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Re: Hovercraft B/C

Posted: April 15th, 2018, 9:32 am
by TheChiScientist
Wise words. The pressure you need for lift is harder to achieve without a skirt so I just think a skirt is more time efficient :D

Re: Hovercraft B/C

Posted: April 16th, 2018, 7:05 pm
by neutrino
Didn't create an account and usually lurked this thread, but darn, it's getting late and I'm getting worried, has anyone else's hovercraft all of a sudden "stopped working" before? How did you fix it? My hovercraft was working perfectly fine, maybe couldn't go straight but maybe it was too fine, clocking in around four to six seconds on two kilograms. And it was for a few meets and months. Then all of sudden it couldn't even carry two. It just was weird, like the hovercraft didn't rise as much and it felt like the skirt was sticking to the ground. And it's never been the same since, even switching out to a new base. In fact I doubt it can carry more than half a kilo now. I checked the batteries and they're fine, at the typical overcharge of 9+V (8.4V NiMH), so is it an issue with the motor? But they're brushless fans which were probably meant for computers where they run a long time, I don't think they wore out. Did they suck in some glue or stuff?
Thanks

Re: Hovercraft B/C

Posted: April 16th, 2018, 7:22 pm
by antoine_ego
neutrino wrote:Didn't create an account and usually lurked this thread, but darn, it's getting late and I'm getting worried, has anyone else's hovercraft all of a sudden "stopped working" before? How did you fix it? My hovercraft was working perfectly fine, maybe couldn't go straight but maybe it was too fine, clocking in around four to six seconds on two kilograms. And it was for a few meets and months. Then all of sudden it couldn't even carry two. It just was weird, like the hovercraft didn't rise as much and it felt like the skirt was sticking to the ground. And it's never been the same since, even switching out to a new base. In fact I doubt it can carry more than half a kilo now. I checked the batteries and they're fine, at the typical overcharge of 9+V (8.4V NiMH), so is it an issue with the motor? But they're brushless fans which were probably meant for computers where they run a long time, I don't think they wore out. Did they suck in some glue or stuff?
Thanks
I'd try cycling your batteries. After prolonged usage, your batteries develop a higher internal resistance, so the capacity drops. This could lead to your batteries dropping in voltage faster than anticipated. I'd recommend cycling your batteries. If that doesn't work, then it's likely your motor just is getting degraded and you need to replace it. My guess is the second one, considering drop in performance, but it's always a good idea to check your batteries.

Re: Hovercraft B/C

Posted: April 16th, 2018, 7:40 pm
by neutrino
antoine_ego wrote:I'd try cycling your batteries. After prolonged usage, your batteries develop a higher internal resistance, so the capacity drops. This could lead to your batteries dropping in voltage faster than anticipated. I'd recommend cycling your batteries. If that doesn't work, then it's likely your motor just is getting degraded and you need to replace it. My guess is the second one, considering drop in performance, but it's always a good idea to check your batteries.
Thanks, my batteries seem fine but I'm guessing it's the motor issue. That or gremlins managed to mess with my skirt some how, darn them :P

Re: Hovercraft B/C

Posted: April 16th, 2018, 8:01 pm
by antoine_ego
neutrino wrote:
antoine_ego wrote:I'd try cycling your batteries. After prolonged usage, your batteries develop a higher internal resistance, so the capacity drops. This could lead to your batteries dropping in voltage faster than anticipated. I'd recommend cycling your batteries. If that doesn't work, then it's likely your motor just is getting degraded and you need to replace it. My guess is the second one, considering drop in performance, but it's always a good idea to check your batteries.
Thanks, my batteries seem fine but I'm guessing it's the motor issue. That or gremlins managed to mess with my skirt some how, darn them :P
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.

Re: Hovercraft B/C

Posted: April 16th, 2018, 8:08 pm
by neutrino
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

Re: Hovercraft B/C

Posted: April 16th, 2018, 8:14 pm
by antoine_ego
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.

Re: Hovercraft B/C

Posted: April 17th, 2018, 9:14 am
by jgrischow1
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?

Re: Hovercraft B/C

Posted: April 17th, 2018, 10:37 am
by nicholasmaurer
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.

Re: Hovercraft B/C

Posted: April 17th, 2018, 11:29 am
by jgrischow1
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.