FD-PCP gets a breath of fresh air...

[Gertrude]

... and now we go from 115cc, to 269cc on deck !
 YAY ! ! !

[Yarp]

Sweet!

[rsterne]

Is that a 3.5 oz. CO2 tank?.... I don't recognize it....

Bob

[StevenG]

Details! Tank and mount, where do we get these?

[Gertrude]

Is that a 3.5 oz. CO2 tank?.... I don't recognize it....

Bob

Hi Bob,

Well it says "4oz. Maximum Co2 Capacity", but I think that is because there needs to be some room for gas in the bottle when used for Co2.

My buddy (who machined the block) used a graduated cylinder, (actually one of his insulin hypodermics), to measure it, filling with water, and came up with almost 6oz. for the bottle alone.
 Then add in the volume of the tube and block, and we come up with 269cc total, (not counting the valve's plenum).

This should significantly increase the shot count I think.
 Might also allow for a bit more hammer tension to be used, while still maintaining an acceptable count.
 What do you think ?

I'll be running it through the chrony in a little while to get some numbers.
Here's a pic of the bottle we used:
(makes for a nice tidy little package I think) 

[Gertrude]

Details! Tank and mount, where do we get these?

Hahaha !... I told my buddy (who machined the block),... THAT AS SOON AS I POSTED THESE PICS,...
... there would surely be folks who were going to start knocking down the door ! HAHAHAHA !

Sure enough,.... that didn't take long !     

(and ya wanna know the best part)
 The "Arrow Guy" ( ) may not be the only game in town for very much longer     

[Ribbonstone]

Think it's one of the fat 4oz tanks.  Part of the sneaky plan to make every co2 tank over 2" in diameter.


But I've thought about the same set up with air (although I have several of the old skinny 3.5oz tanks).   Consider that the FDPCP still runs well in the middle of it's shot string at 1100-1200psi, and that the tanks are rated higher than that, have though of adding one just to increase air volume (not regged, just the tank for volume)


Basically, if I double the volume, with no other changes, should double the shot count.  Adding a tank like that should more than double the volume (by the posters numbers, more like 2.3 or 2.4X the number of shots).

[Gertrude]

Think it's one of the fat 4oz tanks.  Part of the sneaky plan to make every co2 tank over 2" in diameter.


But I've thought about the same set up with air (although I have several of the old skinny 3.5oz tanks).   Consider that the FDPCP still runs well in the middle of it's shot string at 1100-1200psi, and that the tanks are rated higher than that, have though of adding one just to increase air volume (not regged, just the tank for volume)


Basically, if I double the volume, with no other changes, should double the shot count.  Adding a tank like that should more than double the volume (by the posters numbers, more like 2.3 or 2.4X the number of shots).

Yep, and still in a clean little package, that keeps the COG to the rear.
 

[rsterne]

I have a slight (I'm being polite) concern.... CO2 tanks are rated at 1800 psi, and the gauge in your photo is pegged at about 2500 or more.... In addition, I don't see a regulator, which indicates that you are running the same pressure in a gun built for CO2, and recommended by the manufacturer for a 1500 psi fill.... This is safe how?....

Bob

[Gertrude]

I have a slight (I'm being polite) concern.... CO2 tanks are rated at 1800 psi, and the gauge in your photo is pegged at about 2500 or more.... In addition, I don't see a regulator, which indicates that you are running the same pressure in a gun built for CO2, and recommended by the manufacturer for a 1500 psi fill.... This is safe how?....

Bob

Bob,
First, thanks for the justified safety concerns.
 I certainly do not want to have some inexperienced people imitating this build, and getting themselves hurt as a result. 

 That pic was taken as I had just completed assembling the unit, and had filled to 2100psi,
 (by the large liquid filled calibrated gauge on my fill tank),
 to check for any leaks.

 The gauge on the block is not that accuate, and it was certainly not filled at 2500psi.
I do not recommend anyone taking a pressure vessel past it's mfg's ratings.

I have edited that pic from the original post, for the obvious reasons.
Thanks

[moorepower]

I got 3 of the 17ci 2" tanks for $99 on Ebay as a package deal, so there are alot of tank options.