Skout Everything Skout EVO and Epoch

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MSR Workshop said:
So far, I’ve only enlarged the high-pressure regular body. I’m a little chicken now that things are working so well…. I still may.. we’ll see 🤪
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Yeah! I know what you mean, question how does your LP reg behave I know they take lots of winding to achieve any adjustment, but I am trying to find out just why mine seems to drop pressure when adjusted??

It seems that as such a low relative pressure is used to unbalance the valve the pressure is not that important, but I guess volume could be, but then would that necessitate upgrading the solenoid? Food for though.o_O
 
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Tricky-Dicky said:
Yeah! I know what you mean, question how does your LP reg behave I know they take lots of winding to achieve any adjustment, but I am trying to find out just why mine seems to drop pressure when adjusted??

It seems that as such a low relative pressure is used to unbalance the valve the pressure is not that important, but I guess volume could be, but then would that necessitate upgrading the solenoid? Food for though.o_O
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are the threads on the regulators dirty?..It might be possible that you are unscrewing the reg when adjusting. You won't completely unscrew it due to the retaining wire, but is can make a slight difference....just a thought
 
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manabeknives said:
are the threads on the regulators dirty?..It might be possible that you are unscrewing the reg when adjusting. You won't completely unscrew it due to the retaining wire, but is can make a slight difference....just a thought
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Unfortunately not, the adjuster cap will come off completely without removing the wire, and like I said on the sub 12 version the reg is deliberately not adjustable and lacks the plastic insert used, so I made one from delrin, wound in the adjuster by quite a few turns and all I saw was a slight drop in the pressure.
 
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Tricky-Dicky said:
I am intrigued by the LP reg adjustment, so you have opened up the air paths in both regs now? And the final mod was to open up the spool valve poppet?

As my LP reg was not adjustable on the sub 12 version I did make an adjuster for it but found that winding it in did very little even after several turns, and it also seemed to reduce pressure rather than increase? Whether this is due to lower pressure in the HP reg making it not very responsive, I don't know?
My HP reg pressure sits around 1300psi and LP at 150psi this achieves my maximum allowed fps of 720 with a 10.34gr pellet but until I drilled out the poppet valve to 1mm the spread was always well over 10 fps now it stays around 10fps or lower.

The conclusions I draw from this is that although in theory small apertures are not a problem with HPA, but there is an application control it seems in the speed that the HPA can transfer so the aperture is a limiting factor, now I can understand this in relation to the poppet valve but not sure about the regs as the same?
Because of the speed of the air dump as the spool valve opens the poppet air feedback through the drilling is crucial to the speed of operation as the air is already leaving the gun behind the pellet and I suspect this is where calibre must come into it as this will also dictate the diameter and speed which the feedback closes the spool valve.

This is just my take on the way it works and could be completely wrong, as I am only just trying to learn the foibles of the system.
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Your getting there :giggle:
Yes indeed the orifice size within poppet head is crucial in getting a rapid closing cycle and is quite sensitive to pressure used in plenum, caliber which changes flow resistance, volume & time the available pressure within valves throat / transfer path can aid in this closing cycle.
There are many ways to word this same thing & thought I had eluded to this earlier in conversation ;)

You guys are doing great BTW !!
 
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Motorhead said:
Your getting there :giggle:
Yes indeed the orifice size within poppet head is crucial in getting a rapid closing cycle and is quite sensitive to pressure used in plenum, caliber which changes flow resistance, volume & time the available pressure within valves throat / transfer path can aid in this closing cycle.
There are many ways to word this same thing & thought I had eluded to this earlier in conversation ;)

You guys are doing great BTW !!
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Can you give me your thoughts/knowledge on the way my LP reg is behaving?
And is the feed from the HP reg orifice controlled or just solely based on the HP reg pressure, IE because the HP pressure is low the resulting pressure available to is also limited.
If the LP reg pressure is the supply for the opening solenoid then increasing it can only have a limited effect on the opening speed as it's controlled by the electronic pulse/ dwell length and by its own orifice size and those between?

PS also have you tried increasing the poppet drilling size larger than 1mm? Once I get my spares, I will be giving it a go just out of curiosity.
 
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Best I understand it, the LP reg is downstream of the HP reg & this is why that their design of how regs function, changes in HP also shifts LP.
The exact reason is outside my knowledge and would need to come from SKOUT.

I do have to tell you tho .... we who own these wonderful PCP's nearly all own them for the POWER then can produce in the various calibers generally .22 and greater. The extremely low power level your requiring and trying to figure out is for all but a few at the extreme opposing end of the typical users spectrum :cautious: As such much that works for tuning at high power and massaging better than delivered efficiency, we end users have no idea w/o much R&D on porting / jet sizes / pressures and the whole enchilada of perimeters that one might investigate becomes a guessing game for extreme low power application.

I did a lot of it on the high power side over 2 years ago finding the improvements wanted utilizing several years of past experience with balanced valves using a pressure feed back poppet closing designs. That gave me a huge leg up on most who would or will venture into the R&D of said designs.

** We learned very quickly that "Balanced Valve Designs" as we call them were no where near ideal in low power applications being too dang hard the get them to accurately meter there discharge volume be it lift or open dwell control.
It is pretty much known in the world of AG tuners who work with Balanced valves or a Spool valves in a PCP air rifle, that .... there bias is High output !! And the higher the output the more linear there power seems to be once your in the meat of where these valve perform best. Drop to a low power use a conventional knock open poppet type valve is far more consistent and reliable .... in My Opinion :oops:
 
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Thanks! And I agree I have always thought the design is orientated toward the high power large calibres and trying to throttle a design that dumps all the available air in the plenum is always going to be difficult to say the least, and although It's still essentially a knock open design it just functions somewhat differently, and the usual means of throttling for low power applications has still been employed IE a small transfer port, but I am sure there is a better way but opening it up like I would a normal design and using the other various methods of tuning for a specific power just doesn't seem to work, I suspect that re-sizing the plenum/spool valve is the answer to low power applications as air volume plays a big part.
 
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I tried out the new 28” .22 LW barrel with some JTS 22.07 grain pellets at 50 yards at an indoor range
This barrel is fantastic!
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Tricky-Dicky said:
Yeah! I know what you mean, question how does your LP reg behave I know they take lots of winding to achieve any adjustment, but I am trying to find out just why mine seems to drop pressure when adjusted??

It seems that as such a low relative pressure is used to unbalance the valve the pressure is not that important, but I guess volume could be, but then would that necessitate upgrading the solenoid? Food for though.o_O
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I can imagine the upgrading the solenoid would do nothing since even with a high-pressure regulator cranked well beyond 2300 psi, the solenoid that’s on the gun still easily opens the valve at a very low setting. In essence, he would have 2300 psi of pressure keeping the spool valve closed, but the combination of the low pressure regulator, and that little extra puff of air from the solenoid valve is enough to pry open and cycle, the gun.
i’ve heard some theories that the larger the Plenum volume the harder for it is to have very low, extreme spread values since it takes longer for that Plenum to refill…
So the less restrictive, you can make your air path, the quicker the Plenum recovers. all this in theory translates over to a tighter, extreme spread value.
 
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Now that contradicts everything I have read on spool valves, however I see the point, but one thing I have noticed is that even on the sub 12 version it dumps way more air than any normal sub 12 rifle! How do I know, well I make silenced shrouds for all kind of rifle and there are very few that are capable of blowing the shroud off with some force and the Epoch is y far the most powerful!
I will quantify, most of my shrouds use a base collar that is fixed to the barrel or original barrel shroud in the case of some like the DS Alpha Wolf by a grub screw this is plenty to hold the shroud in place even on some FAC/full power rifles yet when I was developing a silenced shroud for the Epoch the base collar was literally ripped through the original carbon barrel sleeve that how much air volume that the spool valve shifts when fired in sub 12!

I had to make a delrin spacer that fitted between the sleeve end lock ring and the back of the start of the original stripper to stop this happening, so don't tell me that the Epoch doesn't shift a big lot of air even when throttled for sub 12 with tiny transfer port/valve seal, so excuse me if I am a little incredulous of that statement.

This is what I had to make to prevent the shroud being ripped off the end of the gun!

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Another tuning 2 tricks that originated from SKOUT, tho I've never seen shared or spoken of .... IS, washers or lets say shims that are placed on the receivers spool valve retention cavity where poppet piston is moving forwards & back.
These thin washers are made of what looks like white acetal or perhaps nylon. They limit the opening distance the poppet head can lift off the seat.

Second is that of the Spring that sits in the rear as well that aids the closing force of poppet or most likely just there to hold poppet shut when airing up / pressurizing the plenum. * Stiffer did cut dwell slightly.
It too can have differing spring rates. ( This I did very early on going to a heavier wire spring )

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How did these mods affect the guns' performance? While I can see that timing can have an effect on the air released, I struggle to see just how this can be quantified other than trial and error?
Going back to the volume thing, my normal way of setting up a normal gun that's been throttled down to sub 12 by various means is often to pack out the plenum with a delrin filler so not only the plenum volume is much smaller, which in turn aids reg recovery time and also air use, and I can see how the spool valves packing, and stronger spring also achieves the same end to a degree.
I would also have thought that the electronic dwell control would have more effect on the amount of air released, but it doesn't, perhaps it needs more programming experimentation unfortunately not my strong point, but I suspect the software could be played with, I'm sure if someone like Jack Gialoukos looked into it there could be some interesting results.
 
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Issue with a spool valve is somewhat similar to a toilet flush valve ... In that the seal needs to be broken enough so that flow ensues, Too small amount of lift and the pressure holding said seal in position never gets flow to overcome the pressure holding it closed. This is what called sail effect to some degree where the passing of water or air around the seal drags it closed to quickly. Enough lift when created between seal and seat the system flushes or burps a somewhat measured amount of air.

In a spool valve similar to an electronic solenoid open conventional valve ( Daystate design ) one is semi controlling the effort to hold the valve seal / poppet off the seat countering sail effect for the flow to close it. But they differ .... where as a daystate system the poppets motion is always dynamic and only lift control is that of strike strength, what ever height that is can be held there more or less changing the valves open dwell duration. But understand the poppet is always moving and never gets held at any fixed position .. Dynamic at all times !!

A spool valve as in the Skout and also electronic in a sense, is used to fire an air discharge solenoid that places air between the back side piston and retention nut. this pressure counters the pressure of the area difference between poppet shaft & head diameters holding the valve shut creating the poppet stem to shift opening seat. The electronic dwell controls HOW LONG this pressure is placed into this space between piston and retention nut holding valve open. Because the spool piston has limited travel and piston generally does bottom out once poppet is forced open. The "WASHER" reduces the distance poppet can be lifted. In a discharge cycle this goes static to dynamic, to static at full opening, then dynamic upon closing to static again.
YES you do have control on lift altering lift limits via spacing, YES you have control to how long poppet is being held there. SORTA :rolleyes: The why not is because of the bleed hole in poppet head taking throat pressure during the shot cycle and taking a measure amount ( Based on bleed hole / orifice size ) placing counter pressure on opposing side of piston where the washer and spring reside. Area of piston is greater on the backside than poppet stem side for one ... then compounded further by the pressure used to unbalance & open the valve is low ( 125-200 psi or LPR setting ) yet the pressure to close it is a metered sip of much higher pressure ( HP reg setting ) and slams the valve shut !!

So ... while the cause & effect you can now hopefully get a grasp on, these all thrown together for a single firing cycle happen sequentially in a VERY fast series of overlapping events. To understand each cause & effect helps one better grasps what changes made have on the total event overall.

Yes you bet your life that the R&D SKOUT went threw and likely is still learning or refining is vast !!!!! We who choose to try and reinvent the wheel we do so at our our peril, time & parts etc ....

Sorry for the soap box ...
Scott
 
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I think I might try turning up a spacer for the back of the valve as in theory the limiting of travel and time the valve is open should in theory reduce the amount of air released, but surly the uprated spring is counter to the opening of the poppet valve feedback/closing aperture as the larger hole should make closing quicker, but the spring is increasing the resistance to this?
 
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Tricky-Dicky said:
I think I might try turning up a spacer for the back of the valve as in theory the limiting of travel and time the valve is open should in theory reduce the amount of air released, but surly the uprated spring is counter to the opening of the poppet valve feedback/closing aperture as the larger hole should make closing quicker, but the spring is increasing the resistance to this?
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Similar to a conventional valve where the AKA: poppet spring does not play a huge part as the pressure over the area of poppet head is many many times stronger !!
Generally in a convention knock open poppet one needs to make pretty substantial spring rate changes to see the effect.

Tho in a spool valve the pressure exerted holding poppet closed is much lighter, as such the spring strength effect is more pronounced and small spring rate changes there I've found more noticed.
 
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Motorhead said:
Similar to a conventional valve where the AKA: poppet spring does not play a huge part as the pressure over the area of poppet head is many many times stronger !!
Generally in a convention knock open poppet one needs to make pretty substantial spring rate changes to see the effect.

Tho in a spool valve the pressure exerted holding poppet closed is much lighter, as such the spring strength effect is more pronounced and small spring rate changes there I've found more noticed.
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The difference being that you're probably used to using reg/plenum pressures of 100bar upwards where I use 60-100bar so spring rate and shims have much more effect with lower pressures.
 
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