20-mm strafing against house, no effect - just bad luck?

[Bulletpoint]

In my recent game, I correctly identified an enemy strongpoint in a house, and called in an aircraft to strafe it with 20-mm cannon. The plane did two runs, hitting the second floor both times with a storm of bullets..

So, I must admit that I was a bit disappointed when I reached the house and found that the defenders were alive and kicking.

I honestly don't know if they might have lost 1 or 2 guys before I arrived, since when they buddy-aid their friends, the bodies disappear. But shouldn't two strafing runs pretty much clear out a house? Wouldn't that calibre just cut straight through a building? I know in war, strange things happen; maybe we can assume all the enemy were out for a smoke when the attack happened, or in the basement to drink schnapps, but still it seemed odd to me.

Should I just forget about using strafing against buildings and only do area targets to catch enemies in the open?

Edited June 19, 2016 by Bulletpoint

[womble]

Tis odd, that. I haven't used planes vs buildings, but 20mm cannon fire from vehicles is plenty effective, and those plane cannon have higher RoF and additional velocity compared with the single cannon on a recce vehicle, for example. I'd expect them to be effective. It'd need a test or two to determine whether there's something systematic going on, or whether you just got (very) unlucky. Or it might just be that the troops you had to fight arrived after the troops you'd identified and targetted had been eliminated. Maybe, depending, naturally, on the sequence of events and opportunities for reinforcement.

[c3k]

^^^

Something to look for would be suppression levels. I don't know how many rounds actually hit the house in your example. Nor do we know if the rounds were HE or AP (usually, without digging into WWII aircraft loadout tables, I'd think AP-I would be standard). House construction would matter, too. Barn walls should act like paper: heavy stone houses should bounce a lot (all?) of the impacts which don't find an opening.

Running a series of tests in wego/hotseat would tell a lot.

Ken

[Bulletpoint]

29 minutes ago, c3k said:

I don't know how many rounds actually hit the house in your example.

All of them hit, as far as I could see. In total, the plane expended about 360 rounds.

29 minutes ago, c3k said:

House construction would matter, too. Barn walls should act like paper: heavy stone houses should bounce a lot (all?) of the impacts which don't find an opening.

I'm not a military expert, but wouldn't 20-mm aircraft guns go through just about any kind of civilian house found in Normandy?

For the record, it was a 2-story modular house. I think that normally, "even" .50 cal go through those walls. And 20-mm would be like .80 cal if I'm not mistaken? Far more powerful round.

By the way, I agree tests would be needed to say anything definitive here, I just wanted to know your opinions, game experience with using strafing against houses, and what you think would be reasonable to expect as a result that (more or less) matches a real life situation.

Edited June 19, 2016 by Bulletpoint

[MOS:96B2P]

15 minutes ago, Bulletpoint said:

<Snip> wouldn't 20-mm aircraft guns go through just about any kind of civilian house found in Normandy?

For the record, it was a 2-story modular house. <Snip>

I would think 20mm would go through any building in the game.  Some buildings would be more resistant than others.  (I have discovered the large stone church in the excellent scenario Pierrefitte-en Cinglais can shed many calibers like the bullets were rain drops.   Admittedly however none of the rounds were 20mm).

I am curious as to the location of the windows & doors on your modular building during the strafing run.  I know aircraft come down at a pretty steep angle during a strafing run but I think one or two sides of a building get most of the incoming.  Did that side(s) have any (or very many) windows or doors?

Even if that side of the building was a solid wall I would still expect 20mm to penetrate.  But I am thinking of the suppression test @RockinHarry did where a floor of a building needed at least one window, facing the incoming, to sustain suppression.  Just trying to think if there was a game mechanic reason for your result ........ not that it would work that way in RL.            

[Bulletpoint]

17 minutes ago, MOS:96B2P said:

I am curious as to the location of the windows & doors on your modular building during the strafing run.

It's a building that stretches west-east, so the two long sides of the house face north-south. On the long sides, there are 3 windows on the side facing south, and 2 facing north.

First strafing run came in from the south, hitting the side with 3 windows. Second run came from the opposite direction, hitting the side with 2 windows.

It's the mission 'Grainville Chateau' from the Scottish Corridor campaign.

When I saw the plane finally coming in, I thought "ok, that's one building I won't have to worry about any more"..

My current hypothesis is that it *might* have something to do with the tight spread of the plane guns. They mostly hit the centre of the building, so maybe it's possible to avoid getting hit by facing towards one of the walls that are not getting hit?

That would be a bit disappointing, as I think the whole building should be riddled with bullets and it should be extremely unlikely you could avoid getting hit by either a bullet or the spray of masonry from each impact.

Edited June 19, 2016 by Bulletpoint

[MOS:96B2P]

15 minutes ago, Bulletpoint said:

<Snip> My current hypothesis is that it *might* have something to do with the tight spread of the plane guns. They mostly hit the centre of the building, so maybe it's possible to avoid getting hit by facing towards one of the walls that are not getting hit? <Snip> 

Interesting ................... So many things to test ........ so little time.

[c3k]

The Normandy farmhouses were built of thick stone walls. (Obviously, there were various construction techniques, especially in towns.) The farmhouses were famously regarded as hardened targets, akin to bunkers.

A bit of internet browsing shows that 3 1/2 inches of 3,500psi (the most common type) concrete can stop most rounds. (Not sure about 20mm.) 8 inches, of 5,000psi concrete (just a minor cost increase), is "proof" against all tested rounds with repeat hits. 

I lost my reference to stone equivalence to concrete. (On the road right now...) Suffice it to say that were I to be strafed by a 20mm aircraft cannon (depending on version, muzzle velocity anywhere from 550m/s to 800m/s or so), a Norman farmhouse would be a nice place to be. (Okay, a Norman farmhouse far away from the strafe pattern would be even better!   ) Roof penetration is obviously a different ball of wax. HE rounds would not penetrate, so this should only concern AP and AP-I (and the tracer variant of each). Roof penetrations should strike internal stone walls and ricochet around a bit. That would show the utility of dirt/wood floors: stone floors would be...bad.

Houses in towns were not quite as robust, but neither were they as flimsy as modern structures. Solid brick (not the modern veneers (full bricks or just fake brick veneers) which have no structural role are not comparable) was often thick and well built to resist impacts. (They degrade rapidly with multiple hits and when over-matched.) Similarly, the modern 25/30mm autocannon youtube footage showing effects against Syrian/Iraqi/Afghani structures is not comparable.

I'm not saying there ISN'T a problem, only that there is far more to it than just saying "an airplane strafed a target and the enemy survived". (Not putting words in your mouth, just using an example.)

More testing is needed and some correlating data from real world tests or experiences.

Ken

Edited June 19, 2016 by c3k

[Bulletpoint]

4 minutes ago, c3k said:

Houses in towns were not quite as robust [as country houses]

That's interesting, because the game has it the other way around - town houses (modular buildings) are much hardier than isolated farmhouses...

[womble]

The first HE round wouldn't penetrate a roof, perhaps, but 20mm HE would blow a hole in a tiled roof, scattering neighbouring tiles so that the following 259 rounds had a good chance of getting into the structure. 360 20mm HE rounds hitting the roof "should" have stripped the whole thing and shredded the inside structure, turning the house into an empty shell of splinters and bloody chunks of pTruppe.

Anything "AP" would mostly ignore tiles. They might be a sharp enough impact to set off the bursting charge, or they might not.

 

[sburke]

1 hour ago, Bulletpoint said:

That's interesting, because the game has it the other way around - town houses (modular buildings) are much hardier than isolated farmhouses...

You mean modular buildings versus independent buildings?  The two have no particular designation in terms of urban and non urban, especially after modding.  I have seen and used modular buildings as independent farmhouses, especially if I want to duplicate the effect the Ken is referring to.  In CMFI I prefer the independents in the city (nice to see railings on buildings, but not have my pixeltruppen getting massacred on balconies).

[Bulletpoint]

I just replayed the mission from start to finish, and it seems my idea was correct: The spread of the bullets is very small, so the chances of hitting anyone inside the building are also small.

They rounds do enter through the roof, and they definitely all penetrate.

[Michael Emrys]

31 minutes ago, Bulletpoint said:

I just replayed the mission from start to finish, and it seems my idea was correct: The spread of the bullets is very small, so the chances of hitting anyone inside the building are also small.

They rounds do enter through the roof, and they definitely all penetrate.

I think the lesson here is quite clear: When attacking buildings, use bombs. Or at least rockets.

Michael

[Bulletpoint]

25 minutes ago, Michael Emrys said:

I think the lesson here is quite clear: When attacking buildings, use bombs. Or at least rockets.

Michael

 

[Sublime]

The interesting thing to take away from this is that any gun fired from an aircraft in a ww2 setting should have a more dispersed and elliptical beaten zone IMO and perhaps this is something to look into

[Michael Emrys]

17 hours ago, Sublime said:

The interesting thing to take away from this is that any gun fired from an aircraft in a ww2 setting should have a more dispersed and elliptical beaten zone IMO and perhaps this is something to look into

In the few cases where I have used aircraft in a battle, during the strafing attack, there is always a line of puff marks where the bullets strike the ground suggesting the movement of the plane during the attack. It's been a long time, so I am wondering if that code has been altered in the meantime.

Michael

[Bulletpoint]

45 minutes ago, Michael Emrys said:

In the few cases where I have used aircraft in a battle, during the strafing attack, there is always a line of puff marks where the bullets strike the ground suggesting the movement of the plane during the attack. It's been a long time, so I am wondering if that code has been altered in the meantime.

That only happens on open ground. Against buildings, all the bullets just hit the facade in a very tight spread.

[c3k]

21 hours ago, womble said:

The first HE round wouldn't penetrate a roof, perhaps, but 20mm HE would blow a hole in a tiled roof, scattering neighbouring tiles so that the following 259 rounds had a good chance of getting into the structure. 360 20mm HE rounds hitting the roof "should" have stripped the whole thing and shredded the inside structure, turning the house into an empty shell of splinters and bloody chunks of pTruppe.

Anything "AP" would mostly ignore tiles. They might be a sharp enough impact to set off the bursting charge, or they might not.

 

Ahhh... My lack of a new paragraph perhaps led to confusion. I agree that a farm roof would be of no use as protection against any type of strafing cannon fire. ( Assuming tile, thatch, or slate as a roof covering laid over a wood frame.

[StieliAlpha]

I just had a Building collapse in MG after ONE staffing run of a P47. 6 Cal .50 machine guns, no bombs...

[Michael Emrys]

2 hours ago, StieliAlpha said:

ONE staffing run of a P47. 6 Cal .50 machine guns

Er, the P-47 had eight MGs. The P-51, on the other hand, like most US fighters had six.

Michael

[StieliAlpha]

18 minutes ago, Michael Emrys said:

Er, the P-47 had eight MGs. The P-51, on the other hand, like most US fighters had six.

Michael

Well, I did not count in the heat of the battle. Let's say "a heap of of Cal .50 bullets poured down in one turn". 

In the end my Pixel-guys did not care, if a P47 or a P51 killed them.

[Bulletpoint]

4 hours ago, StieliAlpha said:

I just had a Building collapse in MG after ONE staffing run of a P47. 6 Cal .50 machine guns, no bombs...

It depends a lot on the type of building. I've seen the little garage type building collapse after sustained fire from just one .50 cal. Barns are also very flimsy. And if some artillery has landed in the area previously, that will also soften up houses, sometimes making them fall down later from just a hand grenade or similar.

The worst thing is that some enemy soldiers inside often survive the collapse, but that has been discussed in other threads.. 

[Michael Emrys]

1 hour ago, StieliAlpha said:

Well, I did not count in the heat of the battle.

You mean you didn't know that already??? You lose 50 grog points! Tsk, tsk.

Michael

[StieliAlpha]

12 minutes ago, Michael Emrys said:

You mean you didn't know that already??? You lose 50 grog points! Tsk, tsk.

Michael

No no, that's "real life effect". Doesn't  matter, if it's 8 or 6 guns, when the oaks are down.

You know "The Green Fields of France"?

[Ivan Zaitzev]

Kinda related to this... Is there any penetration table for the game?