"Regulator & Custom tuning" Evanix .22 rainstorm .... Posting Result updates

[Motorhead]

Having been sold 100% on the merits of regulated PCP's, just can't leave one alone when it comes into my personal stable of AG's 
So find myself working on a newly acquired Evanix RainStorm .22 Gen 1 rifle.

Doing extensive on-line research read over and over about the Power power power these rifles make followed by what air wasters they are & extent folks go threw in de-tuning many of them.  Many change hammer springs, add valve stem buffers and other such means in backing down / lowering the power so modest heavy weight pellets drop under 1000+ fps speeds 

**Researching regulators found only ONE that DOES NOT require you drilling air tube for the atmospheric vent.
Sadly once you drill a vent hole your committed to staying regged with no going back  ... not good for R&D work.

Altaros makes such a regulator that butts up against valve body & vents via the threads of air tube connection with the factory o-ring removed.
Very ingenious allowing reg to be installed or removed with NO gun modifications or vent hole drilling.
* MAJOR down side however of this design as used is it gives you nearly no plenum volume only being that volume within valve body itself

Here that Regulator:

Having so little plenum volume the performance hit is IMO .... far too much due to this issue.

  So ... went about using a early gen Huub regulator from a Marauder which fits a 1.060" tube,  manufactured an adapter to fits the Rainstorms 1.217" tube.
Utilizing the design of a flush o-ring sealing against valve body allowing venting out the tube threads, made a 2 piece adapter from derin to hold the M-rod reg into position while creating a plenum at the same time.

Plenum space in this adaptation is @ 2" long & @ 1" diameter giving about 25cc's of plenum volume. 
Aluminum sleeve used rests on end of adapter right behind o-ring with regulator resting on top of it. All the longitudinal loading from High Pressure tank side transfers between them so very little compression loading is on the delrin parts.
Both 0-rings of regulator seal within adapter parts inner bores with another o-ring on top section sealing it to air tube bore.
GAP between both sections is where regulator vents taking the path out the threads same as the Altaros reg does.









Testing and result data to follow 

Thanks for following along,
Scott

[Hanabata808]

Quite handy and innovative of you! I look forward to the results! 

[William]

Great Idea, Cant wait to see the results. Been Thinking of getting another PCP, I want it regulated and in 25 or 30+ cal. with plenty of shots per fill (24 or more would be fine) this may be my ticket. I have been looking at the Evanix Rainstorm or the bull pup. 

Good luck with this project and let us know how it all turns out.

William

[wwonka]

V. cool. Nice work. Look forward to seeing the results.

[rkr]

Altaros can make those regs with plenum space or you could just use a piece of pipe with o-ring on one end to create that plenum. Still, nice work.

[darren]

scott your killing me.....I wanted that one, I guess I will have to wait until the june shoot to try it....(hint hint)

[rsterne]

It's nice to see that the research I did a few years ago on plenum size between the regulator and valve on PCPs is gaining such wide acceptance, at least in the aftermarket.... Hopefully someday the regulator manufacturers will catch on and start recommending a plenum size to go with the performance their customer wants.... It isn't, after all, rocket science.... just common sense, with an easy to follow rule.... about 1cc per FPE or the efficiency starts to drop (although you can get away with half that by increasing the setpoint a bit).... I'm glad that Scott has taken the lead in developing this idea and made a bit of a business for himself with it....

Bob

[rkr]

It's nice to see that the research I did a few years ago on plenum size between the regulator and valve on PCPs is gaining such wide acceptance, at least in the aftermarket.... Hopefully someday the regulator manufacturers will catch on and start recommending a plenum size to go with the performance their customer wants.... It isn't, after all, rocket science.... just common sense, with an easy to follow rule.... about 1cc per FPE or the efficiency starts to drop (although you can get away with half that by increasing the setpoint a bit).... I'm glad that Scott has taken the lead in developing this idea and made a bit of a business for himself with it....

Bob

Bob, is that cubic centimeters you are referring to?

[rsterne]

Yes, I always strive for 1 cubic centimeter of plenum per FPE the rifle is desired to produce.... You still get a slight pressure drop in the plenum, but not enough to really hurt the efficiency compared to a non-regulated and free flowing PCP where all of the reservoir is available to keep up the pressure at the valve seat.... You can get away with 1/2 cc per FPE, but you will have to increase the regulator setpoint to compensate, which of course hurts the shot count as you have less pressure range in the tank/reservoir between full and going off-reg....

In tube regulators are at their best for low-medium power setups anyway.... If you try to get high power, the plenum gets so big you lose reservoir volume in front of the reg, so it's a balancing act of getting a big enough plenum to not get too great a pressure drop during the shot vs. keeping as much of the reservoir as possible....

Bob

[Motorhead]

Regulator installed being set @ 135 bar ( @ 1960# )
In servicing this rifle decided to also change out the poppet spring to one of a HEAVIER rating to counter the heavy hammer in hope of stabilizing velocity even more 

Assembled rifle with regulator conversion changing NO other tune specs on hammer spring setting and other tune parameters previously done to rifle by William Piatt.  ( His tune stated rifle set to shoot 18.1's @ 900 fps )

Over to the Chrony with some 15.9's / 18.1's / 21.3's

14.3's = 945 fps making 28.36 ft lbs.
15.9's = 900 fps making 28.6 ft lbs.
18.1's = 855 fps making 29.23 ft lbs.
21.3's = 805 fps making 30.37 ft lbs.

So looks like we lost @ 45 fps  ... which is very easy to get back with a tad more hammer spring tension.
* What I really like seeing is what the heavy poppet spring had done in getting valve to breath more consistent & ballanced showing very little efficiency change from the lighter 15.9's to the heavy 21.3's .... Energy difference ONLY 2.01 ft lbs between them.

Ideally going to want gun shoot just a tad harder ( 31-33 # range ) so we're really close in the power department.
Some shot string testing & documentation next 

[Motorhead]

Some shooting last night and WOW ... what an air hog 
Granted a tad better with heavy pellets, but you can hear the woosh of air from either excessive dwell or hammer bounce.

Guess we're neck deep in the quicksand now .... More to follow 

[rkr]

Some shooting last night and WOW ... what an air hog 
Granted a tad better with heavy pellets, but you can hear the woosh of air from either excessive dwell or hammer bounce.

Guess we're neck deep in the quicksand now .... More to follow 

Are you sure the whoosh is not the regulator setting and blowing air out? My Huub regulator makes a rather disturbing vent noise after a shot.

[Motorhead]

Some more testing and tweaks last night ....
Raised Reg output to @ 145 bar, power came up a tad while noise went lower .... we're getting there 

Next started playing with o-rings as hammer buffers getting some idea to a stack height where velocity was just effected.
Once done went to Rubber washers from .090 - .115 - .125 thickness's settling on the .090" as optimum to damp excessive valve lift, do some anti-bounce etc ...

Now we're at @ 31 ft lbs launching the light 14.3's @970 fps and the heavy 21.3's @ 820 fps with a PING of hammer strike and a pop at muzzle no longer sounding like a whoosh 

Still need to get some string data documented however.  But at least for now the "Way" rifle is shooting has been refined over these past few days, so for that I feel rather encouraged to keep after it.

Scott

[QVTom]

Tuning a drag car to drive in traffic before EFI!

I've never been successful getting my RS to shoot well at lower FPE levels.  At one point I did get Barcudas down to 850fps with a decent ES but the accuracy was horrendous.  One thing for sure, the stock hammer/spring combo will bounce like crazy with light ammo.  The factory spring is 2.75"  long and with a rate about 11lb/inch, when I had the Baracudas shooting at 850fps I used as 2.5" long spring with a 8.5lb rate.  No bounce until it was well off the curve around 30 shots but a shotgun for sure.  I had no knowledge of buffers at that time. 


Tom

[Motorhead]

Tuning a drag car to drive in traffic before EFI!

I've never been successful getting my RS to shoot well at lower FPE levels.  At one point I did get Barcudas down to 850fps with a decent ES but the accuracy was horrendous.  One thing for sure, the stock hammer/spring combo will bounce like crazy with light ammo.  The factory spring is 2.75"  long and with a rate about 11lb/inch, when I had the Baracudas shooting at 850fps I used as 2.5" long spring with a 8.5lb rate.  No bounce until it was well off the curve around 30 shots but a shotgun for sure.  I had no knowledge of buffers at that time. 


Tom

Yea Tom, Can so relate to the gun not really responding well to being throttled down  using just less hammer spring.
Before the hammer buffer with same basic settings, velocity swings shot to shot were 30-40 fps 
After settling on the .090" buffer velocity swings shot to shot are now within @ 10 fps 

** Next areas to play with are going to be Transfer path poppet to barrel
Plan on making a delrin "C" ring for valve discharge groove allowing 3 of the 4 holes to be covered but still allow some clearance to get to the gap at 4th hole feeding transfer hole towards barrel.
Next going to make a valve stem sleeve that will just float within valve throat further reducing area there.
Then see what can be done to sleeve the transfer passage it self valve to barrel within receiver ?

Having spent so much time with M-rods with regulators finding the areas that still flow sufficient air while maintaining quite good efficiency numbers, see no reason why some reverse engineering cannot be applied here 
* Cool part is that all can be removed with no physical / mechanical alterations made to rifle 

Street tame dragster is not that far a reach IMO.

Scott

[eelect]

Scott if you ever get this thing to have a shot string anything close to your Mrod you are king tuner of the year. My final thought when I finally sold mine was it has terrible hammer bounce which I tamed a bit with lighter hammer. But all in all it needs a whole new redesigned valve. I think valve pin is too thick and lets too much air out. It would be nearly impossible to get valve and spring hammers adjusted just right.

[Motorhead]

Another night ... more progress 

Made the valve outlet collar to further reduce "Transfer area"
Collar is @ .100" greater in I.D. than O.D. root of groove it covers.





Poppet stem gets a sleeve reducing area between it and throat of body.



We get some holes made seeing what consistency we have happening ?



Looks like accuracy is doing great, shot to shot consistency looks stable enough too 
ALL 3 targets shot in sequence on a single fill. last target has a few shots off regulation which show up on last few shots of the series.  * Fill started at @ 2800#  (all fill tank had left) and reg is set a tad above 2000# ... so we're doing fairly well thus far on @ 800# of air

[Motorhead]

More R&D getting done ...
Built a Light weight hammer from 7075-T6 aluminum adding a carbide insert for weight and a surface to strike valve stem.
Weight @22 grams compaired to the OEM hammer near 70 grams.

Shot cycle is SO MUCH BETTER being a fast SNAP ! rather than the typical long duration Pop it had been.
We're still focused on modest power tuning and gun with the LW hammer still knocking on @ 30 ft lb power levels.
* this at @2K set pressure and the heavy factory hammer spring.

Few days ago went in again to see how breathing would be effected LOWERING regulators set pressure taking it down to @ 1400#
BANG !!! ... shot near 1000 fps and had a very loud report  too much spring !!! with the valve now cracking open easier.

In went the Low power Will Piatt spring that came with rifle ... MUCH BETTER having power instantly drop to @ 26 ft lbs and noise again back to the fast SNAP with little extra noise from wasted air or obvious valve bounce occurring.

So, with the rifles HUGE valve & overall plumbing it appears to be also working well at Lower Pressure. ( Which is in line with any PCP on Low pressure ... Ports need to be larger than HP use. )


Shot count in inching up on @ 50 good shots right now, but still no where near what it could/should be with such a large air tank.
 * Next will be Transfer port diameter deduction and a revisit on completely blocking ALL 4 of the valve discharge holes re-drilling for just 1 as we do on the Hatsan 44 valves. ( Thanks Bob S  )

Scott

[Motorhead]

Late afternoon/evening took valve apart, made a derin throat plug pressing it in.  JB weld epoxy filled the entire discharge groove covering the 4 holes & covered in tape.  1hr on the warm truck motor and the JB set up.  Drilled a SINGLE .170" hole to line up with the receivers transfer passage, belled it into throat with the dremel tool.

Changing NOTHING else assembled action once more and take a few shots over the chrony .... 905 fps
Picked up @ 50 fps by reducing the wasted transfer area the radial groove and multiple discharge holes had added to the valves transfer area volume 

leaving rifle alone went and took a hike as sun was going down taking @ 45 shots randomly ... STILL AT SET POINT !!
Took @8 more before gauge moved from the @ 1.4k reg set point.

53 shots shooting LIGHT 14.3 pellets at @ 900 fps ... not to friggen shabby 
Heavier pellets should be more effecient yet.

Till I can go deeper and chase something else to gain shot count ? .... its doing darn well for a AIR SUCKING Rainstorm 

[QVTom]

You have neutered your RS, no more playing with the big boys

Air sucking is relative to the task at hand

Scott's eunuch - 53 shots at 25 fpe = 1325 fpe total
Factory RS - 20 shots at 56 fpe = 1120 fpe total

Yes 15% less suckage   how she shoot those 14.3 gn pellets?

Tom