Two guys are talking, and the first says, "My wife drives like lightning."

"Drives fast, eh?", says his friend.

"Nah. She hits trees."

Over the last couple of days, we've had massive waves of thunderstorms plow through the area, leaving thousands without power. The storm last night put on a spectacular light show, with frequent lightning in every direction.

Other than flying a kite in the rain (not recommended despite historical precedence), how do we learn about this phenomenon?

It is possible to artificially generate lightning to study it, but it's difficult and expensive. In addition, you're not necessarily duplicating the environmental conditions that produce lightning. An alternative is to use rockets to induce a lightning strike in a specific area where scientific instruments are located.

There are some spectacular photos on that page, as well many interesting links. If you're interested in seeing the process in action, there are QuickTime movie clips here and here.

Posted by: Ted at 11:01 AM | category: Rocketry
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...and no Americans were around to see it, would you still hear cheering?

Alphecca has mentioned it, and IÂ’ve ranted about it a couple of times. I wish I could have put it as eloquently as this.

The Department of Justice (DOJ) now claims in a letter to Senator Orrin Hatch, Chairman of the Senate Judiciary Committee that hobby rockets can be used to make "light anti-tank" weapons with a range of up to five miles. The best the United States military can do is only 3.1 miles with the LOSAT anti-tank missile system. How ridiculous is it to claim that a terrorist can cobble together anti-tank weapons superior to what is produced by Lockheed-Martin for the US Army? This absurd claim strongly suggests that Department of Justice and ATFE simply fabricated claims without any research or supporting analysis.

ItÂ’s clear that many Senators, Representatives and the media simply accepted the Department of Justice & ATFE claims at face value. This blind acceptance was dramatically illustrated by the Senator Schumer and Lautenberg press conference on July 29. During the press conference, they repeated the false claims, which were then repeated in the New York Times and various wire stories.

The Amateur Rocketry Society of America has been conducting research to show the truth about the false claims made by the Department of Justice and ATFE. Every claim made in their letter on the dangers of rocketry in America is provably false. The ARSA has since published reports on the technical feasibility of using hobby rockets as anti-aircraft or anti-tank weapons.

Or as one rocketeer put it: “I'm going to put in a resume to the DoD, as it's obvious I can do better the Thiokol, or Lockheed who are wasting millions of my tax dollars.”

(the above includes excerpts from numerous posts in the Rocket newsgroup)

Posted by: Ted at 11:20 AM | category: Rocketry
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Ray Dunakin flies camera-carrying rockets and gets the most amazing photos. See lots more in his online photo-albums.

Posted by: Ted at 11:10 AM | category: Rocketry
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For the last few days weÂ’ve suffered oppressive heat and humidity, but a thunderstorm-spawning cold front passed through last night. Today was absolutely beautiful, with temperatures in the low 80Â’s, just enough wind to be comfortable, and a bright blue cloudless sky.

MookieÂ’s trip to Michigan last week put her behind on her summer homework, so she decided to stay home and buckle down. I only took three rockets today, deciding to concentrate on the higher end of the motor range I normally fly.

First up was a veteran named the FY2K. You can tell what was going on in my life when I built this rocket. ItÂ’s rather small, but takes a relatively large motor for itÂ’s size, so it screams off the pad and gets great altitude.

Which is exactly what it did this time. People don’t expect a rocket this size – not much bigger than your standard Estes stuff – to be this loud and smokey, so as usual folks jumped and kids screamed in fright and wet themselves (just kidding). But it does get their attention. So she’s boosting arrow-straight, on a slight angle into the wind, and leaving a thick dark line of smoke behind her and just as she arches over at the top the neon-yellow parachute is ejected and fills instantly. Perfect.

I noticed something tiny fall away, and someone says it must be the ejection wadding (protects the chute from the ejection charge). So as weÂ’re watching the rocket descend under chute from almost 2000 feet, out of the corner of my eye I catch a glimpse of something.

Wheeeeeeeee-thunk! The freaking nosecone screams down and hits the ground about 10 feet from where a group of us are standing. It weighs more than a quarter of a pound, and to have that sucker freefall down and almost hit us was way too much excitement. I’m embarrassed about it, but kinda proud too that I judged the wind that well. Thank goodness it didn’t hit anybody. It’s plastic and rounded – not pointy – but it still would’ve hurt.

The rest of the rocket, still under chute, drifts much farther than it should because a large portion of its total weight took the express back to earth. It finally settles down beyond a barn silo, and I walk about a half mile to find it in good shape in a meadow.

Now it’s time for the main event: Ain’t Misbehavin’. And I immediately run into a snag. I’ve forgotten the binder I keep the checklist in. This is far and away the most complex rocket I’ve ever attempted to fly, so I have a detailed checklist to make sure I remember everything and do things in the right order. Step 1 should be: “bring the checklist, stoopid”.

Fortunately, some friends with lots of experience are there to help. This is my first hybrid-motor rocket, and the first flight relying entirely on electronics to deploy the parachutes, so IÂ’m grateful for the assistance. Everyone likes my design to arm and disarm the ejection charges, and since the wind is picking up we decide to go with a slightly smaller chute to bring it down faster.

Three quarters of an hour later weÂ’re ready to go. I get a quick lesson on how to use the remote box to fill the tank with nitrous, and as soon as we see a plume venting from the side of the rocket we do a quick countdown and I press the button.

She hesitates on the pad for a second, and then an electric-red flame erupts from the nozzle and she starts to climb. This is the smallest possible motor I can use in this rocket, so the flight is slow and low, and at apogee the altimeter fires the ejection charge and the parachute deploys perfectly. A very sweet flight.

The altimeter measured 608 feet, which is just fine for a maiden flight, especially one full of personal firsts. IÂ’ve already figured out how to trim at least a pound off of her weight, and can double the motor power with no problem on the next flight, so 2000 feet plus isnÂ’t out of the question.

So that’s what I flew today (didn't get to fly the third rocket). There were many other interesting flights. Roger brought his television rocket. It transmits a rockets-eye view of the flight to a receiver station on the ground, which feeds it into a video camera to record the flight. Neat stuff. There were also several RC rocket glider flights made, and a very interesting monocopter (1-bladed helicopter – weird but cool). There were also a lot of kids and parents flying little rockets. I enjoy watching the kids make flights, their wonder and joy is contageous.

Today was a great day.

Posted by: Ted at 04:27 PM | category: Rocketry
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At the rocket launch this weekend, I plan to fly a couple of my big projects. I talked about our hybrid-powered Ain't Misbehavin' before (pictures here), but I also want to launch a rocket that my oldest daughter and I worked on together. Tinkerbelle was a real learning experience for us, because it introduced us to some new construction materials and techniques. That's what I love about this hobby, you learn something new with each and every rocket you build and launch.

Now here and here are a couple of big projects. This is the kind of stuff that Bill Whittle talks about in his essay Trinity. People pushing the envelope and doing awe-inspiring things - as a hobby. Because it's fun.

Have I mentioned lately how much I HATE the BATFE and Ashcroft and the asinine Homeland Security Act?

Once, a group of us were discussing 'rocket-widows' and 'rocket-widowers' (yes, there are lady-rocketeers), and one friend talked about her husband who worked with satellites. His point was that the rocket is just a vehicle to get the important part - the payload - to where it needs to go. To him, rockets were about as interesting as a bus.

Probably like most of you are thinking, eh?

Posted by: Ted at 08:13 AM | category: Rocketry
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What really happens when you ignite a rocket motor? I'm talking about the magic inside that makes everything go whoosh and get gone real fast. Here's the best explanation of the process I've ever seen, courtesy of Peter Clay. I wish he was my chemistry teacher way back when...

Burning Nitrocellulose BP* is sorta like a party that gets WAY out of hand.

Think of the Saltpetre molecule as an unhappy family. Handsome, dashing, not too faithful Mr. K (Postassium) is stuck with homely, unresponsive Ms. N, who is kind of a loner generally but is very protective of her three lovely daughters, all named O. Actually, it was the daughters that attracted Mr. K in the first place. There are eight such families in this party, all exactly alike. Pretty dull, huh?

Think of Sulfur as eight attractive middle-aged women holding hands in a circle.

Think of Carbon as an eligible young sailor, who is not much interested in the ladies in the circle but has his eyes on the lovely daughters.

Still, nothing happens until some additional couples come into the room behaving in a romantic and suggestive manner. Then:

Each Mr. K gets excited, lets go of Ms. N and grabs an S from the circle. Each Ms. N gets disgusted, lets go of her daughters; thus 24 of them are turned loose.The twelve C-men descend upon the now-free O's like wolves, and each one ends up with an O on each arm. Each Ms. N, alas, ends up alone, but it's OK; she's used to it.

Now all the happy new couples are looking for space and some distance from the others. They push hard against everybody else, and rush for the door. If the door isn't big enough, they may just push out the walls.

8KNo3 + S8 + 12C ==> 8KS +8N + 12C02 + heat.

21 molecules that are solid at room temperature have *suddenly* become 28 molecules, of which 20 are gases at room temperature. In addition, a great deal of heat energy has been released, forcing these products to expand further. Of course the reaction is never pure, and further reactions take place after all this is exposed to the outside air while still hot.

* Nitrocellulose BP is simple black powder held together with Nitrocellulose binder. It's the kind of rocket motors you buy at hobby shops, and it's safe and reliable.

Posted by: Ted at 08:20 AM | category: Rocketry
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