Effectiveness of German 70kg SD Bombs

[StG77_Roo5ter 79]

Let's start with I don't have all the answers here which is why I am opening up this topic.

 

I would guess that the SD munitions are a specialized munition probably for penetrating armor but I'm sure someone else can fill me in with some more details and maybe a quality link.

 

Here is a 16 second video of a bombing run I did on a light tank - https://www.youtube.com/watch?v=nwfL2RsajcY&feature=youtu.be

 

The tank was previously damaged by a 500kg dive bomb.  This 70kg was damn close and it seems to be bombs in general should be doing a little bit more damage to armor in this game.

 

 

Agree or disagree, let's hear it and any historical documents would be highly appreciated.

 

 

[6./ZG26_Emil 998]

SD is a semi armour piercing bomb so I imagine you need a direct hit.

 

Edit: Also 70KG isnt much for a tank. Having said that I noticed the 250 and bigger need to be very close to destroy a tank as well.

 

Is this realistic? I don't know but I think killing a tank with a small bomb is probably quite hard in real life

Edited April 5, 2015 by 6./JG5_Emil

[III./ZG1_HeTzeR 52]

SD ( D for Dickwanding=thicker bombcase) is fragmentation, so use it against light targets. SC has more explosives and is better against hard targets. The SD usually has only 30% Explosives SC usually 50-60%)

Edited April 5, 2015 by I./JG21-HeTzeR

[-=PHX=-Satch 212]

here's a interesting link

http://www.warbirdsresourcegroup.org/LRG/sd70.htm

[6./ZG26_Emil 998]

On the subject of bombs I really hope we get PTAB type bombs when we get later maps/aircraft 

[ShamrockOneFive 2398]

From what I've read... taking out a tank with rockets or bombs is REALLY hard. Disabling is a bit easier but actual total destruction is difficult and this seems to be simulated well.

 

Emil is right that the PTABs would be great and from what I've read about IL-2 anti-tank operations they were found to be, by far, the most effective weapon employed by IL-2s against tanks. The rockets, bombs, and 23mm cannon fire were great at attacking lighter targets and generally causing havoc but to actually eliminate a tank completely you still need a direct hit.

 

I've read varying reports on the 37mm AP weapons that the IL-2s used... it seems that they were excellent when they worked and terrible when they jammed or one jammed and the other threw the planes nose off the target.

[TX-Gunslinger 36]

One might think that the shrapnel damage alone should have stopped the engine.  It's a light tank - very thin armor forward, almost non-existent in the rear.  The weapon actuated

 

Perhaps the current damage model works off blast effects and doesn't handle shrapnel.  I don't know.  Maybe the little tank was lucky

 

It would be nice to see a direct side-on of the tank and bomb explosion to get a more detailed sense of the distance between the light tank and the explosion.  Is it within 1 tank length?  1.5?  2 even?

[6./ZG26_Emil 998]

35mm of armour at the rear....would a small Fragmenting bomb penetrate that?

[StG77_Roo5ter 79]

One might think that the shrapnel damage alone should have stopped the engine.  It's a light tank - very thin armor forward, almost non-existent in the rear.  The weapon actuated

 

Well, here it is classified as semi-armor piercing and that was a light tank at very close range - http://www.warbirdsresourcegroup.org/LRG/bombs.html

 

Seems reasonable to have rear penetration unless there is a shrapnel model that is in use and a piece of shrapnel didn't go in that direction by some dumb luck of the tank

[6./ZG26_Emil 998]

This is an interesting site, it doesn't show bomb damage but it's interesting to see what damage can be resisted and from what range

 

http://www.wwiiequipment.com/pencalc/

[Descolada 26]

i know the germans did some test data at some point with animals inside of a tank, iirc bombs usually left the tank basically fine and killed the crew inside when they were actually effective

[csThor 691]

Fragmentation bombs such as this SD-70 usually had more effect in disabling the vehicle - by damaging the running gear or breaking the track.

[Kongo-Otto 12]

35mm of armour at the rear....would a small Fragmenting bomb penetrate that?

 

No, it wouldn't, but it would cause considerable damage to the tank.

A SD 70 can be compared with a 155mm artillery shell, its shrapnels can damage a tank beyond repair, even when hitting the tanks perimeter in a 30 to 50 meter circle.

The blast wave also would cause lot of damage and most likely injuring some of the crew.

APC's and IFV's, would be almost completely destroyed by a 155mm artillery shell or a SD 70, even by a near hit, just look at the damage larger IED's do to them.

[Wulf 512]

Yeah, it's a tricky subject.  The SD 70 is a pretty small bomb by the standards of the day but hardly a toy.  I tend to agree, if one exploded just a few meters from the rear of an AFV I'd expect the blast would probably do serious damage to the vehicle and in all probability incapacitate the crew.    

[[TWB]80hd-LW 553]

Being as that the SD series of bombs are more heavily weighted to fragmentation (anti-personnel/structure), assuming that those fragments (and their velocity, not to mention some kind of RNG to determine size/mass per fragment) are modeled, burying one in the ground (it WAS a great drop, btw) would almost definitely require the tank to be directly over it when it detonated in order to have any appreciable effect.

 

Now, again, this is more relating to the physics of the speed and trajectory of the drop, the assumed depth and angle that the munition came to rest,  as well as the overall mass and composition of the bomb itself than exactly how the in-game damage model works (because all I know about that, in regard to bombs, is the chart that came out last year I believe).

 

The reason I say this is to illustrate that divergence in the conversation, as stepping through the scenario (and video), my personal opinion is that while the detonation was indeed close, and would have most likely scared the hell out of the crew, I do not believe this exact drop in the real world would have significantly damaged the tank either.

 

If you watch the video again, observe how the bomb itself impacts.  For argument's sake, if the camera is facing 360, then the T-34 is heading say ~130 or so, and the SD 70 impacts with its nose heading say ~160, which puts its tail at ~330 (again, rough estimates).  This is important because with the delayed fuse, the velocity/mass of the munition is going to cause it to embed in the earth to one degree or another.  Now, we cannot descend into the minutiae without also knowing how deep/packed the snow is, not to mention how hard the ground is right there.

 

Let's assume, for arguments sake, that the bomb has embedded half-the length of its body or ~9 inches. (This allows for a T-34's 16 in ground clearance to cleanly pass over as well, which would be the assumption in-game or out at this point).

 

Now, the impact disposition is important because the path of least resistance being what it is, a sub-surface burst is going to cause a conical blast/fragmentation pattern relational to that. 

 

           [ ]---

(*)    [ooo]

   \   

 

Now, assuming the board doesn't wargarbl my masterpiece ASCII drawing above, the way I would expect the majority of the blast to be directed is as shown above... blasting back and away from the tank, toward the orientation of the tail assembly of the ordnance. 

 

Tank passes over, gains a bit of separation, and the detonation directs most of the blast/fragmentation away from the tank.

 

One final point: I do not believe that the fact that I have absolutely no clue as to what I am talking about should factor into this discussion.

 

THIS, however, does merit a bit of a look as it is pretty interesting: http://www.lonesentry.com/articles/ttt07/70-kilogram.html

Edited April 6, 2015 by [TWB]80hd

[[TWB]80hd-LW 553]

To late to edit: but looking more closely at the tank, is that a T-70?  Turret looks offset....  anyway, I don't think a fragmentation bomb of that size would penetrate a T-70 either... directly underneath, sure.

[DD_Arthur 1564]

 

One final point: I do not believe that the fact that I have absolutely no clue as to what I am talking about should factor into this discussion.

 

 

 

Lol and S!  I enjoyed reading it .    You do make some good points about the number of "chance" factors involved in k'splosions.  Interestingly, at Stalingrad during the time period covered in game, the ground was frozen solid.  After the freeze the number of casualties from mortar and artillery shrapnel increased for both sides as the rounds detonated at surface level - when they didn't bounce - rather than buried themselves in the soil. 

 

I think Congo-Otto has it mostly correct.  I also think the effects of air-dropped weapons are a little under modelled in BoS at the moment.  No biggie but could do with some tweaking?

 

[Dakpilot 1902]

There was a table published by Devs

 

http://forum.il2sturmovik.com/topic/11758-fyi-bomb-blast-radius/?hl=%2Bexplosion+%2Bradius

 

Maybe it will be updated to more reflect the expanded loadouts/vehicles and different types of bombs in time, and yes that does look like a T-70 light tank

 

Cheers Dakpiot

[StG77_Roo5ter 79]

Many bombs were shattering instead of exploding on impact, the ground was literally harder than the bombs at this point.  You could say I am lucky the bomb went off but I dont think anyone wants the game to be THAT real.

 

There would be no subsurface explosion.  There are two ways to avoid the impact of an explosion - speed and armor.  The tank was slow moving so lets ignore speed as it wouldnt have spread out the impact.

 

The rear of the tank is angled to where it would have taken a rear explosion from the ground perpendicularly.

 

 

Sure it could be luck of the draw with shrapnel but I dont think that is modeled in the game.   

 

The angle of the blast probably doesnt matter in gamewhen hitting the tank simply because its not THAT important for an explosion in a game like this, what is more important is how the 37mm reacts to angles.  I dont see the developers putting time into armor deflection of blasts when there is a lot more going on in the air.  I do think that armor is a bit overly resistant to damage.  I would say this should have been a mobility kill probably to the tracks but considering the game focuses on the air war simply a smoking engine would have been reasonable in my opinion.

 

As an oddity I dropped 2 70kg SD as a pair and one was in front of a KV1 and the other behind and it was a catastrophic kill.  There could just be a hidden healthbar to tanks and a bomb in the vicinity does so much damage to the tank.

 

Truth be told there are a lot of complexities here and a lot of it would not be time efficient I think for the developers to work on but I would suggest a slight increase of bombs effectiveness vs heavy armor and a bit more vs light armor.

 

If shrapnel is slated to be modeled in the next 3-4 months (or it already is and Im just unlucky) it would be time deficient to even worry about the 70kg blast radius.  Once again I want to note this isnt a b@#%@ thread that the tank I bombed didn't get destroyed in a QMB simply a discussion of whats going on in the game.  If anyone can prove shrapnel is modeled in the game that would be amazing.

[[TWB]80hd-LW 553]

Lol and S!  I enjoyed reading it .    You do make some good points about the number of "chance" factors involved in k'splosions.  Interestingly, at Stalingrad during the time period covered in game, the ground was frozen solid.  After the freeze the number of casualties from mortar and artillery shrapnel increased for both sides as the rounds detonated at surface level - when they didn't bounce - rather than buried themselves in the soil. 

 

I think Congo-Otto has it mostly correct.  I also think the effects of air-dropped weapons are a little under modelled in BoS at the moment.  No biggie but could do with some tweaking?

 

 

 

Strictly speaking, from an "in-Sim" standpoint, I would agree that an SD-70, placed that close to an already damage light tank, should have been a kill.

 

That SC 500... man... they should at least stop and get their bearings a bit hahahaha... NOT ONE STEP BACK, COMRADES! PRESS ON!

[StG77_Roo5ter 79]

 

That SC 500... man... they should at least stop and get their bearings a bit hahahaha... NOT ONE STEP BACK, COMRADES! PRESS ON!

 

DAT LITTLE GUY? DONT WORRY ABOUT HIM!

 

500kg on T34 - no disable well within blast radius.

 

https://youtu.be/JF9RMT9HhNY

Edited April 7, 2015 by Roo5ter

[AeroAce 830]

On the subject of bombs I really hope we get PTAB type bombs when we get later maps/aircraft 

 

This but I believe didnt come out until around the Kursk time line so around 43, as Moscow is before Stalingrad this makes it going in the other dirrection im affraid

[[TWB]80hd-LW 553]

DAT LITTLE GUY? DONT WORRY ABOUT HIM!

 

500kg on T34 - no disable well within blast radius.

 

https://youtu.be/JF9RMT9HhNY

 

Aye dios mio...

 

(related: did that Stuka prop-strike on pull-out? hahaha)

[6./ZG26_Emil 998]

This but I believe didnt come out until around the Kursk time line so around 43, as Moscow is before Stalingrad this makes it going in the other dirrection im affraid

 

Yeh I know...but after Moscow maybe :D

 

They were totally epic in IL2 I used to love watching them explode.

[StG77_Roo5ter 79]

Aye dios mio...

 

(related: did that Stuka prop-strike on pull-out? hahaha)

Nope!

 

I've been working on my SHTUKAZ SHKILLZ when the Eagle's Nest is quiet and due to the incredible accuracy required to destroy a tank (as shown by the last link) I have found it far more effective to pull out at the last second than to do what any sane (or historic) person would have done.  The bomb really needs to be placed onto the tank to ensure destruction unless you move up to 1000kg or larger.

 

There have definitely been a 'few' incidents where my wheels and wingtips have touch the ground at the same time during my egress out of the attack dive.....

Edited April 7, 2015 by Roo5ter

[[TWB]80hd-LW 553]

You having the same problems killing German tanks with Soviet bombs? Because I was dropping FAB-100s on PzIVs, and once I increased my dive angle I had far fewer problems... and I am not accurate bombing in IL-2.

 

Once I get my throttle fixed I will check it out too.

[StG77_Roo5ter 79]

I actually have not had the same problem with the FAB 100s, it seems fairly easy to disable or kill.

 

To follow up on kissing the ground, I have found it may not matter as much as previously mentioned, she flies just fine with a little 'gravity' modifications done to the gull wing!

 

 

[6./ZG26_Emil 998]

I haven't flow the German bombers but noticed it with the IL2 bombs. 

[Venturi 392]

A 70kg bomb, that's probably 30kg of HE.

 

Let's put it this way. If you actually manage to drop it directly on the tank, it will likely smash the deck armor and disable the tank. Perhaps kill a few of the crew or brew it up. Depending on the tank. But in general, top armor was thin on most tanks.

 

However, should you miss by even a few meters, that 30kg of HE might have, at best, blown a track off. Rear, side, and especially front armor on most tanks was much thicker than the deck. Most likely, missing by anything more than a meter or two would do nothing.

 

Energy from a source like a bomb is spread in a spherical manner. That means that as distance from the point of explosion increases, the energy per unit area delivered decreases by the square of that distance.

 

Or, E(delivered)= E * 1/d^2. This is also known as the inverse square law.

 

See attachment for visual (light operates the same way).

 

Now consider that tanks routinely took DIRECT HITS by large caliber artillery pieces firing HE shells over open sights and were able to remain combat effective. For that reason, gunners targeted tracks and running gear to immobilize the tank (and infantry could mop up, later - Brad Pitt notwithstanding).

 

The conclusion is obvious. As much as I love the Stuka, 70kg bombs should not be blowing up tanks short of a direct hit on the tank deck.

 

250kg bombs are a lot larger, and while direct destruction of the tank was still unlikely sans a direct or directly adjacent bomb strike, for game purposes it's close enough.

 

See attachment for visual of 45 ton, or 45000kg Panther blown over by a near miss 500lb HE bomb strike in Normandy (approx 225kg).

 

A better solution for all would be to allow historical bomb loads for the He-111.

Edited April 8, 2015 by Venturi

[6./ZG26_Emil 998]

21 KG of explosive I think

[StG77_Roo5ter 79]

A 70kg bomb, that's probably 30kg of HE.

 

Let's put it this way. If you actually manage to drop it directly on the tank, it will likely smash the deck armor and disable the tank. Perhaps kill a few of the crew or brew it up. Depending on the tank. But in general, top armor was thin on most tanks.

 

However, should you miss by even a few meters, that 30kg of HE might have, at best, blown a track off. Rear, side, and especially front armor on most tanks was much thicker than the deck. Most likely, missing by anything more than a meter or two would do nothing.

 

Energy from a source like a bomb is spread in a spherical manner. That means that as distance from the point of explosion increases, the energy per unit area delivered decreases by the square of that distance.

 

Or, E(delivered)= E * 1/d^2. This is also known as the inverse square law.

 

See attachment for visual (light operates the same way).

 

Now consider that tanks routinely took DIRECT HITS by large caliber artillery pieces firing HE shells over open sights and were able to remain combat effective. For that reason, gunners targeted tracks and running gear to immobilize the tank (and infantry could mop up, later - Brad Pitt notwithstanding).

 

The conclusion is obvious. As much as I love the Stuka, 70kg bombs should not be blowing up tanks short of a direct hit on the tank deck.

 

250kg bombs are a lot larger, and while direct destruction of the tank was still unlikely sans a direct or directly adjacent bomb strike, for game purposes it's close enough.

 

See attachment for visual of 45 ton, or 45000kg Panther blown over by a near miss 500lb HE bomb strike in Normandy (approx 225kg).

 

A better solution for all would be to allow historical bomb loads for the He-111.

Some decent information but I dont think you read through the thread before posting.

 

Please refer to this 

 

The first video should have been a mobility kill on the T70.  The mobility kill beyond engine damage just doest exist in game - yet.  This second video shows there are issues with bombs and armor considering that was a 500kg bomb.

Edited April 8, 2015 by Roo5ter

[Venturi 392]

Personally, I think the engine is using the point of bomb impact versus tank location, at the time of bomb impact, rather than the point of bomb impact versus tank location, at the time of bomb detonation, to determine distance of the tank from bomb explosion and the subsequent damage received by the tank. Because I have gotten very good results with contact-fused (no timer) 250kg bombs against moving tanks.

 

I would be all for mobility damage in the game, but of course for practical purposes, the pilot should be able to know when he has effectively struck the tank, and the best way is the current way - with a small stream of smoke. This seems a fine abstraction to me - I only take objection to the inevitable explosion of the tank. This really wasn't the case. In fact most times, the enemy did not realize the tank had been knocked out immediately. This of course led to many erroneous kill claims. This is also the definition of knocked out vs destroyed - knocked out tanks can be refitted and repaired (they are very expensive and tough vehicles, even when severely damaged), given the capture of the battlefield by friendly forces, or the subtle recovery of the vehicle at night. Destroyed vehicles really are only destroyed by fire or other internal explosive forces which twist and warp the hull.

 

Many killed tanks, you will find if you do the research, were shot multiple times, with multiple penetrations, usually until it brewed up, the crew jumped out, or it was otherwise obvious the tank was dead. You will see victory photographs of the opposing tank crews pointing to the multiple hull penetrations they caused. No one wanted to make a mistake in a tank v tank, or tank v gun duel.

 

So you see, it would be very difficult to model what you are suggesting, convincingly from the air. 

Edited April 9, 2015 by Venturi

[361fundahl 27]

Just grab that sc2500...

[StG77_Roo5ter 79]

 

 

So you see, it would be very difficult to model what you are suggesting, convincingly from the air. 

 

To refute the claim it would be hard to model -If a tank is tracked, the track literally ends up piled and the tank yaws in direction of the broken track and you could easily see the track piled up.

 

but honestly I NOWHERE said that I am suggesting they model it, I said it was not modeled at this time or more precisely I said 'yet.'  I think there are a lot more important things then modeling a tank track at this point in time I simply am saying that bombs effectiveness vs armor is borked.  To be clear you saying that I am suggesting they go ahead and model the tank tracks is the same as me claiming you requested they model tanks flipping over from near misses simply because you posted a picture of that event.

 

Also HE vs tanks not doing anything is a myth.  It has the possibility of causing severe issues but also may do not much more than rattle the crew.  Sights have to be calibrated, running gear is far more fragile than a hull, tracks even more fragile, and high angle artillery is going to drop on the thinnest armor of the tank.  

[FlatSpinMan 812]

I would LOVE to see tanks and vehicles being flipped over! The flipped over damaged vehicles in one of the mod-packs for '46 were so handy for detailing my final, never-released Tunisian campaign.

[Venturi 392]

[snip] my final, never-released Tunisian campaign. [/snip]

 

That, is a depressing thought.

Edited April 10, 2015 by Venturi

[6./ZG26_5tuka 1800]

Agree with bomb damage being too ineffective vs armor ingame. I'm highly assuming that the ga,e uses the typical RTS-like damage to armor model which is similar to simplyfied games such as battlefield.

 

Basicly each unit has an armor value and a health bar. Every kind of damage has a value and class. In addition to that distance is also calculated in BoS (for bombs).

 

So if your bomb has a high enoufh damage class and the effective danage resulting fron the impact on the tanks is higher than it's armor.defned damage block value it deals a certain percentage of damage to it' healthbar. If the detonation happens further away it deals less to no damage depending on the distance.

 

Armor values do not server the calculation for penetration ballistics but damage blocking calculation. Thats the great downside of this model.

 

Another issue is the lack of critical and physical damage modeling on ground vehicles. Engines can be damaged but with no great effect for the tank's vitality.

 

Also tracks, running gear ect are not damageable by splash damage. Fragmentation and shockwave modeling seems very abscent either, as those had great effect on the tanks and crews lethality.

 

So the only way to compensate for all this lack of realiatic modeling (which would take a considerable ammount of time for devs to implement) is to decrease the tanks vitaliy (healthbar) and/or increase the damage to armor modeling for bombs.

 

An additional idea would be to change the terms for tank kills from total destruction to disabling (ie. by taking out the engine).

Edited April 13, 2015 by Stab/JG26_5tuka

[StG77_Roo5ter 79]

I heard the tanks had an AC of 16 base and the 70kg only has a 2d10 attack.  This has me extremely worried.

[6./ZG26_5tuka 1800]

I rather meant armour piercing and high explosiv damage types (again I seriously doubt the game feautures fragmentation damage modeling). It is obvious both should be treated differently.

 

Again this is only my assumption but considering Battlefield and even Arma use this basic armour model it does not seem very wrong. However, BoS does not feauture enought crititcal compoments for ground vehicles to make up for the "health bar" system with modular damage modeling.

Edited April 13, 2015 by Stab/JG26_5tuka

[JtD 2085]

Il-2 did not use this model for tanks.