Tashic's Robots

[Ellis]

Grade 2 titanium will be fine for non-spinner battles, but in truth you needn't use titanium unless it's to save weight. Steels will do for non-spinner events just fine.

If you have a wheel on each motor, I wouldn't recommend connecting the wheels by a belt or similar. Mechanically connecting motors can cause issues, in that two motors are never quite identical and so they struggle against each other. It would probably be fine but I can't see it benefiting the robot, in fact it may make the drive less efficient and you'd lose performance.

Rollerskate wheels and such are viable, I'm sure. Fairly robust, perhaps a little lacking in grip as the rubber will be hard. But as you say the main problem is connecting them to your drive motors. Behind those bearings will be a large, possibly odd shaped (although likely smooth) bore, which is difficult to attach to.

Also, nice work on the ant! The armour looks great, I love the overlapping sides.

[Tashic]

IMG_3156.jpgIMG_3157.jpgIMG_3158.jpgIMG_3160.jpgIMG_3161.jpg
Here's the finished ant.
Only a very small amount of the chassis is plastic and is very asymmetric because it is all hand made by me.
I had to make lot's of holes and cut some parts of the frame, but I managed to remove 8 gr and now it weights 149.6 gr.
The name is F2, because is the successor of F1:
IMG_3162.jpg
Most of the parts of F2 is from F1.
I also still have the chassis of the ants that I took appart!

[Tashic]

Time to post again!

A few days ago was my birthday, so I went with some friends to a go kart track to race.
There was a massive pile of used tyres and I got 2 of them for free! Are they good enough if I screw slices of them to some wheels?
IMG_3262.jpg

[mrsam]

A lot of Heavyweights use go kart tyres so yes they would be usable

[Tashic]

Hi all, I did a search on google for the weapon motor that Mrsam suggested and I found this:http://www.ebay.it/itm/Electric-Moto...item27eb68b78b.
At what voltage should run it?
Is 18V enough, as I intend to use 4 12V drill motors.
Also what's the best ESCs for the drive motors?
And for the axe can I use the servo and microswitches system or I need a esc for that too?
As for the HDPE for the chassis, where you buy it from?

Thanks

[Eventorizon]

Hatchet, Sams robot, runs on a 4S lipo at 14.4v. That drives the 12V drills and that motor. Its not amazing but it can give a good thump regardless.

The best esc will depend on your budget. Hacked TZ85A's are the top notch for most builds but they are over kill for a single drill. I would look at these: http://www.botbitz.com/index.php?rou...&product_id=74
If you buy 4, thats one for each drive motor, one for your weapon and one spare. its just easier to use the same type for everything. You may want to add a bigger heat sink to the weapon ESC to keep it cool.

Run it all on 4S else you will run the risk of burning out your drive motors on 5S without adequate cooling.

Most people get their plastic from Direct Plastics but I am not sure if that will be your best option if you are not in the UK.

[Tashic]

Ok 4S it is!

And for those esc I would need at least 5, as I plan to use 4wd with a drill motor for each wheel.
Also is the weapon motor able to self right the robot, and also what gear ratio is the best for both speed and power?

As for the hdpe, direct plastics can find a way of shipping to the delivery area if I contact them, I'll have to see.
In case there are problems for that, are there any alternative materials that could do the job?

[Tashic]

I was thinking of using two botbitz 85Amp for drive, and with 14.4V are they overkill for 2 motors each?
Also how would polycarbonate compare to hdpe?
And how about a welded steel body, will it end up to heavy?
I will use an electrode welder if steel is good enough.
I'm asking because I can get these materials close to home.
Thanks!

[Revsmin]

For two drills on 14.4v or 4S, 85A is overkill. For reference, I run a pair of 600w motors off two BotBitz 85A ESCs at 6S, and they could supply the motor with so much current that the motors got warm during a fight, and the ESCs stayed cool.
However. It means that your ESCs are unlikely to blow, so can be recycled bot to bot and allows for any upgrades to better drive you might want to do. The only thing I'd say is put fuses in place to prevent the motors stalling, as I believe TZ85 can supply that kind of current for a drill without blowing, so fuses will prevent you from smoking a motor.

[Flag Captured]

The TZ85s are incredibly robust, I've heard them be pushed to insane amp rates and still be fine. Go for a pair of those and shock mount them properly, you'll very rarely have problems I'd imagine.

Heck, I had one of my 900-can motors stalled (on 4S) for a while in one of the whiteboard fights, the motor was pretty toasty afterwards and the TZs still were fine.

Also, HDPE I would say is a lot better than Polycarb, most of the stuff I've seen made of polycarb gets cracked after a good hit from a spinner unless you use very thick stuff or design it extremely well I think. Welded steel would work, but the question is for all of it, what thickness?

20mm HDPE will stand up to most punishment, probably a good starting point perhaps. I went welded hardox with HardWired 2 and got no major damage throughout the champs, but if I did then it's much harder to repair. HDPE, you can take off a panel and replace it, and it's cheap to do so too for the most part.

[Ellis]

I can't say I agree that two drills on a single TZ85a is overkill. I wouldn't go smaller, especially if slightly overvolting. When a gearbox goes and a motor stalls the speedo will just eat it up, which is what you want, the alternative is a dead speedo (much more expensive to replace). They will handle future more powerful drives too. It's cheaper in every way in the long run to get the slightly pricier speedos now.

Polycarb can be used although unlike HDPE it tends to shatter under impact, rather than just gouge/flex. You can mount it loosely or shock mount it to help its brittleness. Less popular now but everywhere a few years ago - it's down to design.

A steel chassis is possible, although yes, heavy. You would need to plan ahead (do some weight calculations, either with rule of thumb or CAD) to make sure you stay under, can't say without knowing the design if you'd be over. A combination of steel and plastics is seen all over the world as a compromise. Steel chassis with rubber-mounted polycarb armour (that can be replaced) would be pretty tough!

[Revsmin]

I can't say I agree that two drills on a single TZ85a is overkill. I wouldn't go smaller, especially if slightly overvolting.

I did run six overvolted drills off a 25A ESC for 3 years remember :P

[harry hills]

The fact you have done that doesn't make it a good idea to do so.

[razerdave]

You were pushing the limits to be fair Jarvis .

Tashic: It's better to be overkill than underpowered, the Tz85's will do your drive just fine for ages (mine get a bit warm after 5 mins of running Satanix at full whack so you'll be fine )

[Revsmin]

I never said it was a good idea. I simply said it was possible as an example as to how TZ85s are overkill for drills . But, as I said, they will allow for upgrades to the drive so I recommend them.