Spike evolution (featherweight)

[Danjr1]

Re: Spike evolution (featherweight)

Just to elaborate on what Gary said, my first proper drum was outsourced and cost £150. That was with all the material provided and with free machining so if you were to pay for machining and didn't supply the material it would cost a lot more. By comparison, my most recent drum cost perhaps £10, but that was achievable mostly due to the goodwill of others supplying pieces, workshop time and machine work. So the cost of making a drum spinning element is really like the age-old question of how long is a piece of string?

As for ratios, again it depends on what motor you use, what your desired output speed is and so on but for reference, Drumroll II running on a Speed 900 motor at 19.2V has a ratio of 2.2: 1 (a 44-tooth pulley on the drum and 20-tooth pulley on the motor).
When I used a brushless motor for a while, it was a ratio of 5:1 as the brushless had a higher rpm and needed a bit more torque when starting up. So it's all just a case of tailoring it to suit your individual needs or preferences.

Ok, cool, thank you. How did you manage the kick back when it hits something? Some form of clutch?

[Anttazz]

Re: Spike evolution (featherweight)

I wasn't sure if you meant for the spinner or in place of the drill motor you mentioned. Having a quick scan of that one shows that if you run at 19.2v you'll need to change the fan of the ESC. Also i've heard that people say that sometimes the ebay ESC's can overrate their current handling a bit.

[typhoon_driver]

Re: Spike evolution (featherweight)

that motor/esc combo is useless. It's an inrunner brushless motor, high rpm (6000 per volt) low torque. Not what you want in a brushless motor setup. You would need large gearing to use that which makes it pointless going light.

Get a speed 900, strap a relay to it, job done. Nice reliable system for your first spinner.

[RogueTwoRobots]

Re: Spike evolution (featherweight)

How did you manage the kick back when it hits something? Some form of clutch?

Not really. I use timing belts and pulleys so technically there is potential for slippage in there but I doubt that very rarely happens. If you want to rely on belt slippage as a clutch, V-belts are the best option.

No I just let the poor motor take the abuse. Maybe not as great an idea with brushless motors, but Speed 900s are tough little jobbies that can take just about anything you throw at them, so once it's running and spinning, I very rarely turn the motor off in a battle, unless it is obvious that the drum is being stalled.

[Danjr1]

Re: Spike evolution (featherweight)

Ok cool. Two 150mm discs on some form of axle on a speed 900! Thinking that I'll keep the discs as close to each other as possible then a wedge on the back (or front). Du really need a esc or just a switch for a spinner? In theory, full range speed control seems a little pointless?

[typhoon_driver]

Re: Spike evolution (featherweight)

a 150mm disc will have little effect unless you go nuts with the weight on them. For a disc you really want to have a 250mm diameter or there abouts with as much of the weight at the outer diameter as possible. The reason being is the kinetic energy that it can store.

http://www.teamcosmos.com/ke/ke.shtml

[typhoon_driver]

Re: Spike evolution (featherweight)

o and a solid state relay on the speed 900 is preferable (at least for me anyway), I tried speed control on a disc with hornet, found a relay much better.

[Danjr1]

Re: Spike evolution (featherweight)

Just looking on technobots for some belts and pulleys now, anyone recommend anywhere else worth looking?

[typhoon_driver]

Re: Spike evolution (featherweight)

rs components if you got a depo beside you can be cheap. HPC gears stocks everything and can make custom parts but you will pay for it.

[Danjr1]

Re: Spike evolution (featherweight)

a few pictures of the latest creation!

[Laser]

Re: Spike evolution (featherweight)

That looks awsome!
I love it in the checkerplate.

[razerdave]

Re: Spike evolution (featherweight)

That looks very nice

[PJ-27]

Re: Spike evolution (featherweight)

Looks really good! Bet it has some push.