Some advice on spinners, please...

[bigsi]

Just out of interest Sam, who do you rate? (Im not fishing - you understand ;-)

Si

[typhoon_driver]

oh and what grade os stell and what thickness would you surgest for the blade

perhaps look into getting something like hardox (our hardox cutters only need a slight sharpening after series 7) and put as much weight as far from the centre as possible. A simple experiment with a set of compasss can show you why.

1) Spin the compass with the legs shut
2) Spin it with the legs fully open

You should definately feel a difference between the 2 and so this gives a simple demonstration as to why to get as much weight to the outside as possible.

[shredderteam]

Simon

Hmmm, I think Ill have to skip that one.. could be a real can of worms

I think our friend Gary here could certainly claim to be one of the few at this point though!

Sam

[typhoon_driver]

we currently have welded on teeth on typhoon 2 and typhoon. The guys that did it for us did a very nice job and the cutters havent let us down.

At extreme 1, we had bolts coming out the side of typhoon and all of these were either sheered off or bent. This is the main problem with removable teeth is that the weakest point on them is always going to be the join and it could result in an unbalanced disc, however it does mean that you can change the cutters. Eg -have one set which are designed to cut and another designed to smack.

Bolt ons also mean that it is easier to change teeth if they become mishapen

It does of course depend on materials etc but as long as bolt on cutters are supported well enough there should be no problems with them.

But its up to you!

[danoh]

well the blade from top to bottom will be about 1m so ill need a very fast motor to put alot of energy into it, before you say it i am going to build my robot so that it can take the shock when it hits an opponent, ive looked into shock mounting and im confident that the robot will do more damage to its opponents that it does to its self. oh an by the way its not a disk its a proppelor spinning at about 45 degrees kind of like the one the six million dollor mouse uses.

[bigsi]

our friend Gary here could certainly claim to be
Id agree with you there!

Daniel,
so that it can take the shock when it
hits an opponent
One other thing you need to consider besides the shock, is the reaction torque when you try to steer - you will notice this most on fast/heavy (high angular momentum) disks - and most particularly when they are not horizontal.

I would say most spinners have welded on teeth - and I know one or two have moved from bolted to welded. We of course, having steel teeth on a plastic drum do not have that luxury! If the placement and type of bolts are appropriate - bolting will not be an issue. It gives a number of advantages like being able to make rubber teeth for friendly fights and being able to taylor the tooth profile to different opponents.

Si

[shredderteam]

Supernova still use bolted teeth

and break them/lose them in almost every fight!

Id personally go for integrated teeth if I were you Daniel, bolted teeth need to be incredibly well mounted (to the point of almost impossible) in order to stay put when the energy transfer occurs.
The only problem with integrated teeth is that youll need to make sure theyre the right material, as the last thing you want is to have to replace the whole disk every time a tooth chips!

Sam

[wenman]

Daniel if your looking at a 1m diameter your looking at a serious amount of energy (dependant on the speed its doing). The key thing with a spinner is to get it upto speed quickly so you dont leave yourself open to attack.

What speed are you planning to spin this thing at since the energy is related to the square of the RPM.

E=0.5Iw^2
E=energy in disk/propeller in Joules (I aim for around 14000J)
I=Polar moment of masses kg m^2
w=angular velocity in radians per second (=2pie x rpm/60)

Assuming you are spinning this at any sort of speed youll probably be looking at Magmotors, Briggs & Stratton, Lynch motors or a petrol engine.

Richard Wenman
Team Mayhem