New Seneca Dragonfly?

[splitbeing]

Getting some breathing room is what I'm most excited about and to see what happens! No suggestions. A request... if there is a big jump in fps between a sequence of pumps, repeat those pumps a couple times to get more data points describing that difference.

[Nvreloader]

Thanks SB

What do you consider a big jumps in fps?
I will do that.

Tia,
Don

[splitbeing]

100 or more fps I would consider a big jump.

[Nvreloader]

OK guys
Next installment, test information.

I just finished the 1 >15 pumps x 3 tests each per pump number,
pumps were a complete cycle, open then closed arm pump arm, per each pump stroke.
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 at less than 1.030",14 gr Crosman.

All air passageways opened up to .145" Dia (reamed), removed air filter at valve inlet.
(D Test)
1 pump = 255 fps
2 pumps= 383 fps
3 pumps= 465 fps
4 pumps= 528 fps
5 pumps= 570 fps
6 pumps= 600 fps
7 pumps= 626 fps
8 pumps= 644 fps
9 pumps= 659 fps
10 pumps= 672 fps
11 pumps= 688 fps
12 pumps= 702 fps
13 pumps= 712 fps
14 - 15 pumps = all below 712 fps
No remaining air in valve after any shot test.

Summary of all the tests
     Test       A     B    C    D
1 pump = 265-288-262-255-
2 pumps= 288-321-380-383-
3 pumps= 322-354-462-465-
4 pumps= 465-361-524-528-
5 pumps= 515-597-574-570-
6 pumps= 567-610-620-600-
7 pumps = 600-616-643-626-
8 pumps = 633-620-672-649-
9 pumps = 652-561-688-659-
10 pumps = 666-688-698-672-
11 pumps = 678-----------688-
12 pumps = 679-----------702-
13 pumps = 681-----------712-
14 pumps = 680---------<712 & under
15 pumps = 679---------<712 & under
there was no extra air left after the 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.
with the OEM 18/19# spring, full length,14 gr Crosman ammo
 
(B Test)
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)
I just finished the 1 >10 pumps x 3 each per pump,
pumps were a complete cycle, open then closed arm pump arm, per each pump stroke.
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)
I just finished the 1 >15 pumps x 3 tests per pump number,
pumps were a complete cycle, open then closed arm pump arm, per each pump stroke.
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 at less than 1.030",14 gr Crosman.

All air passageways opened up to .145" Dia (reamed), removed air filter at valve inlet.

Your thoughts and or suggestions................
Tia,
Don

[Back_Roads]

 Have you done anything with the hammer, as in add weight

[Spacebus]

I think the only thing keeping it from retaining air is hammer bounce.

[2K1TJ]

I think the headspace is holding you back. That's why you're not gaining above 13 pumps. The pressure in the tube per pump has to be high enough to overcome and therefore open the check valve. Or at least that's how I understand it.

I would like to hear from other owners who have taken theirs apart to see if they have as much headspace as yours. That just seems excessive. I'm surprised that you have made as much power as you have with that handicap.

[Nvreloader]

Hi James
No, it is still a stock hammer = Hammer weight is 876 grains x .745" dia
I am looking at a couple of things,
1 = Hammer
2 = Valve seals and poppet, both ends are tapered seal designs = bad design, IMHO.
Thanks,
Your thoughts or suggestions......
Don

Have you done anything with the hammer, as in add weight

[Nvreloader]

JD
I don't think in am getting hammer bounce, as I hear no Bruuup sound, just a clean snap of air release.
I am working on a SSG for it,
as I DON'T like the way the hammer is beating/impacting on the back of the valve, which is being deformed etc.
I may make a new hammer and change the design a little.

Your thoughts or suggestions.....
Thanks,
Don

I think the only thing keeping it from retaining air is hammer bounce.

[Spacebus]

My Stormrider using the very soft Chaser hammer spring and a 100b reg has hammer bounce. I can only hear it with a moderator, but it's there. I'm sure there's bounce happening on the DF MK II, unless your flat wire spring is preventing it.

[Nvreloader]

2K1TJ
IMHO,
I believe that it is the inside diameter of the valve, .390" dia x 2.120" long,
the valve front seal =.290" dia x .600" long with the rear poppet = .315" dia x .500" long,
plus the valve spring = a total length of 2.190", all this inside a .390 dia x 2.120" long
inside valve volume/space???

I am hunting a Storm Rider valve to adapt to this FY II valve, which should have a flat poppet seal (Instead of a tapered seal) for the poppet, the top seal is also tapered (which allows the pumped air inside the valve).
I have some PEEK material for the poppet end, not sure about the top seal?

Yes, I also think the dead headspace is NOT helping either,
reason for the Storm Rider valve hunting.

Your thoughts and suggestions.............
Thanks
Don

I think the headspace is holding you back. That's why you're not gaining above 13 pumps. The pressure in the tube per pump has to be high enough to overcome and therefore open the check valve. Or at least that's how I understand it.

I would like to hear from other owners who have taken theirs apart to see if they have as much headspace as yours. That just seems excessive. I'm surprised that you have made as much power as you have with that handicap.

[splitbeing]

Those are incredible numbers given where you started, Don! Congrats on breaking 700!

The graph of the curve (fps gain vs pumps) is cleaner now that the rifle is breathing better. Something happens around 8 pumps where fps gain vs pumps flattens out to 10 or so fps gain per pump. Something going on there, not sure what.

The original dragonfly maxed out at 8 pumps, an association that comes to mind.

[Nvreloader]

Thanks SB
My swag is, that there is NOT enough Volume inside the valve,
after all the other parts of the valve are stuffed inside, plus with the tapered poppet seat,
as I posted in 2K1TJ post above.
I am sure there is a formula that gives the best performance of a valve/volume,
I am not smart enough to figure this all out, yet.

I would bet that they used (OEM) the same valve in the Mod I model?

As I understand it, the Mod I model was very hard to pumps after a certain point,
I have not seen much info on the Mod I and the pump results for 10 shots or so, in 22 cal,
along with the lack of shooting/pump results being posted by other members,
who have these air rifles etc.

Back to the drawing board.............

Yours thoughts and suggestions...
Tia,
Don

[HPP-Mechanic]

Might that extra head space be designed in there to keep the pump compression intentionally lower to aid in easy pumping? At some point (pumps) no more air is going into the valve... Up the pump compression and/or increase valve volume? A bigger volume valve will have lower fps at lower pumps-unless the pump output can be equally upped at the same time.  Nobody wants to pump 20-30 times a shot!

Im waiting on the weather to compare the stock hammer spring to Stormrider spring...

FYI- you can add hammer weight by installing the stock metal hammer spring guide against the hammer.

[Spacebus]

Might that extra head space be designed in there to keep the pump compression intentionally lower to aid in easy pumping? At some point (pumps) no more air is going into the valve... Up the pump compression and/or increase valve volume? A bigger volume valve will have lower fps at lower pumps-unless the pump output can be equally upped at the same time.  Nobody wants to pump 20-30 times a shot!

Im waiting on the weather to compare the stock hammer spring to Stormrider spring...

FYI- you can add hammer weight by installing the stock metal hammer spring guide against the hammer.

I like to flatten slugs in a vise and drop those into the hammer, but I was thinking about flipping the spring guide. Is it still effective when flipped?

[HPP-Mechanic]

Might that extra head space be designed in there to keep the pump compression intentionally lower to aid in easy pumping? At some point (pumps) no more air is going into the valve... Up the pump compression and/or increase valve volume? A bigger volume valve will have lower fps at lower pumps-unless the pump output can be equally upped at the same time.  Nobody wants to pump 20-30 times a shot!

Im waiting on the weather to compare the stock hammer spring to Stormrider spring...

FYI- you can add hammer weight by installing the stock metal hammer spring guide against the hammer.

I like to flatten slugs in a vise and drop those into the hammer, but I was thinking about flipping the spring guide. Is it still effective when flipped?

I discovered this by accident & shot the gun like that for quite a while before realizing I had put the guide in first. I didnt notice a difference, other than a slightly different sound.

If all the air is exiting the valve, is a heavier hammer necessary?

[Spacebus]

Might that extra head space be designed in there to keep the pump compression intentionally lower to aid in easy pumping? At some point (pumps) no more air is going into the valve... Up the pump compression and/or increase valve volume? A bigger volume valve will have lower fps at lower pumps-unless the pump output can be equally upped at the same time.  Nobody wants to pump 20-30 times a shot!

Im waiting on the weather to compare the stock hammer spring to Stormrider spring...

FYI- you can add hammer weight by installing the stock metal hammer spring guide against the hammer.

I like to flatten slugs in a vise and drop those into the hammer, but I was thinking about flipping the spring guide. Is it still effective when flipped?

I discovered this by accident & shot the gun like that for quite a while before realizing I had put the guide in first. I didnt notice a difference, other than a slightly different sound.

If all the air is exiting the valve, is a heavier hammer necessary?

I suspect the valve only dumps due to hammer bounce. More dwell time for the poppet opening is really the goal, more hammer strike energy is just one path. I think a peek/PEI poppet would have a similar effect without more hammer weight. An SSG would prevent hammer bounce and test if the valve retains air without an additional strike. I also wonder what a lighter hammer would do in regards to velocities. I think Firewalker tried to use a custom light hammer and Stormrider spring in his HPA converted Chaser and increased the muzzle energy. Perhaps a faster strike somehow works better than a slower heavier strike?

[Psipumper]

Thanks SB
My swag is, that there is NOT enough Volume inside the valve,
after all the other parts of the valve are stuffed inside, plus with the tapered poppet seat,
as I posted in 2K1TJ post above.
I am sure there is a formula that gives the best performance of a valve/volume,
I am not smart enough to figure this all out, yet.

I would bet that they used (OEM) the same valve in the Mod I model?

As I understand it, the Mod I model was very hard to pumps after a certain point,
I have not seen much info on the Mod I and the pump results for 10 shots or so, in 22 cal,
along with the lack of shooting/pump results being posted by other members,
who have these air rifles etc.

Back to the drawing board.............

Yours thoughts and suggestions...
Tia,
Don

The valve volume should be about 4 to 4.5 cc for your 20ish length barrel.
That would be close to 30 percent of the barrel volume which is a good balance for a pumper.
Way more important is headspace as close to zero as possible. This would include reducing the inlet hole to 1 mm, square shaped o-ring on the front of the valve, reducing the margin thickness in front of the flattop piston o-ring to 1/64 . Along with adjusting the pump rod length.
So then you can assume 90% pump efficiency to calculate the pressure in the valve at your desired pump count to determine the valve volume needed for example 10 pumps.
One thing that you need to decide is the maximum pressure the pump linkage and gun design will tolerate.
392= 1800 psi.  362= 2500 psi.
DF2 = ? (1750)
So with proper headspace, valve size is very important . It won’t do much if you don’t have compression it won’t build  much over 900 psi anyway.

Charles

[Nvreloader]

Ok Guys
Thanks for the information,

Here is some information on this DFY II,
BBl overall length = 22-5/8" = 22 cal,

Pressure tube dimensions = .875" O/S Dia, .745 I/S dia,
 
Pump rod stroke depth = 6.940" = Maximum stroke depth, head Dia = .730",
with a "O" ring seal = .112" thick x I/S Dia = .527", O/S Dia =.750",

Inside valve dimensions = .390" I/S Dia x 2.120" long, inlet hole .102" Dia,
plus the tapered ends for the top/bottom seal/poppet seats,
did not measure these tapers dimensions.

Hammer weight = 876 grains, with 1.100' stroke length,
hammer spring = 18/19 #'s, 3.150" long x .390" O/S Dia x .300" I/S Dia, 15 coils,

Poppet stem protrusion = .180", hammer rests on the end of poppet stem after the shot,
hammer is marking the rear of the valve during the shot cycle.

I have never had any air left after the shot, in all these tests, I check after every shot,
so I am getting a complete valve air dump.

Guys, I just learned one of my dial calipers is not accurate,
I get different reading every time I use it, reads .550"+ longer per each inch length extensions,
I have dropped it several times..........  

So I'll remeasure all dimensions of everything the next time I open it up,
just to make sure that the info is accurate.

I believe that all the above info is correct, as I was using a different dial calipers, I think?

PSI Pumper
Can you share with me the formula or a site that has this CC capacity's for what you were talking about.
I found a site and entered my info and came up with 11.73 CI for the volume
of the tube for compression = 6.940" stroke x .745" dia, just don't look right.

Thanks All,
Don

[splitbeing]

Thanks SB
My swag is, that there is NOT enough Volume inside the valve,
after all the other parts of the valve are stuffed inside, plus with the tapered poppet seat,
as I posted in 2K1TJ post above.
I am sure there is a formula that gives the best performance of a valve/volume,
I am not smart enough to figure this all out, yet.

I would bet that they used (OEM) the same valve in the Mod I model?

As I understand it, the Mod I model was very hard to pumps after a certain point,
I have not seen much info on the Mod I and the pump results for 10 shots or so, in 22 cal,
along with the lack of shooting/pump results being posted by other members,
who have these air rifles etc.

Back to the drawing board.............

Yours thoughts and suggestions...
Tia,
Don

I've posted some numbers a while ago that might also be in my airgun notebook regarding the DF I up to 16 pumps if memory serves. 3-8 pumps is the manufacturers pump instruction for the DF I. I remember that fps did increase over 8 pumps and then levelled out somewhere in the teens. I can look it up or redo the test if that would help your DF II research.