Seeking advice - looking for a way to flip 1kg without pneumatics

[heyitsdisty]

Apologies if this kind of topic isn't allowed here, but I figure you folks are the best people to ask!

I'm planning to build a combat with a flipper weapon, using only purist parts. The flipper needs to be able to flip over opponents which weigh up to 1kg.

I've ruled out pneumatics for several reasons; they're expensive, bulky and I have no experience using them. I've also ruled out using a motor to power the flipper, as I don't think it will be able to launch at a high enough speed while still being able to tip opponents over. (A slow motor-powered lifter might work, but I'm looking to build a fast flipper.)

I'm hoping to use an elastic or spring-powered mechanism with a single motor to reset, similar to PKW's TC11 entry (which I believe uses a third-party rubber band):

(I'm planning on using a worm gear within my bot's reset mechanism, to prevent the flipper pulling itself back open under tension.)

Here's some other methods I'm considering. The trouble with almost all of them is that I don't have enough of the parts listed to test them, and I don't want to invest in a bunch of new parts until I'm sure that they'll work.

Hockey spring blocks (aka return to center springs)

These seem nice and compact, but I only have one, and one alone isn't strong enough to lift (let alone flip) 1kg.

Pullback motors

I'm thinking of attaching these directly to the flipper arm at the pivot point, and pre-winding them before installing them. Again, I'm not sure how many I'd need, and I'm concerned that these motors might need a bit of run-up time to reach max torque/speed (so they wouldn't be able to launch the flipper instantaneously). They're also fairly heavy, so they could push my bot over the weight limit for competitions.

Shock absorber springs

I'm leaning against using these as I need the flipper to open to a reasonable height, and even the longer shock absorbers are too short. They're also pretty expensive on BL.

Rubber bands

Reasonably affordable and super space-efficient - but again, I don't know how many I'd need, and I'm also concerned about them snapping (which would leave the bot defenceless in the middle of a battle).

Elastic string

Same as above - I don't know how thick this is and I don't want it snapping during a battle.

Clikits hairbands

I bought four of these of Bricklink, hoping they'd be a thicker, more durable and higher-tension alternative to Lego rubber bands. Unfortunately they're not that much thicker than rubber bands and they actually seem to offer less tension.

Minifig dog lead (https://www.bricklink.com/v2/catalog/catalogitem.page?P=xLeash&name=Dog Leash Elastic with Gem&category=[Animal, Accessory]#T=C&C=3)

This looks more promising than the Clikits bands, but it's pretty rare on Bricklink and fairly expensive.

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Does anyone have any tips on which method to use? Do you have any experience using these parts in any lifting/throwing/launching mechanisms in your own MOCs? Thanks for reading!

 

 

 

Edited May 30, 2019 by heyitsdisty