing tolerances and post flight shrinking.
4. BT50 3D printed Launch Lug assembly
5. Nine (9) inches of BT-50 type body tube
   • A standard 18 inch tube makes two kits
   • 3D printable tube cutting guide included in repository files
6. Three (3) feet of Kevlar string for Recovery Harness
   • Flight tested on 9KM DWLIFE Black Braided Kevlar Cord (1.3mm, 300 lb) but others may work
7. Twelve (12) inch parachute (Streamer can also be used but it descends fast)
8. Tape

Assembly:

1. Tie Recovery Harness to hole in Fin Can
2. Thread Recovery Harness thru Body Tube
3. Slide Body Tube onto top of Fin Can
4. Tape Body Tube to Fin Can - avoid blocking integrated launch lug
5. Tape Launch Lug Assembly midway up Body Tube - check alignment with Fin Can launch lug
6. Tie loose end of Recovery Harness to Nose Cone
7. Attach parachute to Recovery Harness

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 dimensions in the FreeCAD file

Launch Preparation:

1. Insert 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 motor into Fin Can
5. Screw Motor Retention Cap onto base of Fin Can
   • Depending on your printer, the larger sizes may fit better
   • After a flight or two, the smaller size may fit better
6. Launch using standard model rocket procedures

Recommended motors and expected performance:

A8-3 = ~150 ft (Optimum delay = 2.9 s)

B6-4 = ~300 ft (Optimum delay = 4.3 s)

C6-5 = ~600 ft (Optimum delay = 5.3 s)

IMPORTANT POST FLIGHT NOTES:

• 3D printed material shrinks after cooling down from heat of motor
• Removal of motor may be difficult or impossible after one or several flights
• The smaller motor retainer cap may fit better after the first flight
• If existing motor retainer caps no longer work, friction or tape may suffice for retention
• PLA filament most susceptible to shrinking. Others may last longer.

Entire kit fits in a gallon sized ziplock bag!

Need an extra Boost? The "18mm Booster" file enables the easy addition of a booster stage.

Flight Test Info:

2022-12-10 A8-3, PLA, Motor easily removed. A8s do not get very hot. 2024-11-09 C6-7, 86g, 588ft (Firefly), PLA 2024-11-09 C6-7, 86g, 619ft (Firefly), PLA 2025-01-11 B6-0 to A8-5, First stage stuck on pad but the staging still worked. * This version had a launch lug on the booster stage. I thought they might be needed to help keep the stages together on the pad but test flights showed this was not necessary. Subsequent versions of all Ez3D designs removed the launch lugs from boosters.

2025-02-22 C6-0 to C6-7, 155g, First stage was a little slow and went a bit off angle. Use 3/16 rods?