I researching Pejsa it seems that a standard G1 constant model for retardation would be somewhat incomplete. So, it "assumes one invariable drag function" As we know many modern bullets can exhibit behavior of multiple forms across the life of it's trajectory. I.E. G1-G7. However It does seem to have some alternate slope constants for slower machs.
I am not arguing that there is not empirical data that Pejsa is effective (it's obviously effective). But is seems that it's somewhat of a sandwich fix. As well appears that it's geared for supersonic transform.
My question is: how does Pejsa ascertain transsonic behavior?
I would imagine that a 6DOF calculation involving all pertinent data (Mv, Da, Temp, etc..etc) would derive a much more accurate solution as there would be no cross over calculations/curves for the sonic/subsonic-transsonic variation, only Cp shift through a mach range.
My second question: Though seemingly much more accurate is 6DOF unnecessary? Or do ballistics programs want to move in that direction?
Perhaps this is simply academic as such intense fluid (air is a fluid) calculations are currently not possible with handheld devices. But in the day of multithreading and cloud computing I can see a PDA type device that simply uploads parameters to be calculated in cloud and spits back a value/fire solution to the user real time.
Either way, my understanding is incomplete, but as I understand it Pejsa is as well? I have not doubt that someone will shoot my statement to swiss cheese, but this is what I am looking for, some understanding.
Thanks
I am not arguing that there is not empirical data that Pejsa is effective (it's obviously effective). But is seems that it's somewhat of a sandwich fix. As well appears that it's geared for supersonic transform.
My question is: how does Pejsa ascertain transsonic behavior?
I would imagine that a 6DOF calculation involving all pertinent data (Mv, Da, Temp, etc..etc) would derive a much more accurate solution as there would be no cross over calculations/curves for the sonic/subsonic-transsonic variation, only Cp shift through a mach range.
My second question: Though seemingly much more accurate is 6DOF unnecessary? Or do ballistics programs want to move in that direction?
Perhaps this is simply academic as such intense fluid (air is a fluid) calculations are currently not possible with handheld devices. But in the day of multithreading and cloud computing I can see a PDA type device that simply uploads parameters to be calculated in cloud and spits back a value/fire solution to the user real time.
Either way, my understanding is incomplete, but as I understand it Pejsa is as well? I have not doubt that someone will shoot my statement to swiss cheese, but this is what I am looking for, some understanding.
Thanks