|
|
#671
09-18-2014, 10:54 PM
|
|||
|
|||
Quote:
So, there are plenty of cases where I've seen "arcade arrows" skewer my pilot with no ill effects because armor glass and armor are doing their job at stopping the actual bullet. Likewise, there are plenty of screenshots I've taken where the damage subsequently makes absolute sense, such as when a bullet goes right down the barrel of a gun and IL2 records it as a gun hit. Where it's appropriate, I call out good DM work as well as bad. Quote:
Here's the problem with IL2 and engine hits. First, there doesn't seem to be any consistency as to how damage to a particular engine is modeled. For example, damage to a Wright-Cyclone R-1820 engine mounted on a C-47 might make it behave differently than the same damage to the same engine mounted on a P-36, SBD, FM-2 or B-239. My guess is that the creators of the B-239 DM assumed that the R-1820 wasn't a durable engine, since the Finns reported trouble with oil leaks and other problems with the used engines supplied with their planes. Since the engine didn't change for the F2A or Buffalo Mk I, whoever did the DM for those models just used the engine DM for the B-239. The problem is that there's plenty of evidence that, apart from overheating problems, the R-1820 was a very good engine. Second, many DM seem to just model the engine as a homogenous block, and fail to distinguish between empty space between cylinders in a radial engine, hits to the crankcase (potentially quite devastating), hits to cylinder cooling vanes (trivial damage) and hits to cylinders (damaging, but not immediately lethal). While realistic engine damage models are probably beyond IL2's limits, the model could be tweaked a bit so that bullets that don't actually hit the engine don't damage it, and so that bullets which hit near the same place on the engine don't do any extra damage. After all, you can only destroy the same cylinder once! Third, the bullets that are consistently killing the Wright Cyclone R-1820 engine on the Buffalo series are 0.30 caliber bullets being fired from anywhere from 50-300 meters distance, and they cause near instant engine-stoppage or serious power loss, regardless of where they hit. We're talking about bullets that make small holes and which might not have much power on them when they hit. The problem with fuel tank hits in IL2 is that I don't think that the DM takes into account fire suppression measures, all bullets are treated as being incendiary, and self-sealing tanks aren't always well modeled. (There are a few planes where the self-sealing tanks actually work, though.) Realistically, perhaps 1 in 5 or 10 bullets is going to be tracer, incendiary, explosive, API, or similar. The bulk of the bullets are going going to be plain ball ammo. That means that you basically only have a 1 in 5 or 1 in 10 chance of getting a hit with a bullet that has a chance to start a fire. Next, the first bullet to go through a container of gasoline isn't likely to start a fire, since it's going through liquid (or possibly through a blanket of cold exhaust gasses protecting the empty space in the tank). That bullet is likely to create a spray of gasoline vapor, which might ignite if the bullet is explosive or incendiary, but a ball bullet on its own is just going to set things up for a subsequent bullet (or a spark, or heat from an engine) to start a fire. Multiple ball bullet hits are most likely to further shred the fuel tank and splash the fuel around, rather than starting fires. Third, fires start instantly and automatically appear at full size. In most cases, this is just cosmetic since IL2 does a really bad job of modeling fire damage to airframes, but fire size makes a difference when determining damage to the pilot and risk of explosion. Realistically, what might happen is that a bullet hit to a fuel tank splashes fuel around and creates pools of uncontained gasoline that get vaporized by contact with the wind blowing through the bullet holes in the airframe. A second bullet with explosive or incendiary qualities hits and ignites the vapor. The fire spreads more or less quickly to involve all the vapor (possibly creating an explosion if there's a lot of oxygenated vapor in a small place), then starts volatilizing and burning the remaining liquid. Fuel in the tank won't have that much oxygen to burn it, but spilled fuel is likely to burn quickly. So, you'll get small fire to start with (sometimes well modeled by black smoke in the game) that burns the spilled fuel, followed by a big "fully involved" fire that starts to volatilize fuel stored in the tank. Quote:
But, the hole made by a 0.50 caliber bullet in aluminum is going to be the thickness of a man's thumb. Exit holes are perhaps going to be a bit bigger, as might holes made if the bullet enters at an oblique angle or tumbles after impact (although bullet tumbling or fragmentation is unusual for the 0.50 BMG round). Like you said, that's going to cause drag. My point, however, is that 8-9 bullets shouldn't be enough to cause much more than drag, like making the airframe fail under stress. Since damage modeling is an art, it seems to me that IL2's developers have made planes that were notably vulnerable in combat for any reason excessively vulnerable to any sort of damage. That means that planes like the TBD and D3A1, which were mostly vulnerable because they were slow and didn't have good armor and fuel protection, are potentially too vulnerable to airframe damage. Last edited by Pursuivant; 09-19-2014 at 05:50 PM. 
|
|
#672
09-19-2014, 06:01 PM
|
|||
|
|||
|
Further information about fuel tank fires. Ball bullets not causing fires in fuel tanks isn't just my opinion: Small caliber bullets vs. gas tank: http://www.discovery.com/tv-shows/my...g-gas-tank.htm 0.50 caliber sniper rifle at 20 yards vs. unarmored car fuel tank: http://www.discovery.com/tv-shows/ot...w-up-a-car.htm The latter clip pretty much proves my point about how hard it really is to start a fuel tank fire using just ball bullets. Massive bullet at close range against a small unsealed fuel tank, which splashes lots of fuel around and pretty well makes the fuel tank useless. Even so, the shooter has to wait 10 minutes for the gas to properly volatilize to ignition point and then his second shot with a ball round fails to ignite the fuel! If you look at the video, the firemen give a very good explanation as to why bullets aren't likely to start gasoline fires. To take things to further extremes, this video shows a 0.50 BMG sniper rifle at perhaps 50 yards firing a Raufoss (NATO general purpose Incendiary explosive round) against a PROPANE TANK with no result other than puncturing the tank. |
|
#673
09-19-2014, 06:51 PM
|
|||
|
|||
|
Harping further on damage model flaws to fuel tanks. I was finally able to get information about how self-sealing fuel tanks worked in WW2. Basically, they were multiple layers of rubber and/or leather, that self-sealed by allowing raw rubber to flow into the hole to seal it. Also, they were all soft-sided so that they wouldn't rupture as a bullet passed through them. Patent application for one form of self-sealing fuel tank here: http://www.google.com/patents/US2401627.pdf Contemporary article on the Ju-88 which explains the self-sealing fuel tanks in detail: http://www.flightglobal.com/pdfarchi...0-%203429.html http://www.flightglobal.com/pdfarchi...0-%203430.html Note that the Ju-88 was equipped with fuel dumping capability for its fuselage tank, although the fuel tanks don't appear to have been blanketed with engine gasses as a fire-protection measure. Advertisement for self-sealing fuel and oil-tanks, which claims that they will not ignite even when hit by tracer, incendiary or ball ammo. http://www.flightglobal.com/pdfarchi...0-%202064.html This video is extremely helpful: |
|
#674
09-19-2014, 08:25 PM
|
|||
|
|||
|
|
|
#675
09-22-2014, 01:34 AM
|
|||
|
|||
|
This is not relavent to the discussion, but which C-47 had Wright R-1820? I only know of P&W R-1830. Both reliable, but very different.
|
|
#676
09-22-2014, 08:00 AM
|
|||
|
|||
|
Quote:
My point still holds, though, that the amount of damage an engine can absorb should be independent of the plane it's mounted in. While the worst offender in the game is probably the Alison V-1710 (immortal in the P-39, P-400 and P-63, made of thin glass when mounted in the P-40), there are other engines, like the R-1820, which vary widely in their ability to absorb damage in the game. Mind you, I'm only talking about the engine and its ability to absorb damage before losing power or stopping. Oil and coolant installations are a different story entirely, so time until overheat can vary, as can amount of damage to oil and coolant systems required to make the engine overheat and shut down.
|
|
#677
09-22-2014, 11:46 PM
|
|||
|
|||
|
Somewhere in this thread (I can't find your exact quote now), you say that you suspect that engines are modeled as one big block. There are threads a year or two old here that deal with damage modeling, they show that damage models are more sophisticated than you believe them to be, there are inf fact several small components modeled in each engine. I think there are only two or three planes in game (P-39 being one of them) that have a simple, old damage model like you describe. So if your Buffalo's engine loses power after only 2-5 bullets, that means one of those bullets hit an important component.
You also say that the engine on a Buffalo seems to damage differently than the same one on a C-47. Are you taking shots to the engines from the same angle for both planes? I.e., are you chasing a Wellington or Val with the C-47 to take hits from the front? "The bullets that are consistently killing the Wright Cyclone R-1820 engine on the Buffalo series are 0.30 caliber bullets being fired from anywhere from 50-300 meters distance, and they cause near instant engine-stoppage or serious power loss, regardless of where they hit. We're talking about bullets that make small holes and which might not have much power on them when they hit." Don't rifle-caliber bullets have plenty of energy even after traveling 300m, never-mind just 50m? "all bullets are treated as being incendiary" Sorry, you're simply wrong here, check the fourth post of this thread: http://forum.1cpublishing.eu/showthr...hlight=belting "Since damage modeling is an art, it seems to me that IL2's developers have made planes that were notably vulnerable in combat for any reason excessively vulnerable to any sort of damage." No, just look at the Zero. Famously fragile, and in-game the early-war Zeros are particularly easy to set on fire, but have you ever had a damaged or stopped engine in a Zero? Fragile fuel tanks in wing-roots, but super-tough engines.
|
|
#678
09-23-2014, 04:53 AM
|
|||||
|
|||||
|
Quote:
Quote:
Flyable planes in the game with versions of this engine are the Buffalo series, the SBD, and the CW-21. I will try to fly them all to see if it's a problem with how the engine is modeled, or how the engine is modeled in the Buffalo series. The P-36 also used this engine but it's not flyable. My procedure is to get up a QMB flight in arcade mode using Ace Wellington III (or TBD-1 for the slower planes), then deliberately use stupid tactics by overtaking them from 6 o'clock level without maneuvering much. It's a good way to get a nose full of lead and test engine and front armor DM. Arcade mode lets me see exactly where the bullets hit. I then compare odd results against a 3-view drawing to see if they actually make sense. Quote:
It's very realistic for a .30 bullet to punch into an aluminum engine block or go through 20 mm of armor glass at 50 meters or less. But, at 300 meters, armor glass should easily be able to defeat most .30 caliber rounds, and there's even a chance that a bullet might be stopped or deflected by an engine block. Early war planes with armor plate were specifically armored to be protected against .30 caliber bullets fired at even close combat ranges, so at anything other than point-blank range, armor plate should stop them. "all bullets are treated as being incendiary" Quote:
First, you'll notice that there is no ball ammo in the mix for any of the guns listed. It isn't even modeled! That's highly unrealistic, since supply shortages or deliberate loadout choices might have meant that ball ammo was used. Second, you'll notice a very high percentage of bullets that can start fires - HE, API, Tracer, APIT, Minengeschoss, etc. They're not all incendiary, but they might as well be! In some beltings, there's a 5/6 chance that a particular bullet is a potential fire starter! Third, you'll notice that many beltings have a very high ratio of tracer bullets, sometimes as low as 1:3! 1:5 or even 1:10 was more typical. "Since damage modeling is an art, it seems to me that IL2's developers have made planes that were notably vulnerable in combat for any reason excessively vulnerable to any sort of damage." Quote:
I'd also suggest that the A6M2 is another exception that proves the rule. It's very flammable - perhaps too flammable - and falls apart nicely if it's hit by a few cannon shells or a solid burst of 0.50/12.7 mm MG fire. Seemingly realistic. But, since the A6M2 was a wonderful, well-liked airplane, and early war Sakae 21 engines were very good, arguably the designers went the other way and made the engine "too tough" (or "just right" depending on how you look at it). After all, in terms of power, mass, compression ratio and power to mass ratio what makes the Sakae 21 so much better than contemporary radial engines like the R-1820 or Bristol Hercules? Last edited by Pursuivant; 09-23-2014 at 05:24 AM.
|
|
#679
09-23-2014, 05:20 AM
|
|||
|
|||
|
A couple of quick missions using the H.75-4, testing the P&W R-1830 Twin Wasp engine.
There isn't the same problem with massive loss of power like in the Buffalo, but the bad engine damage model here is that even a very few .30 caliber bullets in the engine at 100-200 meters are sufficient to trigger a massive fuel leak (i.e., one that triggers the RTB result when the autopilot is on). Comparing these hits to a 3-view drawing of the H.75, I can see nothing which could realistically cause a massive fuel leak. After all, even if the bullets hit the fuel intake to a particular cylinder, or punch a hole in the cylinder itself, there's not much more loss of fuel than that cylinder would consume normally. 3-View here: http://www.histaviation.com/Hawk_75_...g_1424x926.jpg 2 .30 caliber bullets in the engine from about 100-200 meters away. Notice giant fuel leak and "RTB" message from AI http://forum.1cpublishing.eu/attachm...1&d=1411449277 Same hits, but a different angle. Notice that there's no way that the bullets in the engine could have hit the fuel tank. Different mission, same result: http://forum.1cpublishing.eu/attachm...1&d=1411449337 Different view of the same hit: http://forum.1cpublishing.eu/attachm...1&d=1411449337
|
|
#680
09-23-2014, 04:46 PM
|
||||
|
||||
|
The Hawk 75-4 used the Wright Cyclone R 1820 single row engine, not the P&W Wasp R-1830 twin row engine.
Better do your research before posting any more of your subjective "findings".
__________________
 Personally speaking, the P-40 could contend on an equal footing with all the types of Messerschmitts, almost to the end of 1943. ~Nikolay Gerasimovitch Golodnikov
|
 |
|
|
Linear Mode
