In this blog, I will show all the steps I took in the making of my prototype of a brand new hovercraft!
Question: How did first start off drafting for the creation of your hovercraft?
Kelly: I've learned from my Machines & Tools class with Mr. G that every design has to start off with paper and or cardboard. This took a long time because we first had to make a cardboard model that was stable and could hold up at least 50 pounds.
Question: Was it any easy task? How many times did it take until you got to hold 50 lbs?
Kelly: My team and I had to make at least about 4 different prototypes before we finally got the one and final design. It was always tricky because sometimes your designs don't work the way you imagine them to. But you just have to keep on designing. And that's what we did. Eventually we were able to make one hovercraft that could hold up way more than 50 pounds. As you can see from the pictures, the last design was very very simple. But it ended up holding at least 120 pounds! Once we finally had a set design, next it was time to move on to steel.
Question: When you started off making the steel model, did you have to make adjustments?
Kelly: Yes there had to be adjustments made. Although the cardboard version held up so much weight, you could see that hovercraft actually dragged at some points and at some points it didn't. SO we have to come up with a design to put on our steel version since it would still be flexible. So we made a draft design on Solidworks with our teacher Mr. G about making a cone/dome like structure that when it's attached to the main board, it will not bend. We realized when we had a beta testing piece being printed out that it would be difficult to make because of the round shape. And in order to make this shape in what we were going to use, A Pull Max, it would take much more time.
Question: That's a shame. So did you have to use something different to stabilize the hovercraft?
Kelly: We didn't make it too different. In fact, it was almost the same thing. However, all we did was just make the top and bottom part with a squared figure. It would end up looking like a frustum. We made two of these because we were going to connect them with a hex bolt through the middle. And that would create a seal for the bag to still have all the air trapped inside. But my job was to figure how to make the paper startup version. It required a lot of math! But eventually, I made the calculations to make a 2D piece of paper into a 3D model.
Question: Wow! How did you do that?
Kelly: To start off, I had to make a bigger circle. This is because in order to make it 3D, I have to cut off a certain fraction of the circle off and then connect those two end together. I then had to make a cover for the top of the frustum piece. Since every piece would be screwed in together, I need the frustum pieces to have a center platform in order to using a hex bolt to connect them all.
Question: Did everything go to plan? Was there anything else you had to add?
Kelly: Yes actually. We actually had to change the design for the bottom half of the hovercraft. It turned out that as I was examining the prototype on Solidworks that the bottom piece would be taller than the actual bag. That means that it won't even float! So instead, we actually inverted the bottom piece and had the center board have a hole through the middle with the same diameter of the bottom of the bottom board/frustum..
Question: Now that the problem was solved did you continue to make the paper models?
Kelly: I made the paper version of the bottom piece since it required different calculations than the top piece to make. But I did start making the center board. My team mates made the hole in the center. They made the hole with a diameter of the bottom diameter of the frustum. You can also see that I made legs on both frustums. I did this so that it would make it more still in place and it would not tear the bag once they are being tightened more by the hex bolt
Question: Now that you made your practice pieces, how did you start to make them in metal?
Kelly: I first started off by making the lines on the sheet metal with a radius stick and had the rotating side be pointy and sharp. Then I cover it with blue ink and redrew the line and made more of an indentation. And I also made my lines of how much degrees I needed to cut off. Then it was time to cut! I used two tools to cut this piece. I used hand shears and then I used what's called Beverly Shear. These were the tools that could best help me get a close and clean finish.
Kelly: When I cut something out in the shop, I had to make sure that the piece had no splinters sticking out. And of course it had a few splinters. So I began filing the edges out. Once I cut out the part I didn't need anymore, I filed the inside of the circular piece. Then I ran the piece through a roll machine in order to help the piece maintain its circular shape when the two ends are connected together. I also added in another space because I would have to spot welding the ends one on top of the other. If I added the small extra space, then it would not interfere with the measurements of the frustum parts.
(To be continued...)