I’m reasonably new, at least to internal design of airguns. I’ve only ever seen (on YT and web) hammer designs. What other kinds of valves are there ?
When potato launchers were the rage, they used to use differential valves on some.
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The Next Breakthrough in airguns
- Thread starter jps2486
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When potato launchers were the rage, they used to use differential valves on some.
Not really, as once above @ 3500 psi the amount of air molecules in compression are starting to lose room for more as you compress the pressure to even higher levels.
The AMOUNT of usable air IS NOT PROPORTIONAL to the volume & pressure once above @ 3500 psi .... as it is for pressures under 3500
Gotta love nerdy threads like this. According to Boyle's Law the equation to get the volume of air it seems to be linear based on pressure.
Volume of free gas in a Storage Volume
The amount of free gas at atmospheric pressure in a given volume - like a cylinder storage - can be calculated my modifying (1)V a = p c V c / p a
p a = atmospheric pressure (14.7 psia, 101.325 kPa )
V a = volume of the gas at atmospheric pressure (cubic feet, m 3 )
p c = pressure after compression (psi, kPa )
V c = volume of gas after compression (cubic feet, m 3 )
So filling that pistol to very high pressure/5000psi does make the shot count look very reasonable or doable under normal efficiency.
My question is: how da hell does anyone fill it up to 5000 psi? Hand pump?
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I had a Huben hand pump, it would do 5000 psi.Gotta love nerdy threads like this. According to Boyle's Law the equation to get the volume of air it seems to be linear based on pressure.
Volume of free gas in a Storage Volume
The amount of free gas at atmospheric pressure in a given volume - like a cylinder storage - can be calculated my modifying (1)
V a = p c V c / p a
p a = atmospheric pressure (14.7 psia, 101.325 kPa )
V a = volume of the gas at atmospheric pressure (cubic feet, m 3 )
p c = pressure after compression (psi, kPa )
V c = volume of gas after compression (cubic feet, m 3 )
So filling that pistol to very high pressure/5000psi does make the shot count look very reasonable or doable under normal efficiency.
My question I have is: how da hell does anyone fill it up to 5000 psi? Hand pump?
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The most recent "breakthroughs" have been in both the electric controlled valves (Daystate, Skout, etc), and the dual valved guns (Huben, LCS, Western, ect). Let's not forget the balance valve, which is fairly new and efficient to the conventional hammered poppet system and brings advantage to the table too. These are new technologies are both efficient and seemingly superior to the simple weighted hammer and poppet valve systems that airguns have used for centuries. Everyone makes some type or another of the "original" weighted hammer" type of pcp.
With all, we're going to see who takes a back seat to who in a few years. My guess is simplicity coupled with high power and efficiency will continue to trump the battery-required bench gun in sales. And as far as Huben, LCS and Western come out with their fairly complicated but efficient dual valved mechanical systems, if they evolve to become 'bulletproof' that will be the best seller; because so far they don't seem to have too many problems afield as of late.
With all, we're going to see who takes a back seat to who in a few years. My guess is simplicity coupled with high power and efficiency will continue to trump the battery-required bench gun in sales. And as far as Huben, LCS and Western come out with their fairly complicated but efficient dual valved mechanical systems, if they evolve to become 'bulletproof' that will be the best seller; because so far they don't seem to have too many problems afield as of late.
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I think my Omega trail charger will do 4500, as I fill one of my guns to 4300 max.. but I'm not sure I'd want to try 5000 as it's close to the top end of the gauge.. it's been a great compressor for 8 years and unless I know for sure from someone else, I don't think I'd risk the compressor.. it might be fine but I don't like to push things to hard and have them brake.Gotta love nerdy threads like this. According to Boyle's Law the equation to get the volume of air it seems to be linear based on pressure.
Volume of free gas in a Storage Volume
The amount of free gas at atmospheric pressure in a given volume - like a cylinder storage - can be calculated my modifying (1)
V a = p c V c / p a
p a = atmospheric pressure (14.7 psia, 101.325 kPa )
V a = volume of the gas at atmospheric pressure (cubic feet, m 3 )
p c = pressure after compression (psi, kPa )
V c = volume of gas after compression (cubic feet, m 3 )
So filling that pistol to very high pressure/5000psi does make the shot count look very reasonable or doable under normal efficiency.
My question I have is: how da hell does anyone fill it up to 5000 psi? Hand pump?
Mark
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I don't know that any of the manufacturers are reading this thread but it would be nice to see some compact PCP pistols in the entry level price range.. think of the notos without the moderator and shrunk to 12" or less.. or if they made a Colt SAA that would do at least a six gun worth of shots per fill.. unfortunately the huben gk1, evinix viper, and the tequila gun are the only ones that fit 12" and they are all $1000 or more.. a couple of them are probably worth it if you have the spare cash..
Mark
Mark
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The key, I'd think, is instant very high cross-sectional area of the channel between the barrel and high pressure air. This eliminates throttling and also maybe serves as a mini plenum full of HPA directly behind the barrel, after the valve closes.
You could imagine that in some PCPs, by the time the pressure behind the pellet has reached the tank or regulator pressure, the pellet is already half-way down the barrel, due for example to slow valve opening and a narrow transfer port. Slow valve opening is of course relative to the time the pellet spends in the barrel- a partially opened valve would also serve to throttle the flow of air in the initial stages of acceleration.
You could imagine that in some PCPs, by the time the pressure behind the pellet has reached the tank or regulator pressure, the pellet is already half-way down the barrel, due for example to slow valve opening and a narrow transfer port. Slow valve opening is of course relative to the time the pellet spends in the barrel- a partially opened valve would also serve to throttle the flow of air in the initial stages of acceleration.
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There is also a Z factor in the equation to account for variation in temperature and pressure:Gotta love nerdy threads like this. According to Boyle's Law the equation to get the volume of air it seems to be linear based on pressure.
Volume of free gas in a Storage Volume
The amount of free gas at atmospheric pressure in a given volume - like a cylinder storage - can be calculated my modifying (1)
V a = p c V c / p a
p a = atmospheric pressure (14.7 psia, 101.325 kPa )
V a = volume of the gas at atmospheric pressure (cubic feet, m 3 )
p c = pressure after compression (psi, kPa )
V c = volume of gas after compression (cubic feet, m 3 )
So filling that pistol to very high pressure/5000psi does make the shot count look very reasonable or doable under normal efficiency.
My question is: how da hell does anyone fill it up to 5000 psi? Hand pump?
Compressibility factor - Wikipedia
Practically speaking, at the temperature we operate at, air is 3% less compressible at 200 bar, but that rises to 10% at 300 bar and 14% at 350bar.
So, at 300bar, 1 liter of air contains 270 liters of air at atmospheric pressure.
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