Engineering Projects/Rubberband gun/Howard Community College/fall2011/501 Rubberman

Problem Statement

Our goal here is to create a working gatling gun that fires rubber bands as ammunition. It needs to be fully automatic and very similar to its military counterpart.

Team Members

Fahad

Charles

Mderrick

Corey

Summary

We just got the project of making this gun. The biggest issues in the previous teams were that the gun had a problem getting stuck and not actually shooting rubber bands. We made a design that will eliminate those problems and is a very simple yet effective plan to make this gun with as less issues as possible. we had intinally gone with the same design as the previous team, but decided to change the design as we realized soon into the project that it was a bad idea. we decided to go with the idea of a gun like the disintegrator http://www.youtube.com/watch?v=0GAUnuuBkW4

Poster

Story

We started out thinking this will be a easy project looking at many designs and going with the one we thought was the best one. we started to construct the project and soon figured out that it is much harder than it looks as we faced many difficulties. We had initially assumed that the design we chose, a cardbord cylinder would be perfect for it. Thinking about its light weight and already round shape we decided to build the gun of the cardboard cylinder. Then later we fell into sea of troubles, From finding the right materials, getting the materials in time. We had to spend a lot of time trying to get the measurements of pegs we need the pcv pipe we need. The barrel would be made out of cardboard. Then ordering the materials was the easy part. Getting the materials 3 weeks into to the project was very disapointing. especially since we only have about 4 weeks to do this project. Then when we got the materials, we started to make holes into the barrel to get the pegs to fit in. Then we ran into a problem of the cardboard becoming very week with every hole we made. We decided to not make so many pegs in the barrel for the support purposes. When we got the pegs we set them on top of the shleves in the work shop and when we returned, we had lost more than half of our pegs. We were only left with 12 of them. We then decided to just go with what we have and continue the project. We then just started putting the support in for the barrel. we used cutters to cut the paint rollers in the middle and attched the barrel onto it and then we found The barrel was not spinning smoothly. So putting that issue aside we started finding a motor for the barrel to spin and unfortunately couldnt find any in time. Not finding the right motor to spin the barrel was hard. The barrel being to fragile to handle all the force of the rubberbands and all the cutting and constructions required. As we approached the end of this project we realized that we werent going to complete it. We are going to continue this project but with a different design.

Decision List

1.We decided to go with the design which uses the string to release the rubber band. we found it more effective and a simpler design.

2. We are going to be using cardboard cylinder to be the barrel

3. We are going to be using paint rollers to be the support for this gun

4. We decided to carry on this idea even though we ran into some trouble

5. We arent going to finish this gun, so are continuing this project

Material List

1. Large cardboard tube

2. Small PVC pipe piece

3. String (any size string would work)

4. Paint rollers x3

5. Small wooden pegs

6. Cordless battery powered drill

7. Rubber bands (as ammo)

Software List

We have used no software for this project, and we see no further application of software in the future of the project.

Time

In class is always there, but most of the time for this project was spent outside of class. The group decided to do indiviual work as it seemed to best fit everyones schedule. All of our team members spent more than 4 hours a week working on this project.

Tutorials

BEFORE YOU BEGING TO FOLLOW THIS TUTORIAL. NOTE WE DID NOT SUCCEED IN MAKING THIS GUN.

1. Start out getting a good solid, light cylinder base for the barrel.

2. Start by getting the wodden pegs and cuttin every 4 pegs 3/8" less then the previoius size

3. Start marking holes on the barrel for the pegs

4. Drill the holes in the barrel

5. Start putting in the pegs starting from the tallest one on the first row

6. Used Gorilla glue to glue down the pegs

7. Cut the pain rollers in the middle

8. Bend the paint rollers stokes up at 90 degrees

9. Cut notches to the end of the barrel of where the stokes of the pain roller would fit into.

10. This is as far as we got and faced many problems along the way. follow tutorial with caution.

Next Steps

Try to get a good motor in first before anything. Use a better design. The design we used was full of problems. Get the barrel to be a lot stronger. DO NOT USE A CARDBOARD CYLINDER FOR THE BARREL. Get a better support for the barrel to spin freely. We thing the best way would be to use bearings. Good luck to the next team.