For I think these issues cannot be considered apart
I use to have great ideas (at least till someone tells me better
)
First of all: What a name "Transfer Port" for such a humble bore, the pressure nozzle. (I'm quite sure if there was a valve acting fast enough with 3 mm full clearance it stuck there instead of that bore.
My idea about the above is that the larger the swept volume the bigger TP they accept. That schouldn't suggest that a large TP is better than a small one.
TP length is at least an issue as its width. As long as the width isn't much less than 3 mm the resistance to airflow (which might be the first concern) isn't the point but its dead volume is.
A powerful spring will easily press the complete swept volume (the air cushion) into the TP when it's too large. (before the pellet has started moving) Thus any enhancing of the TP will yield nothing but increase of dry firing.
The air cushion itself has no direct impact on pellet speed in the way: the more the higher the power. This is because the air cushion does not deliver the energy, it's the spring. The cushion is nothing but a clutch or like the string in an longbow translating the energy stored in the spring to the pellet. It does so quite efficently. Compress for example a spring and put a pellet on top of it and release. The pellet won't be nearly as fast as it is blown through the barrel. For good shooting consistency it is important to attain a high iniitial (maximum) pressure thus optimally sealing the pellet into the breech. A too large TP with respect to the swept volume might be degrading there.
Only, if the initial (maximum) pressure was too high (don't know if that ever occurs) a larger TP might flatten that pressure peak and yield a smoother action. This depends on the pellet type at what pressure it releases, too. Pretty sure hard and tight pellets need higher initial pressure thus a small TP (by volume). But when the pellet was soft and loose, only a small enough (by width) TP makes sure of a constant and good initial (maximum) pressure at all. So the small TP (by volume) is good for both pellet types the small TP (by width) is good at least for soft, lightweight and undersized pellets.
What minimum swept volume is necessary for a certain pellet energy depends surely on TP volume. But I've no idea at moment how to estimate the minimum air cushion volume for a certain pellet energy. For my calculations on pellet speed I just suppose a sufficient amount of air involved.
And then ther're those splendid combinations of a certain airgun with a certain power, certain barrel and pellet which do better than any other combination. Maybe that can never been properly calculated just tried. When the pellet is released just at the perfect moment to subdue any slam and vibration, the situation is called "aperiodischer Grenzfall" sorry, lack of proper translation.
Just how I think.
And piston weight must be considered, too. None will stand alone
The shorter the TP the wider it may possibly be. The longer it is the narrower it must be in order to avoid dead volume. but a 1 inch long TP is no aperture but a tube where diameter reduces airflow by 4th power (Hagen-Poiseulle's law), so TP length is more degrading than width (as long as resistance to airflow is an issue at all)
I use to have great ideas (at least till someone tells me better
)First of all: What a name "Transfer Port" for such a humble bore, the pressure nozzle. (I'm quite sure if there was a valve acting fast enough with 3 mm full clearance it stuck there instead of that bore.
My idea about the above is that the larger the swept volume the bigger TP they accept. That schouldn't suggest that a large TP is better than a small one.
TP length is at least an issue as its width. As long as the width isn't much less than 3 mm the resistance to airflow (which might be the first concern) isn't the point but its dead volume is.
A powerful spring will easily press the complete swept volume (the air cushion) into the TP when it's too large. (before the pellet has started moving) Thus any enhancing of the TP will yield nothing but increase of dry firing.
The air cushion itself has no direct impact on pellet speed in the way: the more the higher the power. This is because the air cushion does not deliver the energy, it's the spring. The cushion is nothing but a clutch or like the string in an longbow translating the energy stored in the spring to the pellet. It does so quite efficently. Compress for example a spring and put a pellet on top of it and release. The pellet won't be nearly as fast as it is blown through the barrel. For good shooting consistency it is important to attain a high iniitial (maximum) pressure thus optimally sealing the pellet into the breech. A too large TP with respect to the swept volume might be degrading there.
Only, if the initial (maximum) pressure was too high (don't know if that ever occurs) a larger TP might flatten that pressure peak and yield a smoother action. This depends on the pellet type at what pressure it releases, too. Pretty sure hard and tight pellets need higher initial pressure thus a small TP (by volume). But when the pellet was soft and loose, only a small enough (by width) TP makes sure of a constant and good initial (maximum) pressure at all. So the small TP (by volume) is good for both pellet types the small TP (by width) is good at least for soft, lightweight and undersized pellets.
What minimum swept volume is necessary for a certain pellet energy depends surely on TP volume. But I've no idea at moment how to estimate the minimum air cushion volume for a certain pellet energy. For my calculations on pellet speed I just suppose a sufficient amount of air involved.
And then ther're those splendid combinations of a certain airgun with a certain power, certain barrel and pellet which do better than any other combination. Maybe that can never been properly calculated just tried. When the pellet is released just at the perfect moment to subdue any slam and vibration, the situation is called "aperiodischer Grenzfall" sorry, lack of proper translation.
Just how I think.
And piston weight must be considered, too. None will stand alone
The shorter the TP the wider it may possibly be. The longer it is the narrower it must be in order to avoid dead volume. but a 1 inch long TP is no aperture but a tube where diameter reduces airflow by 4th power (Hagen-Poiseulle's law), so TP length is more degrading than width (as long as resistance to airflow is an issue at all)
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