MagLev C

[iwonder]

I like the idea of a sled and mass to drag, and limiting the types of batteries that can be used.

The reason I suggested that ducted fans be required is because if the size limit was removed then teams not wanting to spend a lot of money could make something like a paper tube and mount it around their motor to qualify for ducted fans with less than a few dollars in parts.

On the idea of safety, I understand switch based cutoff systems are beyond the scope of some teams, but it'd be nice to see some kind of cutoff system be required, even if it's using a long rod to flip a switch. Also, limiting the mass of the vehicle is something to consider, I've heard of vehicles heavier than 2kg and that kind of mass going 2m/s or so seems rather dangerous if proper end stops aren't used.

[erikb]

Some good observations, Erik. Think we’re pretty much on the same page.
What got me started on this topic was the belief that for the building events, because they are open to observation, anyone interested should be able to see/get the scored performance results – examples-MagLev- run distance, run time, mass, predicted time; boom/tower/bridge- mass of structure, weight carried, Grav vehicle-run dist, ramp height, predicted time, distance from target.

I don't see anything wrong with that. Build events are pretty black and white. You either did it or didn't. However, i do like the kids having to interact with the other teams to get information.

First, and foremost, this pushes them; last year’s secrets/good ideas are out there, and you’re going to have to improve it if you want to stay out in front. Second, it’s consistent with how science and engineering in the real world works-there is the “state of the art”/ “the body of knowledge”- building something that does “x” starts w/ the research and understanding of how others have done that, so far, then the problem becomes how to do it better.

I agree, competition makes them raise the bar, we spend a few months at the beginning of each year reverse engineering all the things that were noted the previous years. Then the kids design. However, my main goal is life skills. How to plan, and then execute that plan. How to set reasonable goals to achieve their main goal: standing on the stage at nationals. Anyone can set a lofty goal. But, it takes life skills to reach it. So many times designs are cut back or changed to meet the intermediate goals. It does no good to design the most awesome and perfect item if it will take all your time building it and you have none to test it.

I believe in making sure all students have the same access to science and opportunity for success. That way it comes down to who is the best prepared team. Not who has the best resources. I will help any student that comes to me.

I really want to go for it this year on this event- “I want to beat Poudre...”,

I would say, don't worry about us. We will do what we do regardless of your goals. Aiming to beat some team is a wandering target. Aim to medal. The build team set out to score a 9 points in the 5 build events at state. That was their goal and they reached it. They understood that beating everyone is a fools errand. But being in the top two or three. That can be done. That is an achievable goal.

Because they look to medal they are the most prepared team in the building. Their is not line to cross and say "we are ready, we can beat so and so, we can stop and relax until the tournament." They know random things happen that can cost them a medal and one can never be prepared for random. You can never sit back, thinking you have all the bases covered.

I deeply respect how, over the years, Poudre has been able to nurture and maintain a program where a whole team (even multiple teams) is inspired to work to winning levels. It sets a very high bar. When, in a few building events, our kids get over that bar, and actually beat Poudre, they know they have accomplished something,

The IB program gives poudre a deep pool of students who want success but we have one awesome resource here at poudre. Mr. Lundt who knows science olympiad inside and out. These kids are prepared.

[erikb]

The reason I suggested that ducted fans be required is because if the size limit was removed then teams not wanting to spend a lot of money could make something like a paper tube and mount it around their motor to qualify for ducted fans with less than a few dollars in parts.

Valid point i did not think of that. A rolled balsa wood tube would be cheap and easy also.

On the idea of safety, I understand switch based cutoff systems are beyond the scope of some teams, but it'd be nice to see some kind of cutoff system be required, even if it's using a long rod to flip a switch. Also, limiting the mass of the vehicle is something to consider, I've heard of vehicles heavier than 2kg and that kind of mass going 2m/s or so seems rather dangerous if proper end stops aren't used.

We have found that the heavier vehicles are safer, simply because they don't fly off the track when things go bad. Next we have a steel plate that the mag lev runs onto after it's run. That is on a separate track that attaches to the main one. So when the sled hits it, the sled sticks and the whole thing, metal plate and all slides for a bit then comes to a complete stop.

When they were under 1500g it gets a lot sketchier.

However, making it a tractor pull event will force lighter sleds.

We also have a stop plate on the start end, with a big sticker on it reminding them that the blades cut. The stop plate prevents the mag lev from sliding off the back end right as the power is switched on (it can be an issue when 95cm is used. next year we are going to build a track that has more room) and when the mag lev is mistakenly put on the track the wrong direction it won't come flying at anyone.

On a side note. Don't sit behind the mag lev track ever.

[wlsguy]

We are considering some tweaks to the rules for next year. One involves simplifying the motor / prop restrictions by just limiting the overall size of the prop. Does anyone have any suggestions as to what 'standard' prop sizes are and what limit we should impose?

...
However, the battery is the safety issue. A lipo can dump enough amps to make the propellers dangerous. The kids were cut several times and bruised even with heavy gloves on. At state i made them use flexible propellers even though it cost them points. At nationals they will be using apc composite propellers. APC don't flex or break when they hit a hand, that worries me and their parents.

Limiting the batteries to rechargeable nicd vs nimh batteries with a maximum voltage for the circuit, would make them safer and if they wanted more amps it would be a design and additional weight problem for them to figure out.

I disagree with limiting batteries at this point. Those of us who have already spent considerable resources should not be required to buy new batteries, motors, or switches because a few people haven't figured out how to make thier device safe. I really doubt simply changing the battery type will prevent someone from designing a dangerous device.
The rules already prohibit unsafe devices. Now we just need to consistantly enforce them.
Unless the kids have figured out a way to insure they will not contact the blades, don't let them run.

How about changing the entire concept from who can run the fastest to who can run at a pre-determined "ideal time" over a given distance.
Let the kids adjust the weight, power (through the use of a Potentiometer), and setup of the cars and have the event supervisor pick an ideal time and distance between some given values for all teams.
If needed, include an additional supervisor supplied "Bonus weight" of 200g (or something variable) for the 2nd run. This would break the ties at the top.

All of the rules about ducted fans, track width, magnet height, vehicle weight, type of motor, type of battery, etc all become unneeded.
Any team would have the potiential to win and it would come down to science and repeatability rather than money spent.
It would also be easier to run because no longer would every vehicle need weighed.

[Schrodingerscat]

How about changing the entire concept from who can run the fastest to who can run at a pre-determined "ideal time" over a given distance.
Let the kids adjust the weight, power (through the use of a Potentiometer), and setup of the cars and have the event supervisor pick an ideal time and distance between some given values for all teams.
If needed, include an additional supervisor supplied "Bonus weight" of 200g (or something variable) for the 2nd run. This would break the ties at the top.

All of the rules about ducted fans, track width, magnet height, vehicle weight, type of motor, type of battery, etc all become unneeded.
Any team would have the potiential to win and it would come down to science and repeatability rather than money spent.
It would also be easier to run because no longer would every vehicle need weighed.

I support this idea, as setting goal times around say 10 or so seconds could make the event far safer by requiring far less powerful means of propulsion. Personally I would also suggest either way limiting it to one motor and propeller, as I at least felt my first model was far safer before we added a second prop (although the previous suggestion would remove the need).

[erikb]

I disagree with limiting batteries at this point. Those of us who have already spent considerable resources should not be required to buy new batteries, motors, or switches because a few people haven't figured out how to make thier device safe. I really doubt simply changing the battery type will prevent someone from designing a dangerous device.

You have proven my point.

Given the students an option to just purchase the most power available it is creating a dangerous situation and blocking other teams from competing because of money.

Here is calculator so you can play with volts and amps to see that if you limit the number of amps the amount of work that can be done is a fraction of what is possible:

http://www.calcunation.com/calculators/ ... Horsepower

As an example i will use one of our sleds.
7.4 volts and 30 amps gives over .3 a horsepower.
9 volts and 2 amps less than .02 horsepower

That is a magnitude of over 10. Physics limits the possible work, thus safer propeller speeds.

In addition, your school has the money to purchase lipos. lipo chargers and everything else but they can't spring for $20 for rechargeable batteries a battery case and a connector. I would have a talk with the budget people.

Or is your point, since you have already purchased the items the event can't be changed because it would inconvenience you next year?

The rules already prohibit unsafe devices. Now we just need to consistantly enforce them.

I really don't think you understand this event. The goal is to make an unsafe device. Remember, the fastest most powerful device wins.

Unless the kids have figured out a way to insure they will not contact the blades, don't let them run.

By your logic no one can do this event. There is no way to guarantee that an accident does not happen. By design the students have to put something in front of an object that can generate more than 2 times the force needed for low earth orbit. That same object has rotating blades that can shred clothes and cut deep into the tissue. There is no way to make the event safe. This year by design, it is unsafe.

However, i do like your idea of making it a time to distance event.

[Stingray355]

While I definately support changes to make MagLev safer I hope the changes don't force teams to discard much of the hardware they have purchased for this season. This years rules favor performance and we spec'd the motor(s), batteries , magnets and props accordingly. Changing battery requirements will also impact motor and prop selection and at some point you are building from the ground up again.

I would prefer changes to address the safety issues, there are a number of simple and effective ways to cover this. The other changes , to mix up the scoring parameters, I would hope will be consistent with the hardware teams have already purchased.
As I have commented before in our Region we have lost some great competitors to lack of funding. We also have schools fielding partial teams in part because of a lack of funding for all events. Often times the build events consume much of the available funds so they can be the first ones impacted. We also compete against schools that field multiple teams at invitationals so this is not universal. Our school district is one that provides minimal support for academic endeavors like Science Olympiad, robotics and others. From my conversations with coaches and parents from other districts this is not uncommon. I am not in favor of handicapping the schools with better resources and support, good for them and they are able to expose more kids to SO. I would like to see the cost burden discussed as part of any considerations for changes to existing events or new events. I think we can all agree that anything we can do to get more schools/kids involved in Science Olympaid is a good thing.

I think there are plenty of ideas on how to change MagLev for next year that will allow teams to keep most or all of their current hardware but still have to reevaluate/redesign their device to be competitive next season.

[wlsguy]

I agree, the current rules are written where the goal is to make an "unsafe" device.

Anytime you have a 1.5kg device moving at 1m/sec it has enough energy to smash fingers, etc.
Add in the fact it is propeller driven and the potential exists for injury.

This event, however, is no more risky than others if proper safety precautions are taken. (we use saw, drills, and power tools to build everything)
Making a device you can turn on and off safely is one of the engineering challenges of the event and something faced in the real world every day.

My original opinion is unchanged. Make kids create a safe device first and enforce the safety rules already in place.
If the kids cannot show how they can operate their device without cutting their fingers, don't let them run.

No one can predict every possible dangerous situation so accidents can still happen.
The rules writers need to put enough limits in place to prevent as many injuries as possible.

Now, with respect to changing rules;
Unless the vehicles are lightened and slowed, they will still be somewhat dangerous.
The easiest option is to only allow 1 propeller. This prevents kids from reaching between 2 operating props to turn the device on / off.
The more involved measure would be to change the focus of the event from speed / weight based to speed / time based (and give an ideal time).

Our team has the money to spend regardless but I think other schools may not. These are the schools I worry about.

[iwonder]

I don't understand the idea of limiting the types of batteries people can purchase. It doesn't necessarily make the event much safer, as I have an 8.4v rechargeable NiMH pack right now and it can still seriously injure someone's finger(or take a large chunk of wood out a pine dowel), LiPo's may be more dangerous, but anything is dangerous, so it doesn't really get you very far. Sure, I may only slice two or three mm into my finger instead of five or six, but it doesn't stop someone from hurting themselves. Furthermore, my understanding is that people like chalker try in every event to make sure it doesn't become a contest of who has the most money(which is why there's a time prediction component), but limiting the materials that students can buy and use to try and level the playing field is not the appropriate solution. If you limit everything down so that now one can get away with spending more money, we'd all walk into the competition with basically the same device, everyone would use the same batteries, same cheap motor, same cheap propeller, etc. as a competitor I can tell you there's no fun in that. I want to go to competition and see what the teams with tons of money have come up with, and see what other teams have designed as well. Walking into a room full of cheap highly similar maglev vehicles just isn't the same. A better solution is to change the event rules so that it doesn't matter how much money is spent, and scores are improved by spending more time in the event. Things that do this have been discussed. How about one of these instead of battery and money limits.

-Pulling a weight behind the sled with a heavy time prediction
-Being given a target time to hit
-Traveling a specified distance(sort of like the old electric vehicle)

Admittedly that last one would be difficult, but personally I think it'd be a lot of fun to try. You'd probably have to remove the integrated circuit restriction to deal with it.

Basically, I don't see how limiting the type of battery makes it safe, it'd be safer, but it's still dangerous, it's the teams responsibility to make sure no one gets hurt, it's not NSO's job to constrict the rules and limit us so we can't hurt anyone. No one complains about 2M HCl in events like forensics, but that's just as dangerous. And the solution to the money problem isn't limit what we can use, it's making sure that money spent isn't so directly related to score.

[joeyjoejoe]

While I understand the need for safety, I disagree that sweeping changes need to be made to secure it. Our students had to use several tools during the construction of their devices that were immensely more dangerous than any spinning prop. A radial arm saw was used to cut the wood for the track base. A table saw was used to cut plywood for the car base not to mention they drive 2000 lb vehicles to and from school each day. It should be up to the coach to insure that a sufficient safety briefing is performed for the students tailored to their event. I agree that it is hard to convince them to ignore the desire to reach for the car that they've put their heart and soul into before it crashes to the ground after bypassing the stop position for some reason but that's why I have them say over and over: "don't worry, we can always make a new one".


Edit: And yes, I realize the irony that this is coming from a coach who has already admitted (on this very thread!) to cutting himself with the prop. Once we realized the power of the vehicle, we treated it with the respect it deserved.