Rockets Down Under
GDT-2
Two Stage Rocket with Video
Transmission
David Boyd's Australian Rocketry Home Page
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Rockets Down Under |
GDT-2 |
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David Boyd's Australian Rocketry Home Page |
GDT-2 Two Stage Rocket with Video Transmission |
| The GDT project was conceived as a group project in late 1998. The
concept was to build a large two stage high powered rocket with an advanced payload
including real-time video transmission capability. The GDT-1 was the first incarnation to fly. See the GDT-1 page for more information including in-flight video footage.. The GDT-2 was a full two-stage version with triple clustered L motors in the booster, and a single L in the sustainer. The payload has been extensively upgraded, and none of the original electronics remain. Features of the GDT-2 payload were:
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Pre-Flight Preparation
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This is the payload. It is constructed on a locally developed 75mm
diameter payload bus. In this photograph the payload is upside down and undergoing pre-flight testing on the range. Working down from the top: 1. Blue transmitter antenna (2.4GHz) adjacent to the main parachute pyro charge and parachute hook. 2. Aluminum bulkhead. 3. 2.4GHz video transmitter. 4. Flight computer with telemetry modem. 5. Backup timer for redundant drogue pyro charge. 6. Switchmoade power supply. 7. Battery Pack. 8. Aluminum bulkhead. 9. Drogue parachute pyro charge and backup pyro charge and drogue parachute hook (not visible). 10. Umbilical cable for RS485 link to control PC located 200m away.
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Here is a view of the payload from the other side. |
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Final assembly of the payload into the fiberglass body. |
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Here is the assembled payload module, complete with electronics, parachutes, and pyro charges. |
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This is the CCD video camera. |
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The video is received by a tracking station which consists of two
operators and the receiver "rifle". The rifle stock has mounting a high gain 2.4GHz yagi antenna, a video receiver, a digital video camera with LCD display, and a power supply connection. The video operator tracks the rocket via open sites, and can also see the received video image. An enclosure shields the LCD display from direct sunlight. An assistant provides additional tracking assistance using binoculars, and also has a two-way radio for communication with the launch pad. |
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Preparation of the upper stage motors. |
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The rocket is being assembled in to the launch tower. |
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Installing the ignitors into the upper stage motor. On the right is the
clustered three motor booster stage. Redundant timers are used in the booster to initiate redundant igniters in the upper stage. Alternate channels on the timers also fire the recovery parachute in the booster. |
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The initial assembly is complete. |
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The rocket is erected fully assembled in the launch tower. As you can see the rocket is approximately 4 metres (12 feet) tall. |
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The umbilical computer link is installed. The launch tower is of simple construction. The platforms are laser cut MDF (craft wood). They support 6 verticle aluminium extrusions that form the rails. Each pair of rails guides a fin. The tower is held down by guy ropes and pegs. |
3 - 2 - 1 - Lift-off
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The rocket leaves the tower... These still images were captured by video camera. Download and watch the launch video of this flight in MPEG1 Video 320x240 Format |
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Arcing over slightly... |
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Arcing further over... |
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Stage Separation.... To the right the 3 motors from the booster can be seen falling away. They separated after the upper stage motor ignited. The booster disintegrated. To the left there are two streaks. Further analysis is required to determine why there are two. This should be just the upper stage motor firing. They are likely to be remnants of the booster. |
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Igniters Firing. Two igniters are installed in each of the three motors. The umbilical payload command cable can be seen on the left. The slots on the left and right are for the fins. Download and watch the in flight video of this flight in MPEG1 Video 320x240 Format. |
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Leaving the tower. |
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At full power. Part of the mobile irrigation system can be seen on the upper right. |
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The booster motors have burned out and the smoke trail can be clearly
seen. An umbilical cable tail comes loose and partially blocks the video camera. |
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The upper stage ignites. |
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The upper stage is in full power. |
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The upper stage motor has burned out and the rocket is coasting. The rocket is arcing over. |
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The drogue parachute deploys early at 20 seconds when the rocket is traveling at high speed. It is immediately torn apart and the shroud lines can be seen flapping. |
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The rocket is rolling and arcing over. The horizon is now vertical on the left. |
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The rocket is heading to the ground at full speed. The tracking smoke can
be seen trailing behind the rocket. Despite loosing the nosecone the rocket remains fairly
stable, thus insuring a high speed return back to the earth. An area up to 5km from the launch site was checked for nearly 2 hours but the payload was not found. |
Post-Flight Inspection
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The booster disintegrated - probably due to pressure build-up when the upper stage ignited. At the left are two of the rocket motors. In the centre is the inter-stage coupler. On the right are shredded parachute lines. |
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This is the base of the launch tower. The road surface was removed and the tower was moved sideways about 30cm. |
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Here is the recovered payload. It was found 2 weeks after the launch approximately 5km down range. It was largely intact, with damage to the camera housing and the internal mounting brackets to the airframe. Most of it will fly another day ! |
Post-Flight Analysis
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The GDT2 Payload logs thefollowing data at 1/10th second intervals:
Altitude The true altitude reached was 14,980 feet at 20.5 seconds into the flight, this was 0.5 seconds after the drogue chute fired. The payload fired the main chute pyro at 79.7 seconds. The payload landed 0.4 seconds later. Interesting to note the decent rate increased after the main chute was deployed. |
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Acceleration The accelerometer data shows a peak acceleration reached for the booster stage at 2.6 seconds of 10.5g The accelerometer also shows the sustainer upper stage motor kick in at 4.8 seconds, with a peak acceleration of 10.3g. The deceleration of the payload as a result of drogue deployment can be clearly seen at 20.4 seconds. The main chute deployment can be seen at 79.7 seconds. |
This page created 26 May 2002, last updated 5 July 2002.
This page has been accessed times since 26 May 2002.
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