Doorknob Plywood Fin Upgrade Set of 4

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  • Doorknob Plywood Fin Upgrade Set of 4
  • Fin can unit assembled without glue for test fitting.
  • Assembled fin can unit in stock Doorknob tube.

Order now to ship on 21st Apr 2021



These 1/8 inch thick plywood replacement fins for the Estes Doorknob kit are a great option to improve your build strength and durability over the stock multi-part balsa fins that can be damaged in transit or during assembly.  Laser cut to the original specifications for accurate fit in the stock fin slots, with the stock motor tube. You can use the stock cardboard centering rings or replace the 3 cardboard centering rings with either 2 or 3 plywood centering rings. The Plywood centering ring option works nicely with just a pair of rings, but it is available with the original design of a 3rd centering ring in the middle to interlock the fin to ensure straight alignment.  The forward centering ring includes a sturdy and accessible shock cord mount. You can also add common additional components for this retro build.

The 4 plywood fins weigh in at 2.15 ounces (61 grams), compared with 1 ounce (28 grams) for the stock balsa fins.

The 2 plywood centering ring configuration weighs 0.5 ounces (14 grams), compared with 0.25 ounces (8 grams) for the stock 3 cardboard centering rings.

The 3 plywood centering ring configuration weighs  0.7 ounces (21 grams), compared with 0.25 ounces (8 grams) for the stock 3 cardboard centering rings.


 Currently, specifications in the Additional Information tab are not accurate for this kit. Updates coming soon.



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Additional Information

Weight (per centering ring):
0.25 ounces (7 grams)
Weight (complete set of 3 fins and 3 centering rings):
4.85 ounces (138 grams)
Weight (per fin):
1.35 ounces (38 grams)
Root Edge:
5.55 inches (141.0 mm)
Semi Span:
6.00 inches (154.8 mm)
Trailing Edge:
4.89 inches (124.2 mm)
Leading Edge:
7.40 inches (188 mm)
Tip Chord:
4.39 inches (111.6mm)
1/8 inch (3mm)
Tab Depth:
0.879 inches (22.3 mm)
Tab Length:
2.84 inches (72.3mm)
Tab Offset:
2.14 inches (54.3mm)
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