Basic Information

Name

Z-12

Launch date:

4 April, 2015

Rocket description

- 63.5mm aluminum airframe

- 4 fins, birch plywood

- birch elliptical nosecone

- 3 ft. ellipsoidal parachute

Payload

-Raven altimeter

-On-board mini camcorder (set to 1280x720 resolution)

-Out-board micro camcorder mounted on forward fuselage

- Smoke Charge (initiated by Raven, 2 sec. post-apogee)

- BRB900 GPS transmitter

Liftoff mass

2.348 kg.

Flight objectives

- Smoke charge  for tracking free-fall descent during clear-weather flight

- Track using BRB transmitter beacon

Motor details

Motor name

Impulser

Propellant

KNDX

Grain mass

279 grams

Nominal impulse

329 N-sec

Class

I

Weather conditions

Temperature

-5°C

Wind

N 15 km/hr

Sky

Clear sky; bright sun

Other

-

Launch Event Description

Sled was once again used for hauling launch supplies, despite sparse covering of snow on ground. The setup of the rocket went well with no glitches. After verifying the sky was clear, the countdown proceeded and at “zero” the rocket immediately came to life, rapidly climbing skyward, veering noticeably into the north wind. The pencil-thin smoke trail was highly visible against the blue sky. The rocket was seen throughout much of the ascent, but disappeared as the rocket approached apogee. Several seconds after disappearing from view, the ‘pop’ sound of the apogee separation event was heard, followed by a second ‘pop’ of the backup charge a few seconds later. A thin jagged trail of smoke then appeared, generated by the smoke charge. The rocket was seen free-falling, leading a trail of smoke, distinctly visible against the blue sky. As the rocket tumbled downward, the sun glinted off the rocket several times, aiding the visual sighting. As the rocket got nearer the ground, the smoke cloud from the main charge appeared and the parachute was seen to deploy shortly after, fully blossoming. The smoke trail ceased a short while later. The rocket drifted with the wind and touched down quite near the launch pad.

We then noted the GPS coordinates on the BRB receiver and entered these into the handheld GPS unit. Although the landing site was only about 300 feet from us, we wanted to test the recovery process using the GPS signal from the rocket. The handheld GPS unit indicated distance to touchdown site, and direction. We proceeded to “track” the rocket, which led us directly to the downed rocket. The rocket appeared to be in pristine condition. Raven beeped out an apogee of 2779 feet.

Flight Analysis

Event:

Time (sec)

feet

metres

Apogee

12.8

2792

851

Separation

13.6

2762

842

Main deployment

43.2

604

184

Touchdown

69.2

Range

91

28

Descent rates:

ft./sec.

m/sec.

Free-fall

76.2

23.2

Main parachute

19.5

5.9

Post-flight analysis and comments:

Good Raven data, on-board video footage and out-board video footage was obtained. The smoke charge once again served very well to track the rocket during free-fall, thanks to the bright sun illuminating the smoke. The BRB GPS beacon functioned nominally and once again demonstrated its ability to direct us to the exact touchdown site.

Examination of the BRG GPS tracking data indicated that the rocket “weather-cocked” quite significantly (as observed). The rocket tracked 241 metres northward (directly into wind). This was a result of an unnecessarily large “stability margin”, a consequence of having fins designed for the original Zeta rocket, which was shorter and less nose-heavy. For the next flight, fin size reduction will be implemented in order to reduce weather-cocking.

Based on video footage from the outboard camcorder, the forward fuselage tumbles a lot more than the aft fuselage during free-fall descent.

As an overall summary, the flight was completely nominal, with all objectives achieved.