First Post From Thunder Guy

[Thunder Guy]

My apologies!! I think I did my first post in the wrong area.

I am a high school teacher. I am starting an aerospace club at my high school. I had no idea that water rockets were soo totally cool!!

1. Has anyone been able to put the water rocket designs into Rock Sim 9 to do CP an CG calculations? Can I do this using the mass override function in the software?
2. Does anyone have a wind tunnel design that is cheap to build?
3. Does the swing test work for CP?

Thank you in advance for all of your help

[rockets-in-brighton]

Welcome to the forum!

There is a thread about water rockets and rocksim here:

http://www.wra2.org/forum/viewtopic.php ... it=rocksim.

There is a fairly simple home-brew design for drag testing water rockets in this document (WARNING: PDF):

http://www.seeds2lrn.com/WaterRocketLab.pdf

and NASA has some excellent resources on wind tunnels, including links to build-your-own designs:

http://www.grc.nasa.gov/WWW/K-12/airplane/shortt.html

Yes, you can use the swing test for checking that your rocket is aerodynamically balanced. You can also use the Barrowman equations to get a numeric approximation of CP, as long as your rocket fits the criteria (which most do.)

Good luck!

[U.S. Water Rockets1]

My apologies!! I think I did my first post in the wrong area.

I am a high school teacher. I am starting an aerospace club at my high school. I had no idea that water rockets were soo totally cool!!

1. Has anyone been able to put the water rocket designs into Rock Sim 9 to do CP an CG calculations? Can I do this using the mass override function in the software?
2. Does anyone have a wind tunnel design that is cheap to build?
3. Does the swing test work for CP?

Thank you in advance for all of your help

Welcome to the forum! Your question about wind tunnels brings up an interesting idea that was inspired by a design that NASA used and which was recently featured on Mythbusters. The "wind tunnel" they used was actually a looped system of water running through a trough about a foot deep by a foot wide. It had a clear glass pane along one side. The test object was fixed under water and the flowing water was used to test the aerodynamics of the objects. They even injected a dye stream into the flow to show the vortex the object made.

Now, this kind of thing would probably be hard to make due to the expense of the pump needed, while the rest of such a tunnel would be pretty simple to build. However, someone who lived near a stream or river could theoretically divert some of the water to supply the flow for their "wind" tunnel.