3.14159265358979323846264338327950288419716939937...
My first custom-built cluster rocket
First Try
Second Try
First Flight
Better Ideas
Second Flight
Conclusion
WAEC Rockets
Space Racer
SAM-66
Sunbird II
Pi
Sprint
Leviathan
Space Racer II
Arcturus Mk. 1
Roswell or Bust!
Brinley
Short March
Discovery
XW-1
Apollo-LES
Sprint II
Lone Star
Mercury-Redstone
Shenzhou
Saturn 1B
Saturn V
Gemini-Titan II
Juno I
Chrysler Building
More Information
WAEC
Inventory
I carefully planned this rocket, which was a first, since I usually just did some concept sketches, then threw the parts together. I drew up plans for this new rocket. The plans called for a rocket based on a BT-60 body tube that would be 18" long. It would have two 18 mm engine mounts. This was kind of a bad idea, because I had no previous experience with clusters.
I started construction with excitement. I made the Gemini spacecraft out of a balsa adapter and a sawed-off nose cone. When I was almost finished I realized that I had neglected the adapter section while I was building the rocket. Without the adapter section the rocket wouldn't be a scale model.
So I stopped working on it for over a year. It sat on my desk as a potent reminder of something that was just too good to be true.
Until November of 1999.
After I had launched SAM-66, which was itself a rebirth of an old design, I decided to resurrect my Titan II. This time I would not try to make it look like a Titan II. After brainstorming several ideas I came up with the perfect name: Pi.
Pi is a great name for a rocket because rockets (at least most of them) are made out of cylinders. Pi has five different cylinders, along with several other circular pieces.
I didn't need to do much to make Pi launchworthy. It's kind of sad that I was almost there when I quit. All that I had to do was paint it and make it stable.
I painted Pi to look sort of like the Redstone IRBM. I gave it a base coat of white and added striping tape to spice it up. I painted one side of each fin black and left the other side white. I painted black the nose cone that was originally intended to be the Gemini capsule. I had originally intended to replace it with a generic nose cone, but I decided that the spacecraft looked pretty cool.
For decals I printed out the first 57 digits of Pi. I ran the digits along the body tube. I also applied a huge Pi symbol above the digits. For some time afterwards, I worked on memorizing the "name" of my rocket. I got up to about the 45th digit and couldn't go further.
After checking stability, I was finally ready to launch.
On a cold winter morning I went to the park at the end of our street and started setting up. This was to be the first time ever that I would launch a rocket in the snow.
The time came to launch. I did a wordy countdown and pressed the ignition button.
Nothing happened.
I tried again.
Still nothing.
Finally, on the fourth try Pi took to the air for the first time after almost two years of working. It flew to an altitude of about seven meters and pitched over and fell to the earth of its side. The ejection charge blew and the nose popped off, but the chute didn't deploy. When Pi landed one of its fins broke off.
So what went wrong? I picked Pi up out of the snow and examined it to find that one of the engines was missing. I searched the launch site and found the engine sitting by the pad, unburnt. I had no idea why that happened.
Much later (in June of 2000) I discovered the answer: The Estes Electron Beam Launch Controller is about half as powerful as it should be for succesful cluster ignition. I realized that, since each Electron Beam controller is 6 Volts, then it theoretically would be possible to hook my two identical Electron Beam controllers together, for a total of 12 Volts. I tested them together with my digital multimeter, and they appeared to work all right. I had yet to see if this would actually work in practice.
Eventually (November of 2001), I was able to attract more sponsors to the WAEC, who each gave much-appreciated contributions to the WAEC fund. For several weeks, I did a lot of thinking to figure out the best way to spend the WAEC money. I eventually concluded that I should build a better launch pad that would handle heavier and higher-powered rockets1 and a launch controller that used more voltage2.
I built the launch pad from plans found on Rocketry Online's InfoCentral, but it was clear that I would have to design my own higher-powered launch controller myself.
At this point, I had already custom-built a 9-Volt launch controller from parts I had bought at Radio Shack and the Fry's Electronics in Sacremento (one majorly cool store). When I tried test-firing a rocket with it, however, nothing happened. I had a problem with my launch controller.
For a while, I didn't know what to do with it, until I came up with the great idea to use it as part of a relay system, which would use the the nine volts of my existing launcher simply to trip a more powerful launcher located near the pad3. I thought through a variety of ideas for producing the requisite 12-Volts, everything from stealing voltage from a car battery to using a really expensive 12-Volt nickel-cadium battery intended for charging model airplane equipment. I eventually settled on a cheaper approach: using eight D-cells wired together.
On March 21, 2001, I successfully fired off a rocket engine with my original 12-Volt launcher design. It was only a mini-engine (from Estes), but later on, I lit a C with my launcher. I was confident that I could use the same launcher to light two of them at a time.
It took a little while for me to aquire the engines and get around to testing them. I bought a pack of three B6-4s from Quest to propel Pi on its first successful (with luck) cluster flight.
All I had left to to would be to fire off one of the Quest engines with an Estes ingitor to make sure that the two technologies were compatible4. I did this on July 27, 2001, and I found that they worked fine.
Now would come the big test, when I would lob Pi into the air by two engines at once. I had never successfully done anything like it before.
That big test came on August 16, 2001, in the evening. My brother Ted, WAEC Member Kevin Pokorney, and I set off to the WAEC Space Harbor after supper with Pi in hand. But, the Space Harbor was being used for a soccer game, and so was one of the backup locations. We eventually decided to go to a smaller park to launch Pi. By now, it was getting pretty dark.
Pi finally took to the air at about eight o'clock in the evening, with both engines burning5! It climbed up like a bat out of Hades, although I didn't really have trouble tracking it to altitude. (Neither did our tracker, Kevin.) It nosed over and headed downward, but I couldn't really tell what was happening to the recovery system at that point. I raced after it, as it appeared to have disappeared near some houses.
Pi, I eventually found, had landed in the backyard of some nice and helpful people (thankfully). It had suffered a crash-landing in a garden, taking a core-sample of the ground it had plowed into (quite literally). The nose section (originally the Gemini space capsule) was nowhere to be found, and we never recovered it.
The parachute and wadding were still packed into the body tube, so it's evident that they never deployed. It's not very apparrent exactly how the nose managed to fall off, or where it ended up. Obviously, the ejection charge wasn't the culprit, but I don't know what was.
The cause for the unsuccessful recovery system deployment was obvious: a pressure leak. I hadn't adequately stopped up all of the possible leak points, which is a must for successful cluster recovery system deployment.
There was another very definate good aspect to this launch (in addition to the successful cluster ignition): we got a good altitude reading: 56 meters high. That's not really stellar, but it certainly was way better than the first time.
Pi has only flown the two times described in this narrative. Beside this, Pi is one of the most scientifically-valuable rockets in the WAEC fleet. Its two flights, and the means by which I obtained them, were some of the most challenging and informative yet in the history of the WAEC.
image,
image: Official WAEC plans
of Pi.
image: A very early sketch of Pi. Note the clipped-delta fins and the method of shock-cord attachment. Both were changed in the final version.
image: An early plan drawing of Pi, ca. February 1998. The stuffer tube was added after construction began, and is not shown in this picture.
image: A very early sketch of Pi. Note the clipped-delta fins and the method of shock-cord attachment. Both were changed in the final version.
image: An early plan drawing of Pi, ca. February 1998. The stuffer tube was added after construction began, and is not shown in this picture.
More Pi Pictures and Graphics
image: Pi in its "natural setting" for the next year and a half: on my desk incomplete. That's me in the front, serving as the worst host ever on my abombidable "Willy's Strange Stuff Show." This image is captured from 8 mm camcorder footage shot on June 5, 1998.
image: My friend Heather serves as the second-worst host ever on the "Willy's Strange Stuff Show." Here she's demonstrating the techniques used to create Foley Sound. In this case, and accordion is used to simulate a dying cow.
image: The business end of Pi. (from the jaegerfesting archives)
image: The "spacecraft" atop Pi (really a balsa adapter), which was originally built to be a Gemini spacecraft. It was left on the rocket just because it looked cool. (from the jaegerfesting archives)
image: The Redstone IRBM inspired Pi's paint job. (Redstone Arsenal)
image: An archive shot of Pi taken soon before its first flight on December 13, 1999, lest something terrible should happen to the vehicle during flight.
image: I'm explaining the ins and outs of the new WAEC rocket Pi to my dad behind the video camera soon before launch.
image: A smoke halo forms around the pad as Pi prepares to take off with only one engine on its first flight.. This image was captured from 8 mm camcorder footage.
image: A bright flame shoots out of Pi as it heads skyward. This image was also captured from 8 mm camcorder footage.
image: An extrapolation of Pi's first flight.
image: A stylized drawing of Pi, pencil on paper. Circa early 2000.
image: Pi being prepped for its second flight, August 16, 2001. The camera makes the ambient lighting look darker than it really was. (from the jaegerfesting archives)
image: I'm rigging up the ignition system in this picture. This picture is grainy because I had to digitally brighten it. (from the jaegerfesting archives)
image: I'm about ready to launch. (from the jaegerfesting archives)
image: Pi about ready for launch. (from the jaegerfesting archives)
image: Pi has taken off, but its smoke remains. (from the jaegerfesting archives)
image: A slightly fuzzy photo of me with Pi after I have recovered it. (from the jaegerfesting archives)
Pi
Specifications
Length: 53 cm Core diameter: (BT-60)
Engine mount: (2) 18 mm
Nose: Conical, imitation space capsule
Recovery: Parachute
Fin shape: Elliptical
Number of flights: 2
| Date: | Propulsion: | Remarks: |
| December 12, 1999 | 2 A8-3, only one lit. | First flight of Pi. Only one engine lit and Pi rose to an altitude of about 7 meters. |
| August 16, 2001 | 2 B6-4, both lit | First fully successful ignition of Pi. Both
engines lit, but problems ensued in the recovery phase. Space capsule nose lost. Rocket tracked to an altitude of 56 meters. |
Footnotes:
1At that point, all I had were two yellow Estes pads and a tiny Quest Micro-Maxx launch pad
2Collectively, this hardware is known as Ground Support Equipment
3One of the possibilities for the failure of the 9-Volt system was that I used seven meters of speaker wire to pump the current from the battery to the pad and back. Evidently, speaker wire has built in restistance.
4I had to do this because Quest manufactures a strange type of igniter which is unsuitable for cluster launches.
5Whoo-hoo!
willy@wilhelm-aerospace.org