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Prototype Tractor Rocket II

A project log for Project Rockoon

Actively stabilized model rocket by means of a motor gimbal, originally designed for launching a rocket from a high-altitude weather balloon

julian-costasJulian Costas 06/27/2016 at 00:390 Comments

I've iterated on my tractor rocket from last time. First of all, I'm using a larger shipping tube I got from work as the rocket body, and I've incorporated a safety mechanism into the the ignition system. I've also made the contact pads on the launch pad removable, so that they can be disposed of after being covered in sulfur.

The main incremental change in this prototype is that there is a ball bearing press fit into a cavity in the nose cone, with paracord suspended from the center. This allows the paracord to rotate independently from the rocket. The cord runs through the middle of the rocket, where is suspends a small test mass below. The idea is that the camera can be attached to this part of the rocket, preventing the camera from spinning as it records footage.

During the launch, only one of the rocket motors ignited. The spinning worked, the nosecone caught at the coupling, but then the test mass caught onto the bottom of the launch pad, and the lopsided thrust caused the rocket and the launch pad to fall on its side until the engine burnt out.

At least the rocket came out unscathed and will live to fight another day.

With regards to the design, I'm thinking about going back to the drawing board. I am now looking into a single gimbaled engine for stabilization. With a single engine, the ignition would be more reliable, and could be done externally. With no spin, I could ditch the whole pendulum rope thing and put the entire payload inside the rocket.

However, gimbaled thrust will provide plenty of its own challenges.

Despite this setback, the fortune cookie I ate today was inspirational, so I'm gonna keep on keeping on.

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