Thinking about Level 3

Someone at a recent launch was overheard saying, 'you can't start thinking about level 3 too early.' Even though I'm still a J350 (and an open chute) away from an L2, I've already started firming up details for my L3 project. And it doesn't matter if you are NAR or Tripoli -- L3 is L3, and is always a challenge.

Some folks just build a kit for L3, and simply fulfill the technical requirements without really learning anything new (aside from the fact that J-B Weld is more expensive than 30 minute epoxy). That's fine, if your certificate collecting. But I really want this to mean something. Its an opportunity to learn a lot of new, cool stuff -- why not take advantage of it?

Knowing that I am primarily interested in (A) avionics and (B) materials as they related to rocket design should drive my requirements. The thought of a lightweight, fully ground-controllable rocket that gets 100k feet out of a Q engine definitely gives me that 'special feeling'. My L3 should help me progress in that direction, since that is where I seem to be getting my rocketry buzz.

That said, I have a few simple goals for an L3 project:

• scratch build -- I have done plenty of kits of all sizes, so I wanted to try something more challenging. One reason to do this is to challenge yourself, and kits are getting a little ho-hum.
• keep it simple -- I didn't want to try anything fancy. In fact, I didn't even really want to do my own design -- I'd rather just 'borrow' a proven and useful one that appealed to me.
• use composite materials -- I have my eye on a 100 percent carbon-fiber airframe. We'll see how close I can get balancing the first two constraints of amateur rocketry (practicality versus price).
• come out the other side truly at another level -- I really want to learn a lot from this experience. So I'm going to keep the goals a bit 'lofty' (har, har).
  

Then came the scope creep:

• RF device 'friendly' -- must be 'easy' to hook up antennas to RF devices. Would be nice to be able to hook up antennas for up to six bands (23cm, 33cm, 70cm, 2m, 6m and 10m). These are used for mostly amateur radio related activities (ARPS, ATV, telemetry and propagation experiments). Also provides RF shielding to the electronics bay. RF choke system for firing leads going to the motor (to prevent RF-induced ignitions). Pyro lines are intentionally designed to not resonate at the used RF frequencies.
• Camera friendly -- Live video/audio (on amateur 70 cm), live video recording to hard drive, two aerodynamic (hidden) camera bays.
  
• Altitude hog -- something light, that eats up space. something that almost begs for an 'N' when its on the playa.
  
• Design must be scalable -- I didn't want to just jump into the Level 3 design. I wanted to build a smaller J-K prototype so I could 'learn' the new techniques (such as carbon fiber) and minimize risk to the main project (didn't NASA do it this way?)
  
• Use a flight computer of my own design -- I just converted to embedded systems (after 20 some-odd years of software engineering). I have an idea for an avionics system, that includes pyro firing and a telemetry bus. We'll see how that pans out.
  

As a 'really nice to have', being able to run an M hybrid motor with little modification to the rocket would make it even sweeter.

After looking around a bit, I believe I found a design that meets all of my requirements. The ARLISS-M is a Level-3 class rocket that is used by AeroPAC/ARLISS for low altitude student projects and experiments. It also comes in two flavors. The K class is designed to carry a CANSAT payload (a payload that is the size of a 'regulation' 12 ounce soda can) to 10-15k feet. The M class is designed to carry a larger payload to 30k feet. There's plenty of room for electronics, antenna systems could be deployed in the nosecone, and/or worked into the carbon fiber (thin wire). Cameras? No problem. There's plenty of places to put a microcamera. I also like John Coker's 'keep it simple' attitude towards design after spending a lot of time and hassle with the more complex version of the craft a few years earlier. That right there is free bug and beta testing, compliments of a pro (John, you don't know me, but thanks!! Now I'm going to steal your design. :) ).

Plus the design is already scaled down. What's not to love? And, I just joined AeroPAC, so it will likely be easier to find folks to help with this, since it is their design.

While I'm still new to HPR, some things are true anywhere: know what you want from your L3 experience. Do you just want to be able to burn expensive engines, or do you really want to know how this crap works? If it is the former, that's great! Get a well-designed kit, build it solid and fly the hell out of it! If you don't really know what your L3 goals are, then ask yourself why you got into HPR to begin with. Your goals are probably speaking to you there, in disguise.

If you decide that scratch building your L3 project is your thing, then hang out with me over the next few months. I'll be learning many new things -- drop by and I'll share them with you. And feel free to share your knowledge with constructive comments or critiques (especially if you know how to make long, strong and straight carbon fiber tubes).

kind regards,
-r