Hovercraft B/C

[MIScioly1]

I wouldn't say sig figs are super important in physics events... I wouldn't take off points for them, and the only tests that have very explicitly stated they would. I think there's a different mentality between chem and physics for sig figs.

Seconded. I tell students to just use a reasonable number of decimal places. But some event supervisors are more picky.

[syo_astro]

I wouldn't say sig figs are super important in physics events... I wouldn't take off points for them, and the only tests that have very explicitly stated they would. I think there's a different mentality between chem and physics for sig figs.

Seconded. I tell students to just use a reasonable number of decimal places. But some event supervisors are more picky.

I believe it's national policy to account for sig figs (i.e. https://www.soinc.org/sites/default/fil ... 120512.pdf)...regardless of personal decisions / instructions, please be aware when posting (as some people overgeneralize what's said on forums). It says that B events are handled differently, but nonetheless posting just in case >.>.

[SPP SciO]

What are some effective ways to prevent your hovercraft from turning 90 degrees halfway through the run and getting stuck?

New idea (also untested in competition, but I've personally seen it have a strong effect) - try adding a sail to the Hovercraft. I'm talking just a simple, paper triangle + popsicle stick, cartoon-sailboat looking sail.

I do not understand the physics of airflow but adding one to the left side of the vehicle (ours had a tendency to turn right) seemed to make a difference. Hopefully someone more knowledgeable can chime in with science reasons as to why this is or is not a good idea.

[MIScioly1]

What are some effective ways to prevent your hovercraft from turning 90 degrees halfway through the run and getting stuck?

New idea (also untested in competition, but I've personally seen it have a strong effect) - try adding a sail to the Hovercraft. I'm talking just a simple, paper triangle + popsicle stick, cartoon-sailboat looking sail.

I do not understand the physics of airflow but adding one to the left side of the vehicle (ours had a tendency to turn right) seemed to make a difference. Hopefully someone more knowledgeable can chime in with science reasons as to why this is or is not a good idea.

I've seen teams put rudders on their hovercrafts before. I cannot really speak to the effectiveness of them because I don't know how those same vehicles would work without them. Theoretically, it is an interesting idea.

[Unome]

I wouldn't say sig figs are super important in physics events... I wouldn't take off points for them, and the only tests that have very explicitly stated they would. I think there's a different mentality between chem and physics for sig figs.

Seconded. I tell students to just use a reasonable number of decimal places. But some event supervisors are more picky.

I believe it's national policy to account for sig figs (i.e. https://www.soinc.org/sites/default/fil ... 120512.pdf)...regardless of personal decisions / instructions, please be aware when posting (as some people overgeneralize what's said on forums). It does not B events are handled differently, but nonetheless posting just in case >.>.

If it's not specified in the test, I usually just ask the ES each time.

[geniusjohn5]

What are some effective ways to prevent your hovercraft from turning 90 degrees halfway through the run and getting stuck?

New idea (also untested in competition, but I've personally seen it have a strong effect) - try adding a sail to the Hovercraft. I'm talking just a simple, paper triangle + popsicle stick, cartoon-sailboat looking sail.

I do not understand the physics of airflow but adding one to the left side of the vehicle (ours had a tendency to turn right) seemed to make a difference. Hopefully someone more knowledgeable can chime in with science reasons as to why this is or is not a good idea.

I've seen teams put rudders on their hovercrafts before. I cannot really speak to the effectiveness of them because I don't know how those same vehicles would work without them. Theoretically, it is an interesting idea.

Again the best way to test whether it's effective is to test it out yourself. A sail works on the principle that there's a higher pressure on side facing the air/wind and a lower pressure on the side facing away from the wind/air. Therefore, the craft moves from the side of higher pressure to lower pressure, causing it to actually move. Which direction it moves depends on your own Hovercraft. But TBH, there are much more significant factors in determining the success of a Hovercraft (strong batteries, fans, adequate skirt designs, etc.)

[Tesel]

I guess I should clarify what I said about sig figs. Based on my experience, hovercraft tests (and other physics tests) will usually explicitly state whether they require the use of sig figs or specific rounding. Chemistry events, however, will always assume the use of sig figs. It is always a good idea to ask the supervisor to confirm this rule, and you should never assume that the supervisor will be doing anything but official sig fig policy.

[UTF-8 U+6211 U+662F]

Just to share my experience, most of the tests I've taken awarded points for appropriate sigfigs.

[Tesel]

Just to share my experience, most of the tests I've taken awarded points for appropriate sigfigs.

Interesting... I wonder if it's a state by state thing. The last test I took was actually the only one I've seen that awarded points for sig figs.

[Elizabeth.mish]

In the rules manual, it specifies that shielding is needed around each propellor. For the lift propellor, I put mesh shielding on the top but no underneath the propellor. However I do have a skirt that prevents any parts of the propellor from flying out. Is this ok or do I need to put metal mesh shielding under the lift propellor as well?