Fans/Propellers - Are you doing them?

[Greg Peshek]

There was a lot of discussion at the beginning of the build season about fans and propulsion and I'm curious to see how many teams are following through with it. There were a few pictures and videos early on, so if you're willing to, let us know if you are planning it as part of your final design.

If you aren't worried about your design, you could always post your ideas on the fans, etc.

[Urban Hawk]

well you said post my ideas on the fans so here it is:

we aren't planning fans on our robot because they might provide some power but on the whole they probably won't do much. the only real effective means would to be to use a vacuuming unit with its intake on the bottom and its outage on the top to pull it down on the field. The problem with that though is that vacuum's use allot of power and can easily drain a battery. So because of that we decided not to do either.

[Dan2081]

We were speculating and conducting tests on a few different types of fans, and a small prop. Although we found out that we could nearly double our thrust with 3 different fans if they were all on the robot, it wouldn't leave any room or weight for any type of successful manipulator. We decided that we are not using fans

[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...

[Gboehm]

Originally Posted by Urban Hawk

well you said post my ideas on the fans so here it is:

we aren't planning fans on our robot because they might provide some power but on the whole they probably won't do much. the only real effective means would to be to use a vacuuming unit with its intake on the bottom and its outage on the top to pull it down on the field. The problem with that though is that vacuum's use allot of power and can easily drain a battery. So because of that we decided not to do either.

Your Idea isn't as original as you think, Brabham used the Idea in the 1978 Formula 1 season, It was banned after one race.

[Rick TYler]

Originally Posted by Gboehm

Your Idea isn't as original as you think, Brabham used the Idea in the 1978 Formula 1 season, It was banned after one race.

Only after the idea was invented by Jim Hall in his Chaparral 2J Can-Am car, which was banned after one season in 1970.