There is a laser cut hole into the centering ring.
Many builder's have asked why Estes doesn't drop the tri-fold mount and switch over to Kevlar. This hole might be a compromise allowing the builder to add a Kevlar leader under the ring.
The hole is illustrated in the instructions but is not explained.
We've seen this type of thing before. The Estes Bullpup 12D kit had a notch for the engine hook but no hook is included in the kit. Maybe this ring is an existing part from another kit? I don't think so. These rings are made to fit inside the Honest John tail cone.
Anyway, I found it interesting. While I could have used the Estes hole for the Kevlar line to pass through, I still punched a hole closer to the engine mount tube. That's where I usually put it anyway.
I'm wondering if during development, they were thinking of adapting some aspects of the larger BT-80 sized model (long stuffer tube w/ shock cord attachment is on forward centering ring)?
ReplyDeleteInstructions for BT-80 sized model (24mm motor):
http://www.estesrockets.com/media/instructions/002166_HONEST_JOHN.pdf
Instructions for BT-55 sized model (18mm motor):
http://www.estesrockets.com/media/instructions/001919_HONEST_JOHN.pdf
Hi Naoto,
DeleteI don't think so. Tying on the rubber shock cord low and close to the engine deteriorates the rubber very quickly. On kits where the rubber shock cord is tied to the upper ring, there is a slot and not a round hole. The slot would fit the flat elastic or rubber shock cord, the small round hole fits the Kevlar better.
Also, these two centering rings were designed for just this model. They have to fit the plastic tail cone, not a standard body tube.
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