Full Pressure Cutlet

[fwsorg]

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

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!

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.

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.

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!

I must say its looking pretty fantastic. Piping so big you could crawl through it, G1/2 valves, really nice, low friction rams, and an excellent set up in terms of effeciency and leverage, it should raise the bar in featherweight LP pneumatics:-)

I like this what Ian said -
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.

Hopfuly, if Ians statement is correct, and i have done the right things, and the right people have told me the right things = FlowRate should follow that stement from Ian.
Eds mentioned the stats so far, big piping, big valve, found out its the same valve that Dominator 2 and Kat 3 use for their Heavy Weight Axes. Big buffer tank in line with the valve, supplied by using 19mm Inner Diameter Piping.
Will see how it preforms soon.

Cut_Let 540 will have the power
But will it have the speed to flip a 12kg Feather higher than a High flow rate LP flipper? We know the difference from Dantomkia and M2. We shell find out in combat within the next few weeks.

Mr Stu

[jamesb]

Looking forward to the future of featherweights...

with machines like cutlet 540 (is that a ref to the motors?) and my new (should be ready by Enginuity, possibly as early as Aberystwyth) flipper Whiplash (80mm diameter ram, 70mm stroke, full pressure with buffertank) the featherweights shold become event more spectacular that it was this fantastic year.

It can only be good for the sport.

How does this sound:
1.1kg Co2 Bottle Resevor
High Flow Rate Regulator
600g Dry Powder BufferTank
5/2 10bar Valve with 1/2BSP Fittings
80mm Bore 100mm Stroke Ram

All Running at 10 bar with a set up of 2:1 in movement

What do you guys think?

Regards
Ian Mc DOnald

[stu]

Very Heavy!
1.1kg bottle does not mean its 1.1kg. It means it stores 1.1kg of Co2. The bottle is proberly about 2kg.
High Flow Rate regulator, - in a feather weight - again, VERY HEAVY! About 800g to 1.5kg. Yor 80mm bore ram 100mm stroke will be over 1.5kg. Your valve will also be over 1.5kg also. My 3/2 1/2bsp is 600g - and thats a special one i got hold of, a 5/2 will be very heavy.

Your 600g Dry Buffer tank - i bet thats 600g stored powerder, again it will weigh more.

Both RIP and FlowRate are pushing the weight limit BY ALOT already, with smaller stuff. RIP has a shell made out of 1.2mm Ti for god sake which weighes sod all for its chasiss. Rip does not even use a Buffer tank due to weight. Well also due to the high flow reg.

Also another thing - the idea of a Buffer Tank is that you dont need a high flow rate Regulator. Unless your Terrorhurtz. The idea is to have a buffer tank which fills your rams about 2 times. (FlowRates buffer tank can fill my rams 3.2 times)

Im sorrry Ian but - keep dreaming.
Using a 1.1kg Co2 bottle - u aint got a chance to start with.
Were all struggerling to fit 600g Co2 bottles in.

Message to James B - 540 is the amount of degrease it self rights - not motors.

Mr Stu