'STING" is ready to rumble !!

Here it is ....my 3 lbs. drumbot scaled down from MLEC's TTATT

Basically 17 mph, plenty of pushing power and 1500 joules at the moment

Here's some pics.....tell me what you think??





Video coming up tomorrow.....only thing left is to make some more teeth and get them hardened...these are soft S7 at the moment, but have an interesting shape...for max bite...hopefully

Ohhhhh, very pretty. Nice job.

Thanks ...it was a lot of work....

It weighs 1 gram under 3 lbs. hahaha

from what i can see of the tooth, it looks like what we did on one of our drums. We only used it against uknight in miami and altough it got chewed up it work great!

Cody Harris wrote:

from what i can see of the tooth, it looks like what we did on one of our drums. We only used it against uknight in miami and altough it got chewed up it work great!

Should hopefully cause the chips to curl....hahaha

With the minimum charge for heat treating, I may make a few sets ...different shapes, sharp, blunt, etc and possibly different hardnesses from 50 to 55...depends on how much time I have

Also, on a side note....I pretty much balanced the drum in Solidworks...it spins 40k without much vibration....haha...I might take it to get checked if I have time.

RMP is having a competition on the 10th...should be interesting...

holymoly..I need to learn how to drive....lol I've got a week!!!

edit: Both bots are using our Deans Ultra switch ...so the testing has begun !!!

Hmmm--am I noticing an 'articulated" drum? I've thought for some time that one weakness of the drums is that they either A) Must have a diameter smaller than the vertical height of the robot's body, or B) Cannot be truly invertable. It seems you may have found a good way around those problems. Was TTATT like that as well, and I simply never noticed?
Either way, this is brilliant.

Did you happen to see "the Bull" in SF (Battlebots Nationals)? Because the extensions that orient the drum on your 'bot remind me a lot of the supports that the Bull had, and they were quite effective in pushing and ultimately flipping our small vacbot (CuddleBunny), once thier 'eggbeater' was dislodged.

Oh, and some other nice details I'm noticing--
Are those wheels simply Colsons that you have turned to give them a smaller contact? I noticed the same on your powered wedge, and had wanted to ask. Ultimately, what is the advantage (other than looking really cool)? My guess would be that the 'bot turns with much less demand on the drive system, but if that's true then it seems you would have a compensating loss in resistance to pushing by an opponent.

And it seems you are running two timing belts, both 'tooth side out' for the drum. I understand the tooth side out thing (sometimes a little slip is good!), but why not go with a single, wider belt? Also, when you flip belts like that, do you need to adjust your center distance to compensate? And do you typically design to a specific belt/pulley, or do you usually make the center distance adjustable?

Offsetting the drive motors for more internal space (or narrower overall width really) is logical, and requires a belt to avoid offset/asymmetric wheels, but why not drive one wheel directlly, and just use the belt on the other? It seems this would be a bit lighter, and remove one failure mode for one wheel at least.

Are the logos actual sponsors? What did you get out of them, and more importantly, HOW? Also, are the logos simply silkscreened on, or is that machined into the metal somehow?

I fear if too many Ransom students see the kind of work you are doing, they are gonna leave my program to flock to yours!

(Wow--rereading this I feel I'm giving you the third degree--I really don't mind if you want to keep some of this to yourself, or simply don't feel like answering a bunch of dumb questions.)

rdubard wrote:

Hmmm--am I noticing an 'articulated" drum? I've thought for some time that one weakness of the drums is that they either A) Must have a diameter smaller than the vertical height of the robot's body, or B) Cannot be truly invertable. It seems you may have found a good way around those problems. Was TTATT like that as well, and I simply never noticed?
Either way, this is brilliant.

Did you happen to see "the Bull" in SF (Battlebots Nationals)? Because the extensions that orient the drum on your 'bot remind me a lot of the supports that the Bull had, and they were quite effective in pushing and ultimately flipping our small vacbot (CuddleBunny), once thier 'eggbeater' was dislodged.

Wow Bob...you just wrote an essay in 2 posts!!!!

Where to start and what to give away or not??

1) TTATT was the same

2) These are invertable, but not symetrically..Drums spins in both directions, so inverted is no biggie.

3) The 3 blade drum emulates a single blade design.....result is more speed and joules without grinding.

4) I did see the bull, but that was not an influence on our design. Ours actually look like POT bellied birds...lol

the theory behind them is somewhat obvious, but would take some time to explain the whole show

Basically, wedge, to try and lift wedge and low bots, same deal when inverted, but with the ability to hit the wall and get un-inverted...similar to Hummdinger

Lastly, a good forward floor pivot during drum impact....

TTATT's drum was a balancing nightmare, this one was balanced in Solidworks...so far ir seems pretty close.

Oh, and some other nice details I'm noticing--

Are those wheels simply Colsons that you have turned to give them a smaller contact? I noticed the same on your powered wedge, and had wanted to ask. Ultimately, what is the advantage (other than looking really cool)? My guess would be that the 'bot turns with much less demand on the drive system, but if that's true then it seems you would have a compensating loss in resistance to pushing by an opponent.

They are 1 5/8 x 7/8 Colsons...which btw , like all 7/8" Colsons only have 3/4" surface contact with the floor...so we remove the hub extensions...and we also drilled these to soften up the rubber and lose some weight

I was not comfy with foam or thin plastic rimmed wheels, in that we expect to pack a big punch and need to be able to survive our own forces.

And it seems you are running two timing belts, both 'tooth side out' for the drum. I understand the tooth side out thing (sometimes a little slip is good!), but why not go with a single, wider belt? Also, when you flip belts like that, do you need to adjust your center distance to compensate? And do you typically design to a specific belt/pulley, or do you usually make the center distance adjustable?

The drum can be run with 1 belt of that width, so we use 2 in case one goes south . Yes, we do both..calculate c/d based on the OD of the belt, and have a push/ pull system of belt tensioning...Lots of R & D on this

Offsetting the drive motors for more internal space (or narrower overall width really) is logical, and requires a belt to avoid offset/asymmetric wheels, but why not drive one wheel directlly, and just use the belt on the other? It seems this would be a bit lighter, and remove one failure mode for one wheel at least.

1) We run RIGID axles on all wheels, so mounting to a motor shaft is not in the plan. This provides support and rigidity to the whole structure, and also removes loading the motor shaft during impacts.

If you look closely, you'll notice that our Ti sides are supported at 3 or 4 points between the front and rear braces....makes for a VERY rigid setup

2) The weight of the extra belts and pulleys is minimal, especially as compared to the benefits of rigid axles...CODY agrees, I'm sure??

3) If we lose a belt, the other wheel still has power.....

btw: this was simple with TTATT and the 36mm bbots g-boxes, but not on the little bots...new shafts were made from Ti

4) Another reason not to direct drive 1 front and 1 rear, is flexability in wheel location, plus we are able to brace the motors with 1 combo bracket, if needed

Are the logos actual sponsors? What did you get out of them, and more importantly, HOW? Also, are the logos simply silkscreened on, or is that machined into the metal somehow?

The sponsors are part of a larger corp named 'Designatronics'. I do consulting work for them, so a little arm twisting resulted in the sponsorship. Not able to say what was sponsored at the moment. Logos are engraved into the metal

I fear if too many Ransom students see the kind of work you are doing, they are gonna leave my program to flock to yours!

(Wow--rereading this I feel I'm giving you the third degree--I really don't mind if you want to keep some of this to yourself, or simply don't feel like answering a bunch of dumb questions.)

The little bots are scaled down versions of MLEC's 15 pounders, for several reasons....we can test a lot of our theories and find problems, well before the bigger bots see action.

The babies should drive and react very similar to the big boys..

I am advisor to MLEC, but no need for anyone to jump ship...I have always helped ANY and ALL students from any school...just need to ask

I've offered to help Will tweak his Fluffy, but so far no bite

Wow! Thanks for the thorough (and rapid) reply.
It's kinda funny, I had always wondered why the invoices from Stock Drive Products said 'Designatronics" on them--now I know. I suppose one could say that our main sponsor (for whom I work, of course) is Ransom Everglades.

On the axle thing--as soon as I read it, I did a headsmack--Of course you are using 'dead' axles--this was our original plan for a 120lb drive system, for precisely the same reasons you've given.
Sooo, I guess that means some sort of bearings are pressfit into the wheels. (Or maybe not--it's just a wuddle 3 pounder after all)
I don't expect you to reveal all, but in general, what do you think about bearings vs. bushings for drive and other low speed apps? I personally think the nylon bearings that come with the Colsons are plenty good for practically any size battlebot (I think the larger wheels are rated at something like 300lbs load per wheel!) In SpiderPig we went with oil impregnated bushings for the 'cantilever elimination' opposite our drive motors (which of course were direct drive), but that meant that the parts had to align precisely. One of my concerns was that the frame would get just slightly bent and all our drive motors would fry.

Bushings can handle a lot more load especially at low speeds

We are using....top secret material...lol......ptfe acetal...or delrin with teflon in it. trade name is delrin af and it's not cheap....I've done testing against other materials and this stuff is good....it's along story...but maybe one day...

Another thought....if possible make things loose as a goose.....this reduces friction and amperage draw and if you get badly wacked, you might still be able to hobble around.

My first bot had everything according to standard machining practices and amperage draw was too much...also, a couple of good wacks later and things were binding up.

A note on bearings...great for low co. of friction and high speeds, but load is only point contact between the balls and races....a bushing will handle a LOT more load.

That's why machines such as big presses, shears and punch presses use bushings.....a simple 1/4" wall bronze bushing can take hundereds of tons of pressure and if properly lubed, last many years doing so.

Delrin (acetal) is supposed to be self-lubricaing, but I've seen plenty seize...even the teflon impregnated ones...so loosey goosy and add some secret lube...lol..

Haven't used them, but the oem colson bushings are fine if you can use them...we bolt the wheels to the pulleys, and use a longer bushing that both ride on....

These are little bots, but have all the good stuff ....that we can think of...every bot is improved over the last one that we built.....(I hope)

I lost track of all of my comments in reading this haha
With aftershock we ran a single belt with mid mounted motors, it was nice to mount the dead shaft wheels but we snap belts on HUGE hits and have lost matches cause of it, but he is running two on each side making the possibility much slimmer.
SNS we drove the backwheel and ran a belt to the front tho, but it is slightly different then Humdinger or Fluffy
From drum height i believe later models of MI were like that, but the didnt use a reversible ESC.
We tried the flipped belt thing this year, not so much luck lol
umm im sure theres points im missing haha

rjw wrote:

Should hopefully cause the chips to curl....hahaha

Quick question: I've noticed quite a few people talk about weapon design and talk about "shaving" the other robot or getting chips, but I've never understood that very well. Wouldn't cutting into weak armor or simply blunt, brute force, be more effective. I mean I realize that you take just as much abuse as you put out, but is trying to get chips off of, in some cases 1/8th-1/4 titanium or steel, just doesn't seem very effective to me.

Again, love the robot, but can anyone help me understand what I'm missing? Thanks.

Cody Harris wrote:

I lost track of all of my comments in reading this haha
With aftershock we ran a single belt with mid mounted motors, it was nice to mount the dead shaft wheels but we snap belts on HUGE hits and have lost matches cause of it, but he is running two on each side making the possibility much slimmer.
SNS we drove the backwheel and ran a belt to the front tho, but it is slightly different then Humdinger or Fluffy
From drum height i believe later models of MI were like that, but the didnt use a reversible ESC.
We tried the flipped belt thing this year, not so much luck lol
umm im sure theres points im missing haha

I thought that the belts on AS were a little ambitious.....if scaled up. Sting's belts would probably be 3/4" wide ...lol

The reversed belt deal is tricky...I could write a paragraph on the do's, don't and why's....maybe another day.....I have a lot of R & D into the whole philosophy....

SenaiERI wrote:

rjw wrote:

Should hopefully cause the chips to curl....hahaha

Quick question: I've noticed quite a few people talk about weapon design and talk about "shaving" the other robot or getting chips, but I've never understood that very well. Wouldn't cutting into weak armor or simply blunt, brute force, be more effective. I mean I realize that you take just as much abuse as you put out, but is trying to get chips off of, in some cases 1/8th-1/4 titanium or steel, just doesn't seem very effective to me.

Again, love the robot, but can anyone help me understand what I'm missing? Thanks.

Not looking to make chips.....the idea is to get a bit more bite if possible so that the opponent really gets the brunt of the hit.

Mind you against Cody's 'Chewy aluminum' , some serious chips could be carved out..

In a head to head spiner vs spinner assault is where the thinner sections would break off....so in conclusion???? Bring a few different designs for different situations??? but basicly I think that we all agree that the idea is not to carve, but to go for the big hit

So, what are you missing???? I don't know, but when you find it, let us know...haha

Because of the frame design we needed to use tensioners, if we had the weight for a spring loaded tensioner it would have worked great! but we didnt and with rigid tensioners drive belts snap lol
With the special tooth design, it doesnt really matter if you use it against other drums, the teeth get chipped up either way and it hardly effected the balance
Its kinda wierd the chunks that i've shown seem to go with the big hits
Our weapons hardly ever stop spinning so it sorta makes sense haha

Uh, I'm confused (again)--so, MORE QUESTIONS!!

Cody Harris wrote:

he is running two on each side

Is Sting 2 wheel or 4 wheel drive? At first I thought 2, because that's all that's obvious (but with richard I'm learning what's obvious is usually only a tiny part of what's going on--like an iceberg). Now that I'm looking at it, there could be two pulleys on each motor shaft, which would also explain why the front wheels are spaced further apart. (And of course, the front belts are cleverly concealed by the sexy lid.)

Also, Cody sez

Cody Harris wrote:

With aftershock we ran a single belt with mid mounted motors

hmm, how does that work? like this, maybe?


And lastly,

Cody Harris wrote:

SNS we drove the back wheel and ran a belt to the front tho, but it is slightly different then Humdinger or Fluffy

How so? There's really only one way I can think this could be, with the slight exception of having same sized wheels and pulleys rather than the two different sized ones that Fluffy used.

Uh sorry, I cannot seem to get the image to post correctly. copy n paste the link, K?

Like an iceberg, Sting is 4 wheel drive...lol...?????

Now the next question is what are those gizmos on the motor shafts between the drive pulleys???

More iceberg like parts?...it's our latest trick setup that will probably be retrofitted to ttatt if it continues to work as well as it has so far...

THe tensioners setup is almost exact as to what we did but we used two or three tensioners, cant remember.
SNS uses same size wheels and pulleys front and back, there the 1' 5/8 colsons just like Aftershock. I wish you guys could have seen it actually in person, because like Fluffy it wasnt just another Humdinger knock off, just inspired lol. The top of is actually angeled down, with a slight vertex in the middle to make it invertable, the another vertwx at the rear wedge. Also the gearbox we modified, cough hacked up, to be mounted the rear most possible

edit: wasNT another humdinger knock off haha woops

1 5/8" Same size Colsons as Sting...lol

those would be them lol

VERY NICE!!

Will Bales wrote:

VERY NICE!!

Thanks Will....