Designing & prototyping my own Thrust Vector Control (TVC) System Mount

My inspiration - Joe Barnard

Joe Barnard

Every since I became interested to aerospace/rockets, I have watched videos from Joe Barnard on YouTube who runs BPS.Space.

For about 8 years, his goal was to propulsively land a model rocket and in 2021 he successfully did it for the first time! Joe was able to do this by using thrust vector control to control the rocket down to land. His goal now to get to space using a rocket completely built by himself.

Designing my own Thrust Vector Control mount

I found I had a lot of free time later in my sophomore so I decided I wanted to try to design my own version of a TVC mount. The first step for this project was to design a prototype on CAD (Computer Aided Design). I use Fusion 360 for this as it is the main software and the one I feel the most comfortable with.

The first part I made was the engine holder. While it sounds like the easiest part to make, it was actually the hardest to dial in correctly. This is because getting the tolerance correct to ensure the motor doesn't slide out, but it can also be replaced was challenged. It took about 5 prototypes of the holder to get the correct tolerance.

My Current CAD Assembly of the Mount

For the other two parts of the TVC mount the most difficult part was making sure the mount fit good within the body tube, not just the tolerance but also ensuring that the servo's also fit withing the body while they are screwed into the mount. It took a total of 3 prints to get a prototype that worked well enough for testing purposes.

This however will not be the final design for the mount and there a still plenty of modifications and improvements to be made. This is currently were I am in the engineering process, one thing I need to change is too find an easier way to attach the servo arms to correct attachment point on the mount. I am already have another design made in CAD that addresses this issue, I just have to print it out now.

There are three parts total in the mount, and here is how it works; there are two servo holders, the top left servo holder is attached directly too the motor holder with screws, when attaching the screws I bottom them out so that the screws act as a swivel point which allows for the mount to move around.

My 3D Printed TVC Mount Prototype

The second has a ring in between the first and the holder so it is secured by the screw that attaches the first holder to the mount. The first servo (top left) attaches to the second servo holder, and the the second servo holder attaches to the engine holder. It is my current plan the the first holder will control the x-axis movement, and the second will control z-axis movement.

The holder assembly is then screwed into the body tube. There is also a hole cut into the side of the body tube to allow for full actuation of the servo arm. I will next have to find a way to attach the servo cords to the Arduino nano computer I purchased for this project. This will require finding adaptors because there is not a port on the Arduino board to attach the servo cords too.

Other tasks include finding ways to power the board during the flight, writing the test and flight software, and running tests to model the performance of the motor (C6-12) I am using for this model rockets. This project has been a ton of fun for me to work on and I am excited to continue making progress on it.