Info on Japanese AAA

[DaveCumming]

The DP file for AA guns is similar to planes. The line defining the gun has entries for the rate of fire, followed by the gun's position relative to the centre of gravity. At the end of the line are the entries that limit the elevation and degrees of rotation that the gun can have.

For an idea as to how the numbers work I suggest that you look at the entries for a rear gunner on a bomber. You can amend the AA gun to give you a 120 degree arc of fire and an elevation range of -10 to +60 degrees if you wished.

Dave

[james007]

Davecumming great post. I have learn something new. I was was wondering weather we cound use the DEPD utility for AC to alter the DP of the AAA. As for the rotation of the AAA. I was wrong. I'am begining to believe this only effects the position and the direction of the AAA and not the rotational capability of the AAA.

What we can do is place the AAA in different directions as to defend the target better this way.

[Tango_Romeo]

I have experimented with this subject in MB quite a bit, and I can atest that the setting you're discussing is definitely referencing the orientation of the gun, not it's rotation limit.  I've had to arrange AAA with orientations covering all points of the compass to get them to fire in all directions.  :'(

I have never found a reliable answer to what the limit of the guns rotation is, but I can tell you it is very narrow.

I've read most of the material mentioned above, and have never seen this topic discussed.  If someone finds a good reference, how about sharing.  ::)

In fact, the only rotational limits I've been able to set for guns is for those on aircraft...and that is done in editing the DP file.

[Tango_Romeo]

Yes, Dave.  Thanks a million.   I've been doing this on aircraft turrets in MB for years, and never thought of the obvious.....if it works on aircraft DPs, then it should on object DPs as well.  

[piersyf]

This is the relevant section of the DP file for the type 88 AA gun.


[GUNSTATIONS]
; Gun 75mm Type 88
gunstation.0=4,-1,1,3.00,720,10,0.01,8200,7,0,1d1*90,0,5,1.2,0,0,315,-90,180,85,0,232

The numbers you are interested in here are the 3.00 (firing interval, or 20 rds per minute), the 720 is the muzzle velocity, the 10 is the 'time alive' so the projectile is tracked for 10 seconds, then skip ahead a bit to the last 5 numbers starting with -90. The first 4 of these are the angular movement of the weapon given as left, right, up and down. The last number is the projectile weight in ounces.

Does anyone else see a problem with the rotations? This reads as 90 degrees left rotation, 180 degrees right rotation. Was there really a 90 degree dead zone in the left rear quadrant?

Check these against the historical data and see how it pans out...

Piers

[piersyf]

I had a look at the type 96 25mm gun DP and checked the historical data.
First the range. In the DP the range at which the weapon will open fire on you is over 7000m, the maximum range of the weapon. As the effective range of the weapon was 3000m and the ready use ammo was around 2000 rds (making it unlikley that they'd start shooting that far out), I changed that to 3000m. Next was rate of fire. The firing interval was too long! The rate is for a single barrel weapon, the image shown in 'info' is a triple barrel. I compromised and doubled the rate of fire to 220 rpm (the sustained rate for a twin mount). Finally the damage. It was given as 1d1*50. The damage caused by an HE round is partly impact (mass) and partly the bang factor. The projectile weight is 0.26kg (a 20mm Hispano round is 0.25) and the bursting charge is 10 grams (20g in a 20mm hispano). Given how close they are I changed the damage to 1d1*30. Now the gun fires twice as fast, does about half the damage but won't shoot until you are closer. This is far more accurate for the usage of light flak; to keep you at altitude!


OMG!!  The flak is crazy! Get too close to a jap airfield now and it's a nightmare! Only bonus is that it only lasts a few seconds...



It was also a framerate killer. I was also forgetting before that the 25mm was a glorified machinegun, based on an old hotchkiss. The japs didn't have time fuses or proximity fuses for the rounds (as far as I can find). They basically explode if they hit something, just like the 20mm or 30mm cannon on aircraft. I went back in to the weapon's DP and changed one of the leading numbers from 4 (which seems to be gun with flakburst) to either a 1 or a 0. Either will work as the sound is triggered by a different number in the sequence, and the damage will happen regardless. Frame rate much improved, no scary flak, just a sudden stream of nasty red messages telling you your aircraft is being shredded...

Piers