High Altitude Balloon flight
Having modified a camera and built a controller, I wanted to fly it to see how the camera worked. I assembled the payload into a foam box and rigged it up with a parachute.
Photos of the launch
Are available in this album
|Payload mass||650 g|
|Parachute||30" octagonal (corner to corner)|
|Estimated Descent Rate||5.91 m/s (using Hexaagonal)|
Flight prediction input
|Location||Set with map to the Hamfest venue|
|Launch Altitude||Unset (0)|
|Ascent Rate||Initially set to 5.5 m/sec. Predictor overwrote it to 6.3.|
|Burst Altitude||Left to default at 30,000. Predictor over wrote it|
|Descent Rate||6.0 m/sec|
|Target Ascent Rate||5.5 m/sec|
Flight prediction Output and Actuals
|Parameter||Predicted Value||Actual Value|
|Burst Altitude||34315 m||33880|
|Time to burst||93 m||88 m|
|Ascent Rate||6.12 m/sec||6.388 m/sec|
|Launch Volume||103.8 cu ft||103.8 cu ft (est)|
|Descent Rate||5.91 m/sec||10.12 overall |
3.2 m/sec last 2000 feet
|Descent Time||133 m||143 m|
Flight path comparison
The flight followed the prediction almost exactly! It landed 10.24 miles further SSE than predicted. The parachute performed very well. I need to re-measure it to assure it's a 30" (and not 36") chute. That might explain the discrepancy. NB: I measured it. Yup, it was a 36" chute. That explains a lot!
Charts in aprs.fi showed the internal tracker bottoming out about -39 degrees celsius, and the external tracker at -42c. I didn't work really hard on taping up the box, but it seems that such a large open box with a still camera really doesn't have much thermal mass. It'll be interesting to see how that changes when I have a video camera in there on the next flight.
- Using a time profile for scheduling the snapshot frequency worked just fine. It was a good way to get more picture density during interesting periods of the flight.
- I need to work on sealing the payload box better to see if I can stabilize the temperatures some. Everything functioned, but I would have preferred the cameras stayed warmer.
- Using the "Landscape" mode on the Kodak Pixpro yielded blurry pictures. I got some great images, but more than 50% were blurry. I'm going to try "Sport" mode next time.
- The camera performed well enough that I have purchased a second one to use as a video mode camera in the payload, and run two at once.
- I need to remeasure the parachute to see if I can sort out the discrepancy in descent rate.