sjurvetson | June 21, 2009Drag races add a bit to all of the excitement, not only for their competitive elements, but also because the action fills the skies, sometimes with mishap.
This Great Gizmo drag race was sponsored by Wildman Rocketry at LDRS27 in Argonia, Kansas, with each flying the same kit:
It's a rare treat to see them all roar off the pad at the same time, and then spiral around like Keystone Cops. The sparky one at the bottom went into a death spiral and crashed into the farm dirt near me. (Since these are all the same rocket kit, I suspect the difference in flight dynamics derive from differences in…
sjurvetson | June 17, 2009The pop of a supersonic shred, scattering fins below...
and the beginning of a sparky spiral dance in the sky...
Here's a rare catch of a fleeting midair moment - the forward retention for the solid-fuel motor has failed and so it thusts forward up through the rocket, pushing the parachute and nose cone out prematurely:
Even the little Estes motors can have a forward closure failure, with glorious results:
Sometimes the nozzle pops out the back, lowering thrust dramatically... and triggering premature separation and release of the smoke grenades:
The early parachute deployment creates an…
sjurvetson | June 14, 2009Near the ground we call them land sharks:
My rocket buddy Erik and I have developed a knack for spotting a likely train wreck in the sky. There was a certain lack of craftsmanship in this Sonotube build that cued us to be ready with the camera:
I just held the motor drive down for this one... Click...click...click... It does a hop over Black Rock in the first frame, and the O-size motor separates from the body in frame 14/15:
And a couple close ups of this Twisted Firestarter:
Pop goes the motor.
sjurvetson | June 12, 2009Ka-pow. Bing, Bam, Boom.
For launch shots, I shoot with timing priority at 1/3000 seconds or faster to catch the action. This helps freeze the shrapnel in sharp focus. Typically, I am tracking the rocket by hand with a 400mm zoom.
Rockets bursting in air... In this example, a home-brew motor mixed with 8 pounds of black powder hit a bit of a burp midair:
As the solid propellant motors rapidly rise to full pressure and sufficient heat to melt aluminum, a motor casing rupture can burst a rocket apart from within... leading to a shower of rocket confetti overhead. Or at the pad...…
sjurvetson | June 8, 2009And now for something completely different... Pirate flags are the first sign...
Team Numb comfortably launched a fat rocket on a P7000 motor to loft a full beer keg over a mile high straight up.
⢠Keg: 175 lbs of beer. Roots. From Oregon.
⢠Motor: 60 lbs of Alumaflame solid rocket propellant (looks like gray styrofoam, but burns in a violet flame). This home brew P motor is twice as big as what you can buy, and you can buy a cruise missile booster from Cesaroni Aerospace in Canada.
⢠Altitude: 6,100 ft. Perfect flight.
⢠Results: Beer shaken, not stirred, and tapped at the…
sjurvetson | June 5, 2009Looking Outward
With a big enough airframe, the camera can be inside looking out, or bouncing off a 45° mirror, or both. For my Level 3 Certification, I buily a 7.5" diameter GLR Sledgehammer and fiberglassed it for strength:
I simulate the flights before launch, and compare the actual performance recorded by two on-board flight computers:
For her second flight, I switched to a red propellant (Aerotech M1550 motor) and added a video bay (making the rocket taller). I could fit a Sony PC-1 DV tape recorder which has the benefit of recording tape up through a destructive event, were there…
sjurvetson | June 3, 2009Part 1 - Looking Down with a Strap-on Videocamera
I fiberglassed half of a plastic Easter Egg as the nose cone for an Oregon Scientific action cam, so it can be a strap-on on various rockets:
One of my goals has been to capture another rocket launching up after me as a chaser:
And sometimes you see the crowd from a mile up... or on the return:
I'll embed one of the video examples. It allows for frame grabs of blastoff, and the ignition of the outer booster by on-board computer:
and the subsequent launch of three chaser rockets... and a glorious arc over:
The video can also record…
sjurvetson | May 31, 2009The long exposure presents all kinds of interesting visuals, from simple Estes propellant grains showering down...
...to the errant path of an unstable rocket:
Here's another example of an unstable flight followed by the fiery forward spray of a motor closure failure under pressure:
And different propellant grains provide wonderful lighting:
And of course, all kinds of high jinks come out at night in the deep desert, like the washing machine tub full of scrap propellant:
Pyro bliss.
sjurvetson | May 29, 2009For those of you near Silicon Valley this weekend, Maker Faire is a cornucopia of geek delights and sights.
And if you want to learn rocketry 101, the local rocket club - LUNAR, which happens to be the largest in America - will be running workshops throughout the weekend where you can build and fly your own rocket. Here is the schedule detail.
In prior years, we demonstrated the construction of some rockets at different scales... and met many interesting people. The first guy that came up to the booth asked a number of questions, and after a while, he casually mentions that he used to…
sjurvetson | May 26, 2009Gene Nowaczyk is aiming for the big prize - a successful launch to 100,000 ft. After 50 hours/week over two years, he drove his custom airframe from Missouri in a huge truck.
Here is prepping the upper section, packed with electronics. He put an incredible amount of work and craftsmanship into this machined metal rocket. Video camera, x-ray measurements (for atmospheric air quality), avionics for GPS, barometric pressure, accelerometer and other sensors, telemetry...
The complexity of this 17 ft. tall rocket even captured the attention of WIRED magazine:
Gene has had his share of failure…
sjurvetson | May 25, 2009A pair of Army scale rockets line up in the desert...
Five sparky research motors clustered together (four M's and an O) in the Little John give quite a show:
and then a another Deep sub-woofer blastoff with a cluster of five AMW motors. Jack's Nike Smoke is 19 ft. tall, and 422 lbs.
(lots of detail in the original size; you can see the left motor was late to ignite.)
But, one of the five motors blew its forward closure, torching the flight electronics inside... and since the parachutes are deployed by computer... we get a ballistic return to the playa for this maiden flight.
In the…
sjurvetson | May 22, 2009
Richard Hagen's rocket, flying on a Aerotech J500G motor, created a wonderful night light over the Black Rock Desert playa.
With some of the night photos, there are random RGB pixels; digital astronomy photography becomes an exercise in the statistics of noise. The high-end photographers liquid cool their sensors and build images from a large number of relatively short exposure shots. For bright objects, like the local planets, they integrate an image from video. It's fascinating, and totally out of my league. This is just a single digital exposure without Photoshop.
It also helps to be…
sjurvetson | May 21, 2009Beyond the thrust curve, there is an art to the color of the propellant (achieved through special metal salt additives).
My 9 ft tall Sledgehammer, lifting off on a M1550 Redline motor from Aerotech, one of my favorite photos:
The shadow of dusk in the foreground really lets the color pop. The smoke and dust is not red, but looks like cotton candy illuminated by the intensely bright red flame.
Here is a picture perfect launch of my V2.0 with an L730 motor imported from Cesaroni, a Canadian aerospace & defense company. Their unique thermoplastic propellant burns cleanly (few additives),…
sjurvetson | May 19, 2009
Kids at the candy shop... from the DairyAire launch event this weekend. For a sense of how the photonic Ritalin works, this is what my rocket looks like as an example:
For a while, I've wanted to use a funky armored car fisheye lens from Belarus for night rocketry. I tested it at dusk:
and at night...
Green propellant - burnout - orange burst from the BP charge popping the parachute - blinking spiral back to Earth.
That a cable spool with a high power motor in the middle flies straight as an arrow is amazing enough. Strap on some lights, and fly at night, priceless.
Next, I'll show some…
sjurvetson | May 17, 2009It was hot at the Dairy Aire launch this weekend. 103°F, with cows.
What weather forecast is that? The cattle packed into the nearby Harris Ranch pens literally create local fog as they sweat into dusk. Mix with a little methane, and you get Dairy Aire.
Here was one of my favorite shots... 2.25 seconds after liftoff... screaming into the air, the big, fat Thumper rocket suddenly ruptured overhead:
It was part of lineup of ten M-size motor launches (the largest you can launch in California), and this gas-passer had a bit of a hiccup.
There's something about these nitrous oxide rockets that…
sjurvetson | May 15, 2009I was asked to give a three minute talk at the TED conference to try to convey some of the excitement about the hobby. I should have just quoted Microsoft co-founder Paul Allen:
"In terms of sheer coolness, few things beat rocketry."
Instead, I put together a photo montage, and commented on the stream:
The rocket projects have grown significantly since then, so consider this a teaser for future posts. Oh, and here's a sweet video montage from the last BALLS launch. It opens with a ground shot of our big QP rocket blasting off...
I am heading off to Dairy Aire tonight... to launch video…
sjurvetson | May 14, 2009I'll be launching this rocket again on Saturday... well, the upper half of it, which survived unscathed from this dramatic motor rupture a half-mile up in the moonlit sky of the Black Rock Desert:
I just love night launches as you can get a time-lapse capture of the entire rocket flight, especially when something goes haywire.
The Aerotech Green Mojave propellant burned brightly, lighting up the playa and the neighboring launch rails, but it also burned through the center of the forward closure (melting aluminum) and torched the electronics of the bottom section... and even burnt right…
sjurvetson | May 13, 2009Estes is the major brand in low power rocketry, with Quest as an alternative. If you launched rockets as a kid, it was probably Estes. They make black powder motors in cardboard cases. As I have moved on to the bigger projects, the only lingering reason to consider these motors is that you can tape the top of one to the bottom of another for a cheap and easy way to do multi-stage rockets. Realize though that this shifts the weight of the rocket to the rear, which can make them unstable, as I have learned from adding three motors to a rocket designed for one:
"Icarus" came back about 15…
sjurvetson | May 12, 2009I am still collecting topic ideas from the prior post, but several people asked how to get started in rocketry, and what is legal in the local neighborhood. Well, if there is no fire involved, it is probably OK, and so the air, water and baking soda+vinegar rockets are probably fine in just about any town. The later category makes for some sour showers though:
This thing really pops up fast since it quickly evacuates all of its fuel (>95% of its weight). With a regular camera, the human reflex is not fast enough to capture the rocket in frame (there is no signal before it pops). So I set…