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cissp22 · Member

hi everyone ,

having bought a PCP named AT44-10 from Hatsan company , as an engineer i m realy interested to change the mechanism of valve and regulator so i can get more power than normal 30FPE .

i need experts help if i may only change hammer kick power level with better spring so i can get much more power , no problem if i loose 15 BARs each shot .or it needs work on valvs&regulators ?

thanks ,

rsterne · Moderator

AFAIK, the Hatsan doesn't use a regulator.... The velocity is designed to follow a "bell-curve" starting about 5% below peak velocity and ending wherever you decide to stop shooting (typically about 5% below as well to avoid significant trajectory change)....

If the Hatsan is indeed unregulated as I believe.... increasing the hammer spring hit will increase the velocity (and air usage) but also increase the pressure where the peak occurs.... At some point, you will end up with the first shot the strongest and each successive shot lower in velocity.... This will severely limit the number of usuable shots....

Opening up the ports in the valve, transfer ports (if any) and barrel port may increase the velocity, depending on where the greatest restriction occurs in a stock gun.... Typically, making the gun "breathe better" will decrease the pressure at which the "bell-curve" peaks slightly.... It may therefore be possible to get a decent bell-curve at increased power levels with a combination of better porting and more hammer spring tension....

Sorry to speak in generic PCP terms.... but I have never owned a Hatsan....

Bob

packrat · Senior Member

When I was gun "shopping", before buying the Dominator, I looked at the Hatsans......none of advertising mentions anything about gun being regulated..does appear though to be a nice gun..not many "out on the field" so feedback from owners was , in my case, NIL !!

broommaster2000 · Moderator

There is a regulator available, the Audriusize Regulator. This guy'll make a regulator for any rifle with a typical tube reservoir:

http://www.youtube.com/user/Audriusize

On the Dutch forum where I roam, I hear the service is pretty good and the regulators work. You have to drill a hole for atmospheric pressure yourself, but I bet with some technical knowledge that won't be a problem.

Shot the Hatsan a couple of times, they're not bad and well made. Hatsan is doing a good job with this rifle.

rsterne · Moderator

I could be wrong.... but I don't think a regulator is the way to go for increased POWER which is what the OP is after.... The Audrisize regulator is installed as close to the valve as possible (to keep as large a reservoir as possible) and therefore it limits the volume of regulated air that can enter the valve.... This leads to a lower average pressure during the shot cycle.... unless the original gun is very restricted on the inlet side of the valve....

If the inlet side of the valve IS restricted.... then opening up that restriction is one of the routes you can take to get more power.... That option is not very effective with a regulator installed close to the valve....

In my experimenting, I have found that my Disco will produce more FPE unregulated than will my 22XX PCP conversions which are regulated.... even though the valves, porting, and hammer springs are identical.... The loss in performance in the regulated versions is proportional to the loss of volume between the regulator and the valve.... It's not linear, of course.... but once you go less than about 5 times the valve volume of regulated air between the regulator and the valve.... performance drops significantly....

Bob

broommaster2000 · Moderator

Oh, I know that, but I just wanted to point out that you can pretty much regulate anything. Mr. Green

cissp22 · Member

Hi friends ,

its about a month that i m just dreaming to boost my PCP , but yet no courage to manipulate.

i affraid to ruin something and cant return it .what i just curious to do is replacing the hammer spring with ticker one .

realy need experts advice .

my PCP Specs : 200bar max pressure/180CC/no regulator/

it shoots pellets near 30 to 35 Ftlbs. ts22 ..>258 m/s Baracuda match.>270 m/s

my goal is something like EvanixAr6 -_-_-_-_

thanks ,

rsterne · Moderator

Increasing the hammer strike (either more preload or a heavier spring).... will likely increase the FPE slightly at the expense of fewer shots.... Eventually you will end up with the first shot being the fastest and every shot after that with less power.... a very inefficient setup for a PCP....

Bob

cissp22 · Member

thanks rsterne,

u mentioned "Slightly" , this is exactly what i need to know if it worth the trouble or not. may i reach 45 FPE? if so i ll start...

cissp22 · Member

rsterne ,

this is Gamo match Chrono ,from 200 to 100 bar ...
1- 260.6
2- 271.8
271.5-3
277.5-4
282.1-5
280.7-6
283.5-7
283.1-8
294.7-9
291.9-10
292.1-11
296.3-12
298-13
296.8-14
298-15
298.3-16
297.4-17
297.5-18
296-19
294.4-20
292.5-21
291-22
289.6-23
286.9-24
286.1-25
284.5-26
283.9-27
282.8-28
280.2-29
277.9-30
222.2-31
271.6-32
269.1-33

as u see optimum power derives from 150 bar , and when 200bar the hammer seems to be week for that pressure and cant get out enough pressure .

i read ur post about your 50FPE new PCP . so can u help me more on project?? what is better to change? hammer strike weight or spring?

thanks again ,

rsterne · Moderator

First of all, looking at your string, I would throw out all shots not within 5% of the maximum (298 fps) ie anything under 283 fps.... that means the first 6 shots and the last 6 shots.... That only leaves you with 21 shots within 5% of the peak.... Anything slower than that will start stringing vertically at 50 yards....

Assuming your pressure drop per shot is relatively linear.... Your "sweet spot" is from about 180 Bar down to about 120 Bar.... You can move that bell-curve up by increasing the hammer spring.... I would start by shimming the hammer spring or (better) installing a screw adjuster for the hammer spring preload.... Increase the tension until the first shot is 5% below the peak.... ie move the entire curve upwards until the "sweet spot" is from 200 Bar down to maybe 140 Bar.... or whatever it works out to....

The result will be an increase in velocity throughout the usable shot curve.... but even fewer shots available.... When I did this mod on my Disco, I went from 22 FPE to 25 FPE but went down from 25 shots to 21 shots.... the peak of the pressure curve moved up from 1500 psi to 1700 psi....

You can get a rough idea of what to expect for shot count by assuming that the total FPE of all the shots will be a constant for a given fill.... It won't, because as you add power, you will lose efficiency.... but it will give you a goal to work towards.... For example, if you are getting 21 shots at 30 FPE currently (630 FPE).... the MOST you could get would be about 14 shots at 45 FPE.... To do that, you would have to achieve the same efficiency.... Without valve and port modifications (to allow the large amount of air to flow with equal efficiency) you will not achieve that.... if you can even reach that power level at all....

Bob

cissp22 · Member

Thanks rsterne ,

so helpful.....

cissp22 · Member

look at this pic plz ,

as u see a milling mashin can do one of this changes for me , i want ur oppinion which one is better? should it be isochronous and polar all-around?

and at last , could it be dangerous or critical?

thanks,

rsterne · Moderator

I have no idea what I'm looking at.... Is that the end of the air cylinder with a valve?.... It that the valve that the hammer hits to fire the gun or is it just a valve that operates when you screw the cylinder into the gun?....

To answer an safety questions you would need complete dimensions and do a stress analysis.... I thought you were an engineer?....

Bob

cissp22 · Member

its the end where hammer hits , there are also six holes where pressure can come out .

there are 2choices i can expand the airflow .1) widening this 6 holes 2) making 6 other tiny holes among them .

yep , i m engineer but not related .ill give the outcome procedure to handy preson.

thanks for help ,