Although several rocket launches here in Alberta have been cancelled recently, I have continued to build new rockets. Why? There are a variety of advanced construction methods being used today and I want to learn them. Each rocket that I build is designed to include one new fabrication technique that I have not used previously. I hope that by doing it this way, only “one thing” can go wrong at a time.
What have I learned so far? The Estes Crossfire was my first modern model rocket. The instructions were very clear and the rocket was very well designed. It allowed me to build and fly a model rocket, forgiving any minor mistakes that I might have made. My goal was to recover a rocket by parachute, something that didn’t happen back in the “good old days” of amateur rocketry. The Crossfire was fired three times, with a perfect parachute recovery each time.
The Rocketarium VK-7 was next. A little larger, it used a cluster of two motors and also employed a baffle to help protect the parachute from the burning ejection gases. The instructions were not quite as specific as the Crossfire’s, but I built and flew the rocket without problems. Both of the motors ignited on time and the parachute recovery was perfect.
Both of the preceding rockets used “through the body” fin attachment, which gives greater strength. Now I wanted to see what happens when you glue the fins directly to the body tube. I built the Hebe, which flew three times. Because it was little more than a motor with fins, it attained higher acceleration and velocity figures than any rocket I’ll likely build in the near future. Happily, the fins did not get ripped off during flight or broken on landing.
So far, I had been using 18mm motors. I built the Ceres B to gain experience with a 24mm motor. The test flight was perfect, but the rocket drifted away on the wind and was not recovered. Lesson learned: if it is somewhat windy, try a smaller parachute.
Those are the only rocket I have flown to date, but I’ve been busy in the workshop. The Romulus is a 2-stage rocket that uses 18mm motors. I mentioned it before in “Learn to Build Rockets” and showed photos of the unusual fin assembly. It is ready to go.
The Ceres B2 is similar to the Ceres B, but uses a 3D-printed fin can and baffle. It also is ready to go. I will be taking some smaller parachutes with me, just in case…
The Eris II also uses a 24mm motor, a 3D-printed fin can and baffle. It is a smaller-diameter rocket than the Ceres and VK-7, and should reach an altitude of about 1800 feet. Yup, it is ready to go as well.
Lastly, I am building my first rocket to use a 29mm motor. I am using plywood centering rings and fins, instead of balsawood, and using epoxy glue instead of wood glue. The fins are attached to the motor mount in “fin-can” style just like the Romulus booster, and just like the recommended method for the Aerotech Mega-Initiator, which my wife gave me for my birthday. My original goal here was to learn how to glue up plywood parts with epoxy glue. I just finished attaching the fins, and should have the rocket ready to test by November, although I will try for October.
I am also happy to report that the ERC has assigned me a very experienced mentor from among their ranks, who will guide me along the path to high performance rocketry. He believes that the rocket I am now building will be suitable for my L1 Certification flight. HPR flights cannot be done in Calmar, so my first chance would be in February 2023 at the ERC’s annual Fire & Ice launch.
The Mega-Initiator is a 4″ diameter rocket that can take motors of 29mm, 38mm or 54 mm and requires lots of HPR know-how to built it right. That’s why I have been learning these skills on smaller rockets, and why I have been assigned a mentor. With a bit of luck, this rocket might be ready to fly at Fire & Ice, too, provided I don’t spill epoxy all over my feet and get bonded to the garage floor!