Justin72835

For a science competition I have to build a small, compact hovercraft that is about the same size as a shoe box. The goal of the project is to make the device move across a track and reach a certain distance in a specific amount of time. These values are different for each competition too. For example, the target distance and target time may be 1.7 meters in 15 seconds for one competition, and 0.9 meters in 27 seconds for the next competition. Because of this, I need to be able to alter the speed of the hovercraft to meet the requirements. However, I ran into some technical problems and I was wondering if anyone could provide a solution.




The hovercraft works by using two fans. The first fan directs air downwards, which supplys lift to the vehicle and decreasing the friction between the device and the floor. The second fan directs air toward the back of the device, which pushes the device foward.




Here's where we run into some problems. For any object, the force of friction is always greater when the object is still than when the object is in motion. This is why it may be difficult to get a sofa moving by pushing it, but once you get it moving it becomes a lot easier. The same is true for the hovercraft. Once I set the hovercraft down on the track, it doesn't move because friction is holding in place. However, if I give the device a slight push, it travels along the track without a problem.




I need to find a way to give the device this "slight push" without actually touching it (pushing yhe device is a clear violation of rules). So, What I am looking for is a way to give the hovercraft a "boost" of speed for maybe 1 or 2 seconds just so that it's able to overcome the friction and start moving. This could be done by increasing the voltage slightly for that small amount of time and then decreasing immediately after. I am unable to to make the vehicle run at full power right from the start as the battery drains extremely quickly and I need to be able to run the device multiple times at the same competition (you aren't allowed to charge in between runs). Also, I can't decrease the voltage because you aren't allowed to touch or interfere with device while it's in motion. I know you could possibly accomplish this with a microcontroller but the use of integrated circuits are not allowed in this competition. I was thinking I could use a timer or a capacitor of some sort but I have very limited knowledge on what they do or how to use them. How would I go about doing this?

ransch

You should look at a different option. Your craft should not have initial friction to overcome that would be needing a 'physical push'. Perhaps the skirt needs work. A very thin plastic is fine, I use a grocery shopping bag. The skirt needs to be uniform, should inflate and hold air with only a small amount of air leaking out which is what reduces the friction.
Make sure the lifting fan has high static pressure (large fan blades), try to reduce the air that escapes to to the top, (ducted or cowl use).

Txmustangflyer

Wondering maybe a large cpu cooling fan for the lift fan?

Outrider6

My Feedback: (2)

Do you think the high school student is still working on this project over 4.5 years later?

Or maybe you didn't notice the date.