Hovercraft B/C

geniusjohn5
Member
Member
Posts: 85
Joined: Thu Jan 19, 2017 2:57 am
Division: C
State: -
Contact:

Re: Hovercraft B/C

Postby geniusjohn5 » Sun Dec 03, 2017 2:31 am

Unome wrote:
geniusjohn5 wrote:Someone told me that holes poked in the skirt of a Hovercraft make it more effective? Can someone explain how so?

Without holes in the skirt (or some sort of opening), there's no hovering. The hovering is caused by air rapidly rushing out of the hole/holes (anywhere from one fairly small hole to dozens/hundreds of miniscule ones) and escaping horizontally, pushing the bottom of the skirt up.



Sorry I'm very new to Hovercraft? Can you elaborate on that concept more? Thanks!
The physicist says, "In the universe, does matter really matter?"
The chemist replies, "I shall find a solution."

reed303
Member
Member
Posts: 69
Joined: Fri Oct 17, 2014 9:44 pm
State: -
Contact:

Re: Hovercraft B/C

Postby reed303 » Sun Dec 03, 2017 2:51 am

geniusjohn5 wrote:
Unome wrote:
geniusjohn5 wrote:Someone told me that holes poked in the skirt of a Hovercraft make it more effective? Can someone explain how so?

Without holes in the skirt (or some sort of opening), there's no hovering. The hovering is caused by air rapidly rushing out of the hole/holes (anywhere from one fairly small hole to dozens/hundreds of miniscule ones) and escaping horizontally, pushing the bottom of the skirt up.



Sorry I'm very new to Hovercraft? Can you elaborate on that concept more? Thanks!


Some reading here may help: https://scioly.org/wiki/index.php/Hovercraft#Skirt
Div B Asst Coach 2012-2018

mattruff
Member
Member
Posts: 12
Joined: Mon Nov 20, 2017 9:02 pm
State: -
Contact:

Re: Hovercraft B/C

Postby mattruff » Mon Dec 04, 2017 7:51 pm

Are we able to use elastic band motors in our hovercraft?

SPP SciO
Member
Member
Posts: 243
Joined: Tue Mar 24, 2015 3:21 pm
Division: B
State: NY
Location: Brooklyn
Contact:

Re: Hovercraft B/C

Postby SPP SciO » Mon Dec 04, 2017 11:39 pm

dmis wrote:
farmerjoe279 wrote:
shrewdPanther46 wrote:
I was able to lift more than 2kg with a wimpy skirt like that. I Have to agree with the others in that the issue is most probably your fan, although it could be your power source


My fan can cut of a finger. A FINGER! Also I think i have a good battery. Probably because my motor ways like 2 pounds :P


Spinning fast and having a sharp edge does not necessarily make a blade best for the hovercaft. Thought realistically, I would expect you are right about the problem,


Our team is having some trouble solving the weight problem. The more powerful the motor, more powerful battery, all add extra weight. Last year, it wasn't a problem, because of the 2kg limit, but the penny challenge is tough!

Here's what we're working with:

https://www.digikey.com/product-detail/ ... ND/4702514 for a propulsion fan,
https://www.digikey.com/product-detail/ ... ND/2560506 for the lift fan.

Both of them are running on 8.4v NiMH battery packs, which are much heavier than equivalent output lithium batteries. I am not sure if I would advise other teams to buy these fans, since they're expensive, and in our limited experience, they haven't been working out great. The first one is super dangerous too - shielding absolutely a must before even turning it on to test.
Coach
MS 821 Sunset Park Prep
http://www.sppscio.com

Birdmusic
Member
Member
Posts: 51
Joined: Sun Oct 22, 2017 4:33 pm
Division: B
State: CA
Location: In the Milky Way Galaxy
Contact:

Re: Hovercraft B/C

Postby Birdmusic » Tue Dec 05, 2017 1:03 am

mattruff wrote:Are we able to use elastic band motors in our hovercraft?

I doubt that would be very effective, since everyone else will probably be using electrical motors, however, it is allowed.
Science is an art.
Art is a science.

2018 Results
Regionals/States
Crime Busters: 1/2
Disease Detectives: 1/5
Hovercraft (both builds failed, rip): 11/9

timothyre
Member
Member
Posts: 1
Joined: Thu Dec 07, 2017 2:22 pm
State: -
Contact:

Re: Hovercraft B/C

Postby timothyre » Thu Dec 07, 2017 2:38 pm

Just a very quick question that one of my students asked me. The rules for hovercraft state that "Commercial batters, including rechargeable, not exceeding 9.0 V as labeled, may be used to energize the motors on the vehicle." My student asked me if that was limited to 9.0 V batter PER motor, or 9.0 V to power both motors. I am pretty confident that it is 9.0 V TOTAL for the vehicle, but told him I would check to be 100% certain.

Thanks

LittyWap
Member
Member
Posts: 69
Joined: Wed Mar 22, 2017 8:44 pm
Division: C
State: PA
Contact:

Re: Hovercraft B/C

Postby LittyWap » Thu Dec 07, 2017 2:43 pm

timothyre wrote:Just a very quick question that one of my students asked me. The rules for hovercraft state that "Commercial batters, including rechargeable, not exceeding 9.0 V as labeled, may be used to energize the motors on the vehicle." My student asked me if that was limited to 9.0 V batter PER motor, or 9.0 V to power both motors. I am pretty confident that it is 9.0 V TOTAL for the vehicle, but told him I would check to be 100% certain.

Thanks



The limitation is 9V per motor. At competitions last year, proctors made sure to check if batteries were run in series. It doesn't matter how many batteries per motor, the electromotive potential across the circuit has to be less or equal to 9.0V. There's no limit on amperage.
Build score of 49.88/50 at Nationals!? Slacker! :evil:

Shady Side Academy Division C

Hovercraft, Thermodynamics, Chemistry Lab, Mat Sci

Free Thermo Test: https://adobe.ly/2Dnfrhu

Big P

geniusjohn5
Member
Member
Posts: 85
Joined: Thu Jan 19, 2017 2:57 am
Division: C
State: -
Contact:

Re: Hovercraft B/C

Postby geniusjohn5 » Fri Dec 08, 2017 2:41 am

For the written exam, do sig figs and uncertainties matter?
The physicist says, "In the universe, does matter really matter?"
The chemist replies, "I shall find a solution."

Birdmusic
Member
Member
Posts: 51
Joined: Sun Oct 22, 2017 4:33 pm
Division: B
State: CA
Location: In the Milky Way Galaxy
Contact:

Re: Hovercraft B/C

Postby Birdmusic » Fri Dec 08, 2017 3:42 am

geniusjohn5 wrote:For the written exam, do sig figs and uncertainties matter?


I believe the SOInc guidelines say that sig figs only matter for Division C, however, I guess its up to the test writers.
Science is an art.
Art is a science.

2018 Results
Regionals/States
Crime Busters: 1/2
Disease Detectives: 1/5
Hovercraft (both builds failed, rip): 11/9

gcrewmc3
Member
Member
Posts: 1
Joined: Fri Dec 08, 2017 10:03 pm
State: -
Contact:

Re: Hovercraft B/C

Postby gcrewmc3 » Fri Dec 08, 2017 10:12 pm

Hello fellow Olympians,
I was wondering if you can have two 8.4 volt batteries on the hovercraft to power the motors? I know the rules say you can’t have more than 9 volts in a battery.

Thanks!

retired1
Member
Member
Posts: 617
Joined: Thu Jul 26, 2012 12:04 am
Division: Grad
State: FL
Contact:

Re: Hovercraft B/C

Postby retired1 » Fri Dec 08, 2017 11:08 pm

Can you stand that amount of weight?

Birdmusic
Member
Member
Posts: 51
Joined: Sun Oct 22, 2017 4:33 pm
Division: B
State: CA
Location: In the Milky Way Galaxy
Contact:

Re: Hovercraft B/C

Postby Birdmusic » Sat Dec 09, 2017 12:27 am

gcrewmc3 wrote:Hello fellow Olympians,
I was wondering if you can have two 8.4 volt batteries on the hovercraft to power the motors? I know the rules say you can’t have more than 9 volts in a battery.

Thanks!


Yes, we're doing that.
Science is an art.
Art is a science.

2018 Results
Regionals/States
Crime Busters: 1/2
Disease Detectives: 1/5
Hovercraft (both builds failed, rip): 11/9

geniusjohn5
Member
Member
Posts: 85
Joined: Thu Jan 19, 2017 2:57 am
Division: C
State: -
Contact:

Re: Hovercraft B/C

Postby geniusjohn5 » Sun Dec 10, 2017 3:01 am

Just a quick clarification: Is the hovercraft this year(2017-2018) generally going to be a lot bigger than it was last year(2016-2017)?
The physicist says, "In the universe, does matter really matter?"
The chemist replies, "I shall find a solution."

User avatar
Adi1008
Moderator
Moderator
Posts: 412
Joined: Fri Dec 06, 2013 9:56 pm
Division: C
State: TX
Location: Katy, Texas
Contact:

Re: Hovercraft B/C

Postby Adi1008 » Sun Dec 10, 2017 3:02 am

geniusjohn5 wrote:Just a quick clarification: Is the hovercraft this year(2017-2018) generally going to be a lot bigger than it was last year(2016-2017)?

The increased the maximum dimensions to 40x40cm so it's reasonable to expect bigger devices than last year
University of Texas at Austin '22
Seven Lakes High School '18
Beckendorff Junior High '14

geniusjohn5
Member
Member
Posts: 85
Joined: Thu Jan 19, 2017 2:57 am
Division: C
State: -
Contact:

Re: Hovercraft B/C

Postby geniusjohn5 » Sun Dec 10, 2017 2:54 pm

This may sound like a really dumb question but I'm an extreme newbie to this event. Does the hovercraft float on the air-contained skirt or is there a little bit of plain open air beneath the skirt?
The physicist says, "In the universe, does matter really matter?"
The chemist replies, "I shall find a solution."


Return to “Lab Events”

Who is online

Users browsing this forum: No registered users and 0 guests