Engineering Projects/HoverCraft/Howard Community College/Fall2011/501 Glorious3

Problem Statement

There are many working models of Hovercrafts, some large and some small. However, the large ones are often piloted by a person, and the smaller ones are controlled with a remote controller. To the best of our knowledge, there are not many models that utilize an autopilot system and sensors that can avoid people yet travel down a crowded school corridor.

Team Members

James Morgan

Parlette

Blomme

Joon Kim

Summary

At the end of the previous project, our team had a hovercraft body that worked well with the fans attached to provide lift. However, we were still stuck on finding a power source and a motor for the propeller needed on the back of the craft. This was the first task of this project, to find a strong, yet light-weight battery to power the motor we would have to find. We started off by testing with a tenergy 9.6v 3800MAH battery, but after some tests, we realized we needed to try a different battery. We switched to a tenergy 11.1v lipo battery, and found that this battery was much more efficient and powerful, and would suit our needs. We then searched for a strong motor for the back propeller. We found a brushless motor and a model airplane propeller that work very well and produce a lot of propulsion. When hooked up to the battery, and attached to an arduino, the speed at which it spins will be controlled via the remote controller from the RC car. Currently, we have a hovercraft that has working parts in all areas, and the parts just need to be combined to create a fully working model.

[new prop system]

Poster

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Story

This project has mostly been about finding a way to propel the hovercraft forward. We ditched the idea of using some kind of fan, instead, we decided to try to use a motor with a propeller on it to propel the hovercraft forward. We had much trouble getting a good motor and propeller to work. The first motor we tried was a random motor that we found laying around, it already had a propeller attached to it, so we tried to see if we could get it to propel the hovercraft forward. The first hing we tried was to hook it up in parallel with the two downward blowing fans, using the 11.1 volt LiPO battery. the motor immediately started spinning way to fast, and we could tell that this motor was not build to receive the kind of power that we were feeding it, so we turned it off before we could observe anything else. Next we tried the 9-volt battery going directly to the motor and the LiPO battery just going to the two downward blowing fans. This did not produce enough power. So, we tried to go somewhere in between and use the 11.1 volt LiPO battery to power the same motor, and just this motor, not the other fans. But this time we put a resistor in the circuit. No matter which resistor we put in the circuit, nothing would happen exept for the really low resistance resistors. When we used an 18 Ohm resistor, at first nothing happened, then a couple seconds later, it started smoking and the motor started spinning. We quickly turned it off and saw that the resistor had melted a little bit. In addition to the 18Ohm resistor, we tried a 22 Ohm, an 82 Ohm, a 100 Ohm, a 360 Ohm, a 1.1K Ohm, and a 4.4k Ohm resistor, but we could not get any movement from the motor when these resistors were in the circuit.

Since the resistors were not working, we transitioned over to trying to use the power generator so that we could control exactly the amount of volts and current we wanted. But for some reason, we could not get this to work at all. The generator would read 7.0 volts when the circuit was not complete. But right when we completed the circuit, with just the generator going directly to the motor and back, the generator jumped straight to read 0 volts, and nothing would work. We are still unsure of the reasoning for this, but no matter what voltage and current we set it at, it would not get the motor turning.

After that, we just decided to finally give up on that motor. We got a new motor called the "Turbo 3000". this motor could actually handle the power that the 11.1 volt LiPO battery gave it, and all we needed to do was wait for the pinion gear remover so that we could put a propeller on it. The only thing is, the pinion gear remover never came in.

Now, we finally got the motor that we ended up using. A Brushless motor. This Brushless motor is amazing, it runs very smoothly, and it is very powerful. And we got it with a large propeller already attached to it. The only thing was, this motor had to be controlled using an ESC, which is an electronic speed controller. This ESC would plug into the motor. And we needed to plug a strong battery directly to the ESC, and the 11.1v LiPO worked perfectly for that. Also, this ESC needed to be connected to something like an Arduino board. SO we hooked it up to the Arduino board with a potentiometer, and ran the example "servo" that comes with the Arduino software. When the ESC was connected with the 11.1v LiPO battery, it worked very well. We had tried it with just a regular Alkaline 9 volt battery, but that did not supply the ESC with enough power to power the brushless motor.

Now that we were able to get the propeller spinning at the speed we wanted it, we needed to construct something so that the propeller would not hit the ground when the motor spun, since the propeller is so large. This was done by constructing a little wooden structure over the back fan with the motor attached to it. The structure was made out of balsa wood, which is very light, so it did not add any real weight to the hover craft.

One other problem that we have is that our propeller is spinning the wrong way, so the air is being blown in the wrong direction. One possible solution to this might be to just be to attach the 11.1 volt LiPO battery backwards to the ESC, so that the power wire from the battery is attached to the ground wire from the ESC, and the ground wire from the battery to the power wire from the ESC. We have not tested this yet, so we do not know if this will work or not.

Also, we need to find a better way to connect the LiPO battery to the ESC, because we do not have the correct connectors, and we have been using two different alligator clips to attach to the battery and then we have just two regular wires connecting the ground and power from the ESC to the alligator clips coming from the battery. Using this methods we have witnessed several sparks and what looks like a few burn marks on the ESC connector. Also, it is hard to keep the circuit complete because the wires can easily separate from the connector.

The next step is to get the propeller spinning the correct direction and to connect the housing to the hovercraft with the motor on it, then to just test the whole thing since the arduino can just have a 9 volt battery powering it so that it doesn't have to be attached to the computer. And after we see that everything is working, the step after that would be to get the remote control from the RC cars to replace the potentiometer so that we can change the speed of the motor remotely.

Decision List

-Use the 11.1 lipo battery over the tenergy 9.6v 3800mah and 8.4v battery.

-Remove small DC motor and airsoft ics turbo 3000 motor and replace with a brushless motor

-Instead of finding a new propeller, we made a structure out of balsa wood for it so that the propeller would not touch the ground while it is spinning.

Material List

-rectangle of Styrofoam for our base

-the plastic that came wrapped around the piece of Styrofoam.

-duct tape for the skirt around the edges and bottom of the craft

-epoxy glue to glue down the fans

-wire, to attach the motors to power sources.

-remote controlled car controller and receiver.

-2 dc fan motors

-ics turbo 3000 motor

-tenergy 11.1v lipo

-tenergy 9.6v 3800MAH battery

-pinion gear remover

-brushless motor

-model airplane propeller for propulsion

-balsa wood

-arduino

Software List

Arduino software for controlling the ESC(Electronic speed controller).

logview software for recharging the battery http://www.logview.info/cms/e_logview_info.phtml

Time

On average, we each spent about an hour working on the project inside of class. And we each spent about an hour to an hour and a half each week working on the project outside of class. This comes to a total of about three and a half hours working on the project each week per person.

Tutorials

Arduino Introduction: http://en.wikibooks.org/wiki/General_Engineering_Introduction/Arduino_and_Motors/Arduino_Introduction

The get the ESC working with the arduino board, look at week 3 and week 4 of this page http://en.wikiversity.org/wiki/User:Drew_Dollas/enes100/Glorious3

Next Steps

To get the motor mounted onto the hovercraft, and to have the RC car remote be able to remotely change the speed of the fan. Also, some kind of a rudder system would be a good addition so that the hovercraft will be able to turn.