HardWired II

[overkill]

Just using an identical 2nd stage sounds ideal - you already know it holds up in use. You might get away with a single stage Banebots P60 as a first stage but motors you want have too much torque for a 2 stage P60.

The brushless set-up I have is instant reverse and plenty of other ESCs have the feature, particularly the sensored ones. Its important to download and read the ESC manual before buying anything; the reversing details are often vague. There is at least one Hobbyking sensorless ESC that has instant reverse, I will try to find a link.

Another option is to add sensors to an outrunner. Its been done before and someone even had a kit for it. It only works for motors with a certain number of poles but that still leaves a wide choice. A sensored outrunner would be a fantastic resource for bot builders; it would offer low speed torque, instant reverse and lower cost.

[overkill]

I found the sensor ad-on kit here: http://e0designs.com/products/hall-effect-sensor-board/

It only works with 14 pole motors and down to 50mm can size but that still leaves plenty of motors to choose from, including the NTM 50mm series. I might just have to try this out myself! If this works out, I predict an invasion of fast & reliable wedge bots

[Flag Captured]

Yeah, that's the problem with the Banebots stuff... at the most, it was designed for 775 motors I think, putting a massive brushless in it can only only end badly!

I shall have a look at the sensored ESCs too, I've found one non-hobbyking ESC that's got instant reverse but it's a little too expensive. Going to trawl through the manuals when I've got chance!

That's fantastic too, thanks! Though I have to say, if I can get that to work with a 2.5kw brushless NTM on 8s... I think that might be the scariest rambot known to man. That's like, 6 horsepower in theory? Crack a massive magnet in there and we're good to go! Perhaps the two-stage would be ideal there as well, though not quite as heavy a reduction...

Would definitely be a good thing for robot combat as a whole too, might make brushless a lot more accessible if it proves similar to high power brushed motors that seem to slowly be dwindling in numbers...

[overkill]

Its hard to find an ESC that runs on 8S and has reverse. This HK one ticks the most boxes for me: http://tinyurl.com/ofe6mc5 its only capable of 6S but that still gets plenty of power out of an NTM 50mm outrunner. I think you need to get some MUCH wider & grippy wheels to make use of all that power

[Flag Captured]

Yeah, that's one of the ones I spotted, it seems alright! Perhaps not 8s but that's way OTT anyway (that said, that is the name of the game with HardWired haha!) might get some on order when they're back in stock...
Definitely too! I'm aiming for thicker wheels, but will definitely have better tread on there! I think I wore the current set of wheels out during testing, going to get plenty of spares made up next time! I'll probably use some kind of magnet downforce too if I can't get enough grip from the wheels, I think with that much power it'd almost be a requirement. I'll see how it performs though first and make changes accordingly! I'm definitely having a gyro in next year too, it'll help dramatically with the steering. It seemed to drift off to one side and spin during long run-ups which is a pain to deal with, but nothing that can't be sorted!

[overkill]

I was rather disappointed with gyros when I tried them several years ago - do the UK builders have a recommended model? I can use all the driving help I can get!

[maddox10]

Hmm, if I follow the trend in this topic, I should suggest to keep hardwired II for fun, and build a Hardwired II evo for monsterpower. The way Hardwired 2 is build ain't really suited for upgrades here discussed.

[razerdave]

Nick: been using one of these in Satanix for years, couldn't drive without it:

http://m.ebay.com/itm/141256473060?nav=SEARCH

[overkill]

Interesting - quite by accident, there is a perfect gyro mounting point between the motors in Mr Mangle. Its cheap enough to try and not worry if it doesn't work out.

[Flag Captured]

Mario, that sounds like the best plan - was thinking about it today/last night, it'd mean quite a major overhaul to get everything where I wanted it to go, maybe it'd have all fit (just), but a rebuild might mean I could get more weight over those wheels, and have plenty of space for everything else in-between... Will definitely get to designing that on paper! I have had a few ideas based around how Satanix works with the majority of weight being directly on top of those wheels, that'd be ideal for putting that power down. May keep HardWired II but as a thwackbot instead because that might be a heck of a lot of fun - would just need some additional parts put on the back, and it'd be fine I think, but I'll not mess too much with it. Definitely taking it to all the spinner events I can though because it literally does not care about any hits from them!

Also, cheers for that gyro post Dave, I might get one of those too, would be very handy in this new machine, and indeed in HWII, it seems like it works very nicely in Satanix and more control is definitely what I need in a robot like this. How fast does Satanix go too? It seems to go insanely fast at full pelt,got to be a lot of kinetic energy behind that!

[razerdave]

22mph in theory. The new set up will take it down to 18mph but the increased grunt means I should still be hitting them as hard (hard to generate full speed with another 13kg on top).

[mrsam]

I think personally you should make the new one four wheel drive you'll have more than enough weight if you keep it small , plus you'll save weight going to brushless and it would be easy to distribute the weight evenly. Not to mention the fact you could push just about anything with ease!.

[daveimi]

Something that's been interesting me of late is what's the maximum amount of grip possible by a thirteen kilo robot? I say this as my dad is a racing car builder. In a certain championship he's been building for, the car's are front wheel drive, and among the community for this class there is a general consensus that more than 220bhp or so just becomes wasted wheel spin. To this end they'll build the car, and then set the turbo boost on a rolling road so it JUST touches about 210 - 215bhp at the wheels.

This has made me think...I wonder if there's an amount of torque that past a point becomes wheel spin, and you can keep putting bigger n bigger motors in, but you're still sort of restricted by not being able to put the power down. I have been watching your build like every night after work lol to see what sort of results you got. I'm right right on the cusp of building a big power drive train for my robot. But when I've over-volted the drills and locked the clutches up, it will happily push a 10kg weight lifting plate up and down the driveway. If I double the weight the robot tries its best but just smokes it's tires (which feels way cool I may add!!).

Erm...so to sum up...I know building some sort of s900 torpedo 800 type drive train will definitely benefit my plywood La Machine clone given the type of robot that it is. However...if it will happily shove 10kg about, is it worth me spending what I predict will be about £150 sorting a big drive train out if the £30 drill setup is at the invisible border of grip anyway? Would it be best to move onto four wheel drive? Would it be best to get six wheel drive? These are all of my curios wonderings!!!

My working layman's hypothesis is: NO MATTER WHAT MOTORS AND WHEELS YOU HAVE, YOU STILL ONLY HAVE 13KG OF DOWNFORCE TO WORK WITH.

[Shakey]

Don't forget though if you have a scoop you have 13.6kg + some of the weight of the other bot. In addition more torque will help in the event of a wheel becoming clamped to break the clamp or some such. And you still have acceleration to consider (though even drill motors are pretty good for that one). Other things to consider are matching the drive train to the weapons you're running. If I'm running an axe on 6 cell LiPos I'd like a drivetrain that can take 6 cells without large overvoltage.

EDIT: Interestingly I did experiment with this in the antweight class with a 4WD pusher using small pololu wheels. Moving from 1 wheel per motor (4 in total) to 2 (8 in total) was a massive improvement. But I tried 3 per motor (12 in all) and performance suffered, for that I found 2 wheels per motor was optimal.

[Niels - Team K.a.L.M.]

I have to disagree, softer tires will give more grip than harder ones.