About this Product
I created this fin unit to celebrate the ARCAS in BT55 scale for 18mm motors, an homage to the Classic K-26 Estes ARCAS, one of the first scale models from Estes and a watershed moment in the early years of rocketry for larger size rocket kits. This classic rocket design introduced for the first time a new large body tube size in the now standard BT-55, and a new cone, the now venerable BNC-55AC of which so many classics have used in their designs. I wanted for the modeler to be able to use these same iconic parts in their current versions in both the plastic version PNC-55AC, and the ubiquitous BT-55 in production, along with this fin unit. This one piece fin unit is an exact scaled replica, based from Peter Alway drawings and Atlantic Research Corporation documentation. As so designed, there is only one exceptional construction detail concession that has to be made. Because the tail cone section is exactly the profile of the real research vehicle, it has precisely the exact same scaled down diameter for the thrust chamber opening and exactly the actual size model rocket engine diameter of 18mm. There is little or no tolerance to allow passage of engine mount tube through the bottom lip to simply sleeve the tube entirely through this fin unit design, as is possible of all my other fin unit designs. Instead, the motor mount mount tube will slide almost all the way through but will butt against the inner wall near the end of the opening to be joined carefully with glue around centering rings and tube edge. For installation of the motor, the motor casing slips into the rear of the can though the bare nylon lip at first, and subsequently passed into the mount tube from the inside--this all being a friction fit design.
What's in the Box
ARCAS Fin unit BT55 for 18mm motors
in White Strong & Flexible Polished
This model is 3D Printed in White Strong & Flexible Polished: White nylon plastic polished to reveal a smooth matte finish.
Model version 1 |
Last updated on 11/18/2014