How to decrease HPA expent for Talon valve? The answer!
On the one of the best airgun forum in the web – guns.ru – once was a discussion about WERY big expent of HPA per shot on talon. And decision was found!
There http://www.sendspace.com/file/o6kzc0 is archve of that discussion.
Can somebody try to repeat?
If something is not understand – ask questions, I’ll try to explain.
Best regards – Gennady
All Replies
It’s a bit different from that;
The surface area of tha top hat is decreased, so you have a lot less pressure pushing the valve open if there’s any pressure build up in the barrel.
Sound like a smart idea, I’ve actually had valve lock (in the open position.. yeah) when firing van drummen pellets when pressure dropped to under 150 bars; there was no leaking.. just.. click.. when recocking the gun there was a slight bang sound.. and since the pellet got stuck you had to smash it out with a rod; since 200 bars was not enough to press in the grooves in the pellet..
Those things were really hard…
I do think however that this design is a bit over complicated; a firing pot would be just as; if not more effective than this design, as it would also add a lot of consistency (especially for lower powered rifles)
Hi, no one??
Must find some time, maybe I give it a try.
I think it works because the HPA don’t blow the O-rings tight on the barrel and breech, and keep the valve to long open.
2 Years have gone – Is anybody try to rebuild valve like shown above? 😉
I expend 15psi per shot with the lowest power-wheel setting possible, can run down to 1500psi or so before things go to shit, that’s 100 shots for me (with no mods) per fill…
Tophat is set to .065″ IIRC…
850fps average shot velocity with 10.5 grain 0.177cal Crossman pellets… Not a super powerful setup but good enough to have lots of fun with! 😕
That valve idea rocks, he’s getting the same velocity with half the air!!!!!
I got my pump a couple of days ago and find it a breeze. My brother took delivery of his today and found it hard going (with or without the tophat & stem in, we thought it was worth experimenting), until he found the right technique. I’m 14 stone, he’s 12, both of us straight-arm our weight directly down right from the top of the stroke, bending only the knees. Height might make a difference, we’re both very tall.
I’m not recommending that technique to anyone by the way, just saying it works for us. Wouldn’t want to be responsible for somebody putting their ey…I mean back out. 😆
Wow, your results make me wonder why I’d want a regulator. If I had a gun that shot that consistantly, for that long, I’d start to miss my friendly SCUBA shop guy. On the flip side, that would make using a handpump look like less of a chore than I project it would be.
That is great. Thanks South. When I get some time I am going to have to try that.
Absolutly right!
My take on it is that because there is less frontal top hat area exposed to the high pressure that it can close faster than a normal valve.
And now – table of shots, done by PrOsT.
Beginnging pressure – 200 bar
Bullet – CP 10.5
Speed shown in meters per second
1 283
2 284
3 287
4 284
5 285
6 284
7 281
8 282
9 286
10 278
11 277
12 283
13 283
14 282
15 281
16 281
17 290
18 287
19 285
20 290
21 293
22 294
23 286
24 290
25 290
26 290
27 289
28 290
29 291
30 286
31 295
32 294
33 297
34 290
35 298
36 291
37 298
38 295
39 294
40 298
41 295
42 296
43 298
44 298
45 301
46 304
47 303
48 294
49 300
50 296
51 299
52 293
53 297
54 290
55 293
56 293
57 292
58 294
59 298
60 298
61 297
62 302
63 298
64 292
65 298
66 297
67 295
68 292
69 295
70 297
71 298
72 299
73 297
74 301
75 298
76 294
77 294
78 301
79 299
80 296
81 298
82 290
83 296
84 298
85 295
86 293
87 291
88 292
89 294
90 298
91 292
92 299
93 299
94 298
95 299
96 292
97 298
98 293
99 294
100 297
101 299
102 297
103 298
104 301
105 293
106 298
107 294
108 298
109 294
110 299
111 296
112 291
113 294
114 290
115 289
116 291
117 289
Ended pressure – 135 bar
So, do You think, is the sence to rebuild valve? 😉
Ok, I’ll try to explain how it’s work.
Look at the picture. On upper drawing valve of ordinary talon. To close it works forces, shown red color. The spring and HPA that press on red surfaces. To open it works force, shown green – HPA inside slider press on WERY big surface. I know excidents when all air comes by one shot in case of weak spring.
On other drawing rebuilded valve – as You can see green surface is less, than on upper. So force of pressure, that trying to stay valve open, lesser.
All this is not theory – all was done in practic. And expent of air per Joule was 8.5 cc.
And one more – why nobody doing slider of two parts? something like tube in tube. Inner tube with o-rings hold HPA, outer – transfer hit from hammer to valve. In case of shown rebuilded valve it works exelently.
Look how it looks, installed on talon’s reservoir:
Now I’ll try to find table of shots of rebuilded talon.
One more – author of all this rebuilds and idea itself is PrOsT – Pavel from SanctPetersburg, Russia.
PS – beg pardon for my english 🙁
If you look a the rest of the mod it starts to make a bit of sense,
They also mod the breech.
on the stock Talon the whole breech moves, and has to move a o-ring along the barrel, on there mod the valve to barrel portion of the breech does not move only the outer portion of the breech moves, so one less friction point.
at least thats the main thing that sticks out to me, babble fish really doesn’t help much, the pictures tell the story
Could you explain how that works?
Seen this valve a while back , simple design maybe have ago at it …..thats arfter the barrel ive got to do , the regulator ive yet to build ,the new gun im designing , the canoe , the knife , the……
You get the idea! 😕
http://talks.guns.ru/forummessage/30/88979.html
L8r all
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just a start, on the other part I must think, and sleep a night. 😕