Hovercraft Battle Bot

I was browsing the build rules for Robot Wars & FRA events, for an idea me and friend had about hosting, I'll be posting a thread about that in a few days, but one thing on the Robot Wars rules stuck out that I just had to post about, you can view the document in its entirity here. However this is what I am referring to;

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3.1 All Robots must have (easily visible mobility) in order to compete.
Methods of mobility include:
[..]
3.1.4 Ground Effect air cushions such as a hovercraft
[..]

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A quick search led me to note that in Robot Wars, no hovercraft based vehicles have competed, at least listed on the wiki.

This led to me thinking, how would you even approach this, how can it be approached to begin with? It'll be very easy to rupture the skirt and have your air bubble escape faster than its restored and leave you grounded, you might be able to add skirt strips of metal, but good luck against something like PP3D with its low spinner.

Assuming that is overcome, I can't think of any weapons that'd work. Surely everything will bounce you back slightly and not be able to sustain the attack? Maybe a spinner might go fast enough that it'd do some damage before it bounced you everywhere?

I'd love to perhaps see a hovercraft fighting bot prototype, or maybe even an entry attempt (lets face it, if it has any where near potential, it'd probably get on purely for it being a new thing), so how would others approach this? Perhaps maybe the specific noting of that in the Robot Wars build rules is an vague invitation that they'd like to see it come to fruition, so might be worth me trying to pursue any series potential.

You could have a completely solid skirt (as older hovercrafts were constructed with) but that would need to be fairly lightweight to allow the robot to hover and still have the potential for breaking (fibreglass would be a potential way of doing that). Then again, with a powerful enough motor, anything is possible.

As for a weapon, a good overhead weapon (i.e. a fast enough axe or a crusher) in the right place would mean curtains for the robot for movement but as you say, a horizontal weapon, such as a spinner, would be less effective. Heck, if it rose high enough off the ground, low slung spinners would be ineffective but then at what point does it become a drone?

My main concern would be control. Airbrakes in addition to movable ducting on the engine might make it somewhat controllable. Also, what weaponry would work on a hovercraft? Anything pushing (spinners, axes, rams, flippers etc) wouldn't work as there is no grip on the floor. As a distraction half of a clusterbot, I can see this working with the other bot being a "traditional" robot mind.

Hovercraft are a waste of time: they are not invertible and are highly vulnerable to open pits or the flame pit at Robowars. They would also be vulnerable to wedges and flippers and as mentioned, its hard to mount an effective weapon on them - until flame-throwers are allowed :).

So pretty much as I anticipated then, fairly undoable even if you did get enough power to lift a heavyweight rated robot, and even then, I can't think of a way of righting a hovercraft back to the hover side in any sort of reliable method. Unless both sides were capable of hovering, and it just had a large spike or circular saw through the central part of it as its 'active' weapon.

Still a bit of a shame the general consensus is not worth it /impossible, as it'd be one hell of a neat looking monstrosity.

Yeah it might be best to go for invertibility, with a second skirt on top. I'm picturing something similar to Expulsion from Series 2/9, with a weapon in the middle like you mentioned. My personal opinion is that it's not worth it but that's just me; if someone wants to give it a shot though, I certainly wouldn't discourage it and would love to see the results :)

I'm not sure, if double side, where you'd source the air at a high enough rate to pump it into the active side, unless skirt around the edge, and then inside that at both sides was fans for the opposite side. Then a button on your controller, or even automated, to flip air to the other side if its inverted.

Would be a project with a lot of trial and error, and in the end, you might come out with error no matter what you do in terms of viability.

I've been building a fan powered feather for the last 12 months that's been a bit top secret but uses castors instead of a skirt.

I entered a random robot in April to try one of the ideas and it works, so umming and arring about finishing it off. It's finding the cash and time. I originally mentioned the idea to the robo challenge guys and they said the diversity in entrants is something they have been trying to encourage so it spurred me on.

Using air + castors/wheels is an interesting combination. I imagine it must be on the light side of feathers though, to get a decent speed, but also not too much momentum/inertia (always forget the correct word for that) to be too difficult to quickly change direction if you're heading for disaster (say a pit)?

Using air is something i'd considered, but didn't give much though, as I expected the driving to be worse than trying to drive a piano down a hill.

How is the air being directed? I guess there is either one air outlet with directional propellers or is there two outlets which direct one side of the robot to move forwards? Either way, a unique entry to be sure. ;)

Been trying three ideas, first is a fan at either side and it's driven tank style so both suck or blow (hahaha) gives fwd and bkwd, alternate directions steers. This has brushed motors for reversing one side. Doesn't give much power. Second idea is a fan pushing each way (ie 4) and you just start one fan to give desired direction. Lot of correction, nearly lost a finger. ***BUT*** uses big brushless stuff so LOTS of push. Third has been the best so far, big fan at the back for fwd and back, with another on the front at 90 degrees for steering. This drives pretty much like an RC car (ish). Still undergoing testing though.

EDIT - even though I've been mucking about, I can't see the setup surviving the current crop of spinners that turn up every where you go. Tbh they're stiffling creativity. Even if I put the fans in a hardox box, I still couldn't afford to be rebuilding each time they got a big knock.

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Originally Posted by daveimi

EDIT - even though I've been mucking about, I can't see the setup surviving the current crop of spinners that turn up every where you go. Tbh they're stiffling creativity. Even if I put the fans in a hardox box, I still couldn't afford to be rebuilding each time they got a big knock.

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This was another reason I never pursued the idea, I could never think of a way to overcome spinners with the design, no matter the exact method of movement (skirt, wheels etc). I do agree that spinners are somewhat stiffling creativity. Stops you being able to include a neat new idea, that is if you're wanting to have a serious attempt at battle and not be eliminated straight away. I'd hate to end up creating something but it ending up the joke of the competition i entered.

Many ideas are almost impossible to protect against spinners, at least if you still want the design to be maneuverable and not look like a factory reject tank.

Think this is why America have a class that's no wedges n spinners. Maybe "sportsman" or something similar? Not sure.

really hmmm. To be honest the only type of weaponry that this really would effect would be grapple bots as they are generally the ones who loss out the most especially at the featherweight in full combat it spinners or beater/drums and in no spinner events its flippers

Getting OT - it depends on the arena design. In Australia and the US, arenas have little to no 'throw out zones' so flippers have a much harder time winning. I haven't been following the US Sportsman bots but here in Australia, axes and lifters do very well.

Back to hovercraft bots: another drawback is trying to reverse them. Its possible to turn in their own length but a proper reverse takes a lot of extra engineering and weight.

From what I've messed around with I can't see a hover / fan powered robot ever being that competitive.

And if the entanglement rules got relaxed people would soon start panicking about their drive belts getting damaged. EO's want maximum damage for entertainment value, and have crippled other builders by making the means to defend themselves illegal. So now most weight classes will become spinners and bricks. Relax the rules and we'd soon have a plethora of weird contraptions designed to bind up spinner blades.

true but you know what is also boring for EO point of view ? broken bots fights or bots which simply look same with different paint.

<face palm> Entanglement rules are there for a very good reason. Entanglement is anti-everything, not just spinners - how would you feel about a bot that jammed up your hovercraft fan, locked your wheels up, stopped your lifter working? If you thought an all wedge match was a bit boring, just wait until the dual entanglement match becomes common! There is just zero entertainment value in it and we wouldn't see Robot wars on TV ever again.

oh yeah totally agree hence why Mentorn set these rules

14.2 EntanglementDevices designed specifically to entangle other weapons are permitted under the follow conditions:

14.2.1 SeparationEntanglement devices must not cause two or more robots to be entangled together to the point where a battlerequires intervention in order for it to continue.

14.2.2 Materials & Construction typeAny entanglement devices constructed with rope, wire, chain and similar materials may not be interlaced orwoven. Nets, cloth, chainmail and similar are prohibited. For clarification on your device please contact RobotWars.

14.2.3 Maximum LengthThe maximum permitted length of rope, wire, chain and any similar materials is 1m.

not sure how it worked in combat be fun to see

I understand why the rules are laid out the way they are. I feel sometimes that the robot designs have peaked a bit, in terms of destruction.