Week 5 - Progress

Last week was our spring break so I could not get into the lab. Now that I'm back, I've acquired materials for the pendulum.

For the construction of the pendulum, I have:

1- 6 foot long 2x4

1 - 12 foot long wooden dowel about 1 and 1/4'' diameter

1 - spool of fishing line

1- projectile receptacle (box)

I've measured out 1' 3'' pieces of 2x4 to cut and create 4 posts that will support the dowels that will support the box.

I'll take the 4 posts and screw them into a piece of plywood to form a solid base. From there I will drill holes in the top halves of the post about 3/4 of the way to the top for the dowels. The dowel will span from one post the adjacent post, forming a suitable place to attach the fishing line to the box. The box will be suspended by the fishing line between the posts. the design is meant to limit the box's sway in the lateral direction (left or right, relative to the barrel of the launcher).

Once I've mounted the box, I will test fire the projectile to see if it holds.

Since the system has been successfully pressurized and the remote firing system completed tests should be fairly simple. 

Week 4 - Progress

This week I was successfully able to pressurize the system and launch a projectile. I charged the tank with approximately 10psi as a small starting point to ensure that the tank would hold.

I was also able to hook up the solenoid valve which is used in conjunction with a remote trigger that allows the user to trigger the launcher from a safe location. This is achieved using a relay attached to the valve which sends a signal for the valve to open.

Next week, I will be constructing the pendulum and setting up the measurement devices in order to collect data.

Week 3- Progress

Since last week I've drilled and tapped a hole in the back of the air tank for a 1/8 x 27 NPT fitting. Furthemore, I have connected my new small tank of nitrogen and equipped it with a regulator.

My initial pressurization test failed. I may need to rework the Swagelok as it has been sitting on the copper pipe I'm using for a while. After charging the line with the 10 PSI ( a little under 1 atmosphere) of nitrogen. I opened the the valve leading to the air tank. Instead of the 2nd stage of the regulator draining (as it should have) the first stage of the regulator was dropping at a startling rate of 20 PSI per second. It started off at roughly 2100 PSI in the initial stage and ran itself down to ~1800 PSI before I noticed the leak. There was no audible evidence of a leak in the system.

For Wednesday I will be replacing the Swagelok fittings, ensuring the teflon tape is properly installed and checking if it is just the tank on the launcher leaking or something else. If I can fix that I will be able to move forward with wiring the trigger control valve which at the moment is a mystery and requires some research on my part to work.

Week 2- Progress

So far, I've been able to get the launcher out of Dr. Hofstein's office. It is now in RB 104 and I'm able to work on it more frequently. I've doubled the thickness of the back end of the air tank so that when I drill and thread a hole for the air to enter from an N2 tank I'll have more room for threads. The attachment was successful, now all that is required is to find a drill and tap of the appropriate size so that I can attach the pipe. From there I will use Swagelok to get the hose to the air source. This week I will be searching for tanks to order and if the tap is needed we will order that too. Once it is complete I will slowly feed air into the system and check for leaks. I'll also prepare the remote triggered valve we are using to release the air to fire the projectile.

Week 1- Progress

As of this week, no progress has been made. Unfortunately, my project advisor has not been around in order to allow me access to work on the project independently. Due to the nature of the project involving compressed gases and projectiles. The School of Science has advised that I not do work unless supervised.

However, if were able to get into the lab, I would be checking seals on the launcher we created for our ballistic pendulum. I would create an opening for the air tank and for the nozzle so as to feed Compressed Nitrogen into the system to launch the projectile.

Once the system has a good seal and can handle the load of the compressed air. We will move on to the test fire phase. Using, plexiglass guards and a remote controlled valve, we will release the pressure and send the projectile into our test receptacle. If successful, we will begin full construction of the pendulum portion of the project and set up the slow motion camera and the measuring instruments to gather data.

Initial Summary

Summary of the project: Compressed air cannon made of PVC. Designed to be a ballistic pendulum for non-science majors to discover the wonders of energy and ballistics.