GTA
All Springer/NP/PCP Air Gun Discussion General => "Bob and Lloyds Workshop" => Topic started by: Nvreloader on May 12, 2023, 09:41:51 PM
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I have a new DF II 22 cal pumper air rifle I have been testing/experimenting with,
and I have gotten in over my head, as usual..........
Quite lengthy, so get a cup of Jo, before you set down........You have been warned......
Here are the measured spec's for the valve and pump stroke, with the results obtained so far.
Psi pump tube = .745" I/S Dia x 6.940" stroke = 3.03 ci = 49.65cc?
Pump rod = 6.300" long x with .640" alum "O" ring seal head.
Main valve is 2.520" long x .765" dia, with a TP hole of .136", with an air inlet hole .102" dia
top inside valve sealing poppet that is .685" long x .293" dia, with a spring seat of .188" long
x .232" dia, spring length of 1.470" long x .292" dia x .025" dia wire x .236" I/S dia w/3.5#s
weight, bottom poppet = .620" long x .315" dia with a spring seat of.405" long x .234" dia.
Both of these poppets are a tapered cone for the Top = .293" dia x 30* taper x .200" long
w/.125" flat nose, bottom has a .315" x .080" 30* tapered lip for sealing, made from a hard
plastic material, unk type. Total volume of the above parts are approx. 2.13cc,
with a .115" dia poppet stem x .180" valve protrusion.
I/S valve dim are .390" dia x 2.120" long with tapered cone seats at each end,
for the poppets, valve I/s Vol = 4.09 cc minus 2.13 (poppets/sp) = 2.13 cc?
Bbl is 22.625" long x .217" = 84 ci = 1376.51 cc?
Hammer = 876 grains x .745" dia w/a stroke of 1.100",
w/HS of 18/19 #'s x 3.150" long x .390" O/S dia x .300" I/S dia x .034" thick wire
x with 15 coils.
Bbl TP hole is .134" Dia, opened to .156" now
Action TP Hole is .134" Dia, opened to .156" now
Brass TP has a hole Dia of .136" x .295" tall x .356" O/S dia, opened to .156" now,
w/a step on each end that fits into a rubber "O" ring on the action and the valve.
Some photo's of the parts,
https://ibb.co/8b8nZD7 (valve and parts)
https://ibb.co/LQwJLMc (pump rod/head)
https://ibb.co/tKbH03g (pump arm levers)
Question,
You have an air inlet valve hole of .140.0" and one at 156.2",
would they produce or have the same pressure, at the same number of pumps,
when pumped with the same air volume, into the same sized valve volume?
Would the air Venturie effect build/store more internal volume with the .140" hole
as compared to the 156" hole?
Going by the FPS results, I would believe it to be true..........?
This is in ref to tests G & H,
Summary of 2 similar tests Oiled wipers.
Test G H1 *****
1 pump = 262--236 -26 fps
2 pumps= 377--367 -10
3 pumps= 390--449 +59
4 pumps= 436--495 +59
5 pumps= 488--511 +23
6 pumps= 498--574 +76
7 pumps= 639--597 -42
8 pumps= 754--613 -141
9 pumps= 810--757 -53
10 pumps= 833-813* -20
11 pumps= 833-856 +23
12 pumps= 833-869 +36
13 pumps= 770-833
14 pumps= 770-833
15 pumps= 770-833
* Target @ 750-800 fps
Test G & H1 Oiled wiper test
***** Difference between G & H1
There was no extra air left after any pump test, for any shot.
* Target level for 10 pumps @ 800 fps.
*** Difference between H to G, in fps, 3x tests averaged
G test was with the .145.0" dia valve air inlet hole, no other changes.
H test was with the .156.2" dia valve air inlet hole, no other changes
Having a hard time wrapping my head around this stuff,
as I don't really know, what I am doing................... ::)
Thanks All,
Your thoughts and suggestions.................
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Summary of all the tests
Test A B C D E E-1 F G H H-1
1 pump = 265-288-262-255-259-269-269-262--252-236
2 pumps= 288-321-380-383-383------393-377--305-367
3 pumps= 322-354-462-465-465------452-390--383-449
4 pumps= 465-361-524-528-521------479-436--416-495
5 pumps= 515-597-574-570-567-574-538-488--449-511
6 pumps= 567-610-620-600-600------623-498--524-574
7 pumps= 600-616-643-626-623------646-639--567-597
8 pumps= 633-620-672-649-643------652-754--600-613
9 pumps= 652-651-688-659-662------708-810--633-757
10 pumps= 666-688-698-672-679-692-728-833-690-813
11 pumps= 678-----------688-683------744-833-711-856
12 pumps= 679-----------702-712------770-833-754-869
13 pumps= 681-----------712-718------770-833-801
14 pumps= 680----------------721------770-833-801
15 pumps= 679----------------728-741-770-833-801
There was no extra air left after any pump test, for any shot.
(A Test)
Here is the full 15 shot+ pumps test, 3 pumps per the number,
pumps were a complete cycle, open then closed arm pump arm,
per each pump stroke, 3 second count.
OEM Hammer weight of 875gr x 1.695" long, .735" Dia,
with the OEM 18/19# spring, full length, 14 gr Crosman ammo,
Air passage ways OEM stock = .134-6" dia.
(B Test)
Same test as above, CHANGED = 1 complete turn on pump rod,
nothing else changed. A 11# Flat wire spring, 5" long, .415" O/S Dia,
.252" I/S dia, 35 coils, .023" thick Flat wire, coil bound at less than 1.030"
(C Test)
Same test as above, Changed = 2 complete turns on pump rod head,
nothing else changed, with a 11# Flat wire spring, 5" long, .415" O/S Dia,
.252" I/S dia, 35 coils, .023" thick Flat wire, coil bound at less than 1.030"
(D Test)
Same pump test as above, 2 complete turns on pump rod head,
with a 11# Flat wire spring, 5" long, .415" O/S Dia, .252" I/S Dia, 35 coils,
.023" thick Flat wire, coil bound less than 1.030", 14 gr Crosman.
Changed = All air passageways opened up to .145" Dia (reamed),
removed air filter at valve inlet.
(E Test)
Same pump test as all the previous tests, Changed = the only item changed
was the hammer spring. Using a OEM 6/7# Storm Rider Round wire spring,
3.360" long, .384" O/S Dia, .300" I/S dia, 25 coils, .035" thick round wire,
coil bound at 1.020", 14 gr Crosman ammo. All air passageways opened up
to .145" Dia (reamed), removed air filter at valve inlet.
(E-1 Test)
Here is something I found out that is very interesting with this DF II, 22cal rifle
I lubed all pivot points, and the oil wiper seal and shot these Oiled 3 pump tests.
Changed nothing......just oiled everything
(F Test)
Same test as all the previous tests, Changed = was the hammer weight to 533 gr
and Hammer spring weight of 9-10#'s. New Alum hammer weight of 533gr x
1.715" long, .740" Dia using a Flat wire spring, 2.500" long, .415" O/S Dia,
.265" I/S Dia,.022" thick Flat wire, 25 coils, 14 gr Crosman ammo.
2 complete turns on pump rod head.
All air passageways opened up to .145" Dia (reamed), removed air filter at valve inlet.
(G Test)
Same test as the above test, only item Changed was lengthen the pump rod head
to maximum distance, to not block the air inlet hole, and oiled the wiper seal oiler.
Using a Flat wire spring, 2.500" long, weight = 8-9#'s, .415" O/S Dia, .265" I/S Dia,
.022" thick Flat wire, 25 coils, Alum Hammer weight at 533grains. 14 gr Crosman ammo.
All air passageways opened up to .145" Dia (reamed), removed air filter at valve inlet.
(H Test)
Same test as the above test, only item changed was lengthen the pump rod head
to maximum distance, to not block the air inlet hole, and oiled the wiper seal oiler.
Using a Flat wire spring, 2.500" long, weight = 8-9#'s, .415" O/S Dia, .265" I/S Dia,
.022" thick Flat wire, 25 coils, Alum Hammer weight at 533grains. 14 gr Crosman ammo.
All air passageways opened up to .1562" Dia (reamed), removed air filter at valve inlet.
(H-1 Test)
Same as above, Changed nothing, just oiled all pivot points and pump head "O" ring.