regulator and barrel length relations

[daddypaddy]

what’s up everyone!
does anyone have a link or information about the maximum fpe attainable with a regulated airgun and an 11.5” barrel sending .22 cal at 14.3-25 grain? this is with all relevant ports expanded for transfer of air. im expecting there’s a plateau for each given pellet before i went searching for it, i was hoping someone here knows or can point me in the right direction.

is all the information i need found in regulator valve dwell time at different pressure set points?

 

[Stubbers]

I can provide you with estimates based on data modeling I've done on pcp's. Although I need two more bits of information from you. Regulator Plenum Volume and Regulator's Set point / Pressure.

I will happily post a chart with your maximum FPE according to those pellet weights / caliber /barrel length / regulator setting combo once I have that info.

-Matt

 

[Long_Gun_Dallas]

I've got a pistol that does 27 fpe in 7.6", 22 cal. I have it turned down to 16fpe for noise and air consumption reasons.

Power will be dictated by valve size, plenum size, barrel length, and port sizes, as well as hammer ability to open valve. There are many variables.

 

[daddypaddy]

I've got a pistol that does 27 fpe in 7.6", 22 cal. I have it turned down to 16fpe for noise and air consumption reasons.

Power will be dictated by valve size, plenum size, barrel length, and port sizes, as well as hammer ability to open valve. There are many variables.

so what weight are you sending into your targets?
and whats your regulator set to?

 

[daddypaddy]

I can provide you with estimates based on data modeling I've done on pcp's. Although I need two more bits of information from you. Regulator Plenum Volume and Regulator's Set point / Pressure.

I will happily post a chart with your maximum FPE according to those pellet weights / caliber /barrel length / regulator setting combo once I have that info.

-Matt

thanks, i’d really appreciate that.
i dont know what the oem volume is for the notos but i did add a 15cc plenum to it and i have the regulator set to 2000 psi.

my understanding is to set the regulator higher with the spring spring tensioner turned 90%_95% in for heavier pellets to increase fpe while still giving me the ability to back out the spring tensioner to accommodate lighter pellets without wasting too much excess air. does my logic hold any merit with regard to tuning an airgun to be capable of sending different weight pellets effectively?

 

[Stubbers]

A 11.5" .22 cal with say 90% bore porting and a 20cc plenum at 2,000 psi should do the following...

14.3GR = 26~ FPE @ 900 fps and change.

25GR = 26~ fpe @ 686 Fps and change.

Your power won't drop off until your projectile weight drops below 13 gr's, only your fps.

The lightest .22 pellet I am aware of is 9.56 gr, and that would likely only do 22.5 fpe @ 1000 fps and change.

The reason why lighter pellets eventually lose power is because they leave the barrel too quickly, unable to absorb the energy from the air which propels it. Likewise heavier pellets begin no longer adding meaningful energy behind the pellet at a certain point due to other limitations within the gun.

-Matt

 

[Long_Gun_Dallas]

This will be better info to take from, but still leaves many variables on your gun unaccounted for. These figures are from a mk1 fx Crown set at 135bar. Factory plenum is 25cc. Valve and port are relatively high flowing.

Barrel lengths are listed. As well as transfer port sizes (lo and high)

Same gun shoots same pellet at high settings at 960fps in 380mm barrel. (Little over double the barrel length tested here)

 

[Rohmpm]

Is it a notos. My notos, with .167 porting throughout, a peek valve, ebay plenum, self built guage block, .375 porting through the airtube adapter, reg at 148-150 bar will shoot FX16 into the 900's. . I use a softer spring and a 12 gram hammer and get four mags in the 870+. I shortened the barrel because the whole crown was jacked at least a quarter inch. I've done more mods since but this is a string with the 16's. JSB 15.89 are virtually identical.

 

[daddypaddy]

can i set the regulator at a higher pressure and have the hammer spring backed out to

Is it a notos. My notos, with .167 porting throughout, a peek valve, ebay plenum, self built guage block, .375 porting through the airtube adapter, reg at 148-150 bar will shoot FX16 into the 900's. . I use a softer spring and a 12 gram hammer and get four mags in the 870+. I shortened the barrel because the whole crown was jacked at least a quarter inch. I've done more mods since but this is a string with the 16's. JSB 15.89 are virtually identical.

View attachment 394312

yes it’s a notos.
is that peek valve different from the oem? where can i get one?
and where can i get a softer spring and the 12 gram hammer?

 

[Stubbers]

can i set the regulator at a higher pressure and have the hammer spring backed out to

yes it’s a notos.
is that peek valve different from the oem? where can i get one?
and where can i get a softer spring and the 12 gram hammer?

Those are custom machined / fabricated pieces, hopefully someone will offer to make you one at a cost or charitably if you're not able yourself.

-Matt

 

[daddypaddy]

Those are custom machined / fabricated pieces, hopefully someone will offer to make you one at a cost or charitably if you're not able yourself.

-Matt

i am not able to make them myself.. did you make those for yourself?

 

[Stubbers]

i am not able to make them myself.. did you make those for yourself?

@Rohmpm could possibly tell you if he made them himself or who he had make them.

-Matt

 

[Rohmpm]

I was hoping someone else would start making Notos parts. I made my own as I enjoy experimenting as a hobby. I do not make parts for others but gladly share what I have learned. I really did not see much interest in mods I presented so I stopped posting, but I have refined my tune some more. Next, I'll work with a lower reg pressure. The hammer I'm using is a 12 gram brass version. Think I'll try an aluminum one with a brass wear ring for the trigger for even shorter valve opening. All of my hammers have had a peek face about 90 thousandths thinner than factory to allow the light hammer more velocity impacting the valve.