Well, I will be happy if the arm breaks while you are trying to flip Scissorhands, but it still looks a bit fragile to me. If you are happy, that's good enough

What's COSMOS have to say about it Trent?
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as long as nothing horizontal whacks it, looks like it would probably work pretty good. worst case some hollow tie rods between the front arms would probably strengthen it up alot for not much more weight.

are you going to have it all waterjetted? looks great
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www.demon50s.com - Minimoto parts
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Waterjetting - Yes

COSMOS - All clear to boot some bots!

Nick, I wouldn't be intentionally firing the arm into a spinners weapon. I just took 2kg out of the frame you would hate see that.

Thanks guys, input appreciated.
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

Are you guys mainly talking about the arm tips? If so I haven't looked into that much yet.
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

It might help knowing that the front axle going through the ram rod, is a dead axel(the one connected to the front arms). The drawing is not complete there. This adds a lot of sideways/diagonal strength.
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

I think everyone is refering to sideways load on the front arm links. Thats the bit I was looking at.

I was looking at the extreme cut-outs in the top linkage between the pivot points. Although the material is thick in the horizontal plane, I think it has problems in the vertical plane, particularly around the pivot points - will post a sketch showing what I mean shortly.

The front forks look fine to me; having them retract behind the wedge is about as good as it gets.

This is what I was thinking for the top linkage:



Stress will be greatest around the pivot points, so thickening up the linkage there and leaving it thinner in the centre should have the best strength to weight performance.

Another potential problem will be if the front forks get bent sideways slightly, but not enough to stop them retracting. They might then move sideways enough that they don't line up with the slots and your next shot tries to rip off the wedge. The forks either need a guide behind the wedge or they should not retract completely.

I hope at least one of these suggestions helps improve Chucky.

IMHO, the way Ziggy has it flipper recessed into the front wedge provides a good amount of protection for the arm without affecting it's movements.

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https://www.halfdonethings.com/

Thanks Nick, I'll digest that info a bit l8tr. I'm busy @ the moment hehe:


Nice pic of Ziggy Aaron, I'll respond a bit later. Got 2 have tea, and then watch the last ep of the Chaser.
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

I've just been busy trying to get the frame how I want it, not done yet.

Good arm design there Nick, it just feeds more ideas into me, thanks. The arms from memory are more than strong enough, I'll show you some FOS(factor of safety) CAD stuff when I get back too to in a couple of days. Maybe for further discussion.

Yes my slotted arm tips idea has the problem of if it gets bent I'm stuffed. I think @ this stage(look more into it l8r) I can make them strong enough to be reliable concept. Of coarse this design has its positives too. They will be designed with way more strength than needed, and not fired into KE weapons. Remember these tips NEED to be strong in the vertical direction and I guess @ 350 meters per second in that direction with about 720KG of force, there wont be too much horizontal deflection.

BTW the RAM puts out 1440KG of force but its a 2:1 linkage.
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

I can't really claim an original idea for that; it goes right back to Biohazard's arm design. With the tip bending issue, you could weld a strip of steel down the edges of the slot on the rear of the wedge. That would guide the arm tips and also make that part of the wedge much stronger, you might be able to use slightly thinner material for the wedge and end up not increasing its weight

You will end up seeing that my arms do also have more meat around the pivots, its hiding behind the pivot mount.

Thanks 4 the tips with the wedge guide backing, but I've been through that when I first came up with the slotted idea, and will return to it. I do have to keep in mind the flex is sometimes your friend. More l8tr. thx...
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.

I'm not getting anywhere fast with the frame lightening, so here the stress of the arm:



That will handle 1 ton of force before it starts to fail, 7075-T6(14mm).
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Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world.
Albert Einstein.