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Noxx0s
05-06-2010, 06:04 PM
Is it just my imagination or do the cannons on a Hurri or Tempest cause more damage per shot than the 20mm a 109 or 190 fires?

ROXunreal
05-06-2010, 06:06 PM
I noticed this too. Not saying it's true, but it feels that way. I mostly fly the 190 and when I get in a spit I'm amazed at how few cannon hits i need to down a plane.

TinyTim
05-06-2010, 06:40 PM
Firstly, one needs to keep in mind you are shooting at different targets with these two cannons usually, so it's not neccessary the cannon "power" but also the damage modelling of the targets that contributes to the difference.

Secondly, hispano should be more powerful - if we look only at the calibre - 20x110 vs 20x82.

Frankthetank36
05-06-2010, 07:59 PM
I always notice that I blow the wings off of stuff in the Spit. And then the cannons run out of ammo http://forums.ubi.com/images/smilies/59.gif

AndyJWest
05-06-2010, 08:21 PM
Compared to the 190, it may be partly down to the fact that the Spit has less ammo - you are less likely to shoot at extreme range/high deflection than you might in a 190. Arguably you should cause more damage with the limited ammo you have - the 190 can be a bit more adventurous. Kills per sortie is a better measure of a/c effectiveness than rounds per kill.

VW-IceFire
05-06-2010, 10:00 PM
The way I look at it is this. The German 20mm is a very efficient weapon which is reasonably weighted, has a very good muzzle velocity and fire rate and achieves this by firing a smaller shell with a very high explosive. The Hispano on the other hand is less refined but makes up for it with a very high muzzle velocity and a larger shell.

I get the feeling that the MG151/20 does less damage per shot but you can afford to fire more shots and the difference is negligible. These two are first and second place.

TX-Gunslinger
05-06-2010, 10:03 PM
- Minengescho▀ - Minengeschlos

Search for MG 151/20 or Mauser 151/20

Belted in sequence with Armor Piercing.. Something like 1 AP/2 MG...

Hispano - more kinetic energy, high velocity - flatter trajectory...

I always have to come back here every once in a while, to see new twists on old questions.

So glad to see so many are still going at it in the Il2 skies...

It's a satisfactory continium...

S!

Gunny

Jumoschwanz
05-06-2010, 10:08 PM
Having been shot down by all 20mm cannons in the sim, I would rate the Hispanos as most dangerous, the Russian cannons right on their heels, and the german mg151 and mgff third and fourth.

Which is cool that Oleg tried to make all the rounds different, just as they actually were all different.

You do not get hit by a Tempest, F4uC or Hurri-C and keep fighting, you are either crippled or already shot down.

Getting hit by a Yak or La-5 is no picnic either! You are lucky to be able to keep on fighting effectively after this happens.

On the other hand, a number of times I have hit allied aircraft well with german 20mm with minimum effect.

Of course this is just eight years of observation. The only real testing I ever did was at one time I measured the ranges of the 20mm cannons and in earlier patches the Hispanos had 300 meters more range than the german 20mm, but I think this has been changed in recent patches, I will check it again if I have time.....

JtD
05-06-2010, 10:18 PM
The Minengeschoss round the German 20mm cannons use is the most powerful 20mm round in game. However, not all rounds fired by the German cannons are Minengeschosse. Usually, every second or third are. Which, on average, puts the hitting power of the German guns at about on par with the Hispano cannons.

Kettenhunde
05-06-2010, 10:33 PM
http://img691.imageshack.us/img691/8727/ammobelting2.jpg (http://img691.imageshack.us/i/ammobelting2.jpg/)

LEBillfish
05-06-2010, 10:40 PM
http://www.quarry.nildram.co.uk/WW2guneffect.htm

K2

ibeagle
05-06-2010, 11:38 PM
According to the data in Il2 Wingman:

Hispano mk1: 600rpm @ 880m/s, shell weight 130g (HE), belting HET-AP-HE-AP

MG 151/20 : 700rpm @ 800m/s, shell weight 92g (HE), belting APIT-HE-HE-MG(Minengescho▀)-MG

Hispano would seem to deliver considerably more energy per round if this data is correct. Can't really figure weight of fire without more info, but based on HE rounds: Hispano 1300g/sec vs. MG151/20 1073g/sec.

DKoor
05-07-2010, 01:48 AM
In game when it gets to killing stuff A2A you can't beat Tempest in 20mm dept. FW-190 sure is great but the Hispano is a tad bit more powerful.

And it isn't our imagination, they really should hit more hard because they as ibeagle said above me they simply deliver more punch per sec. or per hit, however you like it.

Erkki_M
05-07-2010, 02:40 AM
Yep, the MG round in MG151/20 is the best 20mm cannon round. I find the MG151/20 actually better than the Hispano and ShVak(though not as easy to hit with), but then again, it might be just me.

I remember reading somewhere that the Brits didnt use explosive ammunition at all in the hispano cannon before something like early 1943 - anyone has info on this?

Kurfurst__
05-07-2010, 02:53 AM
Originally posted by ibeagle:
According to the data in Il2 Wingman:

Hispano mk1: 600rpm @ 880m/s, shell weight 130g (HE), belting HET-AP-HE-AP

MG 151/20 : 700rpm @ 800m/s, shell weight 92g (HE), belting APIT-HE-HE-MG(Minengescho▀)-MG

Hispano would seem to deliver considerably more energy per round if this data is correct. Can't really figure weight of fire without more info, but based on HE rounds: Hispano 1300g/sec vs. MG151/20 1073g/sec.

Only if you consider the kinetic energy of the round only (KE= 0.5 x mass x velocity x velocity), but thats somewhat arbitrary for explosive rounds since the rounds explodes and by doing so, it can't pass its KE to the airframe to do "useful work". Instead, practically all damage is done by the kintetic energy of the fragments and the expanding gases, which on the other hand are related only to the amount of explosive filler in the round.

The Hispano HEIT rounds are heavier, because they were of the ordinary thick walled shelled type (steel being much denser/heavuer than explosiver per volume), and contained much less filling than the thin-walled high capacity German Minengeschoss type. Ie. the explosive filler of the German 2cm round was 18,6 grams, the Hispano's iirc was about 5 grams, actually a 50-50% mixture of incendiary stuff and high explosive (ca 2.5 grams). So as far as HE shells go, the Mauser has far more destructive rounds in real life IMHO.

Of course there are other factors as well, like ballistics, which are better for the Hispano. IMHO the reason why the Hispano is good in the game because it delivers a good consistent performance, and it has good ballistics.

BillSwagger
05-07-2010, 03:18 AM
I'd say the early Hispano is a bit hefty all things considered. A while ago i mentioned they hit like 40mm, but it had more to do with the observation that the late war hispano, although faster firing, was not proportionately stronger than the earlier guns. Maybe faster firing doesn't really change the strength it just gives better odds that a burst will hit.
What i mean is that four wing mounted Mk V Hispanos should be twice as strong as a pair of Mk II hispanos. What that leads me to believe is that the earlier pair of hispanos is actually a bit strong.
A contrast would be the type 99 which historically speaking is suppose to be similar to the MG FF. Another interesting observation is that the Ho-5 of the late war Japanese types seems to be the lightest of the late war 20mm, and its effects seem to be more realistic, imo. I haven't sat down and tested these, just somethings i've noticed in the time i've played.
All are capable guns, and i think that most cannon armed planes in Il2 make for quick kills in a dogfight. Trying to compare them is somewhat splitting hairs. How do you compare two sets of guns that easily take a wing off in less than a half second burst?

It probably does have more do to with what you are shooting, and the ranges involved.


Bill

jermin122
05-07-2010, 03:41 AM
Originally posted by VW-IceFire:
The way I look at it is this. The German 20mm is a very efficient weapon which is reasonably weighted, has a very good muzzle velocity and fire rate and achieves this by firing a smaller shell with a very high explosive. The Hispano on the other hand is less refined but makes up for it with a very high muzzle velocity and a larger shell.

I get the feeling that the MG151/20 does less damage per shot but you can afford to fire more shots and the difference is negligible. These two are first and second place.

The MV of MG151/20 and Hispano, especially Hispano V, is actually almost the same. But the lead required for Hispano V on Tempest is MUCH samller than MG151/20 within 300 meters.

TinyTim
05-07-2010, 03:50 AM
Originally posted by Kurfurst__:
Only if you consider the kinetic energy of the round only (KE= 0.5 x mass x velocity x velocity), but thats somewhat arbitrary for explosive rounds since the rounds explodes and by doing so, it can't pass its KE to the airframe to do "useful work".

I'd have to disagree here. When a projectile explodes upon impact, it is not as if exploded while stationary (relative to the target). The fragments, besides the outwards component of speed, still move forward, in the general direction the shell was moving. They do retain the kinetic energy of the shell, only the additional velocity vector of explosion is added in the moment of explosion. Of course only a fraction (let say half) of the fragments hit the plane (the other half being blown away from the plane), but they do still carry the kinetic component of the shell (since, again, the shell does not stop before exploding). Now how much that energy actually is compared to the explosive one, is another story and I agree it might be small.

In other words - glue a shell to a target and shoot one at it with 1000m/s, and the second one will inflict more damage.

DKoor
05-07-2010, 04:36 AM
Originally posted by jermin122:
But the lead required for Hispano V on Tempest is MUCH samller than MG151/20 within 300 meters. Yes, that is correct, transition between them and .50cal isn't at all that great in a sense that they require quite small lead.

MG151/20 on the other hand requires enormous lead depending on gun conv., but still considerably more than Hispano.

ROXunreal
05-07-2010, 06:05 AM
Originally posted by Erkki_M:
Yep, the MG round in MG151/20 is the best 20mm cannon round. I find the MG151/20 actually better than the Hispano and ShVak(though not as easy to hit with), but then again, it might be just me.


Ugh, I find the ShVak by far the hardest 20mm to master.

JG53Frankyboy
05-07-2010, 09:22 AM
something ancient, postet from Oleg himself here years ago:

Here is the direct table of shells and bullets from source code of IL-2.
Comments:

power - here is the TNT, that also modelled (as well as pices of shells).

T - Tracer bullet
AP - Armor-Piercing bullet
APT - Armor-Piercing with Tracer
API - Armor-Piercing Incendary
APIT - Armor-Piercing Incendary Tracer
HE - High-Explosive shell
HEI - High-Explosive Incendary shell
HET - High-Explosive with Tracer
HEIT - High-Explosive Incendary Tracer
MG - M-Geschoss, thin-shell High Explosive

such line destinated the sequence of shells/bullets:
// APIT - AP - AP - APIT - API - API


Hispano-Suiza Mk.I
// HET - AP - HE - AP

HE/HET
mass = 0.129
speed = 860.0
power = 0.012

AP
mass = 0.124
speed = 860.0
power = 0


MG 151/20
// APIT - HE - HE - MG - MG
APIT
mass = 0.115
speed = 710.0
power = 0.0036

HE
mass = 0.115
speed = 705.0
power = 0.0044

MG
mass = 0.092
speed = 775.0
power = 0.0186


ShVAK
// APIT - HE

APIT
mass = 0.096
speed = 800.0
power = 0.001

HE
mass = 0.0676
speed = 800.0
power = 0.0068


MG/FF
// APIT - HE - HE - MG

APIT
mass = 0.115
speed = 580.0
power = 0.0036

HE
mass = 0.115
speed = 585.0
power = 0.0044

MG
mass = 0.092
speed = 690.0
power = 0.0186

LEBillfish
05-07-2010, 09:48 AM
Originally posted by TinyTim:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kurfurst__:
Only if you consider the kinetic energy of the round only (KE= 0.5 x mass x velocity x velocity), but thats somewhat arbitrary for explosive rounds since the rounds explodes and by doing so, it can't pass its KE to the airframe to do "useful work".

I'd have to disagree here. When a projectile explodes upon impact, it is not as if exploded while stationary (relative to the target). The fragments, besides the outwards component of speed, still move forward, in the general direction the shell was moving. They do retain the kinetic energy of the shell, only the additional velocity vector of explosion is added in the moment of explosion. Of course only a fraction (let say half) of the fragments hit the plane (the other half being blown away from the plane), but they do still carry the kinetic component of the shell (since, again, the shell does not stop before exploding). Now how much that energy actually is compared to the explosive one, is another story and I agree it might be small.

In other words - glue a shell to a target and shoot one at it with 1000m/s, and the second one will inflict more damage. </div></BLOCKQUOTE>


Though not really paying attention to the full discussion I will add this.......

The Japanese had terrible problems with their explosive rounds till roughly mid war in that the rounds did indeed explode on "impact".....The result was, the explosive force actually reduced damage. The reason being that explosion would drive back against the greatest mass of the round (the tail) and essentially neutralize or reduce the energy of the round toward the target. The best way to think of how it works is like reactive armor wherein the armor explodes toward the round, and as long as that energy is equal to or greater the round is then neutralized.

The ideal explosive round will go off "after" it penetrates the outer skin, therefor exploding in a confined space and all of the fragments and explosive energy working then for the round.

Easiest way to explain that is setting off a firecracker in your hand........If your palm is open, it may sting yet you'll be fine. Yet if you close your fist you might lose a few fingers. This is why we sometimes see with smaller rounds simply fragment holes when hitting a wide open area of a fuselage, yet massive holes in wings and tail sections....Tighter space results in a greater blowout.

K2

Kettenhunde
05-07-2010, 02:49 PM
With the exception of very early in the war, the German rounds were fused to go off after penetrating the skin of the aircraft.

IIRC, they came into service during the BoB or shortly thereafter.

BillSwagger
05-07-2010, 03:04 PM
Another way to look at it is to consider how much energy is transferred from a solid AP round vs the HE equivalent. It is the design of the HE round to explode and so there is less energy transfer from the impact.
I saw some numbers for the various Hispano MkII rounds:
AP penetrated 27mm of armor plating, while the HE round only penetrated 8mm. (200 yard range). At an angle of impact, there was no measurable amount of penetration, meaning the round bounced off and exploded.

You can see the trouble armor plating represents for HE rounds, which is why they used AP for hitting tanks and other ground targets. In fact, HE rounds were said to have less effective ranges for the simple reason that the energy required at longer ranges also had to insure the round would penetrate deep enough into the aircraft to cause damage. HE rounds having higher explosive content were also softer by nature, and would tend to buckle and ricochet at steeper angles of impact as oppose to their AP equivalents. If energy transfer was the same, then why not load your guns with 100 percent HE rounds?


Bill

Kettenhunde
05-07-2010, 03:52 PM
Bill,

Kinetic energy is about mass and velocity. The velocity of a solid explosive detonation wave is many times greater than the velocity of a bullet.

The formula is KE = 1/2 m * V^2.

Note velocity is squared.

1/2 * .01Kg * (550 m/s)^2 = 1512J

1/2 * .0001Kg * (10000 m/s)^2 = 5,000J

It takes a a very large slug to overcome the detonation velocity advantage of a solid explosive.

BillSwagger
05-07-2010, 05:21 PM
Agreed, crump, but the kinetic performance of the round is not the same as illustrated by penetration tests. I'm not talking about the expansion of gases caused when it detonates, thats a no brainer.

It also goes back to the intended use of the round.



Bill

JtD
05-08-2010, 12:45 AM
Bill, I suppose the 8mm of the HE round is not the rounds best AP capability, but rather the strength of the material even splinters could still get through. Bigger pieces, like the base or the fuse of the round can still do this, so I'd be surprised to learn that the whole round managed just 8mm. It's not that the Hispano round was filled up with HE to the rim, it contained only about 10g of explosives. Still possible, though.

Regarding the energy transfer, even when assuming your numbers were right, while an AP round might transfer more energy to a 25mm armor grade steel plate, the HE round will transfer more energy to 3mm aluminum sheets the aircraft is made of. Basically, it's one 20mm hole against dozens of the same size, and that's just the splinters.

Jumoschwanz
05-08-2010, 07:40 AM
Originally posted by LEBillfish:
http://www.quarry.nildram.co.uk/WW2guneffect.htm
K2

That is a great read. With such a great job done by the author, it makes most posturing and theorizing here moot huh?.........

BillSwagger
05-08-2010, 05:26 PM
Originally posted by JtD:
Bill, I suppose the 8mm of the HE round is not the rounds best AP capability, but rather the strength of the material even splinters could still get through. Bigger pieces, like the base or the fuse of the round can still do this, so I'd be surprised to learn that the whole round managed just 8mm. It's not that the Hispano round was filled up with HE to the rim, it contained only about 10g of explosives. Still possible, though.

Its only one test, and under the conditions presented i don't think there is much room for interpretation.
An AP round goes 27mm into armor plating.
A Ball round only went 12mm at the same range.
An He round got to 8mm, which includes the explosion. You ponder whether a splinter may have gone further, but consider for a moment that was the measured penetration of a splinter or fragment. The details are not given, but you could even say the round explodes at 4mm, and the effects of the round blast and fragmentation go another 4mm into the armor. That's too speculative to say, nor specified, but the result was that the HE rounds didn't penetrate armor beyond 8mm.
Given the numbers on the ball round, there is obviously a component of the AP round that gives it the ability to penetrate armor more effectively. I think you'll find the HE round has more in common with the Ball round, except its hollowed out for the explosive content.

I have to question if they ever considered combining the harder density material of the AP round and hollowing it out for use as an APHE round?

The other thing not included is the size of the hole. An AP round, in theory, makes a hole close to the width of the round, where the HE round may have blasted a considerably wider hole, however that's not what they were measuring.
In this light, its not all the surprising to me. HE rounds are considerably more dangerous to aircraft, and yet armor found on allied planes to protect the pilot was only a mere 8mm to 13mm. In order for a 20mm Hispano HE round to get through it would need to be shot at close range and at a near dead on angle.
Given the ballistics of the Hispano, these results are also likely to be above par when comparing the results to axis 20mm calibers.

When it comes to energy transfer, i think there is also a considerable difference in how HE rounds and AP rounds effect aircraft. HE rounds blow larger holes into aircraft, while AP rounds slam into framing, engine blocks, and other vitals. Both would cause trouble for the pilot(s)


Bill

Sherman8r
05-08-2010, 07:01 PM
APHE does exist, but not for aircraft weapons, called 'HEAT' or High Explosive Anti Tank. Completely different principle though, slow round relying completely on explosive force to get through armour. Quite complicated, but very interesting. Don't think it works on a round less then 75mm though...

JtD
05-08-2010, 11:16 PM
The way you put it now, it sound as if the 8mm really were what you said they were. I simply forgot to consider that they were using soft material for the HE shell.

In ships, they weren't. These rounds would go through a foot of high quality armor and still explode. Probably not really worth the effort for aircraft ammo.

Kurfurst__
05-09-2010, 02:47 AM
Originally posted by TinyTim:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kurfurst__:
Only if you consider the kinetic energy of the round only (KE= 0.5 x mass x velocity x velocity), but thats somewhat arbitrary for explosive rounds since the rounds explodes and by doing so, it can't pass its KE to the airframe to do "useful work".

I'd have to disagree here. When a projectile explodes upon impact, it is not as if exploded while stationary (relative to the target). The fragments, besides the outwards component of speed, still move forward, in the general direction the shell was moving. They do retain the kinetic energy of the shell, only the additional velocity vector of explosion is added in the moment of explosion. Of course only a fraction (let say half) of the fragments hit the plane (the other half being blown away from the plane), but they do still carry the kinetic component of the shell (since, again, the shell does not stop before exploding). Now how much that energy actually is compared to the explosive one, is another story and I agree it might be small.

In other words - glue a shell to a target and shoot one at it with 1000m/s, and the second one will inflict more damage. </div></BLOCKQUOTE>

I agree, and of course you are right about the shells veloctity vector (which, compared to a stationary gun, in many cases is increased further by the aircraft's own speed if we really want to go into details). OTOH I believe that KE is rather insignificant compared to CE at the point of impact. The shell itself is considerably slower at a typical 2-300 meters where it hits the target, having only about 50-70% of its muzzle velocity left (and thus about 1/4 to 1/3 the KE it had in the muzzle). Blast/chemical energy from the filler is constant at all ranges (with its maximum potential reduced somewhat by the energy required to break up the shell). Its difficult to assess accurately how much greater is the HE effect than the KE for an explosive shell (I have energy figures for various explosives, as one can imagine, they are enormously potent), but I think its safe to assess that its many times that of the KE energy of the said shell, considering that ultimately, all of the KE of the shell came from the chemical energy of the powder in the cartridge, usually a far less potent explosive source/force than the one found in the shell itself.

Another thing to consider though is that aircraft are made of light structure. The maximum destructive potential of a round is not always utilized, as this light structure is easy to defeat and if the AP round only passes through the skin, very little energy will passed to aircraft. Say if AP round has 50 000 Joule energy, and 3000 is required to punch the skin, then only 3000 Joule is the "useful" work, the rest of energy will remain with the round after it exited the aircraft. So in this case its pretty much the same whether it was a round with 3000 Joule of energy or one with 50 000 Joule that hit the aircraft..

Its a massively complex subject anyway, the damage done depending to a large extent what round hits and where (ie. AP going through the wing or HE hitting the pilots armor is pretty ineffective)

JtD
05-09-2010, 10:05 AM
Kinetic energy aside, the mass of the projectile is fairly relevant too, if you rely on splinters for damage. The heavier the shell, the more, or bigger, or better penetrating splinters you get. In that regard I think it's a pretty smart idea to use m*v (momentum) instead of the commonly used m*v▓ (kinetic energy) as a more accurate description of the destructiveness of a projectile for the mechanical part.

Kettenhunde
05-09-2010, 10:30 AM
KE is rather insignificant compared to CE at the point of impact.

You are absolutely correct in your thinking. Just so folks do not get the wrong idea of what is going on lets define those terms.

Chemical energy is a potential source of energy. It does not interact with anything until it is converted to kinetic energy.

Momentum is a vector quantity. It is useful for analysis along that vector.

It's useful for comparing the path of a single projectile but if one considers other vectors of force produced by the conversion of CE to KE it does not present a true picture of the damage potential.

It is only going to show the force for that one vector.

Choctaw111
05-09-2010, 11:54 AM
The Hispano should do more damage.
The case is bigger for higher velocity, and the projectile is slightly larger also.
Unless the 151/20 was filled with a more potent explosive, the Hispano will have more power, both kinetic and chemical.
Here is a photo (not the one I was looking for) that shows the 151/20 and Hispano next to each other.
http://img.photobucket.com/albums/v343/PublicPhotoAccount2/il2/WoodenBullets2.jpg

JuHa-
05-09-2010, 12:35 PM
Assuming Wikipedia got it right:
http://en.wikipedia.org/wiki/MG_151_cannon

Minengeschosspatrone 151: 18.6 g HE (nitropenta)

The equivalent TNT:
http://www.economy-point.org/t/tnt-equivalent.html

PETN/Nitropenta 1,7

So HE 20x82 had an equilent of 31.6g TNT as payload.

Hispano round had a payload up to 11g
http://en.wikipedia.org/wiki/Hispano-Suiza_HS.404

So if the sources found by google are correct, the 20x110 had smaller payload - but I didn't find the type of the filler. Maybe somebody else is kind enough to provide that bit of information.

And anyways, the good old A. Williams rated the HispanoII and Mg151/20 to be pretty equal for damage, when using typical belting.
http://www.quarry.nildram.co.uk/WW2guneffect.htm

Bremspropeller
05-09-2010, 02:04 PM
Unless the 151/20 was filled with a more potent explosive


...

Case closed.

bracknell1989
05-09-2010, 02:37 PM
Personally I find the 151/20 the easiest in to use given the choice of that or the Hispano.

This could of course be down the the location of the weapons on the aircraft.