The New 120

Current Working Name: The Sum of All Fears [in sigma notation]

Weapon: Drum (thus far named The Five Dollar Foot-Long)
Drive: 4-Wheel Tank

We should be done with our overall specifications in a week or so, at which point the serious CAD work will begin. The team has already ordered the drum, a beautiful chunk of 6" OD, 4" ID, 1' long steel (for the incredible price of around $5 [instead of $105] - typos on websites are awesome sometimes).

So far we're not entirely sure which competition we'll be attending, Battlebots or RoboGames. If Battlebots is in late March/early April, we'll probably be attending that competition instead of RoboGames. As the head of the weapons design team I wouldn't mind Battlebots, especially since we'll be able to max out the RPMs on the weapon to hit 300 fps almost exactly (around 8400 RPM). This should ensure that The Sum of All Fears has the most powerful drum ever fielded in the 120 lb weight class.

TELL US WHERE YOU GOT THE DRUM!! (have they fixed the typo???)

Dan Curhan wrote:

TELL US WHERE YOU GOT THE DRUM!! (have they fixed the typo???)

Here:
http://www.speedymetals.com/pc-3614-8242-6-od-x-1-wall-dom-steel-tube.aspx
And yes, they fixed the typo. They let us buy it at the lower price because it was their fault/to do otherwise would be false advertising.

EDIT: Oh, btw, can you make me a mod for this section?

done :]
and ShamWOW! lol... i'm gonna scour the internet for typos now!!

CAD work is coming along with the robot, and so far it's just a tiny bit overweight (180 lbs, and we still have to add some parts ). The final design for the drum should be done in around a week, and then optimization of the armor/chassis will take place.

After watching the first episode of the battlebots show on Thursday, I noticed a fatal design flaw in our chassis. More specifically, if the drum does not extend out beyond the chassis far enough, an entire side plate can be torn off when hit by 120 lb spinners. The chassis will be adjusted before the design is finalized.

Were you at Starbots on Thursday?.

If so, sorry we didn't meet up.

I came away with an opposite reaction..I feel that our 120 will be exdtremely tough to beat...especially by any full bodied or horizontal spinners.

Yeah, I made it to Starbot. Guy in the black RoboJackets polo.

The funny thing about your drum robots is they match the change I want to have made to the chassis, mainly in that the drum extends out beyond the corners of the chassis. I'm not sure if your powered wedges are vulnerable or not, but I think the wedge geometry itself prevents that kind of problem.

your drum didnt stick out?!

Cody Harris wrote:

your drum didnt stick out?!

It did, but not enough on the edges/sides. It's difficult to describe wihout pictures. With the changes, most side hits will now meet the drum instead of the chassis.

Jeff L wrote:

Yeah, I made it to Starbot. Guy in the black RoboJackets polo.

The funny thing about your drum robots is they match the change I want to have made to the chassis, mainly in that the drum extends out beyond the corners of the chassis. I'm not sure if your powered wedges are vulnerable or not, but I think the wedge geometry itself prevents that kind of problem.

If and when you see how we tie the whole front end together, I think that you'll agree that it can't get much sturdier..on both the Ti wedge and drum bots (soon to be another pair )

a 10-32 or 1/4-20 on each side holds our shaft in

I don't think that anyone does it like we do...not saying ours is any better, just a bit different..at least on the drumbots that is...

Since we're still having serious weight issues, I'm now investigating the pros & cons of a chromoly tube chassis. If I'm not mistaken, such a chassis is generally much lighter than the typical integrated armor aluminum chassis.

Jeff L wrote:

chrome-moly tube

chromoly
being 4130 steel the biggest thing to its strength in my oppinion(among many others) is heat treating it right
My old jr. dragster was an all tubular chromoly frame

Lots of triangular pockets in the alu...maybe with a sheet of Ti over it.

tubing = throw away frame, possibly and in many cases a lot harder to bolt stuff to without MORE welding or compromising the tube by drilling holes.

without seeing anything?????? pics very hard to really comment

copperhead was also a 4130 chromoly square tube frame. It held up pretty well - same frame survived 2 years with only one significant dent.

welding it was always a fun task with my frames
If you do go this route make sure you pick up some weld nuts(not sure about the technical term lol) They're nuts with tabs off of them to weld so you dont warp it, may add a little weight with enough but ALOT easier then tapping

Feel free to ignore the above about tube frames. Should have more details in a week or two.

Sum of All Fears has officially made weight. More details to follow.

the bot or the cad has made weight? i dont think many of us are having troubles ignoring previous statements anymore

Cody Harris wrote:

the bot or the cad has made weight? i dont think many of us are having troubles ignoring previous statements anymore

why don't you tell us how you really feel?....

The CAD has made weight. We'll be doing a bit more tweaking for about one more week, then pick up material and start water-jetting. We're going with the aluminum chassis (a few changes have been made), and the whole thing should come together very quickly once the CAD is done - it'll be fully operational in mid-February.

becareful with screws and wire, the weight we'll add up. It would be such a wonderful world if everything turned out like it does in solidworks lol
WIth SW and a ti-89 I probably wouldnt even have to go to school!!

edit: with solidworks and a ti-89 why am i going to school?!! hahaha

We're well aware of that. In fact, we haven't even pocketed yet and we're at weight (and we do plan to pocket the internal structure (that much solid aluminum is hilariously overkill)). So we're quite safe at this stage - we should have a CAD at about 110 lbs pre-build (the only guestimated components will be wiring and possibly some decorative features [paint/LEDs]).