How bad of an idea is this?

[Mouldy]

http://www.ebay.co.uk/sch/i.html?_fr...inder&_sacat=0

[Tim The Plumber]

http://www.ebay.co.uk/sch/i.html?_fr...inder&_sacat=0

Thanks but...

Let's assume I am going with this;

http://www.ebay.co.uk/itm/Hydraulic-...Sh7-lt9AzHIgpg

With a 25mm rod size and a 250mm stroke and a bore of 40mm.

How much force do I get out of it? What pump and stuff do I need? Errrr???? Help......

[typhoon_driver]

http://bfy.tw/8CZ4

Google is your friend.

[maddox10]

Those rams are rated @210 bar continous and 250bar intermittend.

Affordable gearpumps in smaller sizes can go up to 250 bar. But in the somewhat larger size, it's 210 bar.

By coincidence, the old maximum pressure on hydraulic pressure.

So, 2/2*3.14*210= 2640 kg of force.

@250 bar = 3150 kg.

For comparisation, Razer was around 6500 kg.

[Tim The Plumber]

Thanks,

Why is the area 2/2 Pi not 4cm² Pi?

And will the compression force be the same or less (I would expect it to be less).

And what do you do for electric power to the epump does it come with such???

[Limitaneus]

Thanks to all the experienced roboteers who've been replying in this thread! You've all been amazing and just so helpful. I really appreciate you taking the time to answer newbie questions.

So. I've refined the "enormo-drum" bot idea a bit, and have elected to go with eight 6mm Hardox/similar plates welded to the outside of the now-notorious 50L Eurokeg. Powering it has proven to be an issue... until I stumbled upon this 'ere site concerning performance dirt bike engines. Of note to me was the performance listed for the second entry (I don't recall whether or not a liquid-cooled engine would be legal under Robot Wars's rules wrt chemicals, so I'm not going to chance it), at 9HP at 11k RPM for only 7.5kg in weight, plus the puncture-proof tank and enough fuel for a 5-minute fight - I say five because, well, it wouldn't do to underestimate how much fuel the thing needs and run out of puff in the middle of a battle. Not good telly. =]

Between the output of my 9HP air-cooled dirt bike motor and (I did the maths and added a bit more on to account for the teeth) a 45kg spinning drum, we might get a pretty reasonable drum spinner out of it. What are the thoughts of veteran (to say nothing of sane) roboteers on this solution?

[maddox10]

Area of a circle is radius x radius x3.14

It's just coincidence that 4 cm diameter the same result gives for the diameter and 2 times radius.


Basic formula for hydraulic power and motor needed. Pressure x Flow/500= Kw needed.

[Tim The Plumber]

Thanks. It's been a long while since I did maths....