4.12.2 de-bugging

[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.

[Pursuivant]

Troubleshooting the DM on the Beaufighter this time.

Cockpit armor and armor glass does what it's supposed to against frontal hits, although it can be penetrated at close range.

One oddity is that compared to most other recently added planes, it's damned near impossible to set the plane on fire or start a fuel leak. Engines are also extremely tough compared to the same engine when mounted in the Wellington, which can be made to die VERY quickly.

http://forum.1cpublishing.eu/attachm...1&d=1405722665

Notice the Beaufighter with it's engines and the leading edges of its wings - directly forward of the inboard fuel tanks - turned into a sieve with no leakage and little damage to the engines.

Unless there's some armor plate there that I don't know about, those fuel tanks ought to be leaking or on fire with that much damage!

[Pursuivant]

Troubleshooting the DM on the Bf-109E series.

This is an old DM and it shows. While I've complained previously about the tendency for the engine to shut down after just a few hits from rifle-caliber bullets fired at extreme range, I've also noticed a few more bugs.

1) The rear fuselage fuel tank is extremely vulnerable - even to hits from the front. Hits from 1 o'clock or 11 o'clock can just bypass the pilot's armor plate to hit the fuel tank, and even one or two rifle-caliber bullets are sufficient to cause unstoppable leaks or even fires. While this is realistic in that the pilot's armor plate didn't fully protect the fuel tank from the front, it's unrealistic for the same reason that a couple of small caliber bullets are unlikely to start a fire in any other self-sealing fuel tank with exhaust gas blanketing.

2) There is a gap between the armor glass and the forward armor plate (for planes where it was fitted).

http://forum.1cpublishing.eu/attachm...1&d=1405745821

This screen grab shows two major problems with the Bf-109E-4 damage model - two rifle caliber bullets fired from about 300 m were sufficient to stop the engine cold. Another bullet has penetrated the gap between the armor glass and the forward firewall (which might not have been armored in the E series) to wound the pilot.

Also notice a penetrating bullet hit from the side which also passes through the pilot model, but which doesn't kill or cause injury.

3) It's very hard to get coolant leaks for the radiators which are located just outboard from the cockpit. But, there's plenty of gun camera footage showing exactly this sort of damage for the Bf-109 series (albeit mostly for the G model).

[Pursuivant]

Ace level AI bombers regularly crash into each other when maneuvering in formation, at least on the Bessarabia map and when setting up QMB missions.

On a similar note, often the third plane in a four plane formation will arbitrarily go into a very steep dive of at least 300 m, then climb to rejoin the formation, possibly to avoid collisions.

By contrast, rookie AI never seems to have this problem, perhaps because they're either slower to react to nearby planes, or because their formations aren't as tight.

I don't know if this is a QMB problem or an AI problem.

In either case, the cause of the problem seems to be that the AI isn't "thinking ahead" far enough to accommodate the very tight turns built into the AI flight paths created for QMB maps.

The quick and dirty solution would be to set QMB AI flight paths so that the turns are much gentler.

The better solution would be to alter AI formation behavior so that the formation "opens up" prior to a sharp turn, with planes on the outside of the formation speeding up prior to the turn and turning later to keep station, and planes on the inside slowing down and starting their turns earlier to keep station. Alternately, planes in formations of four could "cross over", so that the number 1 plane in the formation becomes number 4 and vice-versa. (Not always historical, but it works.)

http://forum.1cpublishing.eu/attachm...1&d=1405747271

Screen grab of two Ace AI Wellingtons about to collide.

http://forum.1cpublishing.eu/attachm...1&d=1405747840

Oops!

[Pursuivant]

Troubleshooting the Corsair I DM

Not surprisingly, there are a few oddities.

1) The fuel tank seems very vulnerable to small caliber bullets.

The armor plate in front of the oil tank, which also provided partial protection to the fuel tank from the front, doesn't seem to be modeled.

Even one hit by a .303 bullet to the fuel tank often starts a big, unstoppable fuel leak. It's as if the fuel tank isn't self-sealing at all.

Regardless of where a bullet hits the fuel tank (i.e., whether above or below the fuel level) you still get a fuel leak. For a big, basically rectangular fuel tank like on the Corsair, that doesn't make sense.

While you don't get the "one shot, instant fire" effect like on some planes, even one later .303 bullet will often start a fire. It's as if every bullet in the game is an Incendiary, API or APEX round.

The overall effect is that the Corsair's fuel system seems very vulnerable, almost as if it were a A6M2.

2) The engine is comparatively vulnerable.

While I haven't compared the Corsair's DM to that of the Hellcat, compared to the P-47D-10, which used virtually the same engine, the Corsair can stand far less damage before the engine conks out. Counting the bullets, I'd say that the same R-2800 engine mounted in a P-47 can take 50% to 100% more damage than if it was mounted in a Corsair.

Additionally, just about any hit to the engine seems to be a cylinder hit, when much of the volume of any radial engine was radiator fins. This might be realistic for .50 caliber and larger bullets, but for a .303 bullet, there's actually a good chance that you'll miss the cylinder.

This isn't a problem unique to the Corsair, but it's one of the ways in which .30/.303 bullets are overmodeled in the game.

3) While it's not exactly an engine-modeling flaw, the Corsair's forward fuselage - the area between the engine and the the fuel tank where the supercharger, etc. were seems to be very vulnerable to damage. Even a very few .303 bullets in the engine, none anywhere near this area of the plane, will trigger a "light damage" result.

This seems strange since contemporary U.S. reports hold that the Corsair was about as tough as the P-47.

4) The machine guns aren't well modeled. Hits to a MG which go right down the barrel don't disable the gun, but hits which arguably might have missed the gun receivers or ammo trays always cause a gun jam. This is a very typical DM problem, especially on the older planes.

5) The wing oil coolers aren't modeled. Bullets that go right into the oil cooler don't cause oil leaks.

6) There's no logic to pilot hits. On one mission I collected an arm wound when none of the bullets actually hit the pilot's arms. On another mission, I merely got a "pilot wounded" result from a bullet right between my pilot's eyes. Normally, that would be a straight "PK" result, or at the very least a "Serious Wound."

Maybe this is a systemic problem, but it seems especially bad on the Corsair I.

7) The armor glass seems to be undermodeled. While I can't say for sure, since I collected most of my "PK" results at relatively short ranges where a rifle caliber bullet might conceivably penetrate armor glass, out of the many QMB missions I flew, I'd estimate that about 15% resulted in PK results through the armor glass.

http://forum.1cpublishing.eu/attachm...1&d=1406108019

Bad DM for the machine guns. Notice a bullet that goes right down the barrel of one gun but doesn't result in a gun hit.

http://forum.1cpublishing.eu/attachm...1&d=1406108155

About those Ace gunners. . . Lots of hits on a fast-moving and maneuvering target at 400+ meters.

http://forum.1cpublishing.eu/attachm...1&d=1406108337

The forward fuselage is extremely vulnerable to damage, as is the engine. Strange considering that the Corsair was considered to be as rugged as the Hellcat and the P-47. Notice, there are more and bigger bullet holes in the light damage texture than there are actual bullets in the plane!

http://forum.1cpublishing.eu/attachm...1&d=1406108531

Just one .303 bullet in the fuel tank starts a gigantic, unstoppable fuel leak.

http://forum.1cpublishing.eu/attachm...1&d=1406108677

A direct hit to the oil cooler doesn't start an oil leak.

[Woke Up Dead]

You guys remember "the bar" in the 190? I think other cockpits may also be suffering from the bar, particularly the Yak 9. Someone on another forum posted a good video showing why the 190 bar should be reduced in game due to refraction of light through glass, it might apply to "bars" at the top of many gunsights and to armored glass in other planes as well; details in this thread: http://forum.1cpublishing.eu/showthr...972#post705972.

[Woke Up Dead]

A minor bug: I have edited my ffb files so that I don't get my Microsoft FFB joystick shaking when I squeeze the trigger. I still get a small "bump" when I release bombs or rockets from a fighter. Funny thing is, I then still get that bump when I squeeze the trigger for the machine guns or cannons. This does not happen if I don't add bombs or rockets to the loadout in the first place.

[Pursuivant]

Originally Posted by Woke Up Dead

You guys remember "the bar" in the 190? I think other cockpits may also be suffering from the bar, particularly the Yak 9.

I think you're right. Just about all the cockpit models in IL2 fail to take the refractive properties of armor glass into account. I didn't realize exactly what was going on myself until I saw the video.

Just about any cockpit with a thick bottom portion of the armor glass frame, or where armor glass is faired into the aircraft's fuselage, is going to have some degree of refraction which reduces the apparent size of the frame or fairing.

Realistically, though, this also means that any damage to the armor glass that destroys the refractive properties is also going to make the "bar" (i.e., fairing or frame) suddenly appear, as well as making any image seen through the armor glass appear is if it were reflected in a cracked mirror.

Also, the refractive properties of the glass will be obvious as a "step down" between the view in the armor glass and the view through the unarmored adjacent canopy areas.