I got tired of not being able to find a Rocketeer Jetpack. So i took the model uploaded by Spoolishness and altered it a bit, adding grills to places, making the fan hole a circle not oval, adding in a grill vent to the base, resizing the exhaust dimensions to better match the real thing. I then scaled it up to as much 1:1 as this model will allow (tube part on rocket diameter of around 185mm which is about what it was in the movie) I have not tried to print this yet, I have no experience cutting up a model for 3D printing and was wondering if someone here could assist with that.
Link to Spoolishness's rocket upload https://www.thingiverse.com/thing:1596560
I altered the model using Blender.
Printed a scaled down version, it works.