Sunday, December 24, 2017

High-Power Rocket Initial Design

It has been a wild year since my last post. Crashed my old Fit, bought a brand new 2017 Prius, took my place as a junior engineer a lot more in my company, passed my OIQ ethics exam, tried to buy a house (and chickened out), finished a bunch of small projects that I won't really be talking about because I didn't document them, got more into the cosplay community...and left because I just stopped doing stuff.

Long story short, I want to get back into something I started getting into with the GAUL in University; High Power Rocketry.

So for the actual initial design:

Design Constraints:

  1. - Use Pro-38 casing (Because they're way WAY cheaper than Pro-54)
  2. - Can accomodate H to J impulse motor to be used as a reliable certification rocket from level 1 to 3
  3. - Gets as close as possible to 6000 ft with the biggest pro-38 J motor
  4. - Dual deployment
  5. - Use a stratologger for the altimeter.
  6. - Must NOT include crazy custom avionics, sensors, or other similar. (Although I do have some ideas for some for a future rocket from my time with the GAUL...)
  7. - Custom Avionics bay. None of this plywood and threaded rod bull crap.
  8. - Must not be 2 inches or less. Fisting a rocket is hard enough, no need to make it harder.

And all the USUAL design constraints of building a rocket:

      - Must survive launch, MAX-Q, Aerolastic effects, and touch down.
      - Minimum 4g of acceleration at lift-off to clear the rail with a speed high enough to be stable
      - Must be Stable with any pro-38 motors, from H to J.

Based on #3, you don't want to go too big in diameter. More Diameter = More surface area = more drag = less altitude. But then considering #8, there are only two real choices as far as rocket diameter go. 2.6 inches and 3 inches. Based on that, #1, #2 and #4 we can start messing around on OpenRocket.

Messing around, I ended up with two possible designs. One with a 2.6inch diameter, and one with a 3inch diameter. All tubes and nose cone measurements are based on phenolic tubes.

Comparison of both preliminary design with a 819-J354-WH-16A-13

As you can see, the 2.6inch gets closer to 6000 feet with the biggest J Motor, gets so close...and yet so far, to being supersonic  (Mach 0.97 with a V-max), which sounds more fun, and looks WAY better.

The 3 inch version would be a lot less pain to fist, designing the avionics bay would be way easier, but the rocket would also be a lot slower (Mach 0.89 with a V-max), would go 300 feet lower, and look more boring overall.

And so in the end, I will be going ahead with the 2.6 inch initial design.

And that's it for today! My next post will either be me talking about the initial design of the avionics bay, or dismantling something.

Sunday, January 29, 2017

Done with Uni! The end of an era.

It's been a while I didn't post here, so here's some catching up.

I'm done with university. I only had one semester left to do, with two classes. One was a laboratory class, where, with a team of 3 other people, we had to calculate the efficiency of a shell and tube heat exchanger for it's whole range of operation. The other was a capstone design class where we designed, but not built, a diesel portable power unit.

The lab class One of our teammates kept writing weird"Heat is the measure of the sensation of hot and cold" Anyway! The set-up looked like this:

The tube and shell heat exchanger is on the left. At the bottom of the exchanger there's a set of valves that permit the exchanger to be operated in either parallel or counter-flow configuration. On the right there's a water cooler along with it's tank, and behind the exchanger there's a water heater, also with it's tank. Temperature could be taken at 3 points in the head exchanger, using thermistances.

The capstone class...well, it took time. And while I didn't enjoy the subject too much, I really loved working with that team. One of the things I've worked on was a 3D-printed control panel.

The 3D printed control panel printing.

Now that school is out, I can re-start doing other projects! The first order of business is cosplay. There's a sword I've been working on for years (!) that I need to finish. I was scared of doing the detail on the handle and pommel, but with Nadeshicon coming soon, and me wanting to have a life and go out at cons...and not wanting to learn to sew yet...well, I guess I did it.

I had tried to carve out the details at first, but it didn't look instead, I took a page out of Bill Doran's book (well...not his actual book...but still...) and made the details out of craft foam!

That makes the 4th material/fabrication method used in this sword. It has literally become a capstone prop making piece. There's wood carving, resin casting, 3d printing, and foam fabrication.

It was also my first time using my new dual-action, gravity fed airbrush and mixing my own paint. I'm really happy with the result too!

And finished! Here it is next to it's sister.

I've been neglecting wirting this post for the longest time, and the longer I waited, the more things I did that needed to be written. So i'm posting this one, and i'll try to write more often. I already have a few projects for which I have pictures that are done or almost done:

An old camera from a fighter jet that I disassembled
Ironwood's gun from RWBY
A cast of my own torso!

And I have way more projects that are in the work! So stay tuned!