Flippers

[julian]

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?

[dmac]

Flippers

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.

[jim]

Flippers

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.

[blazerbotics]

Flippers

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.

[team_ireland]

Flippers

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

[julian]

Flippers

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

[blazerbotics]

Flippers

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

[fluppet]

Flippers

:-) 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

[tunna]

Flippers

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

[julian]

Flippers

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

[team_ireland]

Flippers

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

[kinforester]

Flippers

Ian ,I wasnt aware it was any different.

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

GORD

[woody]

Flippers

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.

[fluppet]

Flippers

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

[blazerbotics]

Flippers

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