3D printed FAI Mandrel for FAI International Competition

These files duplicate using PLA, PETG, or other filaments, the aluminum FAI mandrel\ form that has been traditionally used in International FAI model rocket construction and competition.

WARNING - YOU CAN NOT USE this 3D printed version in any HEATED OVEN to cure fiberglass!!! The filament will soften and collapse in minutes and ruin everything you rolled, or worse start a fire!!!

These files are designed to assist in construction of PAPER or KAPTON FILM for rockets.  This approach offers an alternative to sourcing and acquiring an aluminum mandrel using modern 3D printing technologies.

So far, I have constructed and printed two sets of these PLA tools for helping out our WOOSH members. 

GENERAL CONCEPT: 

Please see the Steve Kristal video on VNARCON 2022-FAI Streamer and Parachute Secrets see vNARCON 2022—FAI Streamer and Parachute Secrets - YouTube to understand how to construct a FAI Paper rocket for use with this PLA mandrel tool. Also, www.nar.org and in particular, the competition pages on international FAI competition.

These files consist of Mandrel Tool that is printed as two (2) major subassemblies. 

• The Main Body consists of three (3) 110 mm segments that are joined together internally with shoulders to form the main cylinder. 
• A separate two (2) piece Cone section with shoulders forms the “Tail subassembly" of the Body. 
  • You have the option of a 13 mm version for Estes motors 
  • Or a 10.5 mm for FAI motors. 
• You can join these as one unit or two pieces again on your preference.
• I provided 2 fin aligner jigs for 1/32 in or 1/16 in thick balsa fins for gluing onto the 13mm airframe tube for Estes motors.

PRINTING: I printed with PLA at 0.3 mm mode, suggest 0 - 15% infill to keep printing time low. No color preferences. These settings can be varied to suit your needs, preferences, resolution, or experience level. 

PRINTER: I used a PRUSA MK3S+

BUILD NOTES: 

Depending on your printer and resolution some optional wet sanding can be used but not strictly needed. The shoulder rings provide internal connection they can be glued with CA or the adhesive of your choice. Import the .stl files into the slicer software you are using. Supports are not strictly needed. Lastly generate Gcode for your specific printer or service. 

RESOURCES: 

See www.nar.org for competition tips, International or Space Modeling competition rules, this can be used to construct for example an NAR NRC competition rocket for parachute duration for example. 

Revision1:

Nar Member Mark Chrumka, contacted me and noticed that he had trouble with 10.5 mm tail cone version, the 13 mm was fine. The 10.5 was off a bit. New files were created and tested by Mark. Thank you this site has been updated with those files including updated pictures and assembly instructions. If you previously downloaded the 10.5 mm tail cone files, redownload and use the new sets with an R at the end. Also I made a universal cone connector for either the 13mm or 10.5 mm tail cones. I apologize for the error.

Revision2:

Added a 13 mm fin jig for 1/16 Balsa fins. Requested by Steve Kristal

Finally have fun and be safe! 

John Cieslak