Richie: The £50, 3 week Featherweight

[Flag Captured]

It's a good tactic! Leaves them completely unable to do anything, at which point you have total control of the battle which is thebest situation you could be in! People will take advantage of that too though, always best being careful...

Leave the 7AH battery in there, and you'll probably not need to charge it till next year haha! Is it an SLA you're using?

4WD that way sounds good! I'd think about the upgrades you plan on, and work from there - 4WD with 4 motors is easily doable if you'd rather have that little bit more power, with a LiPo you'll never need to worry about not having the amp discharge for it either - the only thing you might have to do is review your speed controller's amp rating, make sure it'll handle it OK! If not, belt drive is still as good, just you might have that little bit less pushing power comparatively. Not too sure though, the theory would probably suggest so but I haven't a clue in practice - never used drills in battle!

Definitely a handy thing to have though with a design like that, the last thing you want is having to wait for the forks to go up all the way so you can drive about! Then you can look cool and keep your mobility I'll be very disappointed if you don't put the Razer-style self-righters on there too as well, now that you've mentioned it. (I'm kidding but that's a good idea still)

Also, tyres, you'll definitely want something with plenty of grip, most people just use bike tread - mine are HDPE wheels with bike tread on them, but there are alternatives that do get expensive but can be better grip-wise. What I'd honestly suggest though if you go with 4WD, is that you have grippier compound on your front wheels, and less on the back so that you've got more grip over the front two - I believe both Razer and Hypno-Disc did this (and 360 too, I think), basically means that your machine will pivot around the front and therefore weapon, and could be quite handy - even more so if you end up using a pistol-grip-with-wheel-thing-for-steering style controller (I'm sure that has a proper name). It doesn't suit everyone, but it's an idea!

[Rapidrory]

Was working fine again today until 'Pain in the ass' stabbed Richie right in the ass! Went straight through my armour and into my one good battery That was the second to last fight, so I fitted my other very old "7Ah" SLA for the final fight, which has almost no capacity left. It managed half a fight before it ran out of power (as I kinda expected), and then got floor flippered across the arena... Richie was very dead after that Not planning on doing any events until after July though, so have got plenty of do repairs and upgrades.

I would like to do 4WD with 4 motors, but I don't think I'd have the weight for it, especially having added a few extras. I have some 80mm diameter HDPE bar at home as it happens, so I'm planning to machine that for the rear wheels, then add some bike tread. For the front wheels I'm planning to use some 30mm diameter aluminium bar, which I can machine a groove in for a belt, then tap some holes in to add bike tread as well. I don't plan on the front wheels having a load of power, as they'll only really be needed when the other robot's wheels are off the ground, so they shouldn't be pushing against much most of the time. It will probably steer from the back because of that, but I'm just going for the simplest and cheapest options really.

I do plan on adding Razor style wings, as I worked out they'd take me maybe half an hour to build and fit, would only add another 200 grams or so, and is really the only way it could self right (Plus would look awesome! )

[mrsam]

Sorry to hear about the battery but at least it means you have to upgrade, just stick a lipo in there, much lighter, extremely high power density and very affordable nowadays.

[Porker]

Get one from some kind of clearance-sale. I got a pair in a clearance-sale from Sussex Model Centre really inexpensively.

[maddox10]

12V 7Ah SLA can be replaced with 2 3S 2200mAh for a lower weight and pricetag.

[Rapidrory]

I've used LIPOs in antweights before, and even in them they're vicious little things.. Would just be concerned about making that much power available to a home made speed controller, which are prone to shorting tracks. I'm gonna try it anyway, but still would make me a little nervous. My ESC has survived 12 fights fine so far now though, so i'm a little more confident in it than I was at least. Under voltage cut out for LIPOs is only an advisory rule; I'd like to have it, but depends how hard it is to add, and on what capacity lipo I get; as long as I charge it every fight it should be fine.

Also decided to fit external bearings to my drill motor shafts to take the weight of the robot; the gearboxes on them aren't really designed to take the sideways force of a feather dropping on them.. I almost lost both my motors today in that flip from the floor flipper!

EDIT: Those Lipos are cheaper than i'd expected! I might get away with just one of those; The drive doesn't take a whole lot of power to run the two drill motors, and the lifter isn't running half the time. Obviously would have to try and see how fast it got through one, and fit undervoltage protection in that case, but worth a shot; The moto of this build is the less money spent the better :L

[maddox10]

If you're worried about the speedo's blowing, add a fast fuse.

It's actualy mandated when using LiPo, and nobody says you need to put in a fuse that can get the limit from the battery.


The external bearing on the axle, not a bad plan, but avoid putting that in the outside armor without any shock mounting

[mrsam]

Mario's got a point, a 7ah sla has got to weight 1.5 possibly getting on for 2kg? a 2200mah 3s lipo would be more than enough for a 3 minute fight on two drills and a lifter, would weigh next to nothing and provide much more power than the sla could ever hope to. It would also take less space and like Mario said you could get two for the price of 1 sla.

[Rapidrory]

My wheels are inside my armour, and the bearings would probably be in a HDPE (or maybe even hardwood) mounting, so would have a little bit of shock absorbance. Bearings of that size are pretty cheap, so if they did go then it'd be much cheaper than replacing a motor.

My SLA's actually weigh about 2.5Kg! The plan always was to swap them for a Lipo at some point. The only reason i used SLAs is because i had them lying around at home from an old mobility scooter, and i didn't have time to add the safety features and order lipos... (SLAs like mine are actually only about £6-£12, so not a huge saving, but I'd much rather a lipo for the weight)

[ChrisKazoo]

a 2200mah 3s lipo would be more than enough for a 3 minute fight on two drills and a lifter, would weigh next to nothing and provide much more power than the sla could ever hope to.

I ran Loki for three fights at Yeovil on 4 drills and a lifter on a 2200 mAh 5s lipo without charging it and it was fine (admittedly I didn't last very long in those fights, what with magic smoke and being oota'd and having the link knocked out but still...)

[Rapidrory]

It says the UK warehouse is out of stock on those ones.. Did you get them from the international warehouses or have they been in stock in the past? (with Hobbyking you can never tell..)

[mrsam]

Hobbyking backorder stock if you buy it, usually takes up to 7 days for them to backorder it. So you could buy it now and have it within the next week and a bit

[Rapidrory]

Oh that's good then; won't need it for for another 3 months though so should be back in stock by then :L

[Max]

It managed half a fight before it ran out of power (as I kinda expected), and then got floor flippered across the arena... Richie was very dead after that

Tell me about it, my robot was dead in the first fight and got thrown by the flipper twice but survived fine then in the second fight it died part way through got put on the flipper then chucked straight into the arena wall at the end of the fight, it wrecked the hinge for my flipper arm, somehow bent the threaded inserts in the wheels so they are wobbly as they turn rubbing against the chassis and bent the chassis ripping all the fixings out the GR01 motor. I wasn't able to come to the 2nd day as couldn't repair the damage overnight. I think they had turned the power of the flipper right up for the second fight on the Saturday, they probably did the same in the Sunday. Ahh well, part of the game I suppose.

[tweedermeister]

I too fell foul of the floor flipper, I don't think the power was changed at all since 2 bots hit the roof of the arena in 2 different fights (Mine being one of them).