If those numbers are supposed to be armor values, then the Type 99 has a 1000-1200mm RHS frontal defense.
The Leopard 2 armor is also much better against KE rounds than the Chobam armor variants, which hold better against most HEAT rounds.
The figures I gave were for the KE required to penetrate turret of the tank, not the rounds penetration level, or frontal arc. KE is different to your CE rounds, cause KE is pure impact energy, no heat. Your 1000-1200 front arc defence isnt talking about KE penetration level, its talking about equivalent thickness of steel armour. Its a major difference. For the Type 99 to have 1000-1200 KE resistant level its gonna place the tank over to 60t region not your mid-high 50t.
HKSDU: 45% increase of energy is at muzzle (about 20% increase in velocity). Typically penetration is measured at 2 km. Since friction in fluid is proportional to velocity squared (the simplest model anyway), energy at 2km will increase by much less than 45%. The actual number will depend on a lot of factors and hence why leaking the 45% inc in muzzle energy isn't very informative (and so it was allowed...). You can try looking up the typical drag coefficient of APFSDS rounds and doing a rough calculation.
On the flip side, it means that at muzzle, penetration may be more than 1.45*600, since the 600 mm figure is at 2km.
Thanx, bit rusty on my physics since i haven't used it in a while, forgot about energy conversion. But aren't the fundamentals of KE=0.5*m*v^2, now the round should contain simular mass give or take, now depending on round initial exit speed from the gun, time flight taken, drag coefficient (like you said) we can calculate how much KE is impacted. All Im missing is the exit speed of the round cause I need to know how tight Chinese 125mm smoothbourne is compared to the Russian one initially tested on.
