Unlimited Rotational Kinetic Energy Storage?

[Guest]

I see no limitation on the amount of rotational kinetic energy that can be stored in a flywheel that is not used as a weapon in the FRA rules.

Anyone care to comment on this?

Thanks!
Mack

[maddox]

Unlimited Rotational Kinetic Energy Storage?

Yes, as some people are researching the potential of magneticaly in vacume suspened flywheels for energystorage this seems a potential energysource for a fighting robot.Just crank up the RPM to store more enegery without increasing the weight.

But all experiments up to now are on a too small scale or/and cant handle any mechanical shocks.

So, if you can build a flywheel energystorage, that can power a robot, any weightclass, with satisfying result, we have a new rich man in RW.As that would be a moneymaker.


Now, I had, years ago now, an idea to use a small disks that runs at very high RPM counterclockwise to the weapondisk, to counter the disadvantage of a horizontal disk, the trouble with steering.

It was meant to be an 25 cm diameter 2 kg disk, that would be running at 25000 rpm to counter the 1000 rpm rotating disk.
But after starting to build the basic parts of the robot I noticed that the building of a heavy was so timeconsumong that it wouldnt be fun to see my machine splattered all over the arena.And it goes against my first liferule -dont do anything to anyone what I dont want to happen to me- so I started to look into the non smaching robot technology of flippers.

[geoff]

Unlimited Rotational Kinetic Energy Storage?

Greetings Mack,
Welcome to the FRA forum, always glad to see our friends from across the pond here!
You are quite right, there is no limit to the KE that can be stored in a flywheel, used as a weapon or not. (rule 11.2 & 11.3 applies) What kind of application for a flywheel do you have in mind? If I knew this, maybe I may be able to offer you some more detailed advice.
Regards,
Geoff.

[Guest]

Unlimited Rotational Kinetic Energy Storage?

Well, my comment is: Test it to destruction in a nice, safe, deep hole in the ground.

[typhoon_driver]

Unlimited Rotational Kinetic Energy Storage?

whilst there is no limit, you need a dam well balanced disc to spin at high speeds, jst remember that! and make sure that anything supporting it is as strong as u can possibly make it

[jim]

Unlimited Rotational Kinetic Energy Storage?

Do you think you would be allowed to spin up a flywheel before entering the arena? Obviously you cant do so with an exposed flywheel - it would be worth checking with the powers that be about encased flywheels before spending too much time on a design.

[Guest]

Unlimited Rotational Kinetic Energy Storage?

I see several rules regarding spinning weapons, but nothing other than two fail-safe rules for rotational kinetic energy storage devices (flywheels). I like to demonstrate my point by going to ends of the spectrum, so in this case, consider a flywheel running at 100000rad/s with 1GJ of kinetic energy that has a failsafe that causes it to spin down within 60 seconds to meet the safety rule; is that safe?!

My guess is that there is or *should be* some additional rules governing flywheels. If there is, I want to know what they are. If there arent, then I urge the safety folks to consider adding some.

Mario - Id be more likely to consider existing ball bearings rather than frictionless magnetic/vacuum-packed bearings; theyre alot cheaper! I think that the energy losses in conventional bearings would be tolerable. As for the problem with gyroscopic effects in spinning disks, there shouldnt be any problem with a horizontal disk (here, I mean a vertical disc axis). The problems arise when you have a horizontal disc axis/shaft but vertical disc (maybe thats what you were talking about). Id mount my flywheel with a vertical shaft. I have to disagree with your first liferule - I *want* my bot to beat the other bot, but I *dont want* my opponent to beat me :-). However, I have to agree that I dont want them to dessimate my bot.

Geoff - Thanks for the welcome! I have no specific design in mind yet, only possibilities. Im just trying to find out which of my ideas are good *and* legal.

Do any of you guys know of any bots-of-the-past that used flywheels to power their weapons (not spinners where the flywheel *is* the weapon)? If so, how did they do?

Regards,
Mack

[Guest]

Unlimited Rotational Kinetic Energy Storage?

Theres always Tip-Top (dont have the URL though).

[Guest]

Unlimited Rotational Kinetic Energy Storage?

Tip Top has a spinning disc, but its a weapon. Im talking about a bot that uses rotational kinetic energy to power a *different* weapon. Know of any like that?

Thanks,
Mack

[Guest]

Unlimited Rotational Kinetic Energy Storage?

Yes, but that weapon also powers the robot itself.

[Guest]

Unlimited Rotational Kinetic Energy Storage?

Right, and the name is just as clever as the design! But because it is a spinning weapon, it is limited by the rules of a spinning weapon.

Regards,
Mack

[fluppet]

Unlimited Rotational Kinetic Energy Storage?

There was a time when someone was talking about having a vertical flywheel which would hook onto an axe, thus providing the axe with a lot of kinetic energy. Did this ever get built? Another related idea which Ive not seen implemented is to spin up an internal flywheel and hook onto an external disk/bar once up to speed - which means youre not quite so constrained when shoved against a wall (see Hypno-disk vs Tornado). You could do a CO2-less flipper the same way, possibly with a Cassius III-style (when it was still going to have it) vertical flywheel at the back as an exposed weapon as well, although the engineering would be... challenging.

Ive often wondered about the idea of two counterrotating flywheels mounted above each other on a common axis, thus avoiding torque steer. The effect would be to chew into a relatively limited area on the opponent rather than to throw panels off, but it would stop the robot with the disks being thrown around the arena so much (although of course it puts more pressure on the axle). Is this a bad idea? Not that, for the same philosophical reasons as Mario, Im ever likely to build a spinner...

If youre talking about maintaining the KE in the flywheel for the whole fight (not powering it from batteries or similar) then I think thats more of a challenge; the buffering needed to survive the various forces to which the robot would be subjected would make it very difficult to do anything useful, and youd need a *lot* of energy to be up there with the amount stored in CO2, petrol or even batteries.

Just my tuppence.

--
Fluppet

[typhoon_driver]

Unlimited Rotational Kinetic Energy Storage?

we did toy with the idea of having a second flywheel inside the shell to give a boost to the spin up but it would have taken too much weight away from the actual weapon and it would have been difficult to effectively transfer the energy.

I also thought about the axe idea however the forces involved would require very well mounted components etc and prob in the end wouldnt be any easier than CO2.

[Guest]

Unlimited Rotational Kinetic Energy Storage?

I think I wrote something on the last forum about an axe like that. However, it was just an idea and never anything I had planned to build.

[Guest]

Unlimited Rotational Kinetic Energy Storage?

If all of the kinetic energy stored in a flywheel could be transferred into the opponent in one shot, Im sure that this would be more effective than a gas system. I agree that it may be difficult to design an energy transfer linkage that would be able to withstand the material stresses involved, but Im curious how much energy could be transferred with reasonable linkages (materials and geometry) without them yielding or quickly fatiguing. Transferring some fraction of the energy would simply mean that the unused kinetic energy of the flywheel would be left over for another shot or that it would take less time to spin the flywheel back up to speed.

In theory, you could hook any weapon to the flywheel and could even link the drivetrain as well for bursts of speed for ramming or evasion. Perhaps a flipper *and* an axe/hammer could go into the same design (simultaneously, not as interchangeables), but space would surely get cramped.

Fun to think, about, though! I think itd be fantastic to have a tossbot rather than a flipper that heaves the opponent vertically several meters. Getting under their center of gravity would be the challenge there, but seems possible.

I think that gas systems are a bit of a cheat because they enter the ring with huge quantities of energy that was stored prior to the match. Non-gas systems must convert chemical energy into kinetic energy no sooner than the start of the match. But given that those are the rules, it does seem quite wise to take advantage of this inconsistency.

Mack