Hammer Spring weight and rate

[bowdoc64]

I was thinking and thought I would ask the question to the experts. I have  three springs a .038, .042 and a .045. In my maximus with a modified valve marauder poppet and light spring the magnum spring was to much just my thoughts. I'm currently running the .038 spring with a spring guide power adjuster.

So here is the thought. Does a lighter spring under tension react like a heavier spring under less tension . Are the rates the same. So in theory would a light spring under tension behave like the heavy spring  when opening and closing the valve or would it open and close the valve at a different rate and how would it affect the guns performance. Example would be the lighter spring under tension opening the valve at the same rate as the heavy spring but because its inherently softer it allows the valve to close faster or does the spring behave the same no difference. It was just a thought. I have the .042 spring and the gun is perfect now with the .038 spring. Shoots several pellets of different weights at the same point of impact off one sight in at 30 yards so I would hate to tinker with it if nothing is to be gained or lost.

[rsterne]

The answer depends on whether or not the hammer is still under preload when it hits the valve (it isn't when you use an SSG).... If it is in free flight, then all that matters is the weight and velocity of the hammer, not the spring you used to get it there.... You could use a lighter spring under preload, or a heavier spring with no preload, and if properly adjusted, both might result in the same velocity....

If there is still preload on the spring when the hammer hits the valve, and through the shot cycle, then they would not act IDENTICALLY, even if the hammer weight and velocity at valve contact as the same.... because the lighter spring with preload would have more of that preload left over (trying to resist the valve closing) when the valve reached full lift than the heavy spring.... However, that factor would likely be quite small, so you are back to being able to find an adjustment with both setups that produce the same shot....

HTHs....

Bob

[bowdoc64]

Bob great info as always.

I thought it would be reversed soft spring closeing faster. Heavy spring  closing faster has me rethinking my set up.

In theory on my Maximus the valve opening the same but closing faster would mean same velocity but less bleed off air as the valve closed meaning a more air efficient set up. I might go with the .042 spring now

[Blue]

You could try to find a "Short Stiff Spring" type solution where you find the stiff spring that gives you the velocity you want and is short enough to not have the hammer contact the valve stem at rest.  You'd have the stiff spring properties you're looking for and no extra load on the valve from the spring adding to the forces the valve is overcoming to close.

Blue

[rsterne]

The relationship between lift and dwell is primarily a factor of hammer weight, which is part of the hammer momentum equation.... The spring energy imparted to the hammer (average force times the distance that the hammer is under acceleration) governs the hammer energy, which creates lift, and the momentum which creates dwell.... Increasing spring energy increases both lift and dwell, so I didn't mean to imply that one spring would make the valve close faster while leaving the opening the same, that is not likely the case.... If both springs are preloaded when the hammer hits the valve stem, and are adjusted for equal hammer velocity (energy and momentum) at that point, then the lighter spring, with more preload, will be pushing more on the stem THROUGHOUT the shot cycle.... This will be counteracting the closing forces in the valve the whole time the valve is open.... so it should have more lift and dwell, and therefore more velocity, but also use more air.... You would therefore have to make a minor adjustment to get both springs to shoot the same.... and if you don't change the hammer weight, once the shot cycles are the same, the efficiency should be as well....

I think spending your time trying different springs to gain efficiency, if you are happy with what you have now.... is probably a waste of time, UNLESS you can fit a heavy enough spring to end up with a gap between the hammer and spring when the gun is uncocked.... This setup is called an "SSS" for Short Stiff Spring, and like the SSG (Stopping Spring Guide) helps eliminate hammer bounce because of the gap between hammer and spring.... It is eliminating the bounce that saves air....

Bob

[bowdoc64]

Again good info Bob.. I might play with the whole short stiff spring thing . I have a spring guide power adjust er and two heavy springs so I might. Cut one up