Hovercraft B/C

[andrewwski]

Most hardware stores (Lowes, Home Depot, etc) have rolls of wire screening (for repairing window screens).

[mogrady]

hey guys so i got put on this event for a meet next saturday...

i already have my main events to prepare for so i was wondering what websites you guys have been using for you notes on the testing part.

anything helps at this point. thanks.

[meierfra]

Teams can change the mass between runs to change their speed and thus time.(IIg) There isn't a spot on the scoring spreadsheet to change the mass.

It seems like it's possible to choose the better Time Score and still have a worse Final Score if the Target Time is small and the team gets closer to it by lowering their mass, and thus their Mass Score. That doesn't seem right. Maybe there should be a Vehicle Score that incorporates both the mass and the time and that you can choose the greater Vehicle Score of the two runs.

[windu34]

Teams can change the mass between runs to change their speed and thus time.(IIg) There isn't a spot on the scoring spreadsheet to change the mass.

It seems like it's possible to choose the better Time Score and still have a worse Final Score if the Target Time is small and the team gets closer to it by lowering their mass, and thus their Mass Score. That doesn't seem right. Maybe there should be a Vehicle Score that incorporates both the mass and the time and that you can choose the greater Vehicle Score of the two runs.

I too noticed this, but realized that at higher levels of competition, everyone will have a high mass regardless of time goal so it didn't matter

[MrGood]

My hovercraft has a 28cm by 18cm body with a 103.3 grams weight and a skirt made out of a plastic garbage bag connected across all corners of the body. I have been using one nonbrush-less 3 volt described motor plugged into a 9 volt battery, thinking that the 9 volt battery will give more power to the one motor. It has but the battery usually drains fast and still isn't providing enough air to levitate and propel the hovercraft.I have been using a vent on the back of the hovercraft to act as a propulsion system, but in conclusion, the hovercraft won't move. Does anyone have tips or pointers on how I could improve or even suggest a certain type of motor or propeller that does the job? Thanks.

[windu34]

My hovercraft has a 28cm by 26cm body with a 103.3 kg weight and a skirt made out of a plastic garbage bag connected across all corners of the body. I have been using one brush-less 3 volt described motor plugged into a 9 volt battery, thinking that the 9 volt battery will give more power to the one motor. It has but the battery usually drains fast and still isn't providing enough air to levitate and propel the hovercraft.I have been using a vent on the back of the hovercraft to act as a propulsion system, but in conclusion, the hovercraft won't move. Does anyone have tips or pointers on how I could improve or even suggest a certain type of motor or propeller that does the job? Thanks.

Many problems with your device:
-You violated the max dimensions of 19.5 by 30 cm
-You violated max mass of 2 kg
-You violated rule against brushless motors

Look into ducted fans for propulsion and fans with high static pressure for lift

[Adi1008]

My hovercraft has a 28cm by 18cm body with a 103.3 grams weight and a skirt made out of a plastic garbage bag connected across all corners of the body. I have been using one nonbrush-less 3 volt described motor plugged into a 9 volt battery, thinking that the 9 volt battery will give more power to the one motor. It has but the battery usually drains fast and still isn't providing enough air to levitate and propel the hovercraft.I have been using a vent on the back of the hovercraft to act as a propulsion system, but in conclusion, the hovercraft won't move. Does anyone have tips or pointers on how I could improve or even suggest a certain type of motor or propeller that does the job? Thanks.

If you're using a normal 9V that you'd find in supermarkets and stuff, I don't think it'd work, as they wouldn't provide enough current. Everything windu said is good advice. Make sure your skirt is completely sealed too; you don't want any (unwanted) leaks.

[HeatherFeather]

Are RC's allowed? Gyro's? what type of timers / switches constitute containing a circuit, vs. which do not?

[chalker]

Teams can change the mass between runs to change their speed and thus time.(IIg) There isn't a spot on the scoring spreadsheet to change the mass.

It seems like it's possible to choose the better Time Score and still have a worse Final Score if the Target Time is small and the team gets closer to it by lowering their mass, and thus their Mass Score. That doesn't seem right. Maybe there should be a Vehicle Score that incorporates both the mass and the time and that you can choose the greater Vehicle Score of the two runs.

We deliberately separated out the Mass Score and Time Score. The Mass Score will automatically be from whichever successful run has the higher mass - there is no need to record the lower mass from the other successful run (particularly since any penalties that impact the Mass Score apply to all successful runs. The Time Score is a bit harder to calculate due to potential run-specific penalities, which is why there are spots to record both successful time scores. The Final Score will always be calculated based upon to best combination of the Mass and Time Scores. A technique that this allows is to do one initial run with a light vehicle that gets a very good time score, then another run with additional mass added to the vehicle to try to maximize the mass score. Hence, we are encouraging flexible engineering that can be adapted on the spot!

[chalker]

Are RC's allowed? Gyro's? what type of timers / switches constitute containing a circuit, vs. which do not?

I'm inferring from your questions that you haven't read the rules closely. You really need to prior to building a device or competing. Look at rule 4.i. in particular to answer some of your questions.