Building my first FW ..

Hello everyone,

This is my first thread and I just have a few quick questions to ask. Im currently building my first combat robot, I thought a spinner would be a good place to start (dont want to mess around with pneumatics just yet lol) its gonna be a 2wd machine with a 4kg blunt impact vertical spinning bar im guessing 4kg is at the top end for weight of spinning discs/bars for feathers? And to the guys that are running spinners what motors are the most popular choices? I've read up on speed 900's but im told they arnt being made anymore, any decent alternatives?

I'll throw up some pics of my plans if anyones really interested, hopefully I'll be able to get a look at your machines first hand at an event sometime next year.

Cheers guys,

Dan

Most people start with drill motors for drive and a basic pushy robot :) Spinners are difficult to engineer until experienced (assuming your not a machinist etc.).

Quote:

---

Originally Posted by daveimi

Most people start with drill motors for drive and a basic pushy robot :) Spinners are difficult to engineer until experienced (assuming your not a machinist etc.).

---

I know I shouldnt be 'running before I can walk' but I've already gone and got the bar sorted and bought some more powerful batteries to handle the drive and the bigger spinner motor. I figure with some advice froms guys that have already built spinners I'll be ok! :P

I've also got some 20 mm HDPE im gonna use for the chassis and some 5 mm polycarb which im going to triple up to 15mm for the base .. gonna line the insides of the hdpe in rubber to absorb some of the shock (there must be a massive shock going through these little machines when they get clattered by a spinner ect).

I've got some old speedos from when I was going to build a feather before but never ended up doing it lol .. but I reckon I'll need some better ones so yeah best place to buy speedos online?

Look forward to whatever you build! A spinner as a first machine is always ambitious, but there is no faster way to learn than to build something challenging and then throw it in the deep end.

Many of us are now using "tz85s", which are speedos originally designed for brushless motors, but are "hacked" for brushed use by a group in Australia, called Botbitz. In terms of performance for your money I'd say they're right up there. http://www.botbitz.com/index.php?rou...&product_id=59 - you'd need two, one per side.

They do sell a 30a model, but I know less about these. They should run a single drill, but if you can afford the 85a versions, they'll last, and will serve in future machines.

For motors, Brushless is the most common these days. Which Brushless is obviously something you'd need to have a look at a bit more in detail based on your build so far (There's some low KV NTM Prop drives on Hobbyking.com which are supposedly pretty good and torquey for a heavier spinner like that)

One thing you will need to account for is the stability of such a heavy vertical spinner, you'll obviously want to spread the weight out to make sure it'll stay on at least one wheel, because the higher speed spinners do have quite a bit of a pull to them. What batteries/drive motors have you got for the machine, by the way?

Quote:

---

Originally Posted by Ellis

Look forward to whatever you build! A spinner as a first machine is always ambitious, but there is no faster way to learn than to build something challenging and then throw it in the deep end.

Many of us are now using "tz85s", which are speedos originally designed for brushless motors, but are "hacked" for brushed use by a group in Australia, called Botbitz. In terms of performance for your money I'd say they're right up there. http://www.botbitz.com/index.php?rou...&product_id=59 - you'd need two, one per side.

They do sell a 30a model, but I know less about these. They should run a single drill, but if you can afford the 85a versions, they'll last, and will serve in future machines.

---

They look good, think I'll go for a couple of the 85a ones. Im planning to use something a little more powerful than drill motors as the machine is gonna be running at 18v anyway :) I've got 3 18v 3.0amp lithi batterys, I figure the bar is gonna have to have a pretty big motor to spin it up quickly so I went for the extra power.

Im gonna have to build the machine around the weapon so its not off balance, im going to try and mount the bar as centrally as I can on the chassis .. gonna have some HDPE bulkheads for the bar.

The 85As are fantastic, all things considered. If you're good at all the technological side of things, you can always buy the base speed controller and hack them yourselves at an even lower cost (there's a tutorial somewhere for that) but again, it depends on your skill level and confidence!

You're best off going more powerful than drill motors at that voltage too, I would say speed 900's, but they've gone out of production. BaneBots do motor/gearbox combos that'll be ideal, but they can get pretty costly from what I recall, particularly with shipping. Plenty of high-power brushless motors run nicely on about 18v too, so you'll be fine from that side of things. Maybe look into above 6s though, depending on the motor you get.

On the other hand, Valkiri 2 and Hannibalito 4 drive very nicely (Valkiri without weapon tough) on drives that have a max of 150W each side. Meaning the Botbitz 30A speedo's are perfectly useable.

Of course, those machines have fairly powerfull weapons, so drives ain't the main powerhogs.

I've heard that the 30A's are, but it's a massive safety net if you're new to roboteering I suppose - that was my reasoning for going for the 85A's instead of the 30's. Might be a bit more cash, but if you somehow manage to pull more than 30A by wiring something up wrong or stalling a motor, it's definitely better to not lose an ESC! That, and you're set if you ever choose a much beefier drivetrain that draws a lot more amps.