It’s been nearly a year since I first conceptualized the idea for HORIZON I. A thrust vector controlled rocket, with on-board electronics monitoring and adjusting the rocket’s course. One of my biggest struggles during this time has the thrust vector control mount itself – the hardware that actuates to move the rocket engine.
Why Aluminum?
When I first launched HORIZON I with a plastic thrust vector control mount, I had near-immediate failure. Now, it’s clearly possible to launch with plastic-built mounts (BPS.space has one!), but I wanted to take things one step further.
Now that my CNC machine had been completed and running for a good while now, I decided now would be the perfect time to begin work designing an all-aluminum thrust vector control mount. I wanted this thing to be fairly easy to manufacture, as well as strong and reliable. However, designing this mount would turn out to be quite the challenge.
My First & Second Design Attempts
As someone who’s only really dabbled in 3D printing when it comes to manufacturing, I really didn’t know anything about standard thicknesses, radiuses, or cut sizes. Because of this, my first attempt at designing an aluminum gimbal went very wrong, with me scrapping the idea after realizing how difficult it would be to manufacture. After this first attempt, I realized I’d have to start thinking like a machinist.
My second revision was built in parts. Each part was cut with a specific thickness and had a design that made it very easy to manufacture. In my previous post about my CNC machining, you can see in one of the pictures that I’m cutting what seems to be a circle with two flat edges. That was the main fixture of this mount.
Unfortunately, I scrapped this revision of the TVC gimbal as well for a myriad of reasons.
The issue with my second revision pictured above was I took machining constraints WAY too seriously. Every single piece was very “flat” and very basic. The truth is, I probably could have gotten this revision to work. I decided against working on it more though, because I also wasn’t a huge fan of the servos being raised up above the pivot point. This added a lot more complexity and made the design a lot harder to assemble correctly.
The Perfect Middle Ground
My third revision of the TVC mount took into account two main things:
- I honestly don’t have enough time to machine the entire thing myself on my CNC machine
- For my last two revisions, I was still assuming the use of crappy 9g plastic servos. These simply aren’t reliable enough for my purposes, so I decided to switch to using HV93i servos instead. These are VERY pricey, but significantly better and built out of metal. I figured this made them worth the investment.
This third revision was the middle ground between my first and my second revision. Complex enough to where it’ll work well, but basic enough to where it’ll be possible to manufacture. I took a lot of inspiration from the aluminum TVC mount that BPS.Space designed.
I even designed an animation to show how the parts of this gimbal are put together.
It’s not perfect, but it’s progress. This was also my first time dabbling into making design drawings for these parts, so I decided to release them publicly!
Time Management
As of right now, I’m running into some budget constraints – funding an aluminum TVC mount with the small amount of money I have and the even smaller amount of time I have due to school has been a real challenge. However, I’m pushing forwards and continuing to work tirelessly on this project.
I may be switching to bi-weekly blog posts soon, as I don’t want to be churning out filler content every week & I want to be able to put time and effort into each of my blog posts.
Until next time 🙂
One response
Nice work man push on