HardWired II

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!

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.

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

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

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.

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!

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).

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!.

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.

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.

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