Rocket launcher deliverable #2

Just like last week, you are basically free to do what you want during the lab work period, you just have to deliver to me the result I ask for by the end of the week. My impression so far is that you're all making very good progress, so this deliverable should be easy.

This week, I want you to tell me the following:

• Did you find that you need to use the same rocket and turret for reliable results, or did it not matter too much?
• Give an estimate of the variability in the launcher's range for at least 3 angles. For instance, if you do 5 launches at a given angle, what are the mean, maximum, and minimum ranges? 
• Given the variability you find, approximately what size target do you think you could hit reliably? Ballpark answer is fine.
• How does the actual range of the rocket compare to what you would predict without drag forces, evaluated for at least 2 angles?
• How much kinetic energy must be lost to drag forces for each of those angles (say, a % of the launch energy)?
• Using the example code I've given you (below), or code you've written, what drag coefficient makes your simulations match your measured data reasonably well?

I will give you at least 45 minutes, maybe an hour, on Wednesday to finish taking what data you need and think about these issues. If you want to do some additional work, you can take the launcher home with you until Friday to perform further tests if you let me know by the end of class that you wish to do so.

You might find that the drag coefficient is different for small and large angles, it is possible (the rocket might tumble at high angles, for instance). What you're after is the best prediction of your rocket's motion, by any means necessary.

Here's a basic python program to calculate the trajectory, assuming the acceleration due to drag is -Dv^2. If you want to account for the initial height of the rocket, you'll have to change ytemp=0 to be the starting rocket height.

Finally, Mr. Hampton has figured out how to control the rocket launcher directly from python. This has a number of advantages over the provided program, not the least of which being that you can figure out how to directly set the angle you want. There are a few things to worry about, such as how to know what angle you're at to start with (hint: start from the bottom, it is always the same) and how far you've moved from there (hint: you control how long the motor moves, so you can calibrate this). If you are careful, you can control the start position and backlash in the gears to set the angle with pretty decent accuracy.

If you're interested in trying to control the launcher, let me know and I can give some suggestions for how to proceed. And many thanks to Mr. Hampton for figuring this out. This probably isn't something you'll find doable if you are totally new to programming. In that case you're not at a huge disadvantage, though, I can give you some hints on how to achieve similar accuracy without any code ...