I haven't posted anything on this blog in about two weeks. Apologies to my regular readers, particularly if you've been waiting for the most recent installment of the Rocket Camp series of posts. I write this blog when I have the time, and some posts - particularly the Rocket Camp ones - take a while to finish, as I don't want to leave anything out. I just finished a 7-day work week, so writing anything of substance had to wait.
But I thought I'd get the ball rolling again with a Current Projects post, an idea I had for a regular feature on the blog, which I haven't revisited since last December.
One reason I haven't been writing much lately is that I've been trying to finish a few rocket projects. The most recent I've finished is the Estes Leviathan, a hulking beast of a model rocket on which I started construction nearly a year ago.
Estes stopped making the Leviathan recently, and it's a real shame that they did. It's a very popular kit. The rocket is a big, beautiful, four-finned rocket, part of their Pro Series II lineup. It's three inches in diameter and over 41 inches tall, and has a 29mm diameter motor mount. It's designed to be a mid power rocket (mid power is generally considered to be any rocket which uses E-G impulse motors), but with its strong construction and 29mm mount, it can be flown on motors up to H impulse.
H is where high power rocketry ("HPR") begins, and the Leviathan is a popular rocket for Level 1 HPR certification flights. Because it was relatively inexpensive (especially when Estes was liquidating them at about $22 per kit) and simple to build and fly, it's ideal for certification, because if the flight failed, it didn't cost so much, and could easily be replaced on a lower budget. A lot of dedicated HPR rockets cost much more, so a failure could hurt the wallet a lot more.
Though when I started building the Leviathan, I figured I'd just use it on F and G motors, I've decided to use it for my L1 cert flight, which I plan to do in September.
Because this blog is mainly aimed at beginners - rocket n00bs - we haven't talked about HPR much. And there's lots of exciting stuff to do in LPR and MPR (low power and mid power rocketry, respectively), and a lot of beginner stuff I haven't touched on yet. But the basics of getting a Level 1 certification are pretty simple.
First of all, you do need a certification to fly HPR. You can build all the HPR rockets you want to, but in order to purchase the motors you'll need to fly them, you must be certified.
High Power Rocketry has three levels of certification. Level 1 allows you to fly rockets with H or I impulse motors (or clusters of lower power motors which exceed the propellant weight or combined total impulse allowed in model rocketry - more on this at another time). With a Level 2, you can fly J, K, or L motors. And at Level 3, the top level of HPR, you can fly M motors and above.
Since each letter essentially doubles the total impulse - the total power a motor can impart to the rocket - you can see how quickly the rockets flown by high power rocketeers can get bigger and louder, can fly higher, and certainly get much, much more expensive! And restrictive - there aren't many places in the country where you can fly an N, O, or P motor. But if you get to witness a flight like that, it's really impressive. Motors that powerful are - well, they're very much like "real" rockets (actually, even an Estes Alpha is a real rocket, but you know what I mean).
While Level 2 and 3 certifications are more complicated, including written tests - and redundant recovery system deployment required for L3 - a Level 1 certification flight can be very, very simple. Some people go for more complexity on their certification flight, using electronically-controlled recovery deployment, but an L1 flight can be as simple as a model rocket flight, just with a bigger rocket.
What's required is that you be a member of one of two rocketry associations - the National Association of Rocketry or Tripoli Rocketry Association. You must build the rocket yourself. It can be either a kit or scratch built. You have to fill out some basic paperwork (though there's no written exam). You must then fly the rocket with qualified witnesses, usually at a club-sponsored event. The rocket has to fly on either an H or I motor, must have a stable flight, and must be successfully recovered undamaged, and with the motor still in the rocket (in other words, the motor has not accidentally been ejected during flight). Undamaged in this context means that the rocket must be judged by the witnesses to be immediately flightworthy again without making any repairs. So, while a little chip in the paint job (which will probably happen to any rocket) is OK, losing a fin is not!
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But, I'm getting off track. This isn't meant to be a primer on HPR - it's a Current Projects post.
It took me nearly a year to finish the Leviathan. That's much longer than you need - this is essentially a larger model rocket with pretty simple construction. But I had to make some decisions on how I was going to build it, and I wanted to make it look as nice as I could. For me, that takes a little extra work, and I didn't have the time to do it all at once.
One thing I had to decide - would I attempt to streamline the fins? On most of my smaller model rockets, I sand the balsa fins into airfoil shapes. I enjoy doing it, I'm getting pretty good at it, and I really like the way it makes a rocket look. And it may help increase your altitude significantly.
The Leviathan has fins made of birch plywood - much tougher than the balsa fins of a basic model rocket. I don't have any power tools for shaping, cutting or sanding. My only tool for that is my Great Planes hand sander.
Well, it takes a little longer, but it's no more difficult to streamline plywood fins with a sanding block than it is with balsa. I did about a fin a day, and it came out great.
The finished rocket is flat black with two thin silver bands. Instead of a launch lug, I installed two rail buttons for use with a launch rail - which is fast replacing launch rods on high power launch pads.
I'm pretty pleased with how the Leviathan turned out, and I can't wait to fly it.
Also nearly finished is the Estes Nike Smoke, another large Pro Series II rocket. This is a sport scale model of a NASA sounding rocket from the 1960s, and it's another impressive kit.
|The Nike Smoke was flown during the 1960s, and was used to test wind shear.|
It has also taken me a year to complete. I worked on a lot of rockets at once - probably too many - so it took me a little longer.
Painting the Nike Smoke has given me major problems. My first three attempts at a white undercoat came out terribly - horrible, sharp bumps all over the rocket!
|After my first attempt at painting the Nike Smoke|
|The results of my third attempt...|
In a day or two, I'll move on to the orange and yellow fins, followed by the United States decals, and finally a flat clear top coat (scale models are often painted with a flat top coat - real launch vehicles are rarely shiny like a nice sport model rocket, and flat colors make a model look larger).
Also nearing completion, though lagging behind, is a third Pro Series II kit, the Ventris.
This is a nice tall rocket with a larger payload section. The build has come along slowly but well, and I can't wait to finish it and fly, hopefully in September. I have a launch this weekend, but at a smaller field, and I'm not going to fly the Leviathan until my Level 1 attempt. I hope to show up at the field with all three of these, because they're pretty impressive-looking.
I also finished and flew the Copperhead a while back. The Copperhead is a rocket I designed and built for a friend, and I liked it so much I built my own. I decided to add a booster, transforming it into a two-stage rocket.
I've flown it three times - once with the booster, and twice as a single-stage rocket. I've already broken a fin off both the booster and the sustainer. I glued them back on, so the rocket can fly again. It's not as pretty as it was when I finished it, but they never are after your first flight.
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Back in April, I flew a number of new things, including a rocket from the book Make: Rockets: Down-to-Earth Rocket Science, by Mike Westerfield. This rocket is called Ceres B, and has a hidden camera payload.
The Ceres B has a 24mm motor mount. The original design, from the book, is meant to be flown on E9 black powder motors. But with a composite, you can fly much higher, and use motors up to G impulse.
I had ordered some composites for that launch by AeroTech, but they didn't arrive in time. Well, they're here now! In fact, a few days ago, I took inventory of all the motors I have.
My supply of C6 motors is dwindling. I have no idea where I got all the B6-4 motors. The G40-7 composite motors at the bottom will be used in my Pro Series II rockets. I've heard that these are impressive motors to watch - a decent 2.5-second burn time with a thick plume of white smoke. I'm excited to try these guys out! The Cesaroni H133 is the motor I purchased for my Level 1 HPR attempt.
Finally, I got a hat.
|My official rocket hat|
Joking aside, if you spend lots of time in the sun launching rockets, you should consider getting a sun hat. Sun screen is a must, but you will probably need extra protection. If you join a club, you'll see lots of people wearing sun hats, and it's experience (and possibly a dermatologist) which has taught them that they need these.
Back to instructional posts soon.
I'll do full build posts of the Leviathan, Nike Smoke, and Ventris, when all of them are finished - and probably after they've flown. In the mean time, I am uploading photos of the build on The Rocketry Forum. You can find the Leviathan thread here, the Nike Smoke thread here, and the Ventris here.
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