Re: For those who are skeptical about propellers - Team 2526
 

Only thing. Just because FIRST says it safe, is everyone going to make the same ruling? For instance: We've all seen those "smart" cars. They are ruled to be safe. However, I will never drive one. I just wouldn't feel safe, regardless of whether or not I am. You have to remember when it comes to safety, apparent safety is close to the same importance of actual safety.

Re: For those who are skeptical about propellers - Team 2526
 

Time for my two cents...
I am a lead inspector, and yes I am concerned about the safety of anyone at any time. This includes participants, volunteers, camera people (many of whom I know), judges and refs. If that makes me a Safety Nazi then I can live with that label. I am concerned about safety when your robot is in your pit, on the practice field, on the competition field or anywhere in between. Pits are crowded places in which I spend a lot of time and I have seen things over the years that curdle my blood. First is about innovation and creativity in design and we should encourage those ideals for the betterment of the program, but not at the loss of other equally important ideals such as safety. We have low voltage power sources for your safety, electrical rules for your safety and pneumatic rules for your safety. Expect inspectors to take a close look at your designs not only for safety but I would be prepared to show accoustic output as well. Should the GDC issue guidelines for prop driven robots we will follow those guides explicitly. Until then good luck with your development.

Re: For those who are skeptical about propellers - Team 2526
 

I really think you guys believe that props are bound to spontaneous explode or something. As long as balls or anything of a significant mass does not touch them, there is no reason for them to catastophically fail. We'll most likely be replacing props after every round / two rounds, just to rule out any failure chances due to wear. Beside that, I believe any other precautions are just silly. I mean, I trust the machine... I stand a foot away from it while it's on. Idk if others trust my contruction, but i sure know i do.

Re: For those who are skeptical about propellers - Team 2526
 

Our robots have never had props on them and I'm always more than a foot away from them while they are on unless they are propped up on blocks.

I can't say I understand why your blatant disregard for the safety advice posted by members with experience with these systems means that I should trust your robot to be safe.

If this robot manages to pass inspection with the safety cage shown in those pictures, I will be instructing my team to at the very least put on safety glasses in the stands every time your robot is on the field.

Re: For those who are skeptical about propellers - Team 2526
 

Have you ever been to a competition? After each match you will see various parts from the robots on the floor. What if a bolt or nut was to be flipped into your props.Even if they didn't damage your props where does the part go after hitting the props.
Also, on a safety note. In your videos it shows your robot going along the floor PAST all the students with uncage props. When I'm around running R/C aircraft I NEVER put myself in the plane of rotation. I've seen first hand what a prop can do if it breaks and flies free. I've seen them imbed themselves into 2x4 park benches.
PLEASE BE SAFE!!!!!

Re: For those who are skeptical about propellers - Team 2526
 

I'm not blatantly disregarding, I'm taking them into consideration and adding just enough safety features so that the props can still function.
We will upgrade the cage, in particularly in the 'plane of destruction'.

And really, say a prop was coming at you, I wouldn't be that concerned about my eyes, but rather, other parts of my body. Becuase theoretically (depending the mass of the fragment ofcourse), you'd get some penetration in the skin if that hit you. And then... surgeons would have fun dislodging a 'plastic knife' from your body. Not really the best image, but.. atleast you'd be able to see your own masacre. [sorry for the sarcasm, I'm just a little angry about our progress XD]

Re: For those who are skeptical about propellers - Team 2526
 

Yes. Debris would be an interesting encounter. I'm thinking of loosing the set screws on the gears just at the point of slipping. Then if there is any added resistance [ideally] the prop would simply slip through and maximum damage could be eliminated.

Re: For those who are skeptical about propellers - Team 2526
 

It won't be spontaneous, it'll be in response to a large object passing through your porous safety cage and into the props. Maybe an orbit ball will come apart above your bot and the plastic shards will fall on your bot. Maybe another team's robot will shed bolts, or maybe a human player will accidentily toss their watch. Maybe a wire will break or come loose and will get ingested. Maybe a robot will fall on your cage and bend it inwards, hitting the prop.

Also keep in mind that every time your robot hits a wall or another robot at speed, your props will endure forces well beyond what a normal R/C plane ever encounters. An impact with the wall may decelerate a bot at 10gs, which means your fast-spinning props have to deal with that deceleration and not vibrate themselves to death. An R/C plane never sees accelerations like that.

If you don't want to change your design on safety grounds, not believing that it is a risk, change it based on pragmatic grounds: despite any "no that won't happen" arguments from your team, inspectors will mostly likely not permit your robot to compete. So even if you don't personally believe it is a safety risk, it seems that pragmatism would compel you to make a better safety cage.

Re: For those who are skeptical about propellers - Team 2526
 

Two words. ducted fan.
Bruce

Re: For those who are skeptical about propellers - Team 2526
 

I've already mentioned that we'd construct a better cage. I'll get pics of it up as soon as possible just to stop all these continual scoldings. XD

Re: For those who are skeptical about propellers - Team 2526
 

I can think of all kinds of examples of things that "should" not happen that end up happening. I know in the chemical industry and know in others, things are designed to account for failure scenarios. Why? Because it will happen at some point. That is why people spend weeks doing things like a Layers of Protection Analysis and Failure Modes Effects Analysis for big projects. Do you need to spend weeks doing that? No, this is much smaller, but spending a few hours thinking about things that could go wrong would not be amiss.
Listen to Al, a lead inspector. Listen to all the others who have years of experience both with FIRST and in industry. If it is anything to you, I will be inspecting teams at your regional on Thursday and reffing on the field on Friday and Saturday.
I like that you are thinking of changing the fans and making a better cage. Just remember, the folks on here are trying to help you so that you don't have to scramble on Thursday at the regional.

I think it is an interesting design. I will withhold judgment on it until I see it in action.
Good luck to you!

Re: For those who are skeptical about propellers - Team 2526
 

As stated before, we're all inspectors, spectators of horrible accidents, or Safety Captains, that just want to make sure you (and the event attendees) stay safe. I truly hope that you change your view on the safety procedures of your team.

Hopefully your team has a competent safety captain, good practices for your heavy (and light, for that matter) machinery, procedures to deal with an accident (should one occur), etc. It looks like a great design, very innovative, but remember: Safety FIRST!

Re: For those who are skeptical about propellers - Team 2526
 

I encourage your team to take a look at this post:

http://www.chiefdelphi.com/forums/sh...threadid=73389

That is the kind of safety precautions that are necessary. More fencing to keep fingers and smaller parts out, and extremely safe plane protection.

Also I would like to note that all of us here at FIRST truly believe in the ideals of Safety and GP. Not just as a way to get an award. If these ideals are ignored by anyone the competition breaks down at it's core. I encourage you to visit a local senior team and check out their safety procedures, our you can email me at xanderjanz@gmail.com to find out about 1458's safety procedures. This is no joke and we expect you to take safety seriously.

Re: For those who are skeptical about propellers - Team 2526
 

Good, intresting design, but i have one question. Isn't there a rule about the wheels being parallel to each other? In the one picture you can clearly see how the frontwheels turn with the propelers while the back wheels just stay stationary. Is this still legal? From how i read it and heard, it doesn't seem legal.

Re: For those who are skeptical about propellers - Team 2526
 

You're thinking of <R06>, which specifies that the axis of rotation of the wheel must be parallel to the floor. It doesn't say anything about the axis of rotation of the axis of rotation.