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All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Voltar1 on October 15, 2020, 02:03:19 PM

Title: Mixed load CO2 with HPA
Post by: Voltar1 on October 15, 2020, 02:03:19 PM
Curious whether anyone else ever tested running an airgun on both fuels at the same time?
In ‘08 I tested a disco with both with incredible shot count.
Cheers
Title: Re: Mixed load CO2 with HPA
Post by: fivestar45 on October 15, 2020, 09:25:27 PM
Walter do you have a link to any posted results of your efforts with the dual mix? I'd be very interested.
Thanks
Title: Re: Mixed load CO2 with HPA
Post by: Voltar1 on October 16, 2020, 12:58:26 AM
I do not have a link, it was posted on the yellow way back then.
Filled tube to 50% by volume then topped off to 2000psi air. Shots started at 610 fps ending at 675.
Get this! 235 shots from that fill. I need to test it again.
Have an AT44 that is setup for co2 and will add air when time permits.
Title: Re: Mixed load CO2 with HPA
Post by: Hobbyman2007 on October 16, 2020, 06:31:16 AM
Never tried but that sure sounds like fun. Keep us posted , this might be the next best thing if it gets good results. Any idea at what pressure the gas turns into a liquid ?
Title: Re: Mixed load CO2 with HPA
Post by: Doug Wall on October 16, 2020, 07:34:55 AM
Air-CO2 mix would be a waste of time. You will immediately shoot off the 2000 psi air, and within a few shots, you will be shooting pure CO2 for that "incredible shot count". You can confirm that by looking at the pressure gauge. It will probably drop from 2000 psi to 850 psi within 10 shots, and stay at 850 for the rest of the string.
Title: Re: Mixed load CO2 with HPA
Post by: Hobbyman2007 on October 16, 2020, 07:42:44 AM
Doug, are these findings from actual testing? I have shot quite a bit of CO2 and according to the gauge it usually hovered around 1100psi vs the 850 your giving . I understand that the am I at air temp will affect this. All my CO2 shooting was done indoors at close to 70*F .
Title: Re: Mixed load CO2 with HPA
Post by: Doug Wall on October 16, 2020, 08:08:19 AM
Doug, are these findings from actual testing? I have shot quite a bit of CO2 and according to the gauge it usually hovered around 1100psi vs the 850 your giving . I understand that the am I at air temp will affect this. All my CO2 shooting was done indoors at close to 70*F .

Well, here's the general understanding: "The general standard is that when CO2 reaches 70 degrees Fahrenheit, the gas obtains a pressure of around 852.8 psi when contained in the cylinder or vessel. If there is more CO2 in the cylinder, it will then be converted into a liquid form."

I don't have a precision gauge to measure that, but I do know that most of the little gauges on guns aren't that accurate.
It doesn't really make any difference for the OP question. The added air will be gone very quickly.
Title: Re: Mixed load CO2 with HPA
Post by: avator on October 16, 2020, 08:58:07 AM
Not sure I'm grasping this. I thought C02 turned from liquid to gas when it's exposed to air?
Title: Re: Mixed load CO2 with HPA
Post by: Back_Roads on October 16, 2020, 09:13:28 AM
 I was wondering if the heavier CO2 was working like the pre pressurized air tubes of some of the guns like what Umarex has .   ??? :-\
Title: Re: Mixed load CO2 with HPA
Post by: CraigH on October 16, 2020, 09:19:42 AM
Not sure I'm grasping this. I thought C02 turned from liquid to gas when it's exposed to air?

Turns from liquid to gas upon pressure drop - in our CO2 guns case, pulling the trigger to opening the valve.
Title: Re: Mixed load CO2 with HPA
Post by: Mod90 on October 16, 2020, 10:22:38 AM
Not sure I'm grasping this. I thought C02 turned from liquid to gas when it's exposed to air?

Turns from liquid to gas upon pressure drop - in our CO2 guns case, pulling the trigger to opening the valve.
cO2 goes from solid to liquid to gas when there's either a pressure drop, or increase in temp, or both.
Title: Re: Mixed load CO2 with HPA
Post by: Voltar1 on October 16, 2020, 12:18:44 PM
Air-CO2 mix would be a waste of time. You will immediately shoot off the 2000 psi air, and within a few shots, you will be shooting pure CO2 for that "incredible shot count". You can confirm that by looking at the pressure gauge. It will probably drop from 2000 psi to 850 psi within 10 shots, and stay at 850 for the rest of the string.

So you think there are 225 shots on CO2 with an increase in speed to the end of the fill?
Not how I remember CO2 behaving. Typically the tube chills and pressure drops with reduced velocity. I will see if I can get a shot count on separate fuels
Title: Re: Mixed load CO2 with HPA
Post by: Doug Wall on October 16, 2020, 01:56:48 PM
Air-CO2 mix would be a waste of time. You will immediately shoot off the 2000 psi air, and within a few shots, you will be shooting pure CO2 for that "incredible shot count". You can confirm that by looking at the pressure gauge. It will probably drop from 2000 psi to 850 psi within 10 shots, and stay at 850 for the rest of the string.

So you think there are 225 shots on CO2 with an increase in speed to the end of the fill?
Not how I remember CO2 behaving. Typically the tube chills and pressure drops with reduced velocity. I will see if I can get a shot count on separate fuels
The tube will cool if you shoot quickly. Did you shoot all 225 in one session? What was the temperature at the start and finish of the session? It's not uncommon for initial, higher pressure shots to be lower velocity, as the higher pressure keeps the valve from opening as much. If you really want to prove your hypothesis, you need to do a chart of the entire shot string, with shot number, velocity, and tank pressure.
Title: Re: Mixed load CO2 with HPA
Post by: Voltar1 on October 16, 2020, 02:27:59 PM
Will gather facts as possible on this new trial. Back in 08 the shots all from one session but no way to know pressure on this 2260/Disco.
Title: Re: Mixed load CO2 with HPA
Post by: crazyhorse1 on October 16, 2020, 02:45:56 PM
Why not just fit a 9oz CO2 tank and get a ton of shots..?  My 850 .177 gets 800 fps/300 shots+... just had to fit a stronger hammer spring to prevent valve lock at 95 plus degrees ....
Title: Re: Mixed load CO2 with HPA
Post by: Voltar1 on October 16, 2020, 02:58:21 PM
Why not just fit a 9oz CO2 tank and get a ton of shots..?  My 850 .177 gets 800 fps/300 shots+... just had to fit a stronger hammer spring to prevent valve lock at 95 plus degrees ....

Why?
Title: Re: Mixed load CO2 with HPA
Post by: crazyhorse1 on October 16, 2020, 04:04:37 PM
Why not just fit a 9oz CO2 tank and get a ton of shots..?  My 850 .177 gets 800 fps/300 shots+... just had to fit a stronger hammer spring to prevent valve lock at 95 plus degrees ....

Why?

Seems you wanted a high shot count...?
Title: Re: Mixed load CO2 with HPA
Post by: Earl on October 16, 2020, 04:19:09 PM
Here is a CO2 temperature vs pressure chart.  CO2 is R-744.

https://www.transcentral.carrier.com/CPGTechPubs/toolbox/temp-pressure-chart_r744.html (https://www.transcentral.carrier.com/CPGTechPubs/toolbox/temp-pressure-chart_r744.html)

Title: Re: Mixed load CO2 with HPA
Post by: Voltar1 on October 16, 2020, 05:15:33 PM
Why not just fit a 9oz CO2 tank and get a ton of shots..?  My 850 .177 gets 800 fps/300 shots+... just had to fit a stronger hammer spring to prevent valve lock at 95 plus degrees ....

Why?

Seems you wanted a high shot count...?

See what can be done with an existing design without changing it. So no high shot count was never the goal but may be a reason to do this if it works.