Flippers

Whats the view regarding flippers and where the hinge is? A front hinge like Firestorm vs a rear hinge like Chaos 2. What is the hinge made of?

Depends a lot on what kind of machine, and what pressure, full pressure needs stronger materials that say 10bar.front or rear hinge is entirly ou to you.

The front vs rear hinge argument has been running for ages, so I wont go into that. The hinge on Serranos flipper is a 20mm round bar, mild steel I think. That fits inside a larger steel tube, cut up into sections and welded alternately to the chassis and flipper plate. It runs at 10 bar.

our hinge is built the same as jims, but we run full pressure. With front hinged flippers you normally need alot of drive power to get far enough under the other robot, where as a rear hinged you only need to get the tip of the flipper under.

Yes i agree with alan i think rear hinge is better but a front hinge does give more protection when the flipper has fired

Regards
Ian

I would have thought that self-righting was easier with a front hinge. Some of them sort of roll over.

self-righting was easier with a front hinge waiting for a comment from mute!

:-) Not necessarily true, anyway. Usually (because of the wedge shape) most of the weight of a flipper is towards the back of the robot. If you put the hinge of a rear-hinged flipper far enough back, it can gently roll the robot around its rear end - assuming said rear end is the right shape. See Spawn Again, WBC or Thermidor for examples.

Achieving the same with a front hinge, although it doesnt place any requirements on the shape of the rear of the robot, does mean that the majority of the weight is being flipped, and more of the flipping force gets absorbed by the robot (the rear end, as it hits the ground, will have more inertia because youre moving the centre of gravity higher). So you may need less CO2 to self right (doing this a front flipper is arguably more efficient, in that its shoving more of the robot), but if you dont have a limiting mechanism then the robot will take more of an impact - note the big impact-absorbing tyres on Firestorm, and the way the original Cassius threw a chain when self-righting.

Not that Ive ever built either type, so this is entirely observational and, in addition to being somewhat incoherent, may be rubbish. :-)

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Fluppet

Bulldog is a great deal heavier at the front than the rear,this helps,

Although Im posting in heavyweights, Im looking towards building a middleweight, so theres not a lot of room for weight redistribution.

I know its slightly off the point here but how do you calculate the mechanical advantage on forward flipping flippers like mute or firestorm. I know how to do it on normal (flip ups i.e. chaos 2 big bro) but not on flip downs.

Can anybody help

Regards
Ian

Ian ,I wasnt aware it was any different.

I though it was just force x distance and a bit of trig

:)GORD

Yep calc is the same Ian ....

I think your problems with calculation stems from the action of the reverse flipper .....the weight of your opponent invariably being close to the pivot point.

Tony: Sorry, what does this help, in Bulldog? Doesnt it just mean that youre more prone to flipping yourself forwards, because your centre of gravity isnt as far behind the pivot point as your opponents is?

Thats not a criticism, and Im not denying that Bulldog has a highly effective flipper - Im just confused what youre getting at.

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Fluppet

it means when he fires the front of the robot dont jump in the air.

Oh I *see*. Okay, that makes sense. Better for defence (if you expect to miss), maybe not as good for attack (robot pivots forwards during a flip).

Aint flipper design subtle? :-)

Thanks, Alan.

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Fluppet

Excuse me Andrew, but the word subtle is strictly prohibited from use in RobotWars conversation :)

Subtle!!!!er it also means the front end doesnt
rise up too much when moving forward, and have you ever thrown a dart that is arse end heavy!!
it is more difficult to control,:sad:,like Bulldog sometimes I tell it what to do, but it pleases
its bloody self!!!!!!!!and takes no notice of me,#
must be a bitch,:)
Der Boyz

I have a fire extinguisher with a screw down valve. Is there a regulator (for 10 bar) that is a direct fit onto the male thread of the extinguisher?

Yes there are regs with direct fit, and a 1/8 bsp mounting hole for a 1000 psi PRD. Its the small Gloor I sulpplied to several teams.

Other option is the very small German made reg, that can be adapted with any kind of attachments to go to any CO2 storage vessel.

Just say how much flow you can pay for, and I can make you an offer.

The Happy Shopper end of the market.

At least thats better than the Aldi end :)

Reg of a Mig Welder will fit straight on to an extinguisher, only go up to about 6bar though, can be modded to give 10bar.

This may sound a most trivial of questions but what is the most sensible mounting to hold a fire extinguisher bottle in place?

Bulldog uses two large stainless steel jubilee clips into welded fixings,

That seems entirely reasonable and Ive got a couple of them doing nothing in the garage at the moment.

Where do get a Co2 bottle from?

Theyre relatively easy to come by. Especially say, for use in the home or workplace or car.

Why do you want one?

For my flipper

You will need a fire extinguisher bottle. Technobots is one source. Thats the least of your worries however. Valves, connectors, rams etc etc.

Ok.Whats there URL ? :) :proud:

http://technobots.co.uk/http://technobots.co.uk/

Can sometimes find them at your work as companies are slowly changing to the new eu colours!

Also try phoning a few fire extingusher companies could get a freebie!

Please note its better to get ride of the valve on the bottle as they are not designed to be used constantly like we use them. You can pick up and screw valve quite cheap that fits straight on.

Ive always thought that the front hinged flippers were a better idea than the rear hinged ones.

Any reason why you think that?

Because with front flippers, they guarentee flipping someone over, aka Firestorm. With rear flipper, you might not flip someone over, because the flipper is too powerful or something? See my point?

Yes but kevin if it is too powerful (i think that should be forceful but not 100%) then you could cause damage to another robot and not just roll them over were 100% of robots can either run inverted or self right. Also its very difficult to flip a robot oota with a front hynged flipper.

Firestorm has done it a number of times. Plus, I dont really care if the robot does OOTA or not. A good example of a front hinged flipper V rear hinged one is from the season 3, Facet V Firestorm.

Another good example from series 3 was Firestorm vs Chaos 2. I think Ive made my point. :proud:

The reason why rear hynged wors better is the fact that to flip a bot with a front hynged flipper you need to get a fairway underneath them, with a rear hynged flipper you only need to be 2-3mm under neath and over they go.