Rocket Launch

My friend Chris was flying his plane near Big Bear, California this past Friday when he and his passenger saw this rocket launch East of their location. I was surprised to see the photo because it appears to be a much larger vehicle than what I would expect to see in that area, or maybe the vehicle is not as large as I think.

More video from the April 28th launch

Here is a video taken by Matt Campbell. I also have some still images taken from the video which show some of the key moments. They are from top to bottom:

1. Last minute prep.
2. Arming of the Altimeter and timer.
3. Connecting the igniter.
4. Ignition.
5. Lift off.
6. Clearing the tower.
7. Rocket under way.

Motor Stats

I thought I'd post some quick stats on the motor that I flew on the 28th of April. The motor was designed to produce approximately 425 lbs of thrust for 2.2 seconds for a total impulse of nearly 950 lbs. The motor (nozzle, casing, bulkhead, snap rings, inhibitor, and casing liner) weighted in at 5.96 lbs. The propellant grain, consisting of 4 segments in a bates grain configuration, weighted in at 7.31 lbs, with a port/throat ratio of 1.5625. The propellant was mixed in a ratio of 65/17.5/17.5 (KnO3/Sorbitol/Sucrose) and cast into 3" mailing tubes that have an ID of 3" and an OD of 3.125". The casing insulation consisted of four layers of rosin paper, purchased at Home Depot. The casing and bulkhead are fabricated of 6061-t6 aluminum. Using Richard Nakka's casing.xls the design safety factor was determined to be 2.2 with a burst saftey factor of 2.94. The nozzle is fabricated from 12L14 "leaded steel" and had a throat diameter of 0.64" and an expansion ratio of 12. There was no measurable throat erosion post firing and the nozzle appears to ready for another firing. When I took the motor apart post flight the insulation was nearly intact, having been breached near the bulkhead. The casing appears to be fine and there is no measurable deformation.

Launch video from May 20, 2006

Here is some of the video taken of the first time this yellow rocket was flown. In it's first flight it was flown with a smaller motor, no camera payload, and not boat tail. If you look closely at the video, you can see the shadow cast by the exhaust trail shooting out across the desert behind the launch tower. I also included a photo of both motors that I've flown in this rocket so far. The smaller motor uses steel EMT for the casing. The larger motor uses an aluminum casing and snap ring closures.

The Camera

I was really happy with the video that I got from the launch, but haven't really mentioned the camera that I used. The camera was a Canon SD200 that I got off of eBay for $52. It was a little beat up, but it came with a 512MB card, and works quite well so I've been really pleased with it. With the 512MB card it will only record a few minutes of 640 x 480 video at 30 fps, so for the launch I bought a 2GB card; it was on sale at Best Buy for only about $30. With the 2GB card the recording time is extended to nearly 17 minutes. I made a simple cradle/camera bay for the camera and that was all there was to it. The camera bay had a one inch hole for the lens and a smaller hole 90 degrees away from the lens opening that allowed me to turn on the camera, start recording, and adjust the lens just prior to launch. In the pictures above you can see the tubes used for the camera bay being squared off on the lathe, the cradle that held the camera, and the finished rocket.

More pictures from last weekends launch.

Here's a couple of pictures from last weekend of the rocket at take off. These were taken by Chris Neuhahn.

Shirra and Stafford by Paul Calle