[tyronejk]

This is a brief calculation of the theoretical maximum efficiency of any 0.68 cal paintball maker off a 68/4500 tank.

Feel free to correct any errors!

mass of an average paintball: 3.2 g = 0.0032 kg
300 fps = 91.44 m/s
68 cu inches = 0.0011143 cu meters
4500 psi = 31026407.8 pascals
atmospheric pressure at sea level: 101325 pA

kinetic energy of a single paintball at full velocity:
E = 0.5mv^2
= 0.5 * 0.0032 kg * 91.44^2 = 13.3780 J

stored energy in a 68/4500 tank:
E = pV
= (31026407.8 pA - 101325 pA) * 0.0011143 m^3 = 34459.820 J

number of paintballs fired from the energy in one tank:
34459.820 J / 13.3780 J = 2575.857 paintballs

=================================================

In conclusion: a marker with a bolt of zero grams, zero friction, zero internal volume (including regulators, hoses, and chambers) firing at 300 fps, at sea level, with an outdoor temperature of 0 degrees celsius or 32 degrees fahrenheit, and firing each ball with enough of a delay to allow the tank pressure to reach equilibrium in between every shot (approx. 5-10 seconds), you can get up to 2,575.857 shots!

note: The 2,576th shot will be a break.

[brycelarson]

that seems to be in line with previous calculations.

[cockerpunk]

good work, this is about where other calculations have put it as well.

[tyronejk]

brycelarson, on 31 August 2012 - 08:28 AM, said:

that seems to be in line with previous calculations.

cockerpunk, on 31 August 2012 - 08:32 AM, said:

good work, this is about where other calculations have put it as well.

Thanks!

[Egomaniacal]

Since 4500 psi is gauge pressure, there's no need to subtract atmospheric to get total energy in the tank. It won't make much difference because atmo is so small in comparison to 4500 psi, but since it's gauge pressure the energy of atmo is already accounted for/neglected.

[Cookybiscuit]

No idea how Bob Long gets away with claiming 3k shots off the G6R.

[cockerpunk]

Cookybiscuit, on 31 August 2012 - 04:32 PM, said:

No idea how Bob Long gets away with claiming 3k shots off the G6R.

only way to do that is a slower chrono speed. at 260fps i believe it.

[tyronejk]

Egomaniacal, on 31 August 2012 - 01:36 PM, said:

Since 4500 psi is gauge pressure, there's no need to subtract atmospheric to get total energy in the tank. It won't make much difference because atmo is so small in comparison to 4500 psi, but since it's gauge pressure the energy of atmo is already accounted for/neglected.

Yes! You are correct. I'll have to make some corrections.

[Cookybiscuit]

cockerpunk, on 31 August 2012 - 04:41 PM, said:

only way to do that is a slower chrono speed. at 260fps i believe it.

Well he claims 3k at 280FPS (according to that tour video put up a few days ago) from a 70cu. It must be to do with the tolerances on BL's I hear so much about.

[andrewthewookie]

Don't forget that all the angles are at angles for perfect air flow.

This post has been edited by andrewthewookie: 31 August 2012 - 05:58 PM

[IhasAcellular]

and they cross! Its like porting and polishing engine heads!

[510waffles]

Im going to give the benefit of the doubt that Bob long is not lying and he does have the gun get 3k shots, its just that there are some underyling things that hes not talking about. hes probably shooting at a very low BPS, with a 70CI,cold fill,probably chrono around 260-270,dwell at 4.Hell, probably not even 3k, might be like 2950 or something.


Using 260 as average chrono speed, you can get 3.2k shots according to my calculations, so 3k shots at 280 isnt all that preposterous

after using all the forumlas and back solving,His average chrono must be under 274 and thats with a 68 calculation. add those 2 cubic inches and youre at a reasonably close to 280

This post has been edited by 510waffles: 31 August 2012 - 07:48 PM

[Cookybiscuit]

510waffles, on 31 August 2012 - 07:40 PM, said:

Im going to give the benefit of the doubt that Bob long is not lying and he does have the gun get 3k shots, its just that there are some underyling things that hes not talking about. hes probably shooting at a very low BPS, with a 70CI,cold fill,probably chrono around 260-270,dwell at 4.Hell, probably not even 3k, might be like 2950 or something.

That or hes using the brand new 2013 Bob Long pod, featuring the appearance of a 140, with half the capacity.

[Troy]

510waffles, on 31 August 2012 - 07:40 PM, said:

Im going to give the benefit of the doubt that Bob long is not lying and he does have the gun get 3k shots, its just that there are some underyling things that hes not talking about. hes probably shooting at a very low BPS, with a 70CI,cold fill,probably chrono around 260-270,dwell at 4.Hell, probably not even 3k, might be like 2950 or something.


Using 260 as average chrono speed, you can get 3.2k shots according to my calculations, so 3k shots at 280 isnt all that preposterous

after using all the forumlas and back solving,His average chrono must be under 274 and thats with a 68 calculation. add those 2 cubic inches and youre at a reasonably close to 280

I wouldn't say that he's lying... but I've seen many people, even scientists... hell, even me, WANT a result so badly, that they fool themselves into getting it. If you round up, you don't pack your pods all the way, the chrono is somewhere around 280, etc. you can probably fudge 3k rounds. It doesn't mean he is lying, it just means that he's not objective.

[tyronejk]

At 260 fps and with a 70 cut inch tank, the theoretical maximum number of shots is 3544.919. At 280 fps and with a 70 cut inch tank, it's 3056.588 shots.

So Bob Long could've gotten 3k shots off of a 70 cu in. I think it probably was a cold tank.

[Egomaniacal]

I seriously doubt Bob's valves are good enough to be getting the efficiency numbers of a perfectly ideal valve.

Not to mention you're completely neglecting the air required to cycle the marker, and when you're talking about efficiency numbers as high as these, that volume becomes non-negligible.

This post has been edited by Egomaniacal: 01 September 2012 - 01:54 PM

[mr.satire]

Yeah i dont buy it. If you include losses from friction, and other factors its safe to assume a 20 to 30 percent loss, so if you have the theoretical value of 3544 shots at 260 then a real world guess at 80% efficiency (very unlikely) is 2,835 shots and at 70% it is 2480 shots. So bob longs claim of 3K really is impossible but 2.5K at 260 could happen.

[firebirdjimbo]

He states in his video that he was shooting above 260fps so probably 265 +/-5ish. In his other tests he shoots at about 8bps so that it can all recharge correctly, I believe that he gets 3000 shots off of a cold and full 68/45 shooting 8bps at 265fps.

[misterkyle]

firebirdjimbo, on 03 September 2012 - 11:16 PM, said:

He states in his video that he was shooting above 260fps so probably 265 +/-5ish. In his other tests he shoots at about 8bps so that it can all recharge correctly, I believe that he gets 3000 shots off of a cold and full 68/45 shooting 8bps at 265fps.

I love my victory. But he is full of shit.

This post has been edited by misterkyle: 04 September 2012 - 01:51 AM

[Troy]

Egomaniacal, on 01 September 2012 - 01:50 PM, said:

I seriously doubt Bob's valves are good enough to be getting the efficiency numbers of a perfectly ideal valve.

I think that "seriously doubt" is an obscene understatement... I believe you know that as well, but I just wanted to underline that point.