The body work in the exterior charge connectors is finally completed! It took a lot of hard work and I'm incredibly grateful for the skilled students who have devoted their efforts to it.
For some individual shout outs, see the end of this post.
We had some trouble with deformation of the phenolic tube after applying the fiberglass to the two raceways under which we run the cables for carrying the current to our deployment charges, but, with some sanding we were able to reduce this.
One thing we noticed was that leaving the coupler and shoulder of the nose cone inserted into the airframe tube overnight helped with the static friction the next day. In retrospect, it would have been wise to allow the fiberglass to cure while these were inserted, allowing their stiffness to maintain the phenolic's radial uniformity. However, after that small setback, we are moving forward as planned with intentions to test with full pyros installed this weekend!
While I'm incredibly satisfied with how the entire subsystem has turned out so far (and often humbled by the caliber of students that have assisted us), I can't help looking at the system critically.
Having the connectors on the exterior was a result of several factors:
1. The main parachute is huge (28' in diameter), and needs every milliliter it can get.
2. We initially planned on there being a separate payload bay in the recovery bay, which required having no linear interference which would have been caused by wires.
Those two points acknowledged, we went with charge carrying wires on the outside. With each ematch having two leads, each ejection well (individual charge) being redundant, and having a two charge redundancy per flight event (main and drogue), we are left needing to bridge a total of 8 wires across the separation point of the nose cone and the airframe. The electrical continuity of these connections need to be unaffected by launch forces, but not prone to seizing or jamming when subjected to the separation force of ejection.
If I were to do it again, I'd do it more minimally. Our protrusion from the 7.5" diameter we were given is waaaaaay beyond what I would accept if our financial obligations and schedule were different. We don't need anything near a standard banana plug to carry the current needed to ignite our charges; our decisions were largely made in the context of the continual time crunch we've been presented with.
All that being said, we have what we have and it looks good! If it works, then let's ride on and get this rocket in the air.
Some much-needed shout outs:
- Jefferey Chan. While he's not with SEDS anymore, and pursuing his grad at UCSD, and I often conjure his voice when I need an astute opinion.
- Kris Obellos. I can honestly say I don't think I've met a guy more consistent and honest than Kris. The work ethic I've seen in him ever since I joined SEDS has really set the standard for me.
- Austin Lee. Lately Austin has just been killing it. He's been one of the main factors in pushing this subsystem forward after our botched flight attempt in Utah. I see a hunger for progress in him that often has me undecided on things before I ask Austin. Probably for the better too, because he catches what I don't.
- Zoe Warp. As a new member she has really thrown herself into Vulcan. She's distinguished herself through versatility and an impressive breadth of knowledge she cultivated with her experiences with Triton Rocket Club. I'm grateful someone like her is down to spend weekends with us.
- Nixon Carruthers. He has taken his knowledge gained through surfboard fabrication and directed it toward the world of engineering composites, and I couldn't be more stoked by what I see. Nixon could be wherever he wants in a few years, and I can't wait to see where he takes his talent.
- Jansen Quiros. While I'm still understanding how he works, I get the feeling he's a patient guy. He understands technical concepts instantly and isn't afraid to jump in when he has something to say.