Scratch Aqua-Orion Original Design / Scratch Built

Scratch - Aqua-Orion {Scratch}

Contributed by Dick Stafford

Manufacturer: Scratch
(Contributed - by Dick Stafford - 07/11/06) (Scratch) Orion

Brief:
This is my second rocket based on an Aquapod water bottle. It was inspired by the once-proposed Orion nuclear spacecraft, however, it only fits into a not-even-close-to-scale category.

Construction:
Materials included:

  • 1 Aquapod bottle
  • 1 24mm tube
  • 1 24mm-54mm Birch centering ring
  • 1 6mm (MicroMaxx) tubing
  • 1 clear Lexan
  • 1 small clear ink pen
  • 1 ~1.5" tube
  • Foamboard
  • Posterboard
  • Lead shot
  • Elastic shock cord

On this model, prepping the Aquapod included boring the hole for the 24mm motor tube and 5 holes for the shock absorbers (6mm tubes). These small holes were made in the flat tips of the protrusions on the bottle's base. I also sliced off the top, leaving a hole to accommodate the scrap ~1.5" cardboard tubing that I had on hand. This would vary depending on the tube used. I was hoping this larger tube would make the chute easier to pack.

The inside of the rocket consists of the 24mm motor tube centered in the larger tube with foamboard rings. The elastic shock cord is attached to the motor tube through these rings. This unit and the 6mm tubes were attached to the bottle using Liquid Nails.

The fins were cut from Lexan using a diamond cut-off wheel and are also attached with Liquid Nails. The launch lug is a section of the body of a small, clear ink pen. It is mounted fairly far out on one fin since it has to clear the fat body.

The nose cone is a posterboard cone which fits against the bottle. I built the shoulder from a piece of the aforementioned tubing and cardstock. I added lead shot and epoxy based on the results of my RockSim modeling. There are only three fins mounted on the bottle which naturally would accommodate 5 fins, thus they are not symmetric. I modeled them as three instances of a single fin and let RockSim evaluate the stability accordingly.

Finishing:
The rocket was painted silver.

(Scratch) Orion

Flight and Recovery:
I first friction fit the C11-3 motor and packed the 24mm tube with dog barf. I then picked a large plastic chute from the range box (never measured it). It still was tough to get into the Orion but I thought it was required (as I should have modeled the descent rate, too, I reckon). The C11s high average impulse got it going nicely. Ejection looked to be around apogee, but the chute never opened. Luckily the grass was long and it only lost a little paint. Note to self: if you're going to (re)start using plastic chutes, start packing some powder to dust them!

Summary:
This is just another odd looking Aquapod-based rocket. Now off to the Dungeon to work on the next one...

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