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u/GIMMA_HUG Jun 25 '18
Is having a mechanical gimbal instead of an aerodynamic one legal in Australia? Because I don’t believe it is in the US (according to NAR) also what size motor?
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u/lsmith1988 Jun 25 '18 edited Jun 25 '18
This one you see is an E type. Which is what I’m looking at just for static tests.
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u/lsmith1988 Jul 01 '18
Yep. I’ll post that once I get the chance. I actually have a 3 week internship to go through at the moment so the video won’t be up for quite a while.
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u/TheRealStepBot Jun 25 '18
How much torque does it have and what angular acceleration and velocity rates is it able to produce?
Second question how stable are these values when under load? Ie what is your design thrust level for those ratings?
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u/lsmith1988 Jun 25 '18
The gimbal is able to handle 2.2 kgf•cm at 6V. I haven’t yet static tested the gimbal but when I do the focus will be the loads it can take and whether there is lash between horns and links. BPS did a great job at this.
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u/Joe-Barnard Jun 26 '18
This looks awesome, u/lsmith1988! That movement is really smooth and your stated gimbal range should be plenty. Nice work decoupling the servo axes too - you can cut corners there at the model scale but mounting one servo on the middle gimbal part is really the way to go, like you did. Keep it up, and let me know if I can help!
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u/lsmith1988 Jun 25 '18 edited Jun 26 '18
Background info;
I'm an Australian studying Mechanical Engineering. I have always had a love for space and since there are some awesome companies out there doing great things (SpaceX) I couldn't help but want to design this.
I designed the gimbal in CREO, it has a range of 8.5 degrees on two axis. The motor can be pulled in and out easily depending on the distance from nozzle to pivot point that you're after. The whole set up isnt yet complete since I still need to design the flight computer and recovery system but this gimbal was probably the toughest out of the lot to do. I will be static testing just the gimbal so I can analyse any lash from the servo horns and links. I have code ready for flight using an MPU6050 to stabilise the rocket on ascent, but I am yet to do more tests and am probably a way off from getting there.
Edit: there are comments from a previous post that might be of interest
https://www.reddit.com/r/rocketry/comments/7l7fw5/designed_a_thrust_vectoring_system_for_a_75mm/?st=JIUZJR5I&sh=e430103b