R/C Hovercraft

My main project is the R/C hovercraft. It uses a lift motor to float on a pocket of air and uses a propulsion motor to push itself.

Engineer

Zachariah

Area of Interest

Mechanical Engineering

School

Jewish Community High Cchool of the Bay

Grade

incoming Junior

Reflection

Since I’m a second-year student I wanted to go above and so I found out how marketable my hovercraft is. On Amazon, I found hovercrafts ranging from $12 to $85. The $12 hovercraft was so bad that the specs for it weren’t even provided. The $85 hovercraft was even better than my hovercraft. The hovercraft I made had a total cost of $256, so money is the main reason I think my hovercraft isn’t marketable. However, there are two more reasons. The first is material. My hovercraft is made out of a light foam called Depron, while the $85 hovercraft is made out of high-grade hard plastic. The plastic will last much longer than my hovercrafts Depron. The second reason is the battery. My hovercraft’s battery takes 6 hours to charge fully and only gives me 20 min of play time, plus if my battery gets too low and you try and charge it, it explodes. The battery on the $85 dollar hovercraft never explodes, but it also only takes four hours to charge and gives you 15 min of play time. That means that the $85 hovercrafts battery has a better charge time to play time ratio than my battery. Overall I think that my hovercraft would not be marketable due to its overpriced cost, dangerous/ineffective batteries, and weak foam body. Looking back to last year when I started Bluestamp, I wanted to try hands-on engineering. This year I continued on that path and kept learning and improving. I improved greatly on 3D CAD making, applied physics, and construction. I learned how to make a four bar linkage system, and also had to learn to sew (which is pretty hard). I feel immensely more prepared to take on engineering project and challenges in the future. Coming back to Bluestamp this year only reaffirmed my want to become an engineer and to continue to do what I love. I can’t wait for my next engineering project and am so thankful that BlueStamp helped me find my passion.

Final Milestone

For my Final milestone, I secured the top structure of the hovercraft into place, the electronics into the top of my hovercraft, and created a case for my receiver that I put in the front of the main cabin. First, I hot glued the two pieces of my depron skeleton together. I had to use someone else to help place the hot glue fast enough so that the hot glue wouldn’t set before I placed the top on. After that, I  added a holder for my receiver that would allow it to be farther away from my electronics that would mess with its signal. The next thing I wanted to do was optimize my receivers range so I made antenna holders. After that, I made the holder for my servo that holds up my propulsion motor. I had to make it not touch the ground so that my propulsion motor would not knock into my hovercraft. At first, I gave the holder too little support so I had to add one more pillar to hold it up and use more hot glue to secure it safely. Finally, I put all my electronics in and connected them to turn it on. I quickly found out that I had to add strips of fabric on the bottom of my skirt to hold the sides to each other. Even this didn’t fully work so I  taped the parts of the skirt (with duct tape) that were blowing up too much and that worked. My hovercraft started to fly evenly and smoothly.

Project Resources:

Build Plan

Bill of Materials

Schematics*

*Schematics provided by Sami M

My presentation night

Second Milestone

For my second milestone, I did a few things. First I found a way to connect all of my electronics (this is the schematics for the electronic set up I was using), then I made a stand for my receiver, and finally, I made the skirt. The first thing I did when dealing with the electronics is I had to find a way to connect my ESC’s to my actual motors. The easiest way I found to do this is to solder on bullet connectors to my motors and ESC’s. Then I had to electrical tape the bullet connectors to stop them from touching which would mess up the connection. Next, I had to connect the ESC’s to the batteries. I had to get XT60 connectors because my ESC’s just had wire and my batteries already had the female XT60 connector on them preattached. I didn’t just want to solder my ESC’s to the batteries because then if I wanted to reattach my ESC’s to a different battery I would have to desolder then resolder which would be a huge hassle. So I solder on the male XT60 connector to my ESC and moved on to the receiver. In the booklet for my remote and receiver, it says that the receiver gets the best range if it’s not close to the other electronics in my hovercraft. Since the cabin for all my electronics is so small I made it a compartment in the cabin that’s lifted off the ground so it gets a better range. Then I connected all my electronics to my receiver and turned them on. My controller had a preset setting for which lever/switch activated what on the receiver so I had to try putting different electronics on different channels till I got the right set up. The last thing I did was sew my skirt. To do this I started by drawing out my skirt on ripstop fabric and cutting it out. Then I had to tape it down the way I was going to sew it to my depron skeleton. Then came the hard part, actually sewing it. I had to learn how to sew by watching online tutorials, this was very challenging because I have never sewed before and at first I messed up a lot! It took me four days to learn how to sew, and then actually sew the skirt. The two big reasons it took me so long is because I had to take a day to learn how to sew, and I messed up many seems and had to completely resew them.

First Milestone

My first milestone was building almost all of my hovercraft’s skeleton. I started by designing the base. Then I made three more copies of that base. One of those I cut up so that when sandwiched between two other layers it would let plenty of air through to the edge of the skeleton. This is because when I complete my skirt air will need to get into the skirt through this layer. Then I placed the third base layer on top of the layer for air flow. The last layer is used to carry the compartment for the parts. So I then had to create walls for this compartment leaving enough room on all sides to fit a slanted side piece to make it more aerodynamic. I then glued on all the walls and slanted sidepieces (except the back ones) to the top base layer. I have not glued the top base layer to the bottom three though because the skirt goes between the third and top layer, and I have not made that yet. I also didn’t glue on the back and top because that is where my electronics and motor will go.

Lie Detector

Starter Project

My starter project is the lie detector. It uses three transistors which basically act as on/off switches. If enough current goes through them then they allow the current to pass through. If too little current is passing through than it turns off and it doesn’t allow any current through. There is also a variable resistor which is just a resistor but can resist different amounts. The last part is the smoothing capacitor which evens out fluctuations in current. The way that the lie detector is supposed to work is that the current originally passes through the first transistor which turns it on, in turn turning on the green LED. Since the current is going the first transistor the second and third turn off keeping the red LED off. Then once you touch the two wires to your hand one of two things can happen. If you are not sweating than the green light stays on and the red light stays off. This is because your skin is so resistant that it does not allow for enough current to pass through the other two transistors to turn on. This is not the case however once you start sweating. Once you start sweating your sweat acts as an electrolyte which causes enough current to pass through the two wires to turn on the other two transistors. This means that now the first transistor turns off and the current starts passing through the second two transistors turning them on. This turns the red light on and the green light off. So the key is that the sweat acts as a good electrolyte changing the course of the current from going through the first transistor to going through the second and third transistor.

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