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Progress update:
Driving now, still getting some problems with one chain, think it needs straightening.
https://www.youtube.com/watch?v=GClbOEFiDMk
Got the gas working, think one of the valves isnt opening fully. Will investigate further but now I can crack on with drilling the buffers, plumbing and fabricating the shell.
Oh- I am still looking for a 1000psi blow out valve and a screw top fire extinguisher/ valve. Does anyone have either of these spare or know where I can get them?
I have a 1000psi 1/8 bsp PRV.
The screw top is another matter. Do you need a M25*2 or a tapered BSP sized one?
What would you want for it?
I can't remember and I cant check at the moment as the bottle is not where I am. At a guess it's the M25
Just as you think it's going well....
I manage to plug me speedo into itself... Bugger. Looks like I wont be making it to Newport then :/
I did the exact same thing to Gabriel a few weeks ago. everything is now colour coded :)
Yeah, colour coding is required I think. Glad to know I'm not the first to have done it!
I fear you won't be the last either
havent had an update in a while. Frame is coming along. Got the base, ram mount, back and sides. Need to get some more box section then sides and arm can be done.
Alos Finished the plumbing today. It is reasonably air tight (gonna need improving) but nothing terrible. Waiting on a switcher so I can wire the weapon up.
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Test drove today, sorry for potato quality and fingers being in the way, did it on a non-smart phone whist driving the bot on 2 sticks. Need to wire up a my switcher and get the flipper arm mounted next.
https://youtu.be/Jzu6AzY2Fkc
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Some progress with the frame. The arm is now on and side struts going on too.
The ram is leaking at the moment so will get that sorted tomorrow.
Hope I have sorted the problem with the chain coming off, will give it a proper test tomorrow to find out.
When the gas stops leaking and the chains stop falling off I can get to the finer details like how it looks :)
Nice start and a very different body shape, but I possible you really need the ram a bit further back you need mechanical disadvantage with hp systems
Id be tempted to disagree, people deliberately put in a mechanical disadvantage so that the flipper doesn't move so quickly that ran doesn't have time to come up to full working pressure and so wouldn't be delivering the full possible force. But in an HP system I thought the higher pressure meant you got much better flow so I would imagine you wouldn't need the mechanical disadvantage as the ram would come up to full pressure very quickly.
I'm by no means an expert on this so feel free to tell me I'm wrong but sounds logical to me.
Thanks, seeing as I've gone for a hp flipper I wanted it to be a little bit different.
I'd be interested to hear more theories, my thought was the opposite of yours Max- the ram at the back will give more speed at the cost of max force at the tip. Whereas ram at the front will mean it goes up slower but will have more force.
Based on what-I-reckon and the fact I can move it easily enough if I'm completely wrong, and the fact that watch ing the piston go off there's no lack of speed, I went for less speed more force.
But like I say, I could well have missed something myself so suggestions welcome :)
Mechanical disadvantage is required in hp systems, which means ram as close to the pivot as possible normally 5:1 at least, ram at the front means high force small travel but the ram will expand quickly but too fast and create a pressure vacuum reducing the force. With the ram close to the pivot you require more force to move the arm this means reduced ram speed but increased force due to less pressure drop in the hp system, that's why all really powerful hp flippers have big arms and rams very close to the pivot between 4:1 - 6:1 is about right, sorry for any mistakes posting from my phone
Ah I see. Thanks for the explanation. In theory would a high enough flow negate that problem?
Gravity 3 had a leverage of 4 to 1, and that was with 2 Burkerts feeding a 100*180 ram.
Cheers Mario, I'll have to test it and see how it goes....
Driving test: https://www.youtube.com/watch?v=X98Q...ature=youtu.be
I just wanted to check- there's no reason I shoudnt put water into the pneumatic system is there? I am checking for leaks and I feel it's safer to use water than gas, but just want to be sure :)
It's called hydraustatic testing for a reason.
Normal, clean water works. But you'll have to dry the setup very well before putting any CO2 in it.
Carbonated water is acidic and can corrode aluminium.
One thing I was worried about was drying it... Any tips?
Lots of compressed air.
Sealed the leak. Also discovered that all 3 of my valves had crud in them so had a little clean out and now it's working well. I think that could have been the problem all along...
Had a test with half full buffer tanks and a traffic cone.
https://www.youtube.com/watch?v=OviZ...ature=youtu.be
Flips well but makes some funny noises- in the video you can hear that after the inlet valves fire something continues to hiss. I wonder if this could be the ram leaking?
As you can also see there is quite a bit of resistance in the "to atmosphere" valve. Is this just because I am not running it al full pressure? Or is something else going on that can be fixed?
Hi everyone,
Life got in the way of this project for a bit. I'm trying to find some more time for it now...
Is there a way to calculate the optimum position of the ram re:leverage? Is 4:1 ALWAYS the optimum?
Cheers
No, the 4/1 isn't always the optimum. It depends on the ram and the flow.
A long stroke ram will use a lower leverage. A short stroke ram more, if it has the force to do it.
For Gravity3 I went for a 4/1 ratio to keep the force on the tip around 1 ton. Just felt right, and it was then. This means the flipper was powered up to 720mm .
In Bullfrog, I still aim for the 1000kg on the tip, but the ram is so different that the leverage is closer to 7-1, with a powered stroke on the flipper around 400mm.
Hi, sorry for taking so long to reply to this, other things have got in the way of hobbies!
I'm sorry for being thick, but what would the drawback be to having a 1/1 ratio?
Almost finished! Got the drive and flipper going. Still need to fix down things like the buffers and stuff- and then I'll try to get some videos. http://i.imgur.com/ZLVTrjW.jpg
Cheers for everybody (and Mario's) help. I'm sure this wont be the end of my questions ;)