Gravity's Just a Habit: Difference between revisions

Revision as of 21:36, 1 May 2023

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 built from 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 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. Unfortunately, I have not yet had another opportunity to fly the rocket and try these changes.

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

GJaH and my original L1 Shapeshifter Jr.
Internal fillets in the booster.
External view of interstage (before I found that this type of igniter would not work).
One side of the interstage sled showing the EasyTimer and switches.
The other side of the interstage sled showing the BigRedBee RDF tracker.
Schematic showing wiring of the interstage.
GJaH on the launch pad in Elsberry, MO, November 2021.

@@ Line 15: / Line 15: @@
 GJaH is built from 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 ([[https://altusmetrum.org/TeleMega/ Altus Metrum TeleMega]]), sled and bulkheads as [Kestrel] but it has its own coupler. The interstage currently uses an [[https://altusmetrum.org/EasyTimer/ EasyTimer]] and a [[https://altusmetrum.org/TeleGPS/ TeleGPS]], although I am considering swapping the TeleGPS for a BigRedBee RDF tracker. The booster is recovered by motor ejection and uses a [[https://jollylogic.com/products/chuterelease/ Jolly Logic Chute Release]].
+The sustainer uses the same electronics ([[https://altusmetrum.org/TeleMega/ Altus Metrum TeleMega]]), sled and bulkheads as [Kestrel] but it has its own coupler. The interstage currently uses an [[https://altusmetrum.org/EasyTimer/ EasyTimer]] and a [[https://shop.bigredbee.com/pages/rf-transmitters BigRedBee RDF tracker]]. The booster is recovered by motor ejection and uses a [[https://jollylogic.com/products/chuterelease/ 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. Unfortunately, I have not yet had another opportunity to fly the rocket and try these changes.
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 <gallery mode="slideshow">
 File:Assembly-cropped.jpg|GJaH and my original L1 Shapeshifter Jr.|alt=A red two-stage Shapeshifter Jr. rocket and a green and white single-stage Shapeshifter Jr. in my workshop.
+File:Internal-fillets.jpg|Internal fillets in the booster.|alt=A view of internal fillets of black epoxy inside a red fiberglass rocket tube.
+File:Interstage-1.jpg|External view of interstage (before I found that this type of igniter would not work).|alt=A red fiberglass interstage coupler with a pull-pin labeled "remove before flight" and a high-power igniter attached.
+File:Interstage-2.jpg|One side of the interstage sled showing the EasyTimer and switches.|alt=A yellow 3D-printed electronics sled with circuit boards and wiring.
+File:Interstage-3.jpg|The other side of the interstage sled showing the BigRedBee RDF tracker.|alt=A yellow 3D-printed electronics sled with circuit boards and wiring.
+File:Schematic-rev-3.png|Schematic showing wiring of the interstage.|alt=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.
+File:Gjah-on-pad.jpg|GJaH on the launch pad in Elsberry, MO, November 2021.|alt=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.
 </gallery>