Basic Information

Name

Z-11

Launch date:

14 March, 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

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

- BRB900 GPS transmitter

Liftoff mass

2.364 kg.

Flight objectives

- Experimental smoke charge  for tracking free-fall descent during clear-weather flight

- Track using BRB transmitter beacon

Motor details

Motor name

Impulser

Propellant

KNSB

Grain mass

286 grams

Nominal impulse

337 N-sec

Class

I

Weather conditions

Temperature

12°C

Wind

S 25 km/hr

Sky

Clear sky; bright sun

Other

-

Launch Event Description

The snow covering the ground at the time of the last launch event had nearly all melted due to unseasonably mild temperature. As such, pulling the sled loaded with launch supplies required extra effort. The setup of the rocket went well with no glitches. After verifying the sky was clear, the countdown proceeded and at “zero” the motor ignited and shortly after the rocket soared skyward, veering somewhat into the south wind. The smoke trail was vividly visible against the blue sky, and rapidly became pencil-thin as the rocket climbed at high velocity toward burn out. The rocket was visible throughout the entire ascent. The smoke cloud from the apogee charge appeared, followed by the usual ‘pop’ sound. A few seconds later, a thin trail of smoke appeared, generated by the smoke charge. The rocket was seen free-falling, leading a thin, straggly trail of smoke, distinctly visible against the blue sky. About 20 seconds later, the smoke cloud from the main charge appeared and the chute was seen to be deployed, blossoming shortly after. The smoke trail ceased a short while later. The rocket drifted with the wind and touched down about 15 seconds later.

We then noted the GPS coordinates on the BRB receiver and entered these into the handheld GPS unit. Although we visually spotted and marked the touchdown site with the Landing Locator, 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. However, the data appeared incorrect. The indicated elevation was obviously wrong and the direction that the GPS indicator was pointing was an easterly direction, rather than north-east, where we knew the rocket had landed. We decided to abandon the GPS based tracking attempt and instead we headed to the landing site based on the Landing Locator setting. The rocket was found readily, thanks to the bright red and white parachute, and was in impeccable condition. Raven beeped out an apogee of 2617 feet.

Flight Analysis

Event:

Time (sec)

feet

metres

Apogee

12.5

2617

798

Separation

13.7

2605

794

Main deployment

44.1

396

121

Touchdown

61.4

Range

797

243

Descent rates:

ft/sec.

m/sec.

Free-fall

75.3

23.0

Main parachute

19.1

5.8

Post-flight analysis and comments:

Good Raven data, on-board video footage and out-board video footage was obtained. The smoke charge served very well to track the rocket during free-fall, thanks to the bright sun illuminating the smoke. As such, the smoke charge is of definite value on a clear, sunny day, but is of little or no value on a cloudy day. The BRB GPS beacon functioned nominally during most of the flight, but ceased operating when the parachute was deployed. Post-flight examination revealed that the power switch for the unit was broken, a result of the shifting and inertial load of the BRB unit when the nosecone was blown off to deploy the chute. Due to an oversight during preparation, an aluminum “support” disc that serves to support the BRB during launch and nosecone ejection was not installed. This meant that power to the BRB was inadvertently cut when the switch was damaged, and that the GPS coordinates obtained coincided with that of the location of the rocket when the main deployment occurred, rather than indicating landing site.

There was a minor anomaly with the micro camcorder. The recording apparently ceased shortly before touchdown, then oddly resumed recording 20 seconds later, after the rocket had landed (two separate AVI files were generated).