Pneumatics on middle weights

[maddox]

Basic formula to know the lifting power is simpel

surface*pressure= liftable weight

for a 63mm ram at 10 bar

3.15*3.15*pi*10=310 kg.

So, then the usefullness of the system depends on the flow and the stroke. With a low power ram like that ,you need a long stroke.

[jamesb]

well, i dont know about that mario, low power is a relative term. what is awesome to some is a toy to others. chaos2 vs gravity for example.

if he had a 100mm stroke, he could put a 5:1 leverage ratio on it and have 60kg lift for 600mm at the tip. this would turn over most middleweights ive seen.

any longer stroke and there is more lift available.

i do agree with mario though, it would be a lifter not a flipper, so youd need around 350mm stroke to make a decent fliper from that size/pressure.

as to the original question, you would need a very capable compressor to keep up with the gas usage at those volumes. a very large buffertank will help, but the compressor you choose is paramount.

[maddox]

A compressor makes airpressure by converting electricity.

For a certain amount of electricity you can make a certain airpressure in a certain amount.

Pressure in bar * flow in Liters per minute/500= Kilowatts needed.

I can imagine a car compressor, with a classical 540 size motor. Delivering 25A on 12V. That is .3Kw

so, 10 bar*X flow/500=0.3Kw .05*X=.3Kw X= 6L minute.

A 63*350 ram has a volume of about 1 liter. This means you have about 6 lifts a minute.
But then youll have to fill your buffertank. At least 3 liter. That takes 30 seconds to fill at the start of a fight. And only then you can achive a somewhat functional fast lifter or low power flipper.If you get the valves and tubes right.

Now, I experimented with car compressors. And one of the things they dont like at all is to be overvolted. They melt the hoses and gears.

If I would build a compressor powered flipper, I would rebuild a small 240V compressor (about ‚90) with a Bosch 750 or simular motor. But then you lose a lot of weight on this. 4 kg on the compressor 3.8kg on the motor, 1 kg on the connector/gearbox(a bosch 750 runs to fast on 24V) and then the batteryweight.

You dont have to take my advice, but I would say a short fat ram can deliver a better punch than a long thin one, even if the total calculated amount of energy is the same.

[jamesb]

i agree with mario, a short fat one is better (no jokes please!)

looking at morios suggestion of a 240v compressor with bosch750, the thought strikes me that you could buy at least 8 12v car compessors (cheap ones) for the price of a bosch750. maybe multiple compressors?

i still think a featherweight is your best option.

[big_nipper]

Tried 2 of those car compressors on a featherweight axe (Blue), still not enough, a 36V one we found did the trick after the motor was replaced by a drill motor but was too heavy for a good featherweight. First little flipper also used one compressor to start but we were always waiting for it to reach pressure before we could flip, so in a middleweight 1 or 2 would be out of the question (8?). In a feather its still a good starting point and also good for testing without the need for CO2.

Our middle wont be finshed for a while but would be good for another to be out there as well.

Little Hitter uses an 80mm bore ram with 50mm stroke, and even though its only an axe its quite capable of throwing itself out of the arena at 10 bar .

[jamesb]

nobody to fight. few lightweights around
come to an event, i think youll change your mind about feathers