Re: Team 2526 - Propeller Propulsion Prototype.
 

You intend on playing on the dark side of the moon, I see.

Re: Team 2526 - Propeller Propulsion Prototype.
 

It doesn't have to have enough force to pull the trailer. Think of it as "bonus force" . . . the wheels drive the bot, and the prop helps. The elegance in this concept is that all (ideally) of the excess potential in the battery is put to use in propulsion.

Re: Team 2526 - Propeller Propulsion Prototype.
 

Yes think of the props as a turbo system for our bot. And no we are not ready to give up our creativity award. We have a few more fairly cool ideas in the works as well. :cool:

Re: Team 2526 - Propeller Propulsion Prototype.
 

yes it could pull the trailer this is just a prototyp the final design will have at least 3 more pounds of thrust

Re: Team 2526 - Propeller Propulsion Prototype.
 

I don't want to rain on anyone's parade but there are a lot of issues raised on this thread that come to mind.
1. It will be necessary for you to demonstrate the safety of your design to both the Lead Robot Inspector and regional officials in order to compete. Read that as the fan must be enclosed so that no one and nothing in the arena may come in contact with it. The enclosure will need to be sufficient to protect everyone and everything from damage should a failure occur.
2. The FP motor curve posted earlier in this thread is for last year's KOP. Remember the motor is changed for this year.
3. Using a fan to move your robot around inevitably will interact with the balls on the field, stated another way, possible herding violation.
4. Please act safely in the shop, holding a rotating knife assy. by hand is not in the best interest of those watching.
5. Centrifical forces generated by the fan/propellor will need to be compensated for if you hope to be accurate where you drive.

Please before you paint yourself into a corner, ask the Q&A if this would be considered a legal design. You have already made this public so asking on the Q&A won't harm your development.

Re: Team 2526 - Propeller Propulsion Prototype.
 

Could you post some pictures or post the video somewhere else? I'm using a school network, and youtube is blocked.

Re: Team 2526 - Propeller Propulsion Prototype.
 

See Q&A (first question answered)

FRC1771

Can a team use model aircraft propellers, mounted in a tube and properly guarded, as a means of propulsion and maneuvering?

GDC
Re: Propellers
There is nothing in the rules that would prevent this, provided there is no damage to field elements and it does not present a safety hazard.

Re: Team 2526 - Propeller Propulsion Prototype.
 

Coming from South Florida where Airboats are prevalent, the noise level of the moving prop is going to be a concern. Most airplanes are noisier than jets.

I can't imagine FIRST allowing robots on the field with a sound pressure level approaching 110-120 dB in an enclosed area. It's loud enough in there as it is.

It would be worse than a Monster Truck performance!

I remember one team in 2006 that tried to implement blowing balls into the lower goal with a stream of air. It worked only when they were up tight against the wall.

I will be wearing my earplugs just in case.

Re: Team 2526 - Propeller Propulsion Prototype.
 

The amount of air going out the back is directly dependent on the pitch of the props, now in order to make this a viable option, we were required to get the smallest pitch we could find (3.75) to keep our rpms up. So that being said, the air speed is not that fast, but its still more air movement than your average housefan (let's just say that i got cold standing behind it, and im from minnesota). We did put a spaceball behind it, and it was able to move it when the ball was a few feet from it and accelerate it from there, but if it starts off much farther, it has hardly any pushing effect on the ball.

This Tuesday, we hope to get a good start on the final two props and possible finish Wednesday or Thursday. With luck we may be able to post another test run before the week is up.

Re: Team 2526 - Propeller Propulsion Prototype.
 

Good Advice.

The FP motor curves are referenced from the KOP section of the 2009 manual. I believe the 9015 motor is the same as last year except for the pinion gear.

Some twin engine aircraft (like my Piper Seneca) have engines and props that rotate in opposite directions. The left and right engines are mirror images of each other. We haven't calculated yet whether this would be necessary. I would expect that torque effects would dominate over inertial effects but there might be advantages to the propwash from counter-rotating props.

At our conceptual design review today, we just adopted a horizontally gimballed thruster composed to two 11 inch props from two FP motors in a 24x12x6 envelope as an optional feature of our design. Whether it survives our next design review remains to be seen.

The rule clarifications take out vectoring thrust in other than the horizontal plane.

Re: Team 2526 - Propeller Propulsion Prototype.
 

We got a little anxious and decided to mount the prototype prop onto our chassis frame just to see it go somewhere :). Here is a short video of it moving only by a single propeller

http://www.youtube.com/watch?v=I24NW...e=channel_page
or
http://www.facebook.com/video/video.php?v=45518718790

We are currently looking for a way to attach the big 54 nub sprocket (its the big one) to our 8mm shaft on the cim motor without using masking tape. If anyone has a way of going about doing this, it would be awesome.

We also tested the vehicle on carpet to test if it will move, it did, but it was really slow and boring, so I never bothered uploading it.

Enjoy

Re: Team 2526 - Propeller Propulsion Prototype.
 

I highly recommend that you use at least the 120A breaker between the battery and the motor to avoid the arcing that can be seen in this video.

Ideally you would have an appropriately sized breaker (40A for a CIM) in place as well but this is a bit tougher with the new PD board than it used to be with the Maxi block.

Re: Team 2526 - Propeller Propulsion Prototype.
 

OK, two fans acocunt for two CIMs, what if you were to use two more CIMs in a conventional drivetrain? Would the extra thrust from the fans provide an advantage?

(hint: yes)

Noise will be an issue, and your safety cage will need to be robust to be sure an exploding prop is fully contained, as well as keeping fingers away. Don't want a bird strike to make you drive into the Hudson river....

Don

Re: Team 2526 - Propeller Propulsion Prototype.
 

I would tend to agree that it is a pretty bad idea to prototype by shorting motors--it's bad for the motor, and dangerous to those around it. What exactly is your procedure for the motor catching fire or the battery melting down. Let's say the Anderson connector's terminals happen to arc and weld themselves together... Please wire through a circuit--it's not hard to set up a simple test board with basic circuitry on it. It doesn't even need to consider of "official first components" instead use a 40 amp fuse and a heavy duty switch--it's safer that way.

Re: Team 2526 - Propeller Propulsion Prototype.
 

well, maybe it would float and then they would have a REAL airboat:D