Challenge: Coaster

This project is based upon Mr. Noack's "Project Coaster" instructable, which can be found below:

https://www.instructables.com/id/Building-a-Wall-Mo...

My instructable won't tell you step by step how to build the roller coaster, I highly recommend visiting his instructable above for the basic information on how to get started. However I will discuss several of the modifications I needed to make in order for it to function in my classroom.

I absolutely love this activity since I had most of the equipment like the vacuum former and other supplies for my 9th grade students to use. I have had to make multiple modifications to the activity since I do not have the classroom space to accomodate a 12' x 8' roller coaster. I was however able to develop a 8' x 8' roller coaster on casters that allowed me to move it around the room so the classroom could still be used in the various ways I needed it. Ultimately the coaster is made up of two 4' x 8' wood frames that are bolted together with 4 3/4" bolts. I then covered these two frames with pegboard purchased at Home Depot or any home improvement store.

This activity provided my 9th grade students with an ideal engineering activity that enabled them to experience the engineering design process from start to finish and them present their discoveries to the class.

***Note: Many of the activity sheets I used for this activity were developed by Mr. Noack. I will post the sheets I developed in addition to his in the near future.

In order to build one of these roller coaster fixtures, you will need two different K'nex roller coaster sets (Neither of which is currently produced anymore).

The two sets are:

• Rippin Rocket (Not Rippin Rocket 2)
• Screaming Serpent

In my setup, I obtained about (5) Rippin Rocket sets and (1) Screaming Serpent set to make sure I not only had enough materials to build the coaster, but addition parts incase some of the blasters broke in the future.

The 5 Rippin Rocket sets allowed me to have (10) Blasters the help maintain momentum as the coaster car moves around the track. I only used 7 in my current design and might have gotten away with 6 except I wanted to increase the payload of the cars the students were developing.

Obtaining K'nex

How did I get all these sets? Fortunately my school district is associated with an Education Foundation that allows grants of $600 to enhance and obtain materials for classroom activities. I needed to write for two of these grants over the course of the year in order to obtain enough money for not only the K'nex but the structural materals to build the frame structure, backboard, carriage bolts, brackets, and other materials (Check Mr. Noack's original Project Coaster Instructable for part lists.)

Do not use the new K'nex Sets. While they are easy to obtain and are fun to play with, they won't subsitute the two sets I mentioned above. I found the best way to get these sets was through Amazon.com. If you search for either of the sets, you will notice a section called "Collectibles" (see pic at the top of this page). This is very similar to Craigslist.com where people sell their used items for money. I acquired barely used roller coaster sets with all the components from $30 - $100. While this seems like a lot, a brand new set is almost $300.

Amazon.com is also great for getting the nylon ball bearings, carriage bolts, nuts, and other hardware parts for cheap when compared to Lowes or Home Depot.

In order to get my 8' x 8' coaster to work with my classroom I had to add casters to the bottom of the entire roller coaster. This allowed me to move the coaster out of the way so I can use the markerboard and it allows me better access to the back of the coaster frame so I can feed through carriage bolts and other materials like power supplies.

You can buy casters at any hardware store, but if you work for a school district like I do, you can always ask your friendly neighborhood maintenance staff. They were more than happy to help me with this project and I was very appreciative!

I highly recommend that if you enjoy fabricating random objects out of a variety of random materials that you obtain for yourself a Dremel. This tool was and is a godsend to have in my classroom regardless of what project I am working on.

Modifying the K'nex Cars

The Dremel made modifying the original K'nex much easier and not to mention safer. I found it harder to use the bandsaw to cut out the passengers, remove the front and all the fins.

Modifying the Blasters

I noticed that when I was running my roller coaster cars that some of them were restricted by the orange plastic lip that extends from sides of the blasters. I used the bandsaw and a Dremel to remove this lip to create a greater space through which the coaster cars could pass. This did not impact the effectiveness of the blasters.

When building my track, it becomes very difficult to figure out where to place the next pieces in order to allow your coaster car to continue to move. Due to my lack of space I had to overlay layers of track in order to create a roller coaster that I felt was complex enough to give my students a real challenge when designing their coaster cars.

I felt it was necessary to add additional supports to make the track as rigid as possible to reduce bounce and movement in the track. This actually increased the performance of the coaster cars and allowed me to increase the maximum payload for each car.

The video I included demonstrates how I developed the extension pieces that allowed me to complete 3 layers of track ontop of each other.

Starting the Ride

To start my roller coaster, I wanted to add a cool feature that would allow each car to be launched exactly the same way. I used an old RC Car servo and controller to create a starting gate that when raised would release the car down the track.

Stopping the Ride

To stop the cars at the end of the track, I simply used an old shop brush that we had and glued the bristles together in a wooden mount that I created using the table saw. This really slows down the roller coaster cars without creating a sudden jerk at the end. This is especially useful for the heavier cars that accelerate very quickly at the end.

One of the custom modifications that Mr. Noack made that is required for the roller coaster to work with both the blasters and the chain system is adding the chain hook under the car. When you get the Screaming Serpent K'nex set, you get one car with a chain hook that you can either remove from the Screaming Serpent car or you can improvise a hook of your own.

Making the Hook

I used some 1/16" metal rod and some sheet metal to replicate the hook on the Screaming Serpent car. It helps to have some sheet metal equipment in the wood lab to do this, but you could replicate this process using some pliers if you had to.

I used the sheet metal bending tools to pinch the thin strips of sheet metal around the metal rod to create a hinge for the hook to pivot on.

One of the major modifications I made to the chain system that is used to bring the roller coaster car back to the top of the coaster is adding K'nex wheels to reduce chain snagging.

As I developed the chain portion of the coaster I realized that there is a fine balance between the chain being too loose and too taught. To help with this, I periodically place Knex wheels to help elevate the chain above the yellow track structures that tend to snag on the chain as it moves.

I hope this Instructable was helpful as a companion to the one developed by Mr. Noack entitled "Project Coaster". The activity is a tremendous amount of fun and my students love the year to year competition aspect that it has.

Please let me know if you have any suggestions on possible improvements or modifications!