About WW2 fighter aircraft firing power

[Rob Philips]

Thanks, Tony. I had read the statements from Henning Ruch. I believe that your suppositions made to make the matter manageable, underestimate the power that is delivered by explosives. However, as said, if these, or other, suppositions are applied consistently to all gun/ammo systems in a comparison, then results are likely to be comparable, and perhaps even quite similar. I cannot prove this as I cannot point to objective measurements of explosive force. The cavity size blasted in gelatin would be an objective measurement, if this would be a practicable technique.

"Pattern density is partly a function of the harmonisation arrangements, but equally so a function of the combined rates of fire of the armament."
Exactly. And added to that factors such as gun platform vibration under firing, delivering a dispersion that did not result from design, but that could nevertheless be used in a weapons system design. Density required shall be controlled by the projectiles employed, as in your .303 machine gun vs. 20mm cannon comparison. Now we are heading towards clarity about desirable pattern densities. This cannot be studied by looking at individual guns and/or ammo's. The entire aircraft with multiple gun and/or cannon and ammo needs to be considered as a system. Or ammo's, plural, if more than one type is to be deployed. The last is what you did, calculating for a repetitive 3 HE + 1 AP ammo arrangement in the belt.

Pattern density shall be maximal at the point where projectile trajectories converge. Before and after that the pattern shall be basically conical in the direction of projectile flight. Harmonisation seems to have been done according to this one-point-convergence strategy, that point being about 300 to 200 yards out, as the fashion of the day had it. Are you aware of other arrangements that may have been used? Meaning harmonisation to parallel trajectories, or perhaps to a circular pattern at the envisaged engagement range?

One other point that you raised in the articles. The presence of tracer is mentioned as undesirable, as it reduces space that could otherwise be filled with HE, and as tracer gave away the fact that somebody was shooting at you. On the other hand, wasn't tracer an excellent aid in deflection shooting, as the pilot could see where the rounds were going, enabling him to let the opponent fly into the pattern, or to chase the pattern into the opponent?

Regards,

Rob