High Power Model Rocketry

Centering Rings for 3.90" Airframe

Centering Rings for 3.90" Airframe - Main image
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$3.33 $12.84 In stock

DESCRIPTION

Centering Rings that fit inside of our Airframe tubes and over our Motor Mount Tubes. Various sizes and packages to fit your scratch building needs!

CENTERING RINGS

  • CR-3.90-29mm: Centering rings for BT-3.90 to 29mm motor mount. 2 pack 1/8″ thick. Includes eye bolt and Z Clip motor retention.
  • CR-3.90-38mm: Centering rings for BT-3.90 to 38mm motor mount. 3 pack 1/4″ thick. Includes SCM3 1/4″ eye bolt and Z Clip motor retention.
  • CR-3.90-54mm: Centering rings for BT-3.90 to 54mm motor mount. 3 pack 1/4″ thick. Includes SCM3 1/4″ eye bolt and Z Clip motor retention. 4″ LOC N RING adaptors will bolt up.
  • CR-3.90-75mm: Centering rings for BT-3.90 to 75mm motor mount. 3 pack 1/4″ thick. Forward ring is notched to accept recovery Y Harness or similar.
  • CR-3.90-4x29mm: Centering rings for BT-3.90 to 4x29mm cluster motor mount. 3 pack 1/4″ thick. Includes SCM3 1/4″ eye bolt.
  • CR-3.90-3x38mm: Centering rings for BT-3.90 to 3x38mm cluster motor mount. 3 pack 1/4″ thick.
  • CR-3.90-1x38mm-3x24mm: Centering rings for BT-3.90 to 1x38mm 3x24mm cluster motor mount. 3 pack 1/4″ thick.
  • CR-3.90-3x29mm: Centering rings for BT-3.90 to 3x29mm cluster motor mount. 3 pack 1/4″ thick, Includes SCM3 1/4″ eye bolt.
  • CR-3.90-7x29mm: Centering rings for BT-3.90 to 7x29mm cluster motor mount. 3 pack 1/4″ thick, Includes SCM3 1/4″ eye bolt. Forward ring has 3x29mm motor config. Same rings used in the 4″ ULTIMATE rocket kit.
  • LNR-3.90-54mm3S: Centering rings for BT-3.90 to 54mm motor mount. Slotted rings to accept 3 fin .25″ plywood. 3 pack 1/4″ thick, Includes SCM3 1/4″ eye bolt and Z clip motor retention. Same rings used in the 4″ AWM Red Der Max and Aerotech Mega Initiator rocket kits.
  • LNR-3.90-54mm4S: Centering rings for BT-3.90 to 54mm motor mount. Slotted rings to accept 4 fin .25″ plywood. 3 pack 1/4″ thick, Includes SCM3 1/4″ eye bolt and Z clip motor retention. Same rings used in the 4″ Goblin, IRIS, Black Brant, HAWK and Phoenix rocket kits.
  • BA-3.90: Bulkhead fits inside of tube coupler TC-3.90 tube coupler to fit 3.90″ airframe. 1/4″ wood bulk plate and includes SCM3 1/4″ eye bolt.
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Customer Reviews (4.8 / 5 · 5 reviews)

Penelope K. ★★★★★

Took a chance on these for a scratch-built 3.90" airframe and the fit over a 29mm motor mount tube was spot on, barely any sanding needed. The plywood is thick enough that I'm not worried about it flexing under thrust.

Ava ★★★★★

Finally, centering rings that fit over the motor mount tube without any sanding or forcing. The package had both sizes I needed for my scratch build, and they slid into place snugly.

Emily ★★★★★

The fit on these rings is spot-on—they slide into the 3.90" airframe tube with just the right amount of grip, and the 29mm motor mount hole lines up cleanly for my build. I grabbed a few packs for different scratch projects and the consistency between them has been solid.