Full Pressure Cutlet

[team_ireland]

Hi

I just felt i had to start a topic about this. I have downloaded both videos from the website and all I can say is F**KING HELL

Its brilliant. That hawker flew and the selfrighting is comic.

But that leads me to a question. Why use Full Pressure? Surely a 16bar ram with a larger bore would have the same force and use less co2. Admittedly this may not be as fast but look at m2 it uses 100mm bore ram in a heavy. If you put a 100mm bore ram in a feather at 16bar it would knock people all over the place. I am going with 63mm bore 10bar which is think is loads for a thrower.

What do you guys think?
Is full pressure the way to go?
Will i be out of date with a 10bar ram and high flow rate?

Regards
Ian Mc DOnald

[Guest]

Full Pressure Cutlet

If it fills your needs then it is ok you dont have to go the full press way if you do not want to. I still use 16bar in my heavy and i am happy with it long live low press flippers

[robotwars]

Full Pressure Cutlet

rips low pressure, 10 bar with a big ram ... and ........ need i say more... it speaks for it self

[fwsorg]

Full Pressure Cutlet

Good design is everything. M2 is really really well designed and thought out, and its performance speaks for iteself. Full pressure or low pressure, if youve thought the design out then both should be equally effective (me thinks anyway:-)

However, I rekon if someone were to put the same kind of thought and planning into a FP setup that Paul Cooper put into M2, then wed have something pretty terrifying on our hands. Oh wait- thats gravity :-)

Seriously tho, buffer tanks and big valves for massive flowrate are the way to go. and the more efficient this (reletively) new technology becomes, the better! The future looks good for flippers, and not so great for arenas:-)

[geeza]

Full Pressure Cutlet

I think one reason for using FP is that it may be easier to fit in the the space in a small robot. I think Paul Cooper had this problem with TKM2 and switched from LP to FP.

[blazerbotics]

Full Pressure Cutlet

delta, my new flipper, uses a 63mm bore ram at probably 10bar. its not just a case of power and speed, the shape of the flipper is very important. M2 works well due to its shape also Chaos2. I believe that cutlet has a good shape, this will maximise the power and make sure the other robot doesnt just keep sliping off the end of the flipper.

[ewe2]

Full Pressure Cutlet

Mr McDonald Sir...... The answer to your question Why use Full Pressure? is BECAUSE YOU CAN!!!! hahahahahahahahahahah!!!!!

It just had to be done!

Thanks for the compliment, I have had a lot of fun testing and building it. Cant wait to get it in an arena.

Another reason for going that route was that I had tried a compressor powered Cutlet, and a low pressure C02 version. This was the obvious next step.

If you want my honest opinion of how to build the ultimate feather flipper, and keep within the 12Kg weight limit...... I think the way to go is low pressure with a well positioned in-line buffer tank, and very large piping/flow after the buffer all the way to the ram. Actually the preference would be to have no piping after the buffer at all. Just fittings with big holes in, and a large valve.

Cutlet 540 is restricted at the moment as I have not fitted the buffer tank due to the 12Kg weight limit. I may put it in at an event one day just for a laugh to see how many somersaults it can do!

Ian

[storm]

Full Pressure Cutlet

A wise roboteer once said to me

Ed, just because you can do something - doesnt mean you should.

.... he was clearly talking bollocks

Ed
http://www.stormrobot.comhttp://www.stormrobot.com

[team_ireland]

Full Pressure Cutlet

Guys as a question which would be cheeper:
1. A full Pressure flipper consisting of: Co2 Tank, Buffertank, Valve, Ram
2. A Low pressure flipper consisting of: C02 Regulator, Buffertank, Valve, Ram

I know the cheepest is good old fasioned air but interms of co2 which is cheeper based on the same things (i.e. same bore ram and valve etc)

Thanks
Regards
Ian Mc Donald

[maddox]

Full Pressure Cutlet

Depends on quality and wanted force.

Advantage of the LP system. Commercialy availabe parts.Easy to aquire cheap.
Disadvantage. Big and not neccesarely lightweight.More parts involved.

Advantage of a FP system. Simple and can be very small.
Disadvantage, all custom build parts,or expensive parts still to adapt.

If the parameter of thesame bore ram in hold, the FP system will be very expensive and overly powerfull.

[fwsorg]

Full Pressure Cutlet

Well, my full pressure flipper makes sense as far as i can see, in terms or price and weight. Effectivelly you have components of the same weight in each set up, but youve also got a regulator in LP, its cost, weight, and assosciated freezing probs. Weight is especially important as there arnt that many lightweight 10bar regs around that dont cost a bomb. You can modify some, but my respect (read: fear) of pneumatics is such that I dont trust myself playing around with springs in the reg.

For my full pressure set up, Im half way through building the rams now- surprisingly not as difficult as i expected, and the O-rings were the most expensive part, but Ive been able to build my 40mm bore, 100mm stroke FP ram for about £15.

Working back, weve got the pipes and tubes and so on. Really just a question of using hydraulic instead of pneumatic, and from the bufferto the valve to the ram Im using copper pipe due to increased bore and therefore to make the most use of the G1/2 orrifice on my valve. The valve is a burket- £95 from technobots. You can pick up low pressure ones from technobots for a lot cheaper- the low pressure equivalent (ie 2/2, G1/2) is about the £45 mark iirc. Exhast valve- you could use another burket but that would be silly- very heavy, and expensive, and you dont need the operating speed. Im using a stainless 3/8 ball valve from technobots (about 5 quid) and a servo to do that. weights nothing and only cost about £10. Furthur back youve got the buffer tank- I built this agaon, but that WILL have to be certified. I would imagine that costs tho I need to talk to mario on that one. Low pressure buffertanks you either have to blag or buy or build, tho everyone seems to be able to blag them. further back youve just got your hydraulic pipe from the buffer to the tank. thats nice and simple. And of course the releif valves and gas dumps and what not, but thats all detail )

In all Id probably say FP is cheaper, potentially lighter (tho bear in mind the extra weight of the rams and buffer and so on due to greater wall thickness). But obviosly theres the draw back of getting through lots of co2 very very quickly! And the usual health warning applis: dont do it if youre not confident you can etc etc. A common sense approach to robotics will keep you safe for the rest of your life. Hmm, thats puts quite a large number of us in danger :-p

[ewe2]

Full Pressure Cutlet

One factor that has been missed above is that the forces involved in a FP set up are pretty huge....This means that you have to build the supporting structure very strong...this can often negate the weight saving that you thought you would make by going to FP in the first place!

[fwsorg]

Full Pressure Cutlet

Yes that too ;-)

Massive speed is an issue, and if you fail to flip something, the ram can get fairly upset when it fires up into its end stop and some scary speed. You can stick rubber and all sorts in there but it still will get fairly upset. Some calcs showed that my ram would fill in something around the 0.01 seconds mark. So you can imagine it slams open with quite a bang. but again sensible, well thought out designs are the key and you shouldnt have a problem if you keep that in mind.

[mute]

Full Pressure Cutlet

And one more thing, another down side of a FP system is that you must prove your components are upto the job - no more using LP stuff on a FP system, or just assuming its upto the job.

When the FRA rules kick in (I think), pressure test certs will be needed for any untested equipment which could also increase the cost of the system.

[chris]

Full Pressure Cutlet

i am using low presure on rebel (10bar)
its almost identical stuff to rip cept im using 32mm bore 100mm stroke.
i have a nice co2 bottle from mr jonno sir a nice ram from mr stu the reg im still sorting out and valve... and the buffer is a 600g canister.
hopefully the build will be over the crimbo hols and you should be seeing it in the new year.
thanks to all you who have bene helping me

one thing while we on topics of HP LP FP

FlowRate (mr stus new toy).. going away from ians superb fp feather which i have to comment on you loooon! i dont have enough money for a parachute!!! good job ol man! you really did
but FlowRate... after seeing pics etc and seeing some of the stuff liek the rams. for a LP flipper its looking good. we will have to wait and see...
anyway good luck all and hope to see cutlet asap!