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This footnote is being moved to a headnote. This is written from a male standpoint and references females. Female geeks, take it to heart, as this activity would put you in with male geeks at a 1:20 or so ratio. Same-gender oriented, do your own math.

I combine my need for a geek social life with my need to work with my hands, workshop style. Contradictory? No. I build and fly rockets. Model rockets, large model rockets, and high powered rockets. As they grow, it requires greater building skill, but also requires things like electronic altimeter controlled dual pyrotechnic ejection, the pyro being hand packed also. In high power rocketry there's also experimental rocketry, which just means making your own fuel, for the chemistry/pyroholic geek.

The social aspect comes from participating in a local rocketry group, in meetings and flying. As you get to high power, you can participate in a sense of competitiveness and go for size and power. (Present record is a 1/10 scale model Saturn V). You can do it like the steely eyed missile men and start with a desired flight profile then build the beast to fit it. I wanted to hear my own sonic boom, so I came up with a design via software that would do the job (there are several available for this, all under $100). I built a 9 foot, 6 pound monster that used very fast burning motors, a vertical dragster. It cracked Mach 1 at about 500 feet, the length helping to make it audible. Don't think that didn't earn me geek points with the folks at the flying field (the same field SpaceX tested early motors at; it's still littered with rusting pieces; more geek relation).

Most rocketry groups fly at least once a month, some as often as 4. Some areas may have more than one group close enough to participate in. You can find them at National Association of Rocketry http://nar.org/ and Tripoli Rocketry Association http://tripoli.org/ .

You can spend as little or as much on this as you want. Some regular, long time rocketers stick with the smaller model rockets (http://yurisnight.net/ . Fairly evenly gender balanced, and very geek-attractive should you find a female that's at least somewhat interested in a geek and geekish things.

Most hobby engines (including mine) are ablatively cooled -- the combustion chamber is lined with something (usually an epoxy/paper composite, or something similar -- remarkably closely related to Apollo-era heat shields) that chars and outgases, forming a "cool" layer between it and the combustion gases, thereby reducing heat flow. A 1/16" liner will function for 5 seconds or more without any particular design effort, and that's long enough for most amateur rocketry work.

Making them not go boom just takes paying attention to the design. For solid propellants, there's a burn rate (that's dependent on pressure), and then you just have to balance the nozzle throat size against the burning surface area to make sure that it has enough area to escape through (so the pressure isn't too high), but little enough that the pressure is high enough to produce thrust. Then you have to make sure the casing is strong enough to support that, taking into account safety margins and such.

If you're interested, the place to start is probably with commercial motors and either kit-built or scratch-built rockets, and then moving on to potassium nitrate / sugar propellants. Tripoli is the major group that organizes launches (they'll handle details like sites and insurance); there should be a launch at least somewhat within driving distance, and people are generally quite friendly to spectators -- but get in touch with the launch organizers first. Commercial motors are a little pricey (expect to spend perhaps $70 on the motor and $30 on propellant for an I-class motor -- sufficient to launch several pounds of rocket to a few thousand feet), but the reusable motors are well made and provide excellent casings for custom solid propellant work. Richard Nakka has a most excellent page discussing sugar propellants, both in practice and in theory.

My work is with nitrous oxide hybrids, and is somewhat documented at HybridSky. It assumes you have some working knowledge of how hybrid motors work, though; Nakka's site is a much better starting point.

I am level 2 certified through the National Association of Rocketry and Tripoli Rocketry Association. I have rockets, built from kits purchased for under $200 and propelled by solid fuel motors for around $200 or hybrid motors for about $100 that can carry a 0.5 pound payload far higher than one kilometer. Anybody on this list who is willing to take a few evenings to build a rocket kit, spend the money to join NAR or TRA, and join the nearest high power rocketry club will be able to launch a small TV transmitter with telemetry over one km and save $18,000 over the Japanese liquid rocket. And if you are really into liquid fuels, you can even find amateurs working with those.

The air traffic is not really an issue, even near a airports. It's hard to hit an airplane with a rocket. That's why military missles are guided and typically use some sort of proximity fuse and explosive warhead. Those guidance systems and warheads with proximity fuses are not generally available to the general public.

Anyway, the regulations recognize three different categories of rockets. If you have a rocket that masses no more than 453 grams and has no more than 113g of grams of propellant, with no more than 62.5 grams in any given engine, then you have what is known as a "model rocket" and you can launch from anywhere that isn't near an airport it without telling anybody you're going to do it.

If you have a rocket that masses no more than 1500 grams and has no more than 125 grams of propellant, with no more than 62.5 grams of propellant in each engine, and a total impulse of no more than 160 NS and an average thrust of no more than 80 Newtons, then you have what's known as a "large model rocket", and you need to notify the FAA before you launch it.

If you have a rocket that masses more than 1500 grams, or has more than 125 grams of propellant or has more than 62.5 grams of propellant in any one engine, has a total impulse of more than 160 NS or an average impulse of more than 80 Newtons, then you have a "high power rocket" which requires that you get the FAA's permission to launch it.

There are two organizations supporting model and amateur rocketry in the USA. The National Association of Rocketry and the Tripoli Rocketry Association. Those web sites have links to local chapters all over the country.

Whether or not you can legally buy the propellant (premanufactured "single use" engines are recognized by everyone as legal to buy, sell, and use) is a matter of opinion, and there are lawsuits pending on that subject right now. If you have an interest in these matters, please donate the NAR legal fund or the TRA legal fund.

The guys I know who do high-power (I'm starting to do LMR's now) made a great deal of fun of these Camui rockets because the high-power guys build rockets that go a great deal higher for a lot less money. A $300 investment can get you a completely reusable rocket that goes up a couple of kilometers as well as the propellant for one flight.

High Power Rocketry folks have known for years that the probability of a successful flight is inversely proportional to the cost of the payload divided by the average cost of payloads being flown. For many years, expensive video cameras ensured failure.

It's only been through the addition of multiple onboard altimeters, accelerometers, computers, amateur radio transmitters, GPS units, rocket locators, and other horrendously expensive gizmos that lone video cameras are now fairly easy to fly.

BTW: There's a fun traditions if you are launching an on-board computer running Windows. If the flight fails, you call Microsoft Support and report that your computer crashed.

Of course, if you were running Linux, maybe it wouldn't have crashed....

From dictionary.com:

2 entries found for derriere.
derriere also derriere ( P ) Pronunciation Key (dr-ar)
n.

The buttocks; the rear.

Also:

No entry found for dairy-aire.

It's like the difference between a segway and a segue. One is a normal word used in English, the other is an amalgam coined for some other purpose.

Real rockets for big boys

>> Anyone know what the largest anywhere was? If you are talking in terms of non-professional rocketry and largest altitude record, I believe it was set by Craig Snyder (US) in 2001. He used a multistage rocket (Type M engines) which reached a very respectable 34,988 ft. You can find most non-professional records here.

So, anyone have any links for someone looking to get into amature rockets?

I'm not sure what you classify as amatuer, but the two biggest "consumer" (essentially for stuff you can buy commercially) organizations for model and high-power rocketry are

National Association of Rocketry

Tripoli Rocketry Association

Of course no ones really going to send up a satellite with model rocket engines. However, I was very surprised how much model rocketry has changed since I was a kid. In researching model rocketry (for my kid), I discovered that there are engines a lot larger than 'D', and it's possible to fire a (high power) model rocket up to the stratosphere! Check out the records here.

has 47 ton drive-in door that operates electrically
Phew - I was worried for a second.

Unique, historic, functional property. .
That's good, because I've good, because with this and a few more items, our rocket will be ready to move in!

note: this is meant to be funny!

Tripoli cert works well to :-)

Sorry, here's links http://www.tripoli.org/Photos/TMT/TMT3.jpg

Next high power launch in Massachusetts: July 7. Free and open to the public. See my club's website: http://www.cmass.org.

Our field normally has an FAA waiver that goes to 7000' AGL; we can only launch up to 'K'-class motors.

• Bertrand R. Brinley's books:
• Rocket Manual for Amateurs - 1960 (nonfiction)
• The Mad Scientists' Club - 1965
• The New Adventures of the Mad Scientists' Club - 1968
  "The six members of the Mad Scientist Club experiment with new projects which include making rain and launching a flying saucer."
• The Big Kerplop - 1974
  "When the mysterious object that lands in the lake they're fishing on turns out to be a bomb, a group of boys decide to find it themselves since no one pays attention to their story."
• The Big Chunk of Ice - unfinished manuscript

• Mark Maxham's MSC fan pages:
• general info
• etext archive FAQ
• Cease & Desist letter, reprint info

Ebay has had some decent auctions recently, but another good resource for used books is Bookfinder. Keyword/author = "Brinley" works well on either site.

Do you mean launch bigger rockets .... check out Tripoli find a local group and bowl on down. The Arliss boosters are Ms so you need to work your way up to a level 3 confirmation if you want to do an exact cansat type flight but you could do close enough off of a minimum diameter K. Arliss itself maay start happening in other places - there's been some mention of expanding it across the US so that school kids all over could get a chance to build a payload

For those of you interested in this sort of thing, without the added bonus of nutjobs like the protagonist in this article, there are many serious high-powered rocketry enthusiasts and groups throughout the US and the world.

The most successful is Tripoli, the high-powered rocketry association.

Also of interest is the Reaction Research Society, who has been looking for a real amateur space shot for a few years now...50 miles up.

Check em out. Part of this complete breakfast