Help with disc

[geoff]

Ewan,
Even if you make the disc 20mm wide then you only increse the KE to 180j (still not a lot!!)
If you have access to cnc facilities why not have them cut you, as Christian sugested, a rim biased drum
if you could get say 70 - 80% of the mass at the rim and a width of say 75mm your KE rises to around 0.61Kj @10000 RPM BUT you are looking at around 1.9Kg in weight!! The fundermental problem here is that your dia. of 65mm is too small to allow a reasonable rim speed and therefore an acceptable KE, unless you are going to run it at silly RPM!! +/- 17500!!
If you want my advice, I think you need to have a serious think if this really how you want to go on this bot.

Sorry I dont have an MSN id. I use Yahoo IM

This is just an add-on weapon, just something active to keep the robot exciting as it will be mounted up the wedge, the disc will have very mini teeth, just the nibble the opponents underbelly. I am not looking at anything OTT, and the weight I have remaining in the bot after the fully CNCd chassis is quite small...

[geoff]

Fair enough Ewan, just keep it SAFE!!

Actually, most drill motors does something about 20000 RPM at their rated voltage. So with a bit of overvolting, that speed is reachable!

[ewan]

Seeing as an output of 20,000rpm is quite possible with this type of motor (when overvolted slightly), I have recalculated, using the http://www.teamcosmos.comwww.teamcosmos.com kinetic calculator, that even a tiny disc like this has 1705j of energy stored within it (this is when you take the energy with centre milled out to a smaller thickness...