Hovercraft B/C

neutrino
Member
Member
Posts: 3
Joined: Mon Apr 16, 2018 2:55 am
State: -
Contact:

Re: Hovercraft B/C

Postby neutrino » Tue Apr 17, 2018 3:08 am

antoine_ego wrote:If you replace the motor, I'd recommend buying a bigger one so that if that one too fails at some point, it still can probably hold full weight.

It's a bit late for motor replacement unfortunately, but I got the biggest one I could possibly find (1019 Pa static pressure, pretty expensive too), and it worked well, until...rip

User avatar
antoine_ego
Exalted Member
Exalted Member
Posts: 285
Joined: Wed May 25, 2016 12:37 am
Division: C
State: MA
Location: Acton Boxborough Regional High School
Contact:

Re: Hovercraft B/C

Postby antoine_ego » Tue Apr 17, 2018 3:14 am

neutrino wrote:
antoine_ego wrote:If you replace the motor, I'd recommend buying a bigger one so that if that one too fails at some point, it still can probably hold full weight.

It's a bit late for motor replacement unfortunately, but I got the biggest one I could possibly find (1019 Pa static pressure, pretty expensive too), and it worked well, until...rip

If worst comes to worst, just aim to ace the time score with a lower weight. You could try to put some floor pads on the inside of the skirt to ensure full inflation.
Rest in Peace Len Joeris

2018 Placings
MIT/Yale/States/Nationals
Astronomy: 10 / 3 / 4 /
Hovercraft: 30 / 1 / 1 /
Mousetrap: 3 / 5 / 1 /
Optics - / - / 2 / -
WIDI: - / - / - /

jgrischow1
Member
Member
Posts: 75
Joined: Sun Mar 20, 2011 10:21 pm
Division: B
State: OH
Contact:

Re: Hovercraft B/C

Postby jgrischow1 » Tue Apr 17, 2018 4:14 pm

Not sure if this has been mentioned, but pennies made before 1983 weigh about 25% more than post-1982 pennies. Do supervisors even check how much their rolls weigh?

nicholasmaurer
Coach
Coach
Posts: 148
Joined: Fri May 19, 2017 5:55 pm
Division: Grad
State: OH
Location: Solon, OH
Contact:

Re: Hovercraft B/C

Postby nicholasmaurer » Tue Apr 17, 2018 5:37 pm

jgrischow1 wrote:Not sure if this has been mentioned, but pennies made before 1983 weigh about 25% more than post-1982 pennies. Do supervisors even check how much their rolls weigh?


I don't believe I have ever observed a supervisor weigh their penny rolls to check for consistency. Because of the number of pennies involved, I would assume that supervisors request the rolls from a bank, in which case I would expect most (if not all) of the pennies to be post-1982.
Assistant Coach and Alumni ('14) - Solon High School Science Olympiad
Co-Director - Northeast Ohio Region

jgrischow1
Member
Member
Posts: 75
Joined: Sun Mar 20, 2011 10:21 pm
Division: B
State: OH
Contact:

Re: Hovercraft B/C

Postby jgrischow1 » Tue Apr 17, 2018 6:29 pm

nicholasmaurer wrote:
jgrischow1 wrote:Not sure if this has been mentioned, but pennies made before 1983 weigh about 25% more than post-1982 pennies. Do supervisors even check how much their rolls weigh?


I don't believe I have ever observed a supervisor weigh their penny rolls to check for consistency. Because of the number of pennies involved, I would assume that supervisors request the rolls from a bank, in which case I would expect most (if not all) of the pennies to be post-1982.


Yeah, when I went to the bank, I got 14 rolls of mostly pre-1982 pennies and only 2 of mostly post-. Hopefully my experience was an outlier. 2.5 kg seems like a big difference from 2 kg.

User avatar
UTF-8 U+6211 U+662F
Member
Member
Posts: 655
Joined: Sun Jan 18, 2015 3:42 pm
Division: B
State: PA
Location: (0, 0). Before you ask, yes, I live in a two-dimensional world.
Contact:

Re: Hovercraft B/C

Postby UTF-8 U+6211 U+662F » Tue Apr 17, 2018 7:17 pm

Rules say to assume 1 roll is ~125 g and 16 rolls is ~2 kg.

jgrischow1
Member
Member
Posts: 75
Joined: Sun Mar 20, 2011 10:21 pm
Division: B
State: OH
Contact:

Re: Hovercraft B/C

Postby jgrischow1 » Tue Apr 17, 2018 9:56 pm

UTF-8 U+6211 U+662F wrote:Rules say to assume 1 roll is ~125 g and 16 rolls is ~2 kg.


Indeed. I just wonder how many supervisors are aware the composition of pennies has changed and would think to weigh them.

SlipStrike1244
Member
Member
Posts: 19
Joined: Sat Jan 13, 2018 10:48 pm
State: -
Contact:

Re: Hovercraft B/C

Postby SlipStrike1244 » Fri Apr 20, 2018 1:57 pm

is it better to poke holes in the back of the skirt to make it go forward a bit or is that too little of a difference to matter.

hippo9
Member
Member
Posts: 119
Joined: Mon Mar 12, 2018 4:35 pm
Division: B
State: IN
Contact:

Re: Hovercraft B/C

Postby hippo9 » Fri Apr 20, 2018 2:11 pm

SlipStrike1244 wrote:is it better to poke holes in the back of the skirt to make it go forward a bit or is that too little of a difference to matter.

From what I've seen at competitions, there have been designs that rely on a hole in the back of the skirt as the sole source propulsion, but the issue with this is they are really unpredictable. Also, it probably wouldn't do much if you have a fan dedicated to propulsion already.
"If we knew what we were doing, it wouldn’t be called research." - Albert Einstein

2018: Battery Buggy, Road Scholar, Roller Coaster

User avatar
antoine_ego
Exalted Member
Exalted Member
Posts: 285
Joined: Wed May 25, 2016 12:37 am
Division: C
State: MA
Location: Acton Boxborough Regional High School
Contact:

Re: Hovercraft B/C

Postby antoine_ego » Fri Apr 20, 2018 2:13 pm

SlipStrike1244 wrote:is it better to poke holes in the back of the skirt to make it go forward a bit or is that too little of a difference to matter.


It does make a difference provided that your bottom fan has sufficiently high airflow. I only cut holes in the back if my craft is riding too high and I want it to be a bit lower. So long as you have a pretty powerful back fan, it might not be necessary, but it can be used to modulate the height.
Rest in Peace Len Joeris

2018 Placings
MIT/Yale/States/Nationals
Astronomy: 10 / 3 / 4 /
Hovercraft: 30 / 1 / 1 /
Mousetrap: 3 / 5 / 1 /
Optics - / - / 2 / -
WIDI: - / - / - /


Return to “Lab Events”

Who is online

Users browsing this forum: No registered users and 0 guests