But since I'm writing this blog partly for people just getting into rocketry, I want to make sure that the information I'm giving you is correct, and so I need to do a little fact-checking, and also take a few pictures, and after the work day I had today, that's not gonna happen tonight.
But I did want to show you what I'm up to. I'm building the second edition of my Janus series of scratch-built rockets - the Janus II.
|Janus II - a larger, 3-finned version of the Janus I. With one D and one E motor, this should go more than twice as high.|
|Janus I before glorious flight and tragic fin damage|
I was never really keen on the paint scheme, anyway - I was in a rush to finish it by our scheduled launch date, and it flew really well - I was pretty proud to have designed and built this rocket, and even though I went for a bit more complicated with my first one - two stages, and I'd never even built a two-stage kit before - it worked exactly as I'd hoped.
But I've decided to raise my ambitions a little further. You may have read my mentions of a recent rocketry book, Make: Rockets: Down-to-Earth Rocket Science by Mike Westerfield. This book is great, but I think, for me, the biggest thing it did was to make me feel like I could actually build my own rockets, without necessarily needing a kit. I think if I hadn't read this book, I'd still be a long way from designing my own.
In the book, Westerfield shows how to build a camera payload to go on one of his series of boosters with the name Ceres. Here's an OpenRocket image of the Ceres B booster with what he calls the ICU2 camera payload bay:
Big Bertha has this size tube, so this payload could go on top of that rocket - thought it might be a bit heavy for the Bertha.
Anyway, it's a nice, fat tube for bigger low power rockets - though not the biggest, certainly.
I was building the Ceres B booster, but I had a mishap when I tried to install my own homemade ejection baffle - this is a device that blocks burning propellant from the rocket motor ejection charge, so that you don't need to use recovery wadding (if you're a rocket n00b and don't know what I'm talking about, we'll cover it in the "Launching Your First Rocket" post I promise is coming soon - or you can read this post of mine for now). Also, according to the OpenRocket simulation, this rocket may be a bit overstable. Meaning it can turn easily into the wind, which can be a problem! (I'll have some video up on my Youtube channel soon of this very thing happening to my Big Bertha on a breezy launch day.)
I could have fixed this problem by either shortening the length of the airframe, or making the fins smaller, or maybe even adding cool-looking smaller fins up closer to the front (front fins are not a good idea, unless you've got good sized rear fins first - we'll talk about all this stability stuff in an upcoming post). But I had another idea...
Since the Janus rockets are built from BT-60 tubes, I decided, "Hey! Wouldn't a cool idea be to put a payload on top of the next Janus rocket?" I like the idea of taking what I've done and taking it further, so this is what I've decided to attempt next.
The camera will be pointed downward, and hopefully will see through the fins - perhaps even see the first stage fall away.
Anyway, I recently got a huge box of stuff from JonRocket.com - I love this website! You can find most components you need for low power rockets, and it's all really reasonable - and the more you buy, the cheaper shipping is (flat rate for anything up to $40; free shipping for over $40). I assembled all the parts I'll need for Janus II with Camera Payload Bay. Here they are:
|All the parts I will need to make the Janus II and the payload bay - plus some options|
|So tiny video camera!|
The Rocket Itself
So, that's it for now. I started building this rocket last night, and I have to say, construction goes pretty quickly on these once you have some rocket building experience. The part that takes the longest is the design phase - because you do need to put some thought in to it.
Now, for you rocket n00bs out there reading this - the idea of designing and building your own might seem daunting, I know. Two months ago, I never would have thought I could do this. But I intend to help walk you through the process of designing and building your first scratch build - something simple, that, as long as you feel comfortable putting together a few kits, you can do.
For now, though, I just wanted to show you one of my latest projects. I can't wait to show you the video.