Fans/Propellers - Are you doing them?

[ZakuAce]

Yep it really did not seem practical to us. Too much weight, too much power consumption, and too much room.

[writchie]

We have a modular vectored thruster that provides 5 lbf and could supply as much as 8 lbf if we can find a way to machine our custom props.

There are issues with optimal shooter angle so we might loose it at our critical design review tomorrow or in final testing.

[Rick Wagner]

A few extra ounces of pushing power should always be welcome on the slippery surface this year. I'm surprised not many seem to be doing it because it is so simple to implement. Just take a spare motor and put a hobby shop propeller on it, mount the motor with a hose clamp behind a screen for safety. Have the software turn it on when the wheel motor current (or command level) exceeds some forward value.

[writchie]

Originally Posted by Rick Wagner

A few extra ounces of pushing power should always be welcome on the slippery surface this year. I'm surprised not many seem to be doing it because it is so simple to implement. Just take a spare motor and put a hobby shop propeller on it, mount the motor with a hose clamp behind a screen for safety. Have the software turn it on when the wheel motor current (or command level) exceeds some forward value.

It's a bit more than this but not that difficult.

The major weight and effort is the safety cage. When you throw a prop it can do serious damage and may bounce off obstacles without loosing all that much. The trailing edge is sharp. IMHO only a complete shroud that prevents an exploding propeller from escaping will satisfy the Inspectors.

Props must also be balanced or the vibrations are likely to lead to failure.

[Alan Anderson]

Originally Posted by Rick Wagner

I'm surprised not many seem to be doing it because it is so simple to implement. Just take a spare motor and put a hobby shop propeller on it, mount the motor with a hose clamp behind a screen for safety.

It's simple, but not necessarily as effective as you might think at first.

You'd be surprised at just how much thrust a propeller system can lose when you add the safety screen. In some cases, it drops the force to less than a fourth of what it would be otherwise.

[Rick Wagner]

I flew model airplanes many years ago, and while I have broken nylon propellers, I had to crash the airplane to do it. We used to balance propellers on a pair of single edge razor blades.

[zrop]

Team 2526 is using only props for propulsion. As long as we keep our weight down... we should be able to blow the competition away. =P

[Jared Russell]

The amount of room occupied by fans and the necessary guards are what deterred us from pursuing this idea further.

[DonRotolo]

Although our team has many fans we won't be using them for propulsion (not at this point, at least) primarily because of the safety and noise aspects.

[AHS1599]

We did some tests in the first week with a prototype on the actual floor material with the correct wheels. While it did move the bot, it was inefficient so we opted for a different design...