Tuesday, December 30, 2014

5... 4... 3... 2...

I've nearly completed the three rockets I've been working on for a month and a half, just in time for tomorrow's Epic Rocket Launch. Just a bit of paint here, a few stickers there, and a couple knots tied, and we'll be All Systems Go.
Janus II with camera payload bay, Quest Quadrunner 4-motor cluster rocket,
and 3D Rocketry's Nautilus II, the first kit I ever purchased
which wasn't from Estes (which is where most of us start)
All that's needed now is a few details.

The Janus II - which is the big brother of my first ever designed-and-built (or "scratch built") rocket Janus I - will get a touch of black on the fin tips.

Looking at this rocket, with the gray body and fat payload section, it kind of reminds me of a shark - which gave me an idea for a new design I'm going to play with (but which in the end may be unstable and therefore unflyable) called the Hammerhead. Mostly I like names for rockets that don't try too hard to sound "badass," but I might make an exception in this case. Stay tuned.

Here are the two Janus models side by side for comparison.

Janus I and Janus II. Janus I uses standard 18mm (A-C) rocket motors,  while
Janus II is designed for 24mm motors - one D and one E. Both are two-stage rockets.
Even without a special payload section, you can see that Janus II is taller than Janus I - this is because since it's made to take larger (and heavier) motors, which sit in the aft end, the rocket needs to be either longer or weighted in the nose in order to be stable without using oversized fins. This has to do with the relationship between the center of gravity and center of pressure, and if you're new to rockets, we'll get to that in another post on the basics of rocket stability.

Also notice that Janus I has four fins on the booster and main body (sustainer) of the rocket, while Janus II has only 3. This reduces drag and increases altitude (and makes building faster - less sanding and fewer fin fillets to apply). My simulation estimates that Janus II will top 1700 feet.

But just to check, I also have an altimeter.

Altimeter Two, from Jolly Logic
This tiny little guy will tell me what the peak altitude reached is, and a number of other flight data points - such as top speed, maximum acceleration up to 23 Gs (!!), altitude at parachute ejection and the velocity at which it descends (with that parachute). It's can go up to 29,500 feet, so I think it'll do the trick.

Here's the camera seated in the Janus II payload bay:

So, this rocket will carry two payloads - the camera and the altimeter - it has enough room for both, plus an egg if I wanted to do that (though I'd like to spare my new altimeter the potential humiliation).

The Quadrunner is in pretty good shape, considering the ordeal I blogged about a few days ago. It's not perfect, but once the decals are on, the little flaws may not be noticeable.

The Quest Quadrunner -
tall, powerful, beautiful...

With four C6 motors, this should easily top 2000 feet, although I may add a bit of weight just to slow it down a bit. Four motors can lift a lot of weight. This rocket is not that heavy - and in a recent Youtube video I saw of a launch, the thing took off so fast the camera couldn't keep up. After a month and a half of work, I'd prefer to minimize the risk of my losing this rocket on its maiden voyage.

The Nautilus II by 3D Rocketry will get copper fins and perhaps nose cone, although I'm tempted to leave it this flat black color. It looks imposing like this.

But I got the copper paint, so I feel like I should go through with it. I hope I don't regret that decision! The rocket flies on a D motor, and should go pretty high.

We're also going to attempt to launch Chad's Aspire rocket from Apogee Components. This thing is supposed to top one mile in altitude. Last time we launched, I must have inserted the igniter wrong (it's a composite motor, not black powder, and I'm not used to those yet), because it flashed, and nothing happened. Such a disappointing end! I have four spare igniters for this rocket, so we'll try our best. We'll probably never see it again...

I was going to hold back on a few of my smaller rockets, but I realized, hey, this is the last launch of the year! I should go all out! So I'm launching everything I've got - everything I've built, that is. My pre-made, ready-to-fly models will probably stay at home, or I'll launch one first to check the wind direction and speed.

But here's nearly everything I built myself since I started doing this less than six months ago - the fleet for tomorrow's launch:

Back row: Janus II, Cosmic Explorer (Estes), Nautilus II (3D Rocketry), Aspire (Apogee Components), Magnum Sport
Loader (Quest Aerospace), Big Bertha (Estes), Quadrunner (Quest Aerospace). Middle row: High Flier (Estes),
Crossfire ISX (Estes), Der Red Max (Estes). Front row: Star Trooper (Estes), Mini Honest John (Estes)
Janus I is retired, due to damage, but everything else I've built is going into the sky tomorrow, and I hope to have pictures and video to share - including POV video from the nose of the Janus II!

The weather looks good, so we shouldn't have to scrub the launch like we did Saturday. Honestly, I was glad for a few more days to finish these three rockets, but now it's Go Time.

I've been putting together a video compilation for a few weeks of all my launches - or, at least, all the ones that came out OK, and after tomorrow, I'm going to put a Slo-Mo Supercut on my Youtube channel. Rocket porn, basically. Now that I'm building bigger rockets, I hope to get some good video. Small rockets are really impressive to watch in person - they go so high so fast! But on video, it's hard to convey the exciting nature of the launch. Bigger rockets look better on video.

If I stick with this (I plan on it), I think I'll try to make it an annual tradition of putting out a slo-mo launch supercut of the year on January 1. I've got some bigger rockets to build, so hopefully years to come will see some good video - and who knows, maybe a Level 1 high power rocket certification launch??

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