Hovercraft B/C

[jajefan]

Recently I've been looking at NiMH batteries (and silently expressing dismay at the LiPO ban), but I just can't seem to find one that works (<300 g, 8.4 V)...

Has anybody found a good battery/motor/prop combo that they'd like to share?

I also have not looked into the idea of using commercially available computer fans; What are the advantages/disadvantages of using one as compared to using a traditional RC motor with prop setup?


Some notes: Our team was wary that since the track width is now significantly larger than the vehicle width, the torque of any lift motors would cause trouble by turning the hovercraft and messing with timing, or even worse, turning it entirely around. I'm not sure if SO did this intentionally, but regardless, it makes for interesting way of trying to solve this problem. We thought about trying to offset/angle our propulsion so that the hovercraft would hug one of the railings in order to counteract the torque and keep rolling from being an issue.

Side note: Our team has decided on using the fact that MS and TS can come from different runs to our advantage by having our timing come from varying mass. Thoughts on this method? (Our reasoning came from not having to deal with potentiometers or any form of having to block some of the propulsion fan.)

[windu34]

Recently I've been looking at NiMH batteries (and silently expressing dismay at the LiPO ban), but I just can't seem to find one that works (<300 g, 8.4 V)...

Has anybody found a good battery/motor/prop combo that they'd like to share?

I also have not looked into the idea of using commercially available computer fans; What are the advantages/disadvantages of using one as compared to using a traditional RC motor with prop setup?


Some notes: Our team was wary that since the track width is now significantly larger than the vehicle width, the torque of any lift motors would cause trouble by turning the hovercraft and messing with timing, or even worse, turning it entirely around. I'm not sure if SO did this intentionally, but regardless, it makes for interesting way of trying to solve this problem. We thought about trying to offset/angle our propulsion so that the hovercraft would hug one of the railings in order to counteract the torque and keep rolling from being an issue.

Side note: Our team has decided on using the fact that MS and TS can come from different runs to our advantage by having our timing come from varying mass. Thoughts on this method? (Our reasoning came from not having to deal with potentiometers or any form of having to block some of the propulsion fan.)

Look for lower-capacity Nimh batteries for less weight. Im not super familiar with the rules this year since I am no longer a competitor, but last year, the rules did allow for teams to achieve mass and time scores separately if they wanted to. I chose against this because I wanted to be able to calibrate my device based on the time during the first run to adjust it for the second run. If you are using different masses for the runs, you will not be able to adjust your device. The linear regression that we used allowed us to consistently get our time within 5-10% of the target time

[geniusjohn5]

I have a few questions regarding the Hovercraft event. 1) The target time mentioned the rules page is 15.0 seconds but I thought the target time wouldn't be revealed until the day of the competition. Can anyone clarify? 2)What is the purpose of the rolls of pennies for the hovercraft and how does it contribute to the total Hovercraft score? Thanks in advance.

[shrewdPanther46]

I have a few questions regarding the Hovercraft event. 1) The target time mentioned the rules page is 15.0 seconds but I thought the target time wouldn't be revealed until the day of the competition. Can anyone clarify? 2)What is the purpose of the rolls of pennies for the hovercraft and how does it contribute to the total Hovercraft score? Thanks in advance.

1) that was last years rules. this year is fixed time
2)mass score (increase mass of hover)

[Birdmusic]

Quick question: What type of nets are you using? Nets seem to significantly slow down hovercrafts, so I'm kind of concerned. Last year, our hovercraft was pretty fast before we added a net on, but the net decreased its speed by quite a bit.

[geniusjohn5]

So basically, the greater number of pennies/the greater mass the hovercraft can hold, the higher of a score is earned?

[shrewdPanther46]

Yea by rolls

[DaedalusMinor]

Does anyone know of any good NiMH battery charger?. Preferably one that charges the 6v Racer's edge battery.

[shrewdPanther46]

tenergy

[geniusjohn5]

So for this year, the length of the track will ONLY be given at the competition?