I've been prepping the Rearwin wing for covering but during a cold spell in January it was just too cold to do much in the hangar. So I hunkered down in my office to cruise the interweb ostensibly doing "research." I ran across a post from an "influencer" named Xyla Foxlin. She's a young, very enthusiastic engineer who was building and launching a high power rocket. This was a 4" diameter, 4' tall serious looking rocket. Definitely not the Estes model rockets I launched as a kid. I was intrigued enough to start digging into HPR, i.e. high power rockets. It looked like it could be fun. Down the rabbit hole I went.
Turns out they are legally different too. Rocketry is covered by the FARs similar to aircraft. Like aircraft there are different classes. The Estes-type rockets are generally considered as Class 1 or Model Rockets. Once a rocket exceeds 1.5 kg in weight and/or 160 newton-seconds in impulse (power) it becomes a Class 2 High Power Rocket. Class 2 continues up to motors with 40,000 n-sec impulse. Then you get into Class 3 where serious research rockets and companies like SpaceX play. Class 1 doesn't have any more restrictions than model aircraft. Class 2 however needs certification to play and has 3 levels. Level 1 lets you fly commercial H and I class motors. That's between 160 and 600 n-sec impulse. Level 2 gets you into commercial J, K & L class motors - 640 to 5120 n-sec. Level 3 opens up commercial class M, O & P motors (5120-40,000 n-sec) as well as experimental motors. Oh yeah, you can brew your own propellant.
The HPR certification is done by the national rocketry clubs much like formation cards being issued by multiple signatories rather than the FAA. There are two primary clubs in the U.S., Tripoli Rocketry Assoc. and National Assoc. of Rocketry. Both have chapters in the Houston area. I chose to join Tripoli primarily because they have a launch site at Hearne Airport and I can fly there. Level 1 and 2 certification is not overly demanding - build and fly a rocket using a Level 1 motor and recover it in condition to fly again. Level 2 adds a test and uses a Level 2 motor. Level 3 gets more serious requiring a project plan, supervised build, redundant electronic deployment and, of course, a Level 3 motor.
How could I resist? Big, loud, fire-spouting machines, a certification challenge, electronics, pyrotechnics and a chance to use all the tools in my shop and maybe get some new ones. Plus, I am a rocket scientist - my degree is Aeronautical and Astronautical Engineering. So I'm all in. I started researching which rocket kit to use for Level 1. I chose the Apogee Zephyr which is one of about 4 kits very popular for Level 1 certification flights. It's 4" diameter, 4' tall using a 38mm motor. All that's technically required is a simple, non-electronic hop and pop. The motor ejects the parachute after burn-out and coasting to apogee. True to my nature, I can't do anything that simple. I bought the dual deployment conversion for it too. That makes it over 6' tall and provides an avionics bay with the ability to add an altimeter to deploy a drogue chute at apogee and then the main chute when it gets to a chosen altitude. And since I've got all this payload space, wouldn't it be cool to have an on-board camera for a video of the flight. I plan to use this same rocket for Level 2 just with a bigger, Level 2 motor. That will take it a lot higher and subject to much more drift on descent. Wouldn't it be nice to have a tracker on board? So there's another altimeter that has a GPS tracker built in that also transmits the telemetry with the GPS coordinates to a ground receiver. Having a second altimeter will let me try redundant which will be required when I get to Level 3. Oh, and the altimeters and receiver are in kit form. Can you spell scope creep? I'll make a separate post with details on the rocket itself.