pic: Jake Blues Back

[Schnabel]

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[domoarigato]

So, this definitely counts as blocking/obstructing your trailer. We thought about this idea, but scrapped it because it IS illegal.

[hillale]

Um yeah... i'm almost 100% positive that this is legal and that there have been extensive Q&A questions on it. I don't have time to quote them right now, but do a little research.

[Dan2081]

Lol are u suuure its illegal? I don't believe they had too many problems at DC Good job 45

[thefro526]

Originally Posted by domoarigato

So, this definitely counts as blocking/obstructing your trailer. We thought about this idea, but scrapped it because it IS illegal.

No, Team 45's Fan was not made with the intention of blocking the trailer. If you notice it forces air parallel to the ground so it wouldn't be very effective at blocking balls traveling in a downward arc into their trailer.

However, They use the fan for propulsion. It gives them extra thrust so that they can accelerate and move faster without having to worry about the lack of friction, also it gives them a substantial advantage on the amount of pinning force they have.

And also this fan is legal because it doesn't increase the amount of normal force the robot exerts because once again it blows parallel to the ground not perpendicular to it.

Btw, 45 Congrats on proving a lot of people wrong. Apparently fans do work on the moon.

[EricH]

It's legal. You too can use a stream of air to deflect the balls coming at your trailer. Note that you can't use said stream to add any downforce to your robot and increase your traction. Q&A said so in two rulings:
http://forums.usfirst.org/showthread.php?t=10943 on using fans to deflect.
http://forums.usfirst.org/showthread.php?t=11025 on the downforce.

[BPetry234]

To say that it doesn't deflect the moon rocks AT ALL would be a little incorrect. I was giving a VIP tour when 45 went flying by. The thrust coming off of that fan was impressive. It wasn't designe to deflect but it has to have some effect.

I'm really glad it was legal, though. It would have been a lot harder to bring home a regional championship with out them. Great design and great team.

[Steven Zehner]

Originally Posted by BPetry234

To say that it doesn't deflect the moon rocks AT ALL would be a little incorrect. I was giving a VIP tour when 45 went flying by. The thrust coming off of that fan was impressive. It wasn't designe to deflect but it has to have some effect.

I'm really glad it was legal, though. It would have been a lot harder to bring home a regional championship with out them. Great design and great team.

Believe it or not, even though was wind was powerful, it had very little effect on the moon rocks. The rocks had too many open spaces to be moved by the wind.

[Alan Anderson]

Originally Posted by Steven Zehner

Believe it or not, even though was wind was powerful, it had very little effect on the moon rocks. The rocks had too many open spaces to be moved by the wind.

Before we had the fan guard in place, we did some informal testing to see how much the propwash could deflect a moon rock. With the propeller running at full power (drawing about 55 amps for each CIM from a direct battery connection), we lightly tossed moon rocks in a gentle arc directly across the air stream. They typically landed on the floor less than six inches aft of where they would have with the propeller stopped. A camcorder watching from the proper location confirmed the slight deflection, but casual observers didn't see any effect.

With all the emptiness it contains, a moon rock has a much lower drag coefficient than its size implies.