Hovercraft B/C

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Re: Hovercraft B/C

Postby chalker » October 12th, 2016, 2:05 pm

How is Hovercraft, as an event, supposed to be run? When I saw that it was online scheduled, I first thought you would sign up for a time to run your vehicle and then take the test immediately following, like our State did MagLev last time. But now I just saw the Event Logistics Chart and they recommend signing up for time periods. Is it supposed to be run more like Wind Power, only that you can sign up for a testing period? So, there are no spectators allowed?
It's really up to the individual event supervisor. Both techniques are possible and likely to be used at tournaments this year.

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Re: Hovercraft B/C

Postby Unome » October 12th, 2016, 2:10 pm

How is Hovercraft, as an event, supposed to be run? When I saw that it was online scheduled, I first thought you would sign up for a time to run your vehicle and then take the test immediately following, like our State did MagLev last time. But now I just saw the Event Logistics Chart and they recommend signing up for time periods. Is it supposed to be run more like Wind Power, only that you can sign up for a testing period? So, there are no spectators allowed?
Theoretically you could still do it at individual times. Say there were some number of teams competing, with each team's starting time staggered by ten minutes. In this scenario, you could have each team begin the test at their starting time (say, a 30 minute test) in a regular testing-based room, and then they are scheduled for device testing perhaps 5 minutes after their testing time ends in another area which is open to spectators (although this would require a method to ensure that the same competitors do both the test and the device). This could be expanded for a large number of teams by having multiple teams start their test at the same time in addition to multiple tracks set up.
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Re: Hovercraft B/C

Postby sciencekid7 » October 13th, 2016, 6:40 pm

My original question:
In the rule 4h, it says,"...as long as the expected voltage across any points does not exceed 9.0 V as calculated by [the batteries'] labels." Does this mean that the proctor will look at the battery, and then decide if the circuit is legal, or will the proctor actually take a voltmeter and measure? Also, does the "points" referenced in the rules refer to the terminals of the battery, or can they just be any two points? We are concerned about voltage spikes, so if some were to occur, will the proctor give us violations?

As of now, we want to do 7xEneloop or 6xAlkaline. The rule seems to imply that as long as commercial batteries connected in series do not exceed 9V, it should be okay. We are concerned that if the voltage anywhere exceeds 9V even though our batteries are less than 9V, we will be dinged. Alkaline batteries are typically 1.6V when fresh and with no load, but they are labeled 1.5V - so can we use 6x alkaline?
"Across any two points" means that ANYWHERE in the circuit, the voltage MUST be less than 9V. I assume you are thinking about connecting batteries in series to raise the voltage. A good ES will look for that and catch it. You could likely get away with it at some competitions, but why risk it.
"Points" refers to any two points, not necessarily the terminals
The terminology in the rules is "as labeled." This means that, as far as the rules concern, 6 Alkaline cells in series that are labeled 1.5V but running at 1.6V are still considered only 9V. The rules are designed to protect you against this and the event supervisor from having to check everyone's device with a multimeter.
These replies are contradictory, so does anyone else (SO officials like chalker?) have any input about this? I interpreted this rule similar to RJohnson, but I just want clarification.

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Re: Hovercraft B/C

Postby chalker » October 13th, 2016, 7:06 pm

My original question:
In the rule 4h, it says,"...as long as the expected voltage across any points does not exceed 9.0 V as calculated by [the batteries'] labels." Does this mean that the proctor will look at the battery, and then decide if the circuit is legal, or will the proctor actually take a voltmeter and measure? Also, does the "points" referenced in the rules refer to the terminals of the battery, or can they just be any two points? We are concerned about voltage spikes, so if some were to occur, will the proctor give us violations?

As of now, we want to do 7xEneloop or 6xAlkaline. The rule seems to imply that as long as commercial batteries connected in series do not exceed 9V, it should be okay. We are concerned that if the voltage anywhere exceeds 9V even though our batteries are less than 9V, we will be dinged. Alkaline batteries are typically 1.6V when fresh and with no load, but they are labeled 1.5V - so can we use 6x alkaline?
"Across any two points" means that ANYWHERE in the circuit, the voltage MUST be less than 9V. I assume you are thinking about connecting batteries in series to raise the voltage. A good ES will look for that and catch it. You could likely get away with it at some competitions, but why risk it.
"Points" refers to any two points, not necessarily the terminals
The terminology in the rules is "as labeled." This means that, as far as the rules concern, 6 Alkaline cells in series that are labeled 1.5V but running at 1.6V are still considered only 9V. The rules are designed to protect you against this and the event supervisor from having to check everyone's device with a multimeter.
These replies are contradictory, so does anyone else (SO officials like chalker?) have any input about this? I interpreted this rule similar to RJohnson, but I just want clarification.
As always, this is not the place for official statements. That said, my opinion is aligned with what RJohnson said above. However, keep in mind there will be 300+ tournaments this year, each with a different event supervisor. We can't control every little thing that each supervisor does, so you need to be prepared for that.

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Re: Hovercraft B/C

Postby deji725 » October 14th, 2016, 6:28 pm

Hi, I have a design for my hoverboard but I need to figure out how to control the speed of the hovercraft itself. I was thinking of programming it but brushless motors arent allowed.Any ideas on how I would do this?

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Re: Hovercraft B/C

Postby HandsFreeCookieDunk » October 14th, 2016, 6:43 pm

Hi, I have a design for my hoverboard but I need to figure out how to control the speed of the hovercraft itself. I was thinking of programming it but brushless motors arent allowed.Any ideas on how I would do this?
So far there are two fairly popular methods that have been presented. The first and simpler option is to slow down the hovercraft by restricting the airflow through your propeller. The second option, which has the potential to be more precise but will require more preparation, is to add a variable resistor to the propeller's circuit to adjust its speed.

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Re: Hovercraft B/C

Postby deji725 » October 14th, 2016, 6:49 pm

O ok. Thanks, Ill probably end up testing both methods

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Re: Hovercraft B/C

Postby loordquas » October 15th, 2016, 12:30 pm

How are you supposed to control when the hovercraft stops if you can't use integrated circuits?

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Re: Hovercraft B/C

Postby Unome » October 15th, 2016, 1:07 pm

O ok. Thanks, Ill probably end up testing both methods
You don't need to make it stop; that's what the cushioned barrier after the finish line is for (second clause of 3.d). You only need to control its speed so it crosses the finish line near the target time.
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Re: Hovercraft B/C

Postby loordquas » October 15th, 2016, 2:25 pm

O ok. Thanks, Ill probably end up testing both methods
You don't need to make it stop; that's what the cushioned barrier after the finish line is for (second clause of 3.d). You only need to control its speed so it crosses the finish line near the target time.
Oh yea I forgot about that thanks.


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