HoverCraft/Howard Community College/Fall2012/p3501 NEKK
Electronic Sections Expected
To design a hovercraft that can hover and move forward using only on-board power, as well to be able to move 10 ft within 15 seconds without being pushed.
We are working on building a hovercraft that can be self sustained, self propelled, and to be able to move a certain distance in a set amount of time. Both Neil and Kyle have worked on hovercrafts in the past, and can help use that experience to advance our endeavors. The previous models were comprised of a plastic Frisbee acting as the shell, as well as large amounts of duct-tape, bubble-wrap, and a length of rope. In this design we plan on using Styrofoam over the plastic. We made this choice because Styrofoam is sturdy enough to be used for a hovercraft shell, but significantly lighter than plastic. By the end of these four weeks we plan on having a working hovercraft model that is both aesthetically as well as practically superior to the previous models.
The group discussed what needs to be done in order to satisfy the goal we created: For the hovercraft to be able to move 10 ft within 15 seconds completely on its own. We decided that it would have to be much lighter than the previous hovercraft model, which has been tested to work (simply to hover off the ground) is a good model to base our project off of. We want our design to be able to move forward, and a certain distance in a set amount of time. Because of these additional requirements, we decided the new hovercraft must be lighter and therefore move faster. We also needed a solid power-supply that could power the air-pump we plan to use. Since our idea is to keep the hovercraft at an angle so that one single air-pump is enough to move it both forward and up, we only need 12 volts of power (the power of the battery). In the next few days we will begin building a model for the prototype. During our presentation, Professor Edelen made it known to us that we need to focus on the power being generated from the battery pack and the importance of the weight of our hovercraft. If the hovercraft doesn't have enough power, it will not be able to move; same goes for the weight, if there is too much weight, the hovercraft will not move. We need to work on a balanced hovercraft that has both power and minimal weight to be able to achieve our goals. Over the course of week 1 each teammate researched a certain amount about how hovercrafts work.
Now that we all have some background knowledge of how hovercraft work we all came up with possible hovercraft designs. After creating a design matrix we all decided that the best design would be the one that is depicted to the right in a multi-view sketch in a engineering notebook. And now that we know what our design is going to look like we set out to a craft store to buy the correct materials. We also did some calculations of how much materials we will need and the dimensions of the hovercraft design. These calculations are also depicted to the right.
This entire week consisted of us working together as a team to build our hovercraft design. But before we built our design we weighed every part that we would use with a triple beam balance. Once we did this we calculated the mass of design and compared it to the design that the last group made, the table showing these values is depicted below. The base for our hovercraft design is a Styrofoam disk that is 1 inch thick with a 6 inch radius. I order to make it tilted we made triangular sides that would be attached around the circumference of the disk. The problem with is this that Styrofoam is not malleable, therefore it would not bend around the disk. Our solution to this is to cut the sides into sections that would each individually attach to the circumference. We cut a hole in the middle of our disk. This is where the air pump will such air into and push outward into the bubble wrap skirt that is located under the disk and inside the triangular sides.
This is a data of mass data that shows our designs mass compared to the mass of the last groups design.
Now that we had our hovercraft design built we started testing it. But we ran into a problem. Our bubble wrap skirt was creating too much friction and there was not enough lift for the hovercraft design to move. There are several reasons that this happened:
1. The bubble wrap material was causing friction.
2. The weight of the hovercraft was not distributed evenly.
3. The air pump we were using with a single 9 volt battery did not have enough power.
The issue of whether or not our hovercraft was too heavy seems to be out of the question, considering it weighed 191.4 grams less than the hovercraft design of the last group. No matter what we tried, nothing seemed to get our design to hover. So, we decided to scrap our design and use our back-up design which is just a flat circle hovercraft which resembles the design of the last group except it would be made out of Styrofoam, which would still make it substantially lighter. The problem with this design is that it would need an external force that pushes it forward. The solution would be either design a rear fan that pushes it forward with another battery which would add to the weight, or we could take the easy way out and modify our problem statement to say instead of "moving on it own" to say "moving with some assistance" which implies us giving it a slight push. Taking the easy way out is not very professional, but because of the time constraint it seems like our only option. Even our second design could be more efficient than the hovercraft design that the last group made. Since this final week is a week for testing the hovercraft to see if it accomplished our problem statement, we decided to make a new skirt out of a new material (duck tape) and try a new design for the skirt, with the help of Timothy Fries. We made a lot of progress with this new skirt this week. Even though it did not hover, our air pump was able to inflate the duck tape skirt enough to create less friction with a surface. In conclusion, our final hovercraft design was 74.0 grams lighter than the hovercraft design the previous group and was able to get considerable lift, but was unable to move without friction.
These are different decisions that our group as a whole had to make. Making a decision matrix for some of theseoptions was very helpful in the decision making process. These decisions include:
-Deciding which type of material to use for the hovercraft(frame).
-What shape the hovercraft should be.
-What type of fan should be used.
-What type and material of skirt should be used.
We have these materials at our disposal:
-At least one sheet of Styrofoam, which is large enough to cut out any shape we might need
-An air-pump we are going to use for the fan of the craft
-A few sheets of bubble wrap, which can be used for the skirt
-About half a roll of duct tape, which can be used for the skirt
No software was used in the project
No tutorials were produced from this project.
The next steps would be continue finding ways to make our hovercraft design lighter and more efficient. It would be phenomenal if the next group, that works on this project, would use our same design for the skirt of the hovercraft, because we think that the duck tape skirt has a lot of potential. The problem we ran into most was finding an adequate fan. If our fan was more suited for our designs, then there is no question, that our hovercraft design would be able to accomplish our original problem statement.