Some advice on spinners, please...

[danoh]

Some advice on spinners, please...

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]

Some advice on spinners, please...

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

[Guest]

Some advice on spinners, please...

Supernova still use bolted teeth.

[shredderteam]

Some advice on spinners, please...

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]

Some advice on spinners, please...

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

[jim]

Some advice on spinners, please...

Ian, since you are getting the disc CNC milled, you should be able to machine slots in the disc for the teeth to slide into. If the disc and teeth are appropriately keyed, the bolts should not take any significant load from an impact.

[wenman]

Some advice on spinners, please...

Sorry that should be I= Polar moment of inertia of masses. For a rectangular plate
I=M(a^2+b^2)/12
M=mass
a=width
b=length.

To increase the I value you want to make the propeller broder at the tips.

Also you want to make it of pretty thick material to stop it bending. Mines 12mm thick steel and Matilda still cut through it and bent it slightly up where she hit it.

Richard Wenman
Team Mayhem

[danoh]

Some advice on spinners, please...

richard, what grade of steel do you use for your disk?

[wenman]

Some advice on spinners, please...

I just used standard mild steel since I figured that this would be strong enough in 12mm thick.

Oh boy was I wrong.

What sort of speed are you looking at for this propellor Daniel?

Richard Wenman
Team Mayhem

[supernova]

Some advice on spinners, please...

We use Mild steel aswell. Matilda managed to bend our disc slightly aswell, its 33mm thick at the rim!

[maddox]

Some advice on spinners, please...

Not to mention the contact with Mechaniac that had some effect on the teeth.

[icemanuk]

Some advice on spinners, please...

Gary

Consider an IC motor like ours for Executioner.

The advantage of our IC is that it weighs 3kg and yet still spins the disk to over 8000 in 2 seconds from dead stop. Another advantage is we dont have to carry any extra weight for batterys to power an electirc spun disk! This leaves us more weight for ARMOUR.. A good quality chainsaw motor will never cut out and will start everytime first time. It will also quite happily run in any orientation even upside down too.

The downside is price :sad: I paid 300 I think for the Stihl! So not cheap I know.

We have learnt our lessons from series 7 and now sport a new very tuff scoop at the front and also an aluminum hub for the disk itself with bolt on blades. This has enabled us to increase the reach slightly of the disk and also lessen the weight overall. Along with the new speed controler from here (Anyone want a secondhand vantec?)

http://www.roboteq.com/index.shtmlhttp://www.roboteq.com/index.shtml

We HOPE to at least once manage to get past the first bloody round :sad:

[Guest]

Some advice on spinners, please...

If you know what youre doing, you can get some chainsaws to peak at over 20 horsepower! There are already some teams who have done that with a chainsaw from the Swedish Husqvarna.

[spinnerboy]

Some advice on spinners, please...

I see Whyatchi superheavy i think uses 2 15hp ic engines.

[glen]

Some advice on spinners, please...

im planning on using a small chainsaw in my featherweights spinning weapon.

did you have to modify the clutch to take a pulley/sprocket and if so how did you do it?

anymore info you can divulge on petrol engines?

thanks, glen