Summary

This is an upscale of the BT-50 simulated nozzle (Estes Part No. 072665) that is designed to fit Estes and Rocketarium BT-80 airframe tubing.

There are three models that will either fit a 29mm or 38mm motor mount tube:

1) No shoulder,
2) Short shoulder (about 12mm tall or 1/2 inch),
3) Tall shoulder (about 25mm tall or 1 inch).

I would suggest printing these models with PETG or another high temperature filament.

A big thank you to K. Foss for the photo of a printed nozzle installed into a BT-80 upscale of the Estes Solar Warrior.

Other simulated nozzle designs:

BT-55 Simulated Nozzle (from Estes PNC-50BB)
https://www.thingiverse.com/thing:4141174

Estes Part No. 072665 BT-60 Nozzle Portion
https://www.thingiverse.com/thing:4119920

Q-Modeling Stiletto Simulated Nozzle
https://www.thingiverse.com/thing:4174342