Wouldn’t it be cool to know who has made a backyard coaster? I thought it would be!
This is just the start, but us backyard coaster nerds have to stick together.
Add it here. It will take a while to add it. It’s a manual process right now.
So we are reworking the Widow’s Revenge to actually work. And we are getting close, very close. In the meantime, I wanted to show you the launch system and the brake needed to hold the cart in position. Just the motor idling can make the cart launch when we don’t want it to. We need to hold it in place until we are ready and the track is confirmed clear.
So I messed up. Well at least for AC driven electromagnets. It turns out that everything I told you in Part 4 flips when we change voltage polarity. This is definitely going to change how our linear synchronous motor (LSM) looks and acts.
Let’s see what these changes mean and watch ’til the end for a special announcement.
If you have taken on the challenge of building a backyard roller coaster, congratulations! However, you’ve probably spent way more time on the track design than the cart. Well the cart is more important to the overall performance and safety of your coaster. Spend some time here; don’t make your mom shut your coaster down.
Backyard coaster cart design comes down to four main components. Understanding the motion of the cart and wheel contact stresses. Next, look at proven cart designs and mimic them. Finally, learn some basic fabrication techniques with common tools.
Cart motion can be difficult to understand. For any object in motion there are 6 degrees of freedom. Luckily, a roller coaster eliminates 2 of those (side to side; up and down). These are eliminated because the side and up wheels keep us on the track.
There are 6 Total Degrees of Freedom in a Coaster
This leaves us forward and backward, pitch up and down, roll clockwise / counterclockwise and yaw left and right). This video documents how we plan to handle each one of these.
This is where the rubber meets the road….literally. The interface between track and wheel. I’ve made the following video to answer basic questions of dealing with contact stresses. Short answer, you need larger down wheels.
You may also want to read this article that flushes out track width and tie spacing even more.
In this video, we will go over the basics how the Black Widow Cart was designed to handle roll, pitch and yaw. This is the most in depth we go with the structures on the cart. Use this to get ideas and not a final design
There is a lot to be said about calculating the stress on the structure. Please remember that this is for educational purposes only. Seek help from a professional engineer where needed.
Metal working is far more difficult than wood fabrication. As you will see, I don’t have big and fancy equipment to fabricate with so I improvised to make my cart come to life. Below are the basic tools I used to fabricate. Chances are you have these or know someone who does.
If you have decided to take on a backyard roller coaster project, you probably already like to tinker and learning these new skills won’t be too much of a stretch. Get out there and build a coaster cart.
As an engineer and coaster builder, things don’t always work out the way you plan. Well, that is definitely the case with the Widow’s Revenge Backyard Roller Coaster. What makes it worse is that it falls on the heels of the previous failures of the Black Widow BYRC.
While disappointing, we will overcome. I’m now in the process of determining options for how to save this coaster.
Finally, we are having a spring giveway. Two Season Passes to the park of your choice and a Design of Weldments Course. Watch the video and read its description for more information.
Have you ever wondered if there is an ideal location to put your shelf supports? Well, of course not, you’re normal. But if we look at it mathematically…..
