The Speed Ski

The "Speed Ski" is a pair of classic nordic that are locked together with one wheel between them to move the skis forward. The assembly is made to sit in a pair of classic ski tracks that you might find at a nordic ski center. The speed ski is not made to help be pulled along tracks it is simply made to run along the tracks for fun. The skis motor is powered by a 12V battery that sits in a battery box on one side of the skis. The large motor that sits in a motor box sits on another ski to even out the weight. Both the battery box and motor box are raised slightly by risers, to be out of the way of any ski tracks. This ensures that only the bottom of the skis are touching snow. The speed ski is turned on through a switch and then is live during this time the speed ski with continue to run along the tracks till the switch; which as a long stick glued to it; is hit by a ski pole to turn the switch off. The nordic tracks will guide the speed ski as it coasts along through turns and straight patches. I was inspired to make this as I am a nordic skier who loves the great outdoors. I originally got this idea when coasting down a hill and thought that a robot version would by awesome to see. Unfortunately the snow was bad this year and I did not have a complete speed ski by the time the winter season ended. Although I never got to really test this idea in real life I did learn a lot about how iteration in the design process can change a project entirely for the better.

Supplies:

1. leaf blower motor/ Any higher torque motor
2. 12V battery
3. Old pair of nordic skis
4. wires
5. toggle switch
6. small stick
7. 3D printed parts
8. hot glue
9. tape

Tools:

1. 3D printer
2. hot glue gun
3. general tool box items

My initial thoughts for this project was added space a pair of skis locked together with a battery and a motor. The first idea of pushing the pair of skis. Forward in the tracks was some kind of fan that would push air creating a forward motion. From that idea, I thought of leaf blowers attached to a pair of skis. The leaf blower is known for pushing a large amount of air for it size. Knowing this I went to my local thrift stores and looked for a pair of Nordic skis and a cheap, but decent leaf blower. After playing with this idea, I quickly found out that the size and weight of the motor would not provide enough thrust to push all of the weight. After thinking long about this idea and I went back to the drawing board to think of different ideas. The next best option was a single wheel that would continuously be pressed against the snow while pushing the skis forward. No matter the design I was able to start on the electronics and so I found out that the easiest way to do This was to buy a wireless transmitter and receiver that would make it wirelessly. This would tell the motor to go forwards backwards and stop. This was a new electronics idea that I have not explored yet of wireless receiving and transmitting that was fun to play with. After a while of playing around with it, it worked, and I had a working set of electronics, but after using it for a little bit, the battery rating was too low for the receiver. This meant that the receiver failed after a few uses.

After going through an innovation stage, I'll set my sights on a design with a pair of skis, locked together with a moving wheel between them. This would make for a more even weight distribution and a more reliable design. Then I went into more detail design by ripping out the motor from the leaf blower and taking measurements to create a motor box. I also took measurements of the battery box well, I'm making sure to give room, leniency for 3-D printing errors, and it's snug fit. This would make for an easier time assembling. When designing this idea, I ran into some problems with how strong the skis would be connecting wise. This made me choose to have two arching over 3-D printed connectors to each ski. I also decided to make holes in the back of the battery box, and in the back of the motor box to allow for the wires of both of those to run out of those holes. I also got to design and choose a wheel design that would have ridges in it in one direction to efficiently scoop snow, and push it backwards to create a forward motion.

As I started 3D modeling my design I used the measurement sheet that I previously had made as a reference. Later, I would realize that all of those measurements were wrong, and that I needed to redesign all of the parts. In the design, I am showing an individually design, each piece, and then imported them into one file and assembled it. Skis in the three model or just for reference. Well, 30 modeling by design, I made sure to be as realistic as possible. I did this by raising the wheels so that it could be on the ridge that is between the two tracks in a Nordic track. I also played with the idea of having an arch over the top of the wheel to provide more strength between each of the skis, and to run wires from the battery over to the motor.

When building this project, I ran into many problems. The first of which was when I went to go and glue the arches that connect the two skis on the front and the back with gorilla glue, they sometimes came off because a smooth surface on a smooth surface with glue, connecting them doesn't create the greatest connection. After peeling the past glue off, I made scratches with sandpaper onto the patch of the ski that would be covered and glued by the bottom of the connector and I did the same with the connector. This made it so that the two scratches surfaces would connect to each other because the glue would have something to find the two together. The next problem was how to adjust the motor so that it would rest the wheel on top of the snow. I solve this by screwing two bolts into the bottom of the ski and creating a bridge between them with nuts on top and below the bridge. This bridge would be able to be adjusted by screwing the nuts up and down to lower and raise the motor. I also was able to print a small block to be used as a riser for the battery box. The electronics were very easy it was the battery to switch to the motor. The switch had a long stick connected to it so that in theory when it ran down the track, it would be able to be hit by a pole and turn off. This proved as a much more reliable and durable design, rather than using a wireless receiver and transmitter to control my motor. I was also lucky to find a decent pair of skis that would work for this project. Even though they were backcountry skis instead of classic skis, they were slick enough, so that the assembly could glide on the snow.

In the end, I learned a lot from this project. This included things like wireless electronics, dimensioning is important, and incorporating many different individually design pieces into one design. When I was teaching myself how to use the wireless electronic transmitter and receiver, I found an easy way to do this by buying a receiver that had a input for the battery in an output for any light motor or thing you were trying to turn on and off this made my job much easier. In this project, I also learned how many iterations we must go through to even find a half decent one. This led me down a rabbit hole of would this be better or would this. I also was able to compare the first idea I had, and the last one which were drastically different. I also was able to take experience from Nordic skiing as a sport. She's on this project by noticing waxed skis always make for faster ones. This is because a properly wax ski will make for a faster and low friction surface that the ski and snow can interact in. While looking under the contest details "let there be speed", I was able to learn a lot more of the behind the scenes of different winter Olympic athletes.