Japanese 20mm Cannons

[SmokinLoon]

Just an FYI for all you Japanese aircraft fans in AH, there are actually THREE different 20mm cannons that are in use.  The Japanese Army and Navy could not seem to agree, even within their respective branches on which variants were best.  The Type 99 Mk I, Type 99 Mk II, and Ho-5 are all used in AH.  Like a number of weapons, the Type 99 Mk II and Ho-5 specifics are NOT shown at the AH Trainers website.  I tested all three cannon variants and crossed referenced them with actual cannon and projectile data, I believe AH did a decent job assigning damage values.  I did not test the rate of fire.


The Type 99 Mk I is used in the A6M2 "Zeke" and G4M "Betty".  The HE damage in AH is 3.42, and typical rate of fire is 490 rounds/min.

The Type 99 Mk II is used in the A6M5b "Zeke" and NIK2 "George" .  The HE damage in AH is 3.85, and typical rate of fire is 490 rounds/min.  BTW, the NIK2 has it listed as the "Model II", a typo I believe.

The Ho-5 is used in the Ki-61 "Tony", Ki-84 "Frank", and Ki-67 "Peggy".  The HE damage is 3.35, and typical rate of fire is 750 rounds/min.


For reference, the British 20mm Hispano has an HE damage of 4.02 assigned with a rate of fire of 600 rounds/min. The German MG151/20 has 3.55 HE damage and a rate of fire of 750 rounds/min.  So, as you can see the Type 99 Mk II (A6m5 and NIK2) is second only to the Hispanos *in damage per shot*.    

[E25280]

So, as you can see the Type 99 Mk II (A6m5 and NIK2) is second only to the Hispanos.  

Second in terms of per round damage, but inferior in terms of total weight of fire per second.  It is an important distinction.

<Edit> Should add weight of fire per gun.  4 cannon on the Nik clearly help to make up for the slow ROF vs. a 2-cannon bird.

[Masherbrum]

Second in terms of per round damage, but inferior in terms of total weight of fire per second.  It is an important distinction.

<Edit> Should add weight of fire per gun.  4 cannon on the Nik clearly help to make up for the slow ROF vs. a 2-cannon bird.

Yep.

[SmokinLoon]

I agree that most of the time people forget to look at the bigger picture when comparing weapon data.  Case in point are the aircraft weapons we have in AH.  Looking at the individual projectile damage does not tell the whole story of the performance.

Rate of fire, available amount of ammunition, trajectory, and even the weapons platform are all factors (not just damage/shot) in grading the effectiveness of a weapons system.

I just found it interesting that I hear quite often "Japanese 20mm are not good, etc", when in fact round for round the Type 99 Mk II are 2nd only to the 20mm Hispanos for damage. 

[BaldEagl]

I just found it interesting that I hear quite often "Japanese 20mm are not good, etc", when in fact round for round the Type 99 Mk II are 2nd only to the 20mm Hispanos for damage.  

They are only good if you can hit something with them.  The ballistics of the Type 99 cannons are among the worst in the game (I think they are worse than the 30mm Spud so many have trouble with and only marginally better then the German MG-FF 20mm) and therefore the "Japanese 20mm are no good" label.  It's a perfectly suited description of their effectiveness.

Of course I shoot at moving airplanes, not stationary tool sheds.

[SmokinLoon]

Cartridge/ Projectile weight/ Rate of fire/ Muzzle velocity

Type 99 1 20mmX72/ 129gr/ 490rpm/ 1958fps
Type 99 2 20mmX101/ 128gr/ 490rpm/ 2460fps
Hispano 2 20mmX110/ 130gr/ 600rpm/ 2887fps
Mk 108 30mmX90/ 330gr/ 650rpm/ 1770fps

While I don't have the ballistic coefficient of the projectiles to plug into the formula, I'll put my money on the Type 99 Mk I any day when it comes to trajectory vs the Mk 109 30mm.    

Also, I just realized that the Tempest has the Hispanos Mk V and not the typical Mk II version (Mk V has a shorter barrel and therefore slightly less velocity, but a higher rate of fire then the Mk II)... off to go do some testing.