4.12.2 de-bugging

[Pursuivant]

Troubleshooting the A-20G Damage Model:

This one has a lot of little problems, but the big problem is FUEL TANKS

A) The damage model assumes that the fuel tanks are contiguous with the plane's skin, which was not the case. That means that many glancing hits to the wing and fuselage which realistically would have missed the tanks cause punctures.

B) In a few cases, bullets which completely miss the tanks still cause fuel leaks. Like here:

http://forum.1cpublishing.eu/attachm...1&d=1404378042

Note that damage which is just to the starboard engine nachelle has somehow managed to start a leak in the outboard fuel tank!

C) As is typical for just about all the planes in the game, single rifle caliber bullets cause much worse leaks than they should and ignite fires far too often.

Remember, by about 1940, at least for most planes, self-sealing tanks weren't just self-sealing, but usually blanketed by engine exhaust.

That means that you have to tear open the fuel tank to the point that the CO2 blanket no longer is effective, you also need to have way of vaporizing the gasoline (admittedly, not hard when there's a 200 mph wind blowing through a hole in the plane's skin), and you need a spark. Sparks are a bit harder to come by since aluminum doesn't spark and only something like every 10th bullet in the belt was Incendiary, tracer or explosive.

So, two .303 bullets in rapid succession against a full fuel tank are very unlikely to cause a fire because the gas hasn't had time to spill or vaporize and the integrity of the tank is still good. A burst of .303 bullets might do the trick if it tears apart the fuel tank and the fuel then contacts a hot engines. But, that's not an option for a fuel tank mounted at a distance from the engine.

What might cause a fire is several bursts of .303 fire which tear up the tank, followed some seconds later by another big burst of .303 gunfire, which can be assumed to contain an Incendiary, Explosive or Tracer bullet in the mix, and which hits gasoline vapor.

Example of bad damage modeling here, where two .303 bullets from the same burst started a fire in a previously undamaged fuel tank.

http://forum.1cpublishing.eu/attachm...1&d=1404378818

The other bullets which hit near the burning fuel tank actually hit behind the fuel tank, so the damage looks worse than it is.

E) Fuel fires don't go out when fuel is exhausted.

Example here:

http://forum.1cpublishing.eu/attachm...1&d=1404378916

This screenshot was taken about a minute after I lost fuel due to the fire. Since the fire presumably drew fire from other tanks, it's unlikely that there was any remaining fuel in the burning tank for it to use!


F) Fuel fires also deplete the fuel from ALL tanks, not just the tank where the fire is. I know that IL2 doesn't and can't really model fuel transfer or fuel shutoffs, but it wouldn't be hard to specify that a fuel fire just takes some percentage of fuel and then goes out.

[Pursuivant]

More A-20G DM problems.

1) Pilot injury.

A) Forward Armor Plate Not Properly Modeled: In a few cases, bullets will penetrate the forward armor plate to kill the pilot - just as if the plate wasn't there. This despite the fact that most marks of A-20 had armor plate ahead of the pilot:

http://www.zenoswarbirdvideos.com/Im...otArmorDia.pdf

Unfortunately, no pictures of this one. I got three PK in quick succession and several pilot wounded results from frontal attacks which penetrated the forward armor, but didn't think to take screenshots of them. After that, I couldn't replicate the problem.

B) The armor glass in front of the pilot is mostly well modeled, with a few exceptions:

http://forum.1cpublishing.eu/attachm...1&d=1404379563

Note the hit to the edge of the armor glass, which, rather than being stopped or deflected penetrated to hit the pilot's arm. This isn't just an artifact of the cockpit model not quite matching up to the exterior model, the hit looked just as strange from the outside.

Typically, however, the armor glass does its job except at close ranges were it can be penetrated.

C) Pilot damage modeling is a bit weird. In one instance I got a bleeding wound from a bullet which just missed the pilot. At best, it would have been a grazing wound.

http://forum.1cpublishing.eu/attachm...1&d=1404380010


2) Gun damage. Unlike planes like the P-38 where just about any hit to the nose is a gun hit, it's quite difficult to hit the guns on the A-20G. While they can happen (unlike, say, the P-39 or P-400), I have to wonder if the ammunition runs for the guns could be a bit better modeled.

http://forum.1cpublishing.eu/attachm...1&d=1404380214

Notice loads of hits which might damage the guns or ammo runs, including one hit that goes straight down the barrel of one of the guns, but no damage.

3) Missing Crewman. This isn't bad DM, it's just a bug. The rear gun pivots, but no gunner is visible. He's either not modeled, or he is hiding someplace inside the plane rather than manning his gun. He is visible when it's time to bail out, though!

Finally, this technical report provides lots of good cutaway drawings of various A-20 engine, fuel and control systems:

http://legendsintheirowntime.com/A20/A20_draft_2.pdf

[Treetop64]

Just a side note on this issue regarding the SB-2:

The SB-2 had four fuel tanks, one on both sides of each engine. They were not protected with either armor or sealant. So, as it should be, taking a penetrating hit to a fuel tank will cause a leak until the tank runs dry.

The problem is that there is no way of isolating the leak to the affected tank. For example, if the no.2 tank got penetrated, the resultant leak will continue to run until all four tanks are empty. The aircraft's entire fuel supply from the remaining untouched tanks will drain out even if only one tank was damaged.

Though lovely and an enjoyable aircraft to fly, the SB-2 is already delicate enough without this crippling bug.

[Baddington_VA]

Though lovely and an enjoyable aircraft to fly, the SB-2 is already delicate enough without this crippling bug.

That goes for every aircraft in IL2.
If the leak doesn't stop, it sucks out fuel from every tank.

[Tempest123]

Originally Posted by Pursuivant

Furthermore, there are exactly ZERO places on your average WW2 airplane where a single bullet - even a big one - can simultaneously wipe out rudder, ailerons and elevators, yet it happens occasionally in IL2.

You also bring up another control damage option I forgot to mention - limited range of motion for damaged control surfaces.

Currently, you have loss of control surfaces, complete loss of control of control surfaces, and partial loss of authority from control surfaces. But, you don't have limited range of motion from damaged controls, such as a rudder that you can only turn right, or which only travels through 50% of its full arc when turned to the right.

Yup, I would like to see the instant disabling effect (which is a little arcade IMHO unless the whole surface is blown off) replaced with degrees of limited movement, i.e 20% to 70% (or whatever) of total movement through the full range of motion to simulate damaged surfaces.

[TexasJG]

Version 4.12m, the “Scan MAX Range” function of FOW seems to be inoperative.

[Aviar]

Originally Posted by TexasJG

Version 4.12m, the “Scan MAX Range” function of FOW seems to be inoperative.

Just for your information, DT normally needs more proof/information regarding possible bugs.

However, if you post an example mission, I would be happy to test/confirm this issue for you.



EDIT: I made a quick test mission and it seems to be working fine in both Coop and Dogfight modes. Have you read the MDS Guide which came with the 4.10 patch?

Aviar

[Pursuivant]

Originally Posted by Baddington_VA

That goes for every aircraft in IL2.
If the leak doesn't stop, it sucks out fuel from every tank.

Fire in a fuel tank also means that you lose fuel from the tank - probably at an accelerated rate from just a bad leak.

So, in addition to wing tank fuel fires not weakening the wing at all, they will also suck fuel from all the other tanks at a very rapid rate. This means that a plane like the A-20, with a range of over 1,000 miles and 100% fuel can be completely drained of fuel by a fuel tank fire in just a few minutes.

While it would probably be far too much effort to simulate fuel transfer, or even fuel shut-off, a simple fix for this problem is to just limit the maximum amount of fuel that can be lost from a fuel tank leak or fire to Percentage of total fuel stored in that tank/percentage of remaining fuel.

For example, if 25% of the plane's total fuel is stored in the outport port wing tank, you've got 50% fuel left, and that tank gets holed or set on fire, the maximum fuel you can lose is 50% of 25% or 12.5% of your original fuel load.

Realistically, that's bit simplistic, since it assumes that a leak will completely drain the tank, which isn't always the case, but it's good enough.

[Pursuivant]

Troubleshooting the A-6M Zero/Zeke/Reisen series this time.

Because the early variants are so fragile, I didn't use my standard bad tactics and just hang out at the bomber formation's 6 o'clock. Also, it's a Zero, and how can you NOT climb and turn in a Zero?

Instead, I used modified "boom and zoom" and high-side attacks, keeping my speed up and making fast diving attacks from above and behind, usually starting from 5 o'clock or 7 o'clock high and describing a gentle "S" as I dove to attack from at least a 300 m height advantage.

This turned the A6M2 series into an effective bomber interceptor, but even so I picked up enough hits to effectively pick out any faults in DM.

All in all, the DM isn't that bad. The engine is reasonably robust against small caliber bullets, as is the airframe, and the later series (A6M5 and later) planes are about as good as most Western planes in their ability to take damage.

The early marks catch fire almost too easily - just one or two rifle caliber bullets are enough to make the wing fuel tanks catch on fire even on a full tank of gas.

http://forum.1cpublishing.eu/attachm...1&d=1404791035

For example, in the picture above, two rifle caliber bullets in a single burst instantly made the port side wing fuel tank burst into flame.

All of the variants are vulnerable to fuel tank fires, and any fuel tank fire is more likely to run the engine out of fuel than burn the wing off, although on the early versions you might get a fuel tank explosion.

In a very few cases, the "bug" that the DM doesn't recognize that a fuel tank is filled with fuel also comes into play. As in this case where the bullet not only punched through the forward fuel tank but also injured the pilot:

http://forum.1cpublishing.eu/attachm...1&d=1404791269

Other than systemic bugs in IL2's damage modeling mentioned above, there are also a few cases where clear fuel tank hits DON'T start fuel tank leaks:

http://forum.1cpublishing.eu/attachm...1&d=1404791602

A6M5 - Notice two penetrating bullets to port wing fuel tank but no fuel tank leak.

http://forum.1cpublishing.eu/attachm...1&d=1404791705

A6M3 - Ditto. Although on second look it appears that the bullets might be a bit outboard of the tank, in which case they might have damaged the wing cannon.


A6M7 - Congratulations to whoever did the damage modeling on this one. Not only are damage results reasonable, but FUEL FIRES GO OUT WHEN THE PLANE RUNS OUT OF FUEL!

Edit: Fuel tank fires only go out and stay out when: A) You run out of fuel, B) The fuel fire has already been reduced to black smoke due to a long-hard dive which partially extinguishes the fire.

Other than that, they keep on blazing away even after you've run out of fuel.

[Pursuivant]

Two more planes:

B-239 Buffalo - I had trouble testing this one because it was so slow that it couldn't keep up with the bomber formation.

DM seems reasonably sound, except that the engine seems quite vulnerable for a radial engine, consistently smoking badly and losing lots of power after just a few hits.

Fuel tanks might be hard to damage; I got few leaks and no fires.

Guns might be hard to damage; I got no gun hits.

Mostly, the bombers just shredded the engine enough that I had to abort.

B-25H - Damage model seems reasonable, except for the usual problems.

* Nominally "self-sealing" fuel tanks don't - even when hit by just a few scattered rifle-caliber bullets.

* Wing tank fires start far too quickly and easily - just a few rifle caliber bullets in the same burst will consistently start fires if they hit a wing tanks.

Remember, the B-25 and other bombers usually blanketed the fuel tanks with exhaust gasses to reduce the chance of a fuel fire. IL2 doesn't seem to take this feature into account.

* Fuel fires don't weaken the wing or make it fail, but they will quickly run the plane out of fuel in just a few minutes.