Gravity's Just a Habit

From Danno's Rocket Wiki

Gravity's Just a Habit ("GJaH") is my first two-stage high-power rocket. The initial build took place between May and July 2021, and I had it finished by November for its first flight.

GJaH is a Wildman Shapeshifter Jr. with the optional booster kit. I built a Shapeshifter Jr. for my level 1 certification in 2013, and my initial idea was to just build a booster for it, but then I decided I was sentimental enough about that rocket to just build a whole new one. The booster fins are reversed from the normal orientation (with the curved edge facing backwards) just because I liked the way it looked.

The sustainer uses the same electronics (Altus Metrum TeleMega), sled and bulkheads as Kestrel but it has its own coupler. The sustainer also carries a Mobius Maxi video camera. The interstage currently uses an EasyTimer and a BigRedBee RDF tracker. The booster is recovered by motor ejection and uses a Jolly Logic Chute Release.

GJaH's first (and so far, only) flight in November 2021 resulted in a safe recovery, but the sustainer motor did not fire. The rocket was not stable enough while flying on the booster, and was well outside its tilt limit when it would have staged. I've made two changes since then: I've added about 10 ounces of nose weight, and I have selected an I-470 booster motor instead of the original I285 to increase velocity off the pad.

A second flight was planned for February 10 2024, with the I-470 booster staging to the same I-175 used in the first flight. Predicted altitude was 7000 feet AGL. Sadly, this flight had to be cancelled due to low cloud cover at the launch site.

The rocket's name is a lyric from the song "Upside Down and Inside Out" by OK Go.

  • A red two-stage Shapeshifter Jr. rocket and a green and white single-stage Shapeshifter Jr. in my workshop.

    GJaH and my original L1 Shapeshifter Jr.

  • A view of internal fillets of black epoxy inside a red fiberglass rocket tube.

    Internal fillets in the booster.

  • A red fiberglass interstage coupler with a pull-pin labeled "remove before flight" and a high-power igniter attached.

    External view of interstage (before I found that this type of igniter would not work).

  • A yellow 3D-printed electronics sled with circuit boards and wiring.

    One side of the interstage sled showing the EasyTimer and switches.

  • A yellow 3D-printed electronics sled with circuit boards and wiring.

    The other side of the interstage sled showing the BigRedBee RDF tracker.

  • A wiring diagram showing the EasyTimer and BigRedBee connected to two batteries (one for electronics and one for pyro) via the pin switch and screw switch.

    Schematic showing wiring of the interstage.

  • Me standing next to an eight-foot-tall, two-inch diameter two-stage rocket, wearing an R2-D2 t-shirt, sun hat and safety goggles.

    GJaH on the launch pad in Elsberry, MO, November 2021.

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