Here is what I meant by concentric stems.... The concept is the same as your original idea, but IMO easier to make.... The idea is to use a smaller poppet (black) inside the main poppet (red), which opens first to equalize the pressure across the main poppet.... The small poppet stem is inside the main stem, which is tubular, concentric, and slightly shorter, so that the hammer first opens the small poppet, (which allows the pressure to equalize across the main poppet making it easier to open), and then the main one.... The green dotted line is the valve spring....I know of at least two guys who suggested or tried this, one was Travis (who built several working prototypes), the other one may have been Tim, but I honestly can't remember.... It is NOT my idea, but I don't see any reason it should not work as intended.... The key would be sufficient mechanical strength of all the components, and finding the optimum difference in the stem lengths.... If the small center stem is longer than needed, the pellet might start to move before the main poppet opened, and if it is too short, the pressure difference on the main poppet may not drop enough to reduce the opening force on it as desired.... My gut feel is that the stems only need to be 0.010" or less different in length, but I have never made one to test....Bob
I thought I explained how it operated.... The hammer first opens the small, black, inner poppet, about 0.010" or so, which allows air to pass through it, and through the vent holes in the main poppet, into the exhaust port area of the valve.... This (mostly) equalizes the pressure across the red, main poppet, so that when the hammer hits the end of the tubular valve stem to open it, there is less force holding it closed.... The concept is similar to what the OP had in the drawing in the first post in this thread.... but instead of having a flange (umbrella, or nut) on the stem to open the main poppet, it uses concentric stems.... Same concept, different exectution.... Which is easier to make is debatable, I guess.... Please note, this is NOT my design, I merely said that it has been suggested, and used, by at least a couple of people for the purpose of making a valve easier to open.... I have no doubt that a proper, balanced valve design such as the one Lloyd did many years ago, or the one in Tom's Slayer, once optimized, would perform better.... Bob
When I locked at rkr's initial valve design first I thought that the second stage on the stem wich breaks the large valve poppet open finally does, by the way, close the smaller bypass again. But this must not be - there could also be ventholes in this second ring so that it just breaks the valve fully open without closing the bypass again.Then the design, to me, seems to have no disadvantages to rsterne's design - seems to be the same in principle unless I missed something.And it seems to be more simple, as it don't need to have this filigree stem in stem design.
...Although as the poppet opens the vast majority of air will flow through the actual valve seat so I'm not exactly sure if those channels are needed...