Technical feather stuff

[kickboxer]

yes haz

[MicroGravity100]

Yes, but would it be heavy or stand up to spinners?

[kickboxer]

it isnt that heavy.
and yes if you get the right thckness

[haz]

i think its something like 2mm steel is the same weight as 8mm hdpe but dont quote me on that, anyway the new murphys law us twice the size of the old and is made out of 12mm hdpe and only weighs 5.7kg

[terminaldamage]

If you're fighting spinners, 4mm steel is usually sufficient. Yes it can be heavy if used extensively but if you think about the important areas you want to protect and armour them with the thicker stuff, you can then save weight by using the thinner stuff (or alternatives, such as the aforementioned HDPE) on the less exposed areas of your robot.

With regards to pneumatics, it's only dangerous if you don't treat it with respect and don't follow strict safety protocol. If you are aware of, and respect, the power of such systems, then you stand a better chance of avoiding accidents. I've been building and competing with featherweights for a fair few years now but am only recently venturing into pneumatics, so it's a learning curve for me too. If you're confident that you can incorporate a pneumatic flipper into your first build, then go for it. I couldn't give you an overall figure for the cost of the pneumatic parts but it won't be uber-cheap. I'd estimate around £150-£200 for low pressure components.

The ram you linked to would be quite weak for a flipper. One key parameter of pneumatic rams is their bore (the diameter of the inner chamber). The larger the bore, the larger the volume of gas that can enter the chamber to force the piston out, therefore the larger your flipping force will be. For my system, I'm currently looking at cylinders with a bore of approximately 40mm-50mm. The stroke (the length of travel of the piston rod) is something that you can choose based on the physical size of the system rather than the desired force, but one thing to bear in mind is that the longer the stroke, the larger the volume of gas being used each time you fire your piston, so your gas supply will be used up more quickly.

As an example, here's a 50mm bore, 100mm stroke ram on eBay. A bit more expensive than the one you linked to but more likely to produce a better performance:
http://www.ebay.co.uk/itm/PARKER-P1E-T0 ... _603wt_905

If you can make it along to the AWS in Pontefract, I'll be there and will have my featherweights with me so will be happy to chat about any aspects of building these crazy contraptions.

[haz]

hey, ill bring my excuse for a featherweight along too, steet fight!

[MicroGravity100]

LOL, I don't think it'll be ready in time for Maidstone in November, let alone the AWS in two weeks!
Haz, are you sure that street fights are allowed, coz I heard that they were banned for some reason.

[MicroGravity100]

Oh, and the ram on the page says it's double acting, will that diminish the power?

[haz]

ppffft, rubish, i rebuilt murphys law in 4 days!

not a good example i know

yeah it will use more gas but i don't know wheater it will be enough to matter.
i kind o ment it as a joke about the steeet fights but if people are up for it then why not? dont see why they are banned, how would "they" know if there was a figh 8)

[MicroGravity100]

My Grandad is busy most of the time, and I normally only see him a few times a year. He's going to be telling me how to do things because I know nothing and I'm going to do them. Fun, but it'll take a long time.