Spike evolution (featherweight)

[Danjr1]

Currently running 4 Argos motors on 12v nimh, via blue marine escs. Thinking of going to 4 24v drill motors at 30v via a sabretooth 50hv. What do people think?!

[mattsdragons]

Re: Spike evolution (featherweight)

why not just overvolt your argos ones to 18v, that will give you some great speed on the right wheels for less cash

[Danjr1]

Re: Spike evolution (featherweight)

30 is better than 18

[gizz]

Re: Spike evolution (featherweight)

The higher voltage you're using also affects the total weight as you have to have more cells = more weight on the batteries alone which in turn
gives you less to play with for armor / active weapon etc, also a bigger speedo weighs more. Not by much bit it still counts.
12v drills on 18v has been used succesfully and could be a good start, wont have to buy more drills or a larger ESC

[psychostorm]

Re: Spike evolution (featherweight)

Currently running 4 Argos motors on 12v nimh, via blue marine escs. Thinking of going to 4 24v drill motors at 30v via a sabretooth 50hv. What do people think?!

I think you're mad.
24v hammer drill motors will be fragile & force the width out to 30cm minimum. The speed in any case could be well beyond controllable.

[typhoon_driver]

Re: Spike evolution (featherweight)

30 is better than 18

Not necessarily. Overvolting a 12v motor to 18v is a 50% increase, overvolting a 24v motor to 30v is only a 25% increase. When you double the voltage on a motor you get 4 times the power out of it. So it's a % increase that you're after. This is why motors burn out, they produce more power than they can handle, draw too much current, overheat and burn out.

This makes the assumption that the two motors are of the same power output to start with.

[Danjr1]

Re: Spike evolution (featherweight)

Currently running 4 Argos motors on 12v nimh, via blue marine escs. Thinking of going to 4 24v drill motors at 30v via a sabretooth 50hv. What do people think?!

I think you're mad.
24v hammer drill motors will be fragile & force the width out to 30cm minimum. The speed in any case could be well beyond controllable.

The 'bot is 50cm wide already! Why would they be fragile?

[psychostorm]

Re: Spike evolution (featherweight)

Bowing forces due to the length of the overall mechanism make it snap at the plastic gearbox tabs.

Or at least that's what happened when I tried

[ewan]

Re: Spike evolution (featherweight)

Much easier to mount smaller drills too

[Danjr1]

Re: Spike evolution (featherweight)

Got a 24v drill today! A lovely looking motor and gearbox (looks like it's the next grade up from the Argos motors) but doesn't look like it's going to work sadly.

Soooooooooo..........

How much does it generally cost to make a drum/spinner? The actual spinner part? And what ratio do people run?

[typhoon_driver]

Re: Spike evolution (featherweight)

that's like asking what the price of a new car is without specifying what car or what you need from it. It also depends what tooling you have available to you? If you have access to a lathe or a mill then you will be able to do most if not all of the construction yourself. Otherwise you will need to outsource it. Kenny is usually the go to guy for machining parts.

I have built spinner setups for less than 100 quid in the past but it all depends on what you're after.

[Danjr1]

Re: Spike evolution (featherweight)

20cm long by 15cm diameter drum or an axle with 4 or so blades at 15cm diameters. Found a half decent motor (eBay 180644333591). Am thinking of using a belt and pulley system so that it can slip when it hits something?

[Anttazz]

Re: Spike evolution (featherweight)

That is a brushless motor so might not be what you're looking for

[Danjr1]

Re: Spike evolution (featherweight)

Thought brushless was the way to go for a spinner motor?

[RogueTwoRobots]

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.

EDIT: Brushless motors certainly make spinners a more lethal proposition but they are not the be-all-and-end-all of spinning methods. Brushed motors are a perfectly suitable alternative; for the past three years at the UK FW champs, a spinner has finished 3rd, and all those spinners used Speed 900s as weapon motors so they can do the job. It's more difficult to get a brushless spinner setup running reliably; Dave Moulds (360) went through several motors, controllers and money to get his disc running well. In the end though, the more important factors are the properties of your spinner itself (such as mass distribution, moment of inertia and, to a degree, cutter bite)