Two stage telescoping cylinder

Hi there...has anyone ever used a 2 stage ram as a flipper actuator? Looking into options for getting more force on the flipper arm...what's your opinion, are they any good?

Sounds heavy and not giving a lot of advantages in return to me. By the time the second stage comes out the opponent should already be flying.

Most flippers seem to be set up so that the ram is at a severe mechanical disadvantage, with a very small ram stroke.
What you're suggesting is the opposite. Most guys say Flow Rate and Bore is everything for getting the most out of your system.

After Kane's talk on saturday the key thing seems to be air flow and having a large buffer tank, that simple. The reason it works with the pistol hitting right next to the pivot is because the force is so great and so rapid. When it ends up on youtube I will link it so you can hear what was said.

so its preferable to place the cylinder close to the hinge point rather than at the far end of the flipper?
The reason I ask is that I've been watching some clips of flippers in action over here, compared to mine I saw quite a big difference in the height they manage to flip the opponent...so I'm thinking I might change my setup to improve this.
The cylinder is located at approx 1/3 the length of the flipper arm - so there's quite a lot of mechanical disadvantage, thought of moving it forward to get it at about 2/3 the length...but to do that I would need a very short cylinder (probably less than 7cm). That's why I sort of asked about 2 stage cylinders, bec with a 7cm cylinder the stroke would be around 5-4 cm, and thats too little :?

Will have to figure out something else, probably another cylinder with a larger bore, as I'm not yet convinced to increase the pressure...for now :roll:

Increasing the bore of the cylinder is often a more efficient way of improving the power in the system and to utilise this moving the cylinder closer to the pivot increases the movement of the arm while allowing a shorter length to be used. It also allows a more direct movement, as short stroke large bore actuators can deliver the force more efficiently through the arm. There are also friction loses on the seals and so a shorter stoke will be more efficient here too.

However the flow of the gas is what moves the piston and is therefore key to a fast flipper. The regulator is probably the most restrictive component so overcome this with a large buffer tank. You then need a good sized valve and if using double acting pistons quick exhaust valves to vent the other side fast.

Its a balance that will require some adjustment to get right.

I would avoid telescoping actuators as there are more components and therefore greater chance of failure.

Ok than, thanks for the simple yet precise explanation Kane... It was worth asking here before I started ordering material and machining!

So now that 2 stage cylinder is out of the question I'll concentrate on designing and building a new cylinder, I'm currently using a 63mm bore 65mm stroke cylinder. This is fitted quite close to the pivot point, and it lifts the forward edge of the flipper from 0 to 240mm.

I cannot change the size of the buffer ( its a 12oz bottle) as there's no space to go bigger.
The fittings are all 1/2 inch all round for max flow,and the cylinder inlet is connected to a 1/2 inch QEV from the buffertank.
The 5/2 way valve is 1/2 inch as well (But I doubt there is any need for it to be of this size, infact I'm considering replacing it with a smaller valve to save weight)

If I keep the same stroke of 65mm and increase the bore to say 80mm will I have any noticable improvement?
I'm operating at a pressure of 8bar, tried it with 11bar (thats the max as the safety valve is 11bar as well) which gave it more power but was afraid of break something.


http://i8.photobucket.com/albums/a49...d/P1060887.jpg

Due to the size of the buffer tank the pressure will drop significantly. The only way to cure this if it is not possible to increase the buffer is to increase the pressure (reducing number of flips) or use a smaller cylinder (or both).

What about the outlet of the cylinder, or is it single acting?

Its single acting and doesn't have an outlet, instead I had drilled six holes at the top end cap to eliminate any backpressure.
I'll have to fiddle with pressure than, it seems the only option left - my issue is that the pneumatic system is a low pressure one, I could replace the safety valve with one of a higher value say 15bar...but I'd be risking blowing up something!
I have no experience with full pressure systems....yet :roll: and my guess is that parts are harder to find, heavier and much more expensive!

If you know the working pressure limits for your components you could just go up to that. Many of the components available are rated for 10 - 16 bar (but check the rating on the component).

The 5/2 way valve is rated at 8 bar operating press, and 10bar max press...I had gone up to 11bar and it leaked, but then I disassembled it and applied sealant to the gaskets, tried it again and didn't leak.
But the fittings have no rating on them...the push fittings for sure will not take more than 11bar because I've already had one burst. The rest of the fittings are 1/2 metal, they look strong enough... I could pressurise the system until something goes bust, record the pressure and set the pressure at say 20% less...( I'll stay at a safe distance :roll: )