Hovercraft B/C

[kinghong1970]

so just read on the rules revision...

Brushless motors and integrated circuits are not permitted, unless they are an integral part of and are imbedded into a commerically available electronic or computer cooling fan. (9/12/16)

so in such a case where a commercially available fan is a brushless, it is allowed?
noticing some pc fans and it comes with 3 wires on all of the more standard pc fans out there...

oh, and slight typo on the "commercially" vs "commerically" as you have on the website.

thanks

[SPP SciO]

Regarding skirts, a student mentioned disposable shower caps, with the elastic band, and using it similar to a fitted sheet on a mattress. Interesting idea - but will it work! This calls for science.

[chalker]

so just read on the rules revision...

Brushless motors and integrated circuits are not permitted, unless they are an integral part of and are imbedded into a commerically available electronic or computer cooling fan. (9/12/16)

so in such a case where a commercially available fan is a brushless, it is allowed?
noticing some pc fans and it comes with 3 wires on all of the more standard pc fans out there...

oh, and slight typo on the "commercially" vs "commerically" as you have on the website.

thanks

Standard caveat that this is not the place for official statements....

Generally, the 3 wire connectors have an extra wire that serves as a tachometer signal that measures how fast the fan is spinning. Regardless, yes, brushless fans that are designed for pc cooling would fall into the allowed category.

[chalker]

Regarding skirts, a student mentioned disposable shower caps, with the elastic band, and using it similar to a fitted sheet on a mattress. Interesting idea - but will it work! This calls for science.

I doubt the elastic band will provide enough of a seal to keep air from leaking out... but it never hurts to try it!

[retired1]

I agree with Chalker, but a strip of duct tape can solve the leak problem. Not beautiful, but effective.

[Flavorflav]

What was the reasoning behind specifying the width of the beams and the width of the test base? Neither would seem to have any impact on how teams prepare for the event, so as far as I can tell it just establishes a hoop for supervisors to jump through. I can't use angle iron, for example, and running the event on a lab bench might well be out of spec. Is there some way that these measurements might affect competitors that I haven't thought of?

[chalker]

What was the reasoning behind specifying the width of the beams and the width of the test base? Neither would seem to have any impact on how teams prepare for the event, so as far as I can tell it just establishes a hoop for supervisors to jump through. I can't use angle iron, for example, and running the event on a lab bench might well be out of spec. Is there some way that these measurements might affect competitors that I haven't thought of?

Primarily to help the novice event supervisor who wouldn't know where to start or to think through all the aspects of it. If you look at the draft rules from last year, we specified a standard 8' table and 2x4s. We abstracted that out a bit to provide more flexibility by talking about beams and surfaces (which is where the general dimension came from).

The easiest route is to just get 2 metal 2x studs and a standard classroom table. If we just specified a width of the track, some novice event supervisors would like use thin pieces of wood, which will bend and warp. Likewise, many lab bench tops are too narrow to both have the track and standard iron support stands for the lasers / photogates.

Angle iron is going to be a lot more expensive, but in reality is probably an acceptable solution if you want to use it. As event supervisor you have some discretion and can notify the teams in advance about such a minor tweak. As long as you have the same conditions for all teams you should be fine.

[sridevi]

To get a good score do you need to have a fast Time Score and a small Mass score?

[windu34]

To get a good score do you need to have a fast Time Score and a small Mass score?

Read the rules. Larger the mass and more accurate the time, better the score.

[Unome]

To get a good score do you need to have a fast Time Score and a small Mass score?

To elaborate on the time score: the goal is for your device's time to be as close as possible to the target time, hence you will need to design and test your device so that you can modify it for all of the allowable target times (see the rules).