Beeman R9 Spring Experiment

[fwbsport]

What is meant by "lock time"?

The time it takes for the trigger AND action to move the pellet OUT!

[WHITEFANG]

Good share Kirt reguardless!

[HectorMedina]

Excellent discussion!
Thanks!
Just one note about the PG-3:

BECAUSE the tophat is now a longer guide with a helical groove cut to the pitch of the spring, and because Vortek decided to make the position of the spring in the top hat adjustable, you CAN face the condition, where the top hat/fore-guide is set to the shortest OAL (overall length), and therefore the spring is sitting in its deepest position, where if you compress the spring enough the fact that the spring is trying to compress over solid material creates a HUGE "STACKING''  at the end of the stroke.
IF this happens, then just move the spring to the second or third groove and give the fore-guide/top hat less engagement with the spring.

You'll get a bit more vibration, but you will get a more uniform weight increase along the cocking stroke (and therefore the spring distension will also be smoother).

HTH

Keep well and shoot straight!






HM

PS.- on a "Purist" note, I would SUGGEST we agree to call the overall time between sear break and pellet exit, the "Pellet Dwell Time" (PDT).
"Lock Time" has a very specific application in gunsmithing, and means the time elapsed from the moment the sear is released by the trigger blade to the time the primer is struck by the firing pin.
As such it's a CONSIDERABLY SHORTER time and it would be meaningless in the airgun world.
PDT is a much more meaningful time lapse in the shot cycle as it truly reflects the all important time lapse between sear break and pellet exit.
AND there is an order of magnitude between them.
JMHO

[DanD]

...
Last night I had checked the ARH site, I noticed Jim's HW50 spring has 30 coils x .120" (same as the Vortek HO for the R9).  So I never thought the R9 Vortek spring's power could exceed the ARH Hornet spring at 38 coils at .125"....

I've been enjoying this thread, but I'm surprised the inner diameter of the springs have not been mentioned in this thread. Doesn't a smaller ID spring make more power than a larger one, all other specs equal?

[prosportfan]

Update: Shot another 25 - 40 shots:
- JSB 13.72  - Ave 725 fps or 16.0 FPE
- H&N 11.42 - Ave 805 fps or 16.4 FPE

Shot cycle still has quick lock-time, however, I can feel on the 725 fps JSB's the spring is (almost) approaching the point where I can feel a hesitation in lock-time.

What difference does it make??

Which one is more accurate??

Your choices in pellets are very limited. Stay with the one that you can hit the target with. Honestly there's way too much thought process going on here. If a spring doesn't perform as well as you'd like, change it. This isn't rocket science it takes 20 bucks and 15 minutes, 20 tops to change a spring in a Hw95 / R9 platform. It shouldn't take a group decision over 3 days and a pat on the back to decide a course of action. 
More doing and less polling might be in order.

Dig it

[fwbsport]

PDT in a gas ram is quicker than a springer, and this is why a good gas ram can easily beat a springer in my humble honest position!  I've never sold out the Eliminator in any of my dealings for better or worse and he's stayed around for a reason: He sounds like the hammer of Thor when fired--there's a metal "hum" vibration very distinct from the slower spring.  So THAT pellet gets out of the barrel SO fast I never realize it until the target has been absolutely slammed! Long live my Eliminator!

I've left it cocked overnight a few times easily.  But it's not really in my practice unless I have to hold the shot for a better shot and it extends into the next day.

The FWB Sport also has a very fast PDT compared to any HW series I have.  There's a spring inside it that is quite different from an HW type.

[Mark 611]

Kirk u do ur thing! people like us seek our goals! and ask questions and don't settle for the norm! this is what makes us who we are! u will never know until u try something outside the box!!!!!! life is good!!! keep on my friend!

[SpiralGroove]

Excellent discussion!
Thanks!
Just one note about the PG-3:

BECAUSE the tophat is now a longer guide with a helical groove cut to the pitch of the spring, and because Vortek decided to make the position of the spring in the top hat adjustable, you CAN face the condition, where the top hat/fore-guide is set to the shortest OAL (overall length), and therefore the spring is sitting in its deepest position, where if you compress the spring enough the fact that the spring is trying to compress over solid material creates a HUGE "STACKING''  at the end of the stroke.
IF this happens, then just move the spring to the second or third groove and give the fore-guide/top hat less engagement with the spring.

You'll get a bit more vibration, but you will get a more uniform weight increase along the cocking stroke (and therefore the spring distension will also be smoother).

HTH

Keep well and shoot straight!
HM

PS.- on a "Purist" note, I would SUGGEST we agree to call the overall time between sear break and pellet exit, the "Pellet Dwell Time" (PDT).
"Lock Time" has a very specific application in gunsmithing, and means the time elapsed from the moment the sear is released by the trigger blade to the time the primer is struck by the firing pin.
As such it's a CONSIDERABLY SHORTER time and it would be meaningless in the airgun world.
PDT is a much more meaningful time lapse in the shot cycle as it truly reflects the all important time lapse between sear break and pellet exit.
AND there is an order of magnitude between them.
JMHO

Thanks Hector,
Yes, Pellet Dwell Time it is .

In my application, I purchased the PG3 HO spring without any other Vortek components.  Hence, I don't have the Helical grooved Top-hat; I wanted to use the spring in my unique tune to see how it compared to my current ARH Hornet.  I was attempting to achieve a faster PDT with a corresponding increase in power.  I closed the PG3 spring ends so they were perpendicular and installed the spring, new guide and top-hat  after polishing the spring ends.
So far the increase in power/PDT has been worth the increase in hold sensitivity.  Assuming the spring retains its current power, the only thing I may do is install a hardened washer below the T-H to remove the very slight torquing of the barrel.   

[SpiralGroove]

...
Last night I had checked the ARH site, I noticed Jim's HW50 spring has 30 coils x .120" (same as the Vortek HO for the R9).  So I never thought the R9 Vortek spring's power could exceed the ARH Hornet spring at 38 coils at .125"....

I've been enjoying this thread, but I'm surprised the inner diameter of the springs have not been mentioned in this thread. Doesn't a smaller ID spring make more power than a larger one, all other specs equal?

Hey Dan,
I understand that all things being constant, smaller diameter springs create more power.
However, in the case of the Hornet spring (.125" wire) vs. PG3 HO springs (.120") the inside diameter difference wasn't more than about 15 thousands of an inch difference (the PG3 was smaller).
I didn't feel this was nearly the main reason why the PG3 was more powerful.  IMO, it has to do more with aggressive (pitched) wrapping of the spring (w/larger spaces between coils) and higher tinsel strength wire.
IDK, Hector could probably help out here.
So by comparison, the shorter & thinner PG3 spring (30 coils @ .120") out powers the longer ARH spring (w/38 coils @ .125" wire).  I have no idea how long it will hold up, but it seems to be a more stressed coil with a slightly harsher shot cycle.  That's all I know right now.    

[HectorMedina]

Hey Dan,
I understand that all things being constant, smaller diameter springs create more power.
However, in the case of the Hornet spring (.125" wire) vs. PG3 HO springs (.120") the inside diameter difference wasn't more than about 15 thousands of an inch difference (the PG3 was smaller).
I didn't feel this was nearly the main reason why the PG3 was more powerful.  IMO, it has to do more with aggressive (pitched) wrapping of the spring (w/larger spaces between coils) and higher tinsel strength wire.
IDK, Hector could probably help out here.
So by comparison, the shorter & thinner PG3 spring (30 coils @ .120") out powers the longer ARH spring (w/38 coils @ .125" wire).  I have no idea how long it will hold up, but it seems to be a more stressed coil with a slightly harsher shot cycle.  That's all I know right now.

Kirk;

Pitch plays a huge role in the "feel" of a spring, yes a shorter pitch (less distance between coils), generates less stress in the steel, and therefore the spring is smoother to cock, but also usually yields a lower "k" spring rate or spring constant, so that more stroke is needed to achieve the same energy.

If you take things to the extreme and use an infinite pitch, you are compressing the steel along its own axis. So any distance that the steel compresses will mean a HUGE force.

IDEALLY we should use the largest possible OD we can, and the shortest pitch we can while still generating the "k" we need for the power stroke of the gun.

That usually means a thicker wire BUT, as long as the pitch is correct and the OD is correct, it will still be a smooth cocking arrangement.
The amount of weight that the spring coils add to the whole distending mass may or may not be relevant, depending on the weight of the piston, which is the base/main weight. A heavy piston will not be bothered, but a lightweight piston will change completely its firing characteristics.

Another thing that I cannot stress too little is that springs that are subject to smaller TOTAL COMPRESSION RATIO's (TCR) extend their life by the square of the proportion in reduction.
In other words: if your architecture calls for a CL (Compressed Length) to OAL (Overall Length) ratio of 46% (about average for DIANA airguns) and your spring life expectancy is 5,000 shots (also average for DIANA OEM springs), and you change the TCR to 0.63 (Short stroked versions), then the difference in TCR's is 36%, which means that you can count on an average life in excess of 9,200 shots (5,000 X 1.36X1.36). If you start from a spring that already has an extended life (15,000 shots), then you can imagine that the gun will be stable and unchanging for a long time, even with heavy usage (10-30,000 shots per year)

There are many tricks to choosing the right spring and, even then, there is NO SINGLE ANSWER. Shooters want different things and so the designer needs to decide on a compromise where most shooters can be reasonably happy.

It is wonderful that we can have a high level discussion about these intricacies, as it broadens our understanding of what goes on inside the guns.

Thanks for your orderly exposition of results!

Keep well and shoot straight!







HM

[SpiralGroove]

Thanks Hector,
Good information to have in the back of your mind when tuning airguns and guesstimating adjustments that could be made .

[Yogi]

How about PellDwell for short?

-Y

[DanD]

...
IDEALLY we should use the largest possible OD we can, and the shortest pitch we can while still generating the "k" we need for the power stroke of the gun.

That usually means a thicker wire BUT, as long as the pitch is correct and the OD is correct, it will still be a smooth cocking arrangement.
...
Another thing that I cannot stress too little is that springs that are subject to smaller TOTAL COMPRESSION RATIO's (TCR) extend their life by the square of the proportion in reduction.
...

Great post, Hector!

When you mention "smooth cocking arrangement," do you mean light effort, most linear, or something else?

Does changing spacing also change the spring life by the square of the spacing difference compared to the total stroke? Does spacing to the edge of coil bind drastically reduce spring life? Does preload figure into the TCR calculations?

Thank you!
-
Dan

[Mark 611]

Lets look at things this way, u take a piece of wire, u bend it back and forth, eventually it will break! IMO, I think if u let a spring fully relax and stretch ur over working the spring allowing it to expand to its limits, yes this also creates power out of the spring and allows it to expand its energy, but it shortens its life, if all things being equal with good metallurgy, a heavier wire dia will last longer, due to its ability of the larger dia, it will take more stress and take longer to break then a small wire dia, the trade off is its heavier to move, higher cocking effort, if spaced correctly u capture its energy with out over working it, The thinner the wire the faster it will break! their is a balance of stroke length and wire size with a weight of pellet u plan to use! JMO

[SpiralGroove]

Lets look at things this way, u take a piece of wire, u bend it back and forth, eventually it will break! IMO, I think if u let a spring fully relax and stretch ur over working the spring allowing it to expand to its limits, yes this also creates power out of the spring and allows it to expand its energy, but it shortens its life, if all things being equal with good metallurgy, a heavier wire dia will last longer, due to its ability of the larger dia, it will take more stress and take longer to break then a small wire dia, the trade off is its heavier to move, higher cocking effort, if spaced correctly u capture its energy with out over working it, The thinner the wire the faster it will break! their is a balance of stroke length and wire size with a weight of pellet u plan to use! JMO

Yeah Yoda,
I surmised that all things being equal, if your spring has thinner wire, more pitch and generates more power -> more likely than not, its going to fail sooner.  Just basic physics  
Unless, of course ... the thinner wire with more pitch is of vastly superior metallurgy (quality).

[HectorMedina]

Great post, Hector!

When you mention "smooth cocking arrangement," do you mean light effort, most linear, or something else?

Does changing spacing also change the spring life by the square of the spacing difference compared to the total stroke? Does spacing to the edge of coil bind drastically reduce spring life? Does preload figure into the TCR calculations?

Thank you!
-
Dan

Thanks for your kind words, Dan!

Smoother cocking involves all three: Less cocking effort, more linear over the stroke, and no "stacking" (non-linearity of the force to position ratio).

Spacing makes the increases the compression, so your ratio of compressed to uncompressed length goes LOWER, but this is bad because stress (and strain) goes HIGHER. In the same vein, pre-compression is taken into account in the calculations.

Again, thanks, keep well and shoot straight!





HM

[Yogi]

Kirk,

Just wondering if you have ever tried one of those short stroke kits from Tim Bum in the UK?  It might just solve your problem with the OEM or standard spring.
Just thinking.........

-Y

[SpiralGroove]

Kirk,
Just wondering if you have ever tried one of those short stroke kits from Tim Bum in the UK?  It might just solve your problem with the OEM or standard spring.
Just thinking.........

-Y

Thanks for inquiring Y...,
I really haven't had time to get back to the spring issue, plus I've been pretty happy with the Vortek PG-3 HO spring combined with my basic tune .  The gun has a consistently, quick Dwell Time and velocity of 725/740 fps.  However, I have noticed the gun is more hold sensitive than my .20 caliber HW80 that generates more power/recoil.  Thinking I may put hardened steel washer under the (delrin) top-hat and make sure top-hat is absolutely perpendicular to the spring.  I'm thinking the spring is creating a bit of side torque ... also may reduce power a tad by shortening the TH.

I'm not that familiar with the TB short stroke kit, but thinking it will not generate > 15 FPE?
I want this gun to be a 75/80 yards shooter with flat trajectory - not sure the SS kit will cut it?

Also, I purchased a newer ARG Hornet spring which is .128 @ 38 coils so this is another option.
For now ... gonna stick with the Vortek unless something significantly bad happens .

[jason miller]

Any updates on this?

[SpiralGroove]

Any updates on this?

Yeah Jason,
- IIRC, I put the Vortek PG3 spring in my R9 - had to close the coil ends because they come opened for the the PG3 kits (adjustable pre-load) top-hat.  I didn't use anything Vortek other than the spring.

- On my R10, I decided to go with Vortek spring, same diameter as PG3, but a "tuning spring" they list on their website (same cost).  This spring came with more coils, so I cut it down to 2 coils longer than the PG3 spring.  Only had to close the end which was cut, polished and installed.

Both guns are very nice in 20 caliber achieving 16+ FPE, with quick shot cycle - not harsh at all.
My only unknown is: How long with this performance last before the spring looses power?
Some have said they will go 3K shots ... well see .