10/24/10

The Launch

It was a great day, and lots of fun to see all the rocket designs people came up with. There were a lot of great flights... and a lot of failures too! Our rocket performed well, but its second flight randomly went unstable for some reason. We're not sure what was different about the second flight that resulted in the poorer stability because we did everything exactly the same. As usual, blame it on the wind...

In the middle of the day, they paused the rocket launches to fly a model of the Marston Water Tower on an E9 motor. For some reason the rocket just sat and burned on the pad. I can't imagine that the rocketeer who built it didn't calculate their thrust-to-weight ratio, but you never know. Maybe the launch rod was too tight. Maybe the motor didn't work right.

Thankfully the weather turned out great! It didn't rain, it wasn't very cold, and marvelously the wind stayed in a manageable range.

As fun as the event was, I have to say, it was poorly planned.

For one thing, the objective was to stay inside a launch angle of 20 degrees downrange, at apogee. That is a ridiculous objective, especially since it was 100% based on variables beyond our control. The wind, the random weather-cocking, etc. We didn't even get to choose our own launch angle or put our rocket on the launch pad, so how can we have any impact on which direction the rocket takes off? I think maybe the basis of this idea was that stable rockets are going to straighter than unstable rockets, which is true... but pretty much all of the unstable rockets landed within the acceptable range, because immediately after leaving the launch pad they would spin around and plop down, with little chance to veer out-of-bounds.

Other things: They really needed some sort of loudspeaker setup. I'm sure the guy doing all the announcing can't even talk today. Also, I think that if each team were given a queuing number, the launch would have gone much more efficiently, instead of having each group wait in a long line after each flight.

The altitude tracking setup was a little ridiculous, too. The in-class examples of the triangulation methods were similar to the two-station tracking in The Handbook of Model Rocketry, where there is a baseline between the two trackers, an elevation angle, and an azimuth angle. At the launch, the tracking devices measured only the elevation angle, so we were told to estimate the ground angle with our feet... um... yeah. Highly accurate methodology there. I'm sure lot of people just ended up fudging their data, or making it up completely. We'll be comparing these results to our RockSim simulations, but there really isn't any point when we have a precision of + or - 50% to report!

I really shouldn't complain too loudly though, because the event would probably be a disaster if I were given the task of planning it.

Our rocket being placed on the pad


Long lines

Assorted liftoffs
The water-tower-rocket

1 comment:

Evergreena said...

Haha, wow. At least it didn't rain!

ShareThis