George Katz engineering water rockets 

Welcome to Tech Explorations Podcast episode 1.

Yes, this is the very first episode of this new podcast from Tech Explorations. In this episode, Peter Dalmaris talks with George Katz. George has been making things ever since he can remember. As a child, he used to make paper models of all kinds of things until his parents bought him a two-transistor radio kit. From that point, he was interested in all things electronic.

He studied electronics in high school and later completed his degree in computer engineering from the University of New South Wales. He enjoyed the course because it combined electronics with software, allowing computers to interact with the real world. There, he also became interested in robotics and built several research robots for his thesis and for the AI department, which were later used by other students.

After university, his day job involved developing software for various companies, but electronics remained his hobby. About 13 years ago, he saw an episode of MythBusters that featured water rockets. After some online research, he discovered a whole community of DIY makers who were building rockets and sharing instructions.

George talked to his father, and within three hours, they had built a launcher and launched their first rocket in the backyard. From that point on, the whole family was hooked on building increasingly complex and higher-performing rockets. They also joined the local rocketry club, NSWRA, which opened up a world of experienced individuals to learn from. To this day, George and his family enjoy the engineering challenges of building and flying rockets.

George uses his electronics knowledge for rocketry payloads and ground launch equipment. While he occasionally flies solid propellant rockets, his passion is still water rockets. His teenage boys also help with various aspects of the hobby. George shares his experiences online and runs a website with instructional videos, launch reports, and experiment details. His website contains many hard-to-find details about water rockets, enabling others to learn from both his successes and mistakes, just as others shared their knowledge with him when he was starting out.

Peter: George Katz, very happy to have you on the Tech Explorations Podcast. How are you today?

George: Great, thanks for having me on. Hopefully, this will be an interesting conversation.

Peter: Based on the things we discussed while warming up, I think we’re going to have a very interesting conversation. But before we dive into the cool stuff, let’s start with a bit about you. Could you introduce yourself and tell us what led you to where you are now? What do you do today?

George: Ever since I can remember, I’ve been interested in making things. As a kid, I used to make paper models of all sorts of things. Then, one day, my parents bought me a two-transistor radio kit. It had springs to join the wires together. I put it together in about half an hour and thought, “This is great! I can hear music from just a few parts.” That’s what got me hooked on electronics. I continued with it throughout high school, where we had a great electronics teacher, and my interest grew. I became more interested in digital electronics and computers—getting computers to do things.

Later, I pursued a computer engineering degree at the University of New South Wales. It was a great course because it combined both software and hardware. During the course, I also became interested in robotics. I started building robots at home, and for my thesis, I built a robot. After that, my supervisor contracted me to build another robot for the AI department for other students to use.

Peter: That’s fascinating. What happened after university?

George: After university, there wasn’t much work related to robotics or electronics, so I leaned more toward software development. Electronics remained my hobby. But about 13 years ago, I saw an episode of MythBusters featuring water rockets. That got me hooked. I found instructions online and decided to give it a go. The next day, I went to my dad’s workshop, and within three hours, we built a launcher and launched our first bottle rocket. We were hooked from then on. Over the years, we started building more complex rockets, aiming for higher performance. It’s become a family hobby.

Peter: Wow, that’s impressive. You’ve come a long way since that first bottle rocket. I saw your website and the detailed reports you post about each build and experiment. It seems like you’ve created a logbook for yourself but also for others to learn from.

George: Yes, the website serves as both a logbook and a way to share what we’ve learned. We include all the details, including failures, so others can learn from them. When we started, we learned from others, and now we’re returning the favor by sharing our knowledge.

Peter: Let’s go back to your university years. You mentioned you built robots. Can you tell us a bit more about the robot you built for your professor?

George: It was a mobile robot, essentially a box on wheels equipped with cameras. The cameras were used for navigation and vision research. It was an open platform, so students could install their own software. I wrote libraries to control the cameras, sensors, and motors, allowing students to focus on writing their algorithms.

Peter: Was this based on a Raspberry Pi?

George: No, it was before the Raspberry Pi existed. We used a 68HC11 microcontroller for the low-level control, and a 486 PC ran the software. We used a video digitizer card called a Video Blaster to handle video processing. It was pretty advanced for its time.

Peter: What did you take away from that project, and do you still apply any of that knowledge today?

George: It taught me a lot about problem-solving and working with hardware limitations. Sensors would fail, just like they do today, and we had to find ways to work around those limitations. The experience of working within constraints is something that’s essential in engineering, no matter what field you’re in.

Peter: After university, you transitioned to software development. What kind of software did you work on?

George: I started at the Australian Museum, working on interactive displays, mostly using C and C++. Later, I moved to the U.S. and did game development for PlayStation and Sega Saturn, again using C++. When I returned to Australia, I joined a company that developed military simulations for training sailors. Most of that work was also in C++. But in recent years, I’ve been doing a lot more online development using JavaScript.

Peter: That’s quite a diverse background. Do you think C++ is still essential, especially with the rise of microcontrollers and embedded systems?

George: It’s definitely useful, but I think languages like JavaScript are becoming more common as microcontrollers become more powerful. JavaScript is easier to develop with, and for most online projects, it’s a better fit.

Peter: Let’s talk about hardware now. You mentioned MythBusters inspired you to start working on water rockets. What was it about that episode that got you hooked?

George: They were trying to debunk a viral video that showed someone launching themselves across a lake with water rockets strapped to their back. They tried to replicate it with a dummy, but it failed spectacularly. That failure caught my interest, and I thought I’d give water rockets a try. We launched our first rocket, and the performance was impressive. From then on, we were hooked.

Peter: So, what’s the basic principle behind a water rocket?

George: It’s all about expelling a reactive mass—in this case, water—out of the nozzle to propel the rocket in the opposite direction. You compress air inside the bottle to store energy, but you need water to provide the mass to expel. A good rule of thumb is to fill the bottle about a third with water and two-thirds with air. That gives you the best performance.

Peter: How has your rocket design evolved over the years?

George: We started with single bottles and simple launchers. As we progressed, we began splicing bottles together to increase volume and store more energy. We also added parachutes and timers to make sure the rockets could recover safely. Over time, the rockets have become more complex and sophisticated, incorporating onboard cameras, electronics, and even multistage designs.

Peter: You mentioned you flew one of your rockets recently in Queensland and set a new personal altitude record. Can you tell us about that?

George: Yes, we launched the Dark Shadow a few days ago, a high-pressure water rocket. It reached a new personal best altitude of 2,269 feet. We’re constantly pushing the limits of what we can achieve with just water and air.

Peter: That’s incredible! So, what’s next for your water rocket experiments?

George: We’re currently working on a two-stage water rocket that we hope to fly soon. We’re still fine-tuning the design, but the goal is to push the altitude even higher.

Peter: It sounds like you’ve turned rocketry into a serious engineering endeavor. Thank you so much for sharing your story, George. How can people follow your work or get in touch with you?

George: The best way to get in touch is through my website, where I post updates, build reports, and experiment results. I’m also on YouTube, where I upload videos of our launches.

Peter: Thank you again, George! It’s been a pleasure talking with you.

This concludes episode 1 of the Tech Explorations Podcast. You can find links to resources and more information about George on our website, techexplorations.com. Be sure to subscribe on iTunes, and we’ll see you next time!