Twisted Sick Robotics

[Koolaid64]

the UHMW isn't going to offer the same level of deflection as ti but it's still annoying to hit. The real reason I am using UHMW is because it wont fail. hard armor here has a few weak points that it can break at with a good horizontal hit. The UHMW will just absorb it and mar a bit, no big deal and I don't loose one sides drive. As for the wedge. This is something I have always been apprehensive about. I have always been to worried that the middle bit would fail and cause weapon failure to follow. But I'm finally ready to try it, the frame strengthening benefit is worth the risk. The thin bit is .75 wide and there is .1875 clearance all-round. If the worse should happen I already have the split wedges made and ready to drop in, so no big deal.

-Kyle     

[Lucas Grell]

Good point. I'd consider making the titanium sit back a little from the edge of the UHMW, so that vertical hits near the edge won't catch the lip and bite.

[BranYoung]

Shouldn't that saw blade be very fine so it doesn't bind? Also, are you moving the weapon motor up onto the arm for the weapon or keep it at the base. I notice you have two pulleys at the base of the lifter and I was wondering if you were planning on dual lifting power or 1/2 spinning half lifting.

[Koolaid64]

Ok so I have gotten a lot of question this weekend about the new Big Ripto. So I'm going to take a moment and and try to answer as many as I can.

Big Ripto

 
Ok to start with the breakdown,

the entire frame is 3/16" ar400
the base .08 4130

all welded up with top plates and rail supports brings it to 13.5 lbs
 
the weapon is 7/8" thick s7 with a 9" spinning dia. mounted to its hub assemble brings it to 7 lbs 15.5 oz

this leaves me with 8 lbs 9.5 oz for wheels and guts, so let's talk about wheels and guts.

first off the wheels. 


the wheels are actually very simple to make. I purchased some 60A Polyurethane rubber tubes of mcmaster. Now I would recommend when selecting tubes that your wall thickness never be more then half the width of your intended tire. Otherwise the tire may be prone to rolling off the hub with strong horizontal forces. After I received my rubber I slide it over a piece of aluminium round stock and used it as a arbor in my lathe. Then I mounted a exacto to my tool post and squared it to the chuck. With a nice slow speed the knife cuts it like butter. Now that I have my blanks I grabbed some UHMW round and made hubs with a flange on one side, the flange should be over at least half the wall thickness to propperly retain the tire. The Acetal pulley acts as the flange on the other side when the whole thing is sandwiched together. Now I would recommend .05" over size on the hubs dia for every inch of tire dia and .02-.03" under size on the width. this really helps seat and clamp the tire to keep it from slipping, It also makes an over sized tire, so plan accordingly. I was planing on using Loctite 406 to glue the hub and wheel together when I assembled them but I didn't order it in time so a quick trip to walmart turned this up and It hasn't failed yet so I'm content with its performance.

alright, the guts.

Right now the bot runs off a 6s pack of a123s. I designed for a123s because I wanted the option to run it at FI. I may try some 8s lipos next year for moto, undecided as of yet.

For the weapon motor I am using a KB 44-74 Brushless Inrunner 1500KV. I'm not sure how it might feel about being pushed to 8s but it has size able alu mounts to sink heat and the frame is pretty open for air flow from the disc so I will be testing it out in the future. The speed controller for this is not a definitive component yet. I have some things I would like to try out before I decide on a permanent controller.

The drive


The motors are 1100kv B36-74-15-L Brushless Inrunners which I mounted to a 500 series 16:1 p60. There are some hotter wind and more powerful motors on hobby king but this one would give me a matching speed to my hobby which is what I wanted.

the speed controllers for them are 70a Red Bricks that have been flashed with simonK. there are a couple of setting to play with there but more on that later.

I plan on making a really simple simonK for dummies video that shows the basics of the setting and tools to flash a speed controller this week. I know Its intimidation if you are unsure of what you are doing so I want to try and make it more accessible for everyone.

alright i'm out for now. 
-Kyle

[zacodonnell]

This is really great info. I look forward to seeing the tutorial on the simonk stuff because people have been talking about it for a long time and I assume it was mentioned on Facebook but of course has scrolled off the back and I never saw it.

It was really great to hang out with you and the gang this weekend. You really helped me out with working on the shell spinner right before you mopped the floor with me

-Zac

[Koolaid64]

Simple up-date. Just adding some glory shots of the paint job of Big Ripto. For historical purposes.


plus here is a inside look of the layout



-Kyle

[Koolaid64]

Well I have been playing with cad lately. Mostly messing with a new 12lb Ripto design. One of the major things I wanted to change was how damn wide the bot is. Here is where I am at with it.

A lot of big changes and a bunch of little ones. Originally I was going to use some of my short can 3645 inrunners on p60s for the new drive but I decided I no longer wanted the front wheels hanging out of the wedge. This is where a 28mm wang box will come in. It will require some mods but will allow me to sneak my front wheels under the wedge. This along with custom wheels, fingertech pulleys, shorter batteries, and aluminum weapon rails will allow me to bring the width down from 17.5" to 14" 


thoughts?

-Kyle

[zacodonnell]

Wheels behind the wedge is definitely a good thing. It looks like you ditched the pretty angled front sides though on the wedge, and I think that's a huge strength when facing a big horizontal.  Is that another change you're planning to make or did you just drop the thick plastic sides in there because it's way easier to draw?

-Zac

[Koolaid64]

Its a change I am considering. While the angled sides are amazing with horizontal spinners any vd with a wedge will trash them. I am thinking this will be much better over all and they will be super easy to replace. I was considering just making both and swapping as needed but it just ends up being too much work and it's not really my style. I still have to narrow in where the new weight will be and if I can run 10 gauge ar for the wedge.

-Kyle

[zacodonnell]

It sure is easier... but I've gotta say those slanted ones you have on big ripto are the reason I don't think my bot can beat yours more than 1 in 10 times. And I'd hate to see my bot or the arena if we went head to head 10 times....

I'm a big fan of thick UHMW side plates, but I find it amusing that you switched to thinner metal for the weapon supports but then thicker plastic for the sides

-Zac

[Koolaid64]

well if I can do a steel wedge, I will also be able to do those nice gussets and bolt them to the weapon supports. I don't think I could fully mirror the 30s compound side angles though because it would be very heavy. I was playing with a shuffling idea though. 6 pounds is a lot of armor...

-Kyle

[Koolaid64]

So in non-moto prep related news I started working on one of the bots i'm going to take to massD. A mini Mingi. I using what is mostly the same hammer setup. belts and pulleys are the same but i'm going to drive in with the 16:1 brushless planetaries I use for my mantis drive train.



-Kyle

[Koolaid64]

Well I have done a little bit more work and now I have a rolling chassis. Another day and I should have it all finished up.
I just need a name. It is a mini mingi im already in a pun corner.



-Kyle

[Koolaid64]

Better late then never. Here are some finished shots of Dain, beetleweight hammer bot. It actually ended up hitting more legit then the mantis.
aside from some clearance issues which was my own fault it was great. I think it went 3-2 in the end of the day but who remembers. It survived a 30 and that's what matters. 




-Kyle

[Team whanton2]

OMG that is so cool, i want one.