Friday 2010-09-17 Dev. update and Discussions

Blackdog_kt · #1 09-20-2010, 09:43 PM

I think it depends on what people mean by "explosion". I've seen the guncam video on youtube where a 190 gets attacked and the drop tank is set ablaze. The thing is, it doesn't blow up violently enough to outright destroy the 190.

It sure ignites in a spectacular fashion and i don't know what kind of damage the aircraft sustained as a result, but it's clearly seen having its wings in place and continuing to fly.

In theory, a cannon shell hitting the tank under the right conditions would be able force the creation of a fuel-air mixture/spray that could be ingited by a second shell/tracer or even the residual heat from the first shot: the first shell bursts the tank and the shell's explosion sends fuel flying all around, which could then be ignited as it's now mixed with air.

However, let's also not forget that burning doesn't equal explosion. Many things that can cause explosions under certain circumstances fail to do so under others. In order for an explosion to happen, we also need to have the volatile contents under pressure. So, an empty tank full of vapors but sealed and under some kind of pressure is more probable to explode when hit. A tank that gets holed but doesn't explode on first hit might result in a fuel leak that gives a suitable fuel-air mixture to ignite by subsequent bullets but by that point the pressurization is gone, so the most probable outcome would be the fuel burning but not exploding.

It's just like gunpowder. When sealed in a shell casing and ignited, it's capable of propelling shells at speeds high enough to kill people and shoot down aircraft, but if you open the shell casing, empty the gunpowder on the floor and set it alight it just makes nice sparkles

Flying_Nutcase · #2 09-21-2010, 12:23 AM

Looking good Oleg!

Great shadows, the editor UI looks modern and slick, and the grass is awesome!

One question about the grass
Does the grass move in the wind? Sry if someone's asked already.

Cheers,

Flying Nutcase

WTE_Galway · #3 09-21-2010, 12:31 AM

Quote:

Originally Posted by Flying_Nutcase

Looking good Oleg!

Great shadows, the editor UI looks modern and slick, and the grass is awesome!

One question about the grass
Does the grass move in the wind? Sry if someone's asked already.

Cheers,

Flying Nutcase

Not if you mow it

julien673 · #4 09-21-2010, 01:24 AM

http://www.luft46.com/armament/mk108.html

From there .. here is the text,

Rheinmetall-Borsig MK 108 30mm cannon
In many ways, the Rheinmetall-Borsig MK 108 30mm cannon was considered to be a masterpiece of weapons engineering, due to it's compact size, ease of manufacture and hitting power. Although it was first designed by Rheinmetall-Borsig in 1940 as a private venture, the design was finalized in 1942. It met a later RLM requirement for a new aircraft cannon that could knock down enemy bombers with the lowest expenditure of ammunition and stay beyond the range of enemy defensive fire.
In short, the MK 108 was a blow-back operated, rear-seared, belt fed 30 mm cannon using electric ignition and was charged and triggered by simple compressed air. One drawback was that once installed, there was no method to adjust the gun's harmonization. One distinctive physical feature was the very short gun barrel, which gave the MK 108 a low muzzle velocity of 500-540 meters (1640-1770 feet) per second. The maximum rate of fire was 650 rounds per minute. The operating sequence for the MK 108 went like this:

An ammunition can fed the rounds to the gun by means of a disintegrating belt
Once the sear was released, the bolt went forward under the action of the two driving springs
A projection on the top of the bolt passed through the ring, thus extracting a round
This then forced the round into the chamber and fired the round while the heavy bolt was still moving forwards
The empty cartridge case reinserted itself in its link after firing
Ejection was achieved by means of pawls activated by camming grooves that were cut into the top of the bolt
Finally, the new round slipped into position and the sequence repeated
An interesting feature was that neither the barrel or receiver moved in recoil, the entire force of firing was absorbed by the rearward movement of the bolt against the driving springs, which buffered against the recoil. No locking mechanism was needed, because by the time the fired round had overcome the inertia of the firing bolt, the round had left the barrel and the pressure had dropped.
There were two main types of ammunition for the MK 108 to use, a 30 mm high-explosive self-destroying tracer ("M-Shell" or "Mine-Shell") and a 30 mm incendiary shell. The first type was designed to cause a maximum blast effect by combining a very thin shell casing with the maximum load of explosive. Tests carried out at Rechlin (where most of the Luftwaffe aircraft and weapons tests were done) showed that with a "M-Shell" with 85 grains of explosive, five hits could destroy a B-17 or B-24 bomber. The second type of shell, the incendiary, was meant to be targeted at the fuel tanks of the enemy plane. Since some penetrating force was still needed to overcome the armor or airframe of the target, and not have the shell break up or explode upon contact, a hydrodynamic fuse was fitted so that the shell only exploded once it came into contact with liquid.
Although there were drawbacks with the MK 108, such as an insufficient flat trajectory (the shell "arced" too much due to the low muzzle velocity) and that the ammunition belts sometimes ripped when the guns were fired while the aircraft was banking sharply, the MK 108 was chosen to be fitted in a wide variety of Luftwaffe aircraft (please see table below) before the war's end. It was also planned to be used in many of the project aircraft also (please see table below), for the reasons given above: ease of manufacture, compact size and weight and destructive power. The MK 108 30mm cannon earned a fearsome reputation among Allied bomber crews, who named it the "pneumatic hammer" due to its distinctive firing sound.

AndyJWest · #5 09-21-2010, 01:28 AM

Quote:

Although it was first designed by Rheinmetall-Borsig in 1940 as a private venture, the [MK 108 30mm cannon] design was finalized in 1942.

So nothing to do with SoW:BoB then?

BadAim · #6 09-21-2010, 05:11 PM

Since there has been a lot of discussion on fuel and explosions and fire, I thought I might point out a few facts about gasoline. Gasoline is not explosive. Gasoline vapor, however is. (This is not entirely correct either, as it does not technically "explode", but "burn explosively" , which when contained within a fuel tank, can hardly be distinguished from an explosion) It's not the fuel in the tank, but the vapor that is most dangerous. This is why the Russians pressurized their fuel tanks (on many planes) with exhaust gas from the engine, the exhaust gas displaced the gasoline vapor and rendered the fuel tank nearly inert. There was of course always the danger of leaks (which would be vaporized in the slip stream just like in a carburetor) catching fire, but this was nowhere near as dangerous or as likely as a vapor explosion.

So, that nearly empty drop tank is probably more dangerous than the full one you left with! Get rid of the damn thing.

I hope SOW has the finer points of these things built in

Edit: upon further reading I see Swiss commented on this as well. It is really not generally understood by most people though.

McHilt · #7 09-23-2010, 08:43 PM

Quote:

Originally Posted by julien673

http://www.luft46.com/armament/mk108.html

There were two main types of ammunition for the MK 108 to use, a 30 mm high-explosive self-destroying tracer ("M-Shell" or "Mine-Shell") and a 30 mm incendiary shell. The first type was designed to cause a maximum blast effect by combining a very thin shell casing with the maximum load of explosive. Tests carried out at Rechlin (where most of the Luftwaffe aircraft and weapons tests were done) showed that with a "M-Shell" with 85 grains of explosive, five hits could destroy a B-17 or B-24 bomber. The second type of shell, the incendiary, was meant to be targeted at the fuel tanks of the enemy plane. Since some penetrating force was still needed to overcome the armor or airframe of the target, and not have the shell break up or explode upon contact, a hydrodynamic fuse was fitted so that the shell only exploded once it came into contact with liquid.

You don't have to shout boy!,...

Almost another friday, thank God...