CAS in CM2

[John Kettler]

Erwin,

Earlier I mentioned the difficulties of attacking ground targets, right? It occurred to me that I had a worthwhile tutorial available, in the form of "Thunderbolt," a WW II documentary starring Jimmy Stewart and directed by William Wyler, who directed that nothing of a movie (10 Oscars) called "Ben Hur." The film shows the ground attack war from the cockpit, thanks to a series of cameras. You can see for yourself what a big pre- briefed target bridge looks like before rolling in and starting the attack. After watching that, imagine trying to find, still less hit, a much smaller target which is considerably lower in contrast and may or may not be where it's supposed to be.

Regards,

John Kettler

[JonS]

I didn't make the statement, the Air Munitions Data (Appendix 2) did.

Yet again, you didn't understand what you read, and have conflated several different concepts into a mangled and erroneous "understanding". What a surprise.

it would be wise not to confuse the properly sourced message with the messenger.

I'm not. There's nothing wrong with the original FAS article but the message, as presented on this forum, was mangled by the messenger, which is SOP for this particular messenger.

(hint: the 'source' I referred to in my previous post was neither FAS nor the Vietnam Lessons Learned pam)

[Erwin]

I think you miss the point, John, which is that in the GAME, CAS doesn't have the same effects as in RL, and I am talking about the GAME.

eg: In the GAME most maps don't allow for 500m+ distances from a CAS target zone. Plus many times immediately after CAS causes enormous craters a few meters away, they are able to get up and fight you effectively.

I have merely been inquiring as to how to deal with CAS and its effects on friendlies in the GAME.

[John Kettler]

JonS,

Rather than taking potshots at me, why not provide specifics in the form of the correct data?

Erwin,

Point taken. I agree that map smallness has been a big issue in the past, but now that map size has been expanded (see 12,000 point battle AAR), spatial relationships should become much better.

Turning now to weapon effectiveness, this is supposed to be a sim. It should replicate battlefield realities. If it doesn't, then it needs fixing. But here's the rub. Steve recently indicated, over on the CMRT Forum, that if CAS became a problem, in terms of raging ongoing debate, he might decide to remove it from the game outright.

After looking at the sum total of the information in this thread, the only sensible way to use CAS is to have your men in hard cover and with HIDE activated. Failing that, in any kind of cover, not concealment, and with Hide activated. Simply put, you don't want to be any kind of nail when the aerial hammer arrives!

Regards,

John Kettler

[JonS]

why not provide specifics in the form of the correct data?

Because, with you, there is simply no point.

[Baneman]

Because, with you, there is simply no point.

Well, I thought that the idea of the forum ( at least in part ) is to disseminate information.

If you think that the information he has given us is wrong, then isn't it better to tell us how it is wrong or (even better), tell us how it should be, rather than trying to score points off John ?

[JonS]

Ok, here you go: disregard anything JK asserts. Your perception of reality will be vastly improved. Oh, sure, occasionally he gets something right, in the same way that the monkeys at the zoo occasionally hit a small child with their flung poo, but hoping for an accident isn't a great strategy.

Happy now?

(P.S.; I really like your sig )

[Doug Williams]

I wish that all air support worked like BFC said it would for the Soviets in Red Thunder. You buy the air support at the purchase screen, then it is completely out of your hands after that.

[Erwin]

For WW2 I tend to agree with Doug. At least then I can swear at the CAS rather than wonder why when I keep my men at supposed safe-ish distances away, they still get nailed - esp when enemy units seem well-identified.

[JasonC]

Oh boy.

First, safe distances are rough rules of thumb based on how bad it can get. They do not reflect averages or blast effect distances, but outliers of poor shell or bomb placement that can and do happen in real life.

Second, routine errors in placement of artillery rounds by div arty run up to 400 meters for the initial shot, and 200 meters is entirely standard. That is why fire missions called closer than 400 meters from friendlies are "danger close" fire missions. (I leave aside as hopeless Hollywood's screamingly wrong belief that said term means there is danger nearby - just laugh out loud funny, that one).

Third, errors in the placement of air dropped bombs before the advent of smart weapons with terminal precision guidance are way, way larger than the placement errors for artillery rounds. For level bombing from high altitude they are measured in miles - plural. Only a few percent of bombs landed within 400 feet of the intended aim point - that is why entire groups of heavies carrying up to a dozen bombs apiece had to be used to hit anything.

The lethal radius of high explosives is also much less than the figures being bandied about here, from blast effect along. For a 500 lb bomb it is only about 20 yards, with 30 yards for a sure casualty radius by blast effect. Fragmentation can inflict casualties much, much farther than that, but always only with some probability, not the certainty seen in the direct blast overpressure radii given above. Slit trench cover can cut those distances in half, while also reducing fragmentation causalties to nil, if the men are heads down when the bomb detonates.

It is still quite rare for even so large a bomb to cause casualties 100 yards from the impact point. A standing man might catch fragments at that distance if he is particularly unlucky, but mostly he will just duck, and his hearing will be impaired.

Can fighter bombers place their bombs significantly more accurately than the level bombing figures above? If they dive bomb then the answer is "yes". But understand, dive bombing with a release at 3000 feet directly above targets the size of aircraft carriers and battleships obtained hits only about 1/6th of the time. And that counts as by far the most accurate form of bombing with unguided munitions. If they glide bomb, which was much more common, then the answer is "not by much". Pilots vastly overestimated their own accuracy and thought they were achieving great results with glide bombing. That is mostly a function of the towers of earth, dust, and smoke large bombs throw up, and the speed at which fighter bomber pilots were exiting the area. The truth is against land surface targets they hadn't the faintest idea what they hit and there is no possible reason they could have gotten it right.

"If CAS was this bad in RL, I would wonder why it was ever called in."

Mostly it wasn't. Nearly all tactical air support delivered during WW II, especially in the whole European theater, was delivered at the initiative of the pilot or flying formation, without any communication with the ground and certainly without their close direction. There might have been prior coordination at the command level, and some updating of where friendlies were by now, about it. Most fighter bombers were flying "armed recce" - look for enemy assets and attack them where you can. Others were flying group sized missions at specified targets well in the enemy rear - routes, bridges, railroads, whole towns thought to contain enemy troops or rear area services.

Close air support in the modern sense of a guy on the ground with a radio telling the pilot what to hit, was basically invented during the Korean war. There are a few precursors in WW II, cases of a fighter bomber formation flying armed recce in coordination with a whole combat command on a specific road axis, e.g. In the Pacific there were also some closer coordination cases, particularly in the Marines with small formations of their own aircraft, explaining targets by radio to air units on nearby strips or jeep carriers. But the forward air controller who sees both the target and the planes, and plans the attack by the planes, telling them what ordnance to use on it, what axis to come in from, the point of aim to use etc - that was first perfected in the Korean war, long after WW II.

And it still wasn't terribly effective, because the munitions involved weren't precision guided. Ground designation of targets for precision munitions didn't get started until the later days of the Vietnam war, the early 1970s. Modern conceptions of what close air support is and does basically date to that era, and are completely anachronistic when applied to WW II.

FWIW...

[Jack Ration]

nice summary Jason, thx.

[JasonC]

Thanks JR. Curious, I just did the math for the performance of US dive bombers at Midway. It is what you would expect if a dive bomber could put his bomb down somewhere in an area 300 meters long by 100 meters wide, without any appreciable "center weighting" within that area - long on the axis of flight obviously. That might even count as an outlier success rate.

For the curious, 68 SBDs delivered their bombs during that battle at Japanese carrier targets - counting the later strike on the Hiryu - and they obtained all of 12 hits. The carriers measure 248 by 33 meters for the Kaga, which was attacked by 25 and hit 4 times. (Some reports say 5, but I think the 5th is dubious - it coincides almost exactly with one of the four and likely reflects a secondary on the ship caused by that one). Akagi was attacked by only 3, and hit once, dead center, certainly the luckiest bit of the day - the resulting fires were out of control within 15 minutes and forced the Japanese to transfer their flag off of her within 20. She was only sunk later that night by Japanese torpedos to scuttle her, when the fires could not be contained. Soryu was attacked by 15 and hit 3 times - possibly only twice, but there I consider the 3rd hit credible (different location reported, farther aft, etc). Hiryu later in the day was attack by 25 and hit 4 times. Both of the latter two ships (sisters) were 228 meters long and 26 meters wide (flight deck width, they overhung the beam).

Overall, 12 for 68 vs targets over 200 meters long and 25-33 wide... Dive, not glide, bombing. Consider that next time you expect a direct hit on a tank from your one fighter bomber...

[Erwin]

Thanks Jason. So, it does confirm Doug's point that WW2 players should not be able to "call in" CAS.

[JonS]

So, it does confirm Doug's point that WW2 players should not be able to "call in" CAS.

Pretty much, but not quite.

Accuracy issues aside, during the Normandy campaign both the USAAF and RAF were able - after a very rocky start - to provide almost-true CAS, complete with a/c loitering over the battlefield and responsive to a pilot on the ground who could see the target and talk the pilots on to it. But, as a process it was in its infancy, and was horribly expensive in terms of the number of a/c required to provide it, and the pilots on the ground were very very rare. There was, for example, just one FAC for Op GOODWOOD, and when his got knocked out early in the day that was that as far as CAS was concerned for the entire operation.

Several years ago I proposed this as a mechanism for CAS in CM

Broad brush I'd see it for the Allies as something like:

June 1944: you buy some a/c, and they might turn up at some point during the battle and will proceed to pick their own targets from anywhere on the entire map. They'll maybe try to avoid blue on blue (modified by a/c skill and experience).

July 1944: Same as June, or you buy pre-planned strike and get to pick an area target at startup. The a/c will probably appear within 10-20 minutes of battles start, and probably attack something within that area (modified by a/c skill and experience). Or maybe they'll just zero on on something else that takes their fancy.

August 1944: Same as July, or you can buy a (very expensive) CabRank or ACC. You get a FAC that can specify a point target at any time during the battle and the a/c will probably attack it, probably within the next five minutes (modified by FAC and a/c skill and experience). Or maybe they just won't turn up, or maybe they will turn up and attack anything they feel like.

As I understand it the Russians were well on the way towards getting a similar 'August' capability in the second half of 1944. While the Germans technically had a sort of similar 'August' capability, due to an chronic lack of a/c, pilots, fuel, and facing overwhelming Allied air superiority they were never able to apply it.

Fun Fact: despite their vaunted early-war CAS capability, it took the Germans over 24 hours to arrange the air support used during the crossing of the Meuse at Sedan in May 1940.

[John Kettler]

Suggested Reading List on CAS doc.

Not all of what's here is for WW II, but there are several such items listed, including two accounts by P-47 pilots who flew CAS. I spot checked info on the Il-2 pilot's book, but the reviews say it has pretty much nothing on CAS per se (organization, tactics, procedures) and tons on the life of a combat pilot under attack from above (Luftwaffe) and below (flak and groundfire).

http://www.pogo.org/our-work/straus-military-reform-project/resources/suggested-readings-on-close-air-support.html

Case Studies in the Development of Close Air Support, Special Studies, Office of Air Force History. The pieces I've read so far are very good. Pages 258-284 go into a thorough explanation of how the U.S. CAS system got going and developed, right down to typical ordnance loads, targets and attack profiles.

http://www.afhso.af.mil/shared/media/document/AFD-100924-035.pdf

Regards,

John Kettler

[Pak40]

Yes, I was giving the CAS area fire, but shouldn't they make some effort to stay in the circle?

280-300 meters away from the EDGE of that circle seems a looong way off esp on the average CM2 map.

As in real life, there were miscommunications or misunderstandings between the FFOs and artillery/air support. Mistakes were made, bombs and artillery sometimes fell far from the intended target. This should not be news to any one if us playing this type of realistic game.

By the way, the size of the map has absolutely nothing to do with accuracy of any type of support.

And as I said I have been amazed at how little damage can be caused by what must be a huge explosion only a few meters away.

So, my original question was, and still is, IF this is realistic CAS behavior, what is a safe distance away from a target circle?

Yea, this sounds dubious at best. One guy in this forum claims the lethal radius of a 1000lb bomb is 28 meters. So maybe a 500lb bomb might have a lethal radius of 8-10 meters (I'm guessing here). The chart in the link above says the safe distance of a 500lb bomb is 2500m.

[SlowMotion]

That link claimed bomb's blast radius to be 28meters, but effective casualty radius - 200 meters

[JasonC]

Pak40 - more utter confusion, on everything except the 28 meter lethal blast radius.

First point to understand is that lethal blast radii go as the square root of the HE load. A 1000 lb bomb with twice the explosive of a 500 lb bomb does not have twice the lethal radius, but Sqrt 2 times as much or 1.4 times. The 20 meter lethal radius I gave for the 500 lb bomb and the 28 meter lethal radius for the 1000 lb variety are saying the same thing. The radius only goes up as the square root of the load because the surface area of the demi-sphere over which the pressure wave is being distributed goes as 2 pi radius squared.

Next, the item recorded as 200m fragment "causalty radius" just means the farthest a bomb fragment could travel from the impact point and still wound somebody. It emphatically does not mean will wound everyone, or even wound with 50% probability, everyone in that area. You would need to be very unlucky to catch a fragment at that distances - on the order of a 1% chance, not a 50% chance.

The likely fragmentation casualty zone is, unsurprisingly, much larger than the lethal blast zone but much smaller than that possible wounding zone. Very roughly, the blast alone is sure to hurt but not kill someone about 50% farther than the lethal radius. That is the overpressure wave alone - it will stun, concuss, might knock out temporarily, and could even damage the person's lungs, at such distances. At the same distance, fragmentation might kill a modest portion and wound a much higher portion of exposed people. Fragmentation will wound people out to 2-3 times the lethal blast radius with significant probability, 10 to 50%. Beyond about 3 times the lethal blast radius, there can be wounds from fragmentation but they will be rare and exceptions, not the rule, and the pressure wave itself is not dangerous (except to hearing, very temporary stun, and the like).

All of that is without cover. As already mentioned, put a man's body and head below ground level at the time of detonation, and only the blast can reach him, and that at about half the distances given above. This is why e.g. men under carpet bombing by hundreds of "heavies" but in tactical positions mostly survived the experience - though concussed and demoralized, to be sure. If a bomb landed within 10-15 meters it would still kill or wound them.

In the Goodwood prep, for example, heavies dropped 7900 *tons* of bombs, or the equivalent of 31600 500 lb bombs. At 15m distance that saturates only 22.3 square kilometers vs men under cover, and less than half that - about 10 square km - at the 10m distance. Since the bomb pattern was actually much larger than that, only a fraction of the men under it were killed directly, or even permanently wounded by direct blast effect.

[JasonC]

A little more "color" for those who might read too much into the western journalist's myth level understanding of cooperation between early war German air and their ground forces...

The following describes the situation in 1939 and 1940 from Poland through the fall of France.

Air recon units were controlled by the Heer, all bomber units were controlled by the Luftwaffe. They used separate liason officers, the recce guys were in the sky in planes and in communication with ground artillery units they spotted for. The Luftwaffe guys were at HQ levels on the ground, trying to talk to their own rear area services who in turn directed whole air missions, rather than talking to planes in the air. The recce units and bomber units did not share a single radio frequency - they were assigned different portion of the EM spectrum to avoid interfering with one another (!).

Throughout the period and into the battle of Britain, Luftwaffe fighter units and bomber units, and their ground controllers, could not directly communicate with each other. The fighters all used radio voice communications but the bomber units all used morse code (!)

The best coordinated force for Poland featured 4 Luftwaffe ground signals units in armored cars trying to keep up with the spearheads and report where the front line was. 2 of them had radios powerful enough to raise planes in the air, the other 2 did not. These formations were the main eyes for ground developments for roughly 200 aircraft with dedicated ground support missions. Ground commanders did not call or task them, their Luftwaffe commanders did. The biggest challenge was trying to communicate to Luftwaffe staffs (leave aside actual pilots in the air) where the army was. (That's the *German* army, to be completely clear. The Luftwaffe did not as a rule know where they own side's ground forces were on the map).

Guderian reports that his spearhead 10th Panzer division was regularly and vigorously strafed by Luftwaffe planes. Being out in front of where everyone else thought the front line was, over and over, he drew "friendly fire" from armed recce missions out looking for something to shoot up, who had been told when they took off by rear echelon you-know-whatevers in Luftwaffe uniforms where the safe lines were, beyond which everyone should be expected to be enemy. Needless to say they were frequently completely wrong. Ground units report that Luftwaffe air recce reports were frequently 12 hours to a day old, and sometimes just flat wrong (e.g. reporting a position unoccupied by the enemy, as the same moment ground recon in contact reported it held in strength, and the like).

For the first several days of the French campaign, the missions of even the ground attack squadrons was enemy airfields, so heavily was the Luftwaffe focused on the air superiority mission. After that they attacked known fortified positions, and when those were dealt with, daily "bomb lines" were declared, beyond which they were free to blast away at whatever they found. Guderian again managed to run under them repeatedly, once clear of the Meuse crossings.

The biggest impact of the Luftwaffe in both campaigns was psychological rather than physical, and came from success in the air superiority mission, from armed recce, and from raids on known HQs, troop concentrations or routes, and entire cities. Good German signals intelligence sometimes located enemy HQs and artillery positions, but mostly the lighter units found targets of opportunity with the Mark I eyeball, while the bombers blasted towns and such too large to miss and unable to move. Front line air support of troops in contact was minimal throughout, and never coordinated from the ground by real time communication. The outlier success in cooperation was achieved at Sedan, and took 2 days to plan. Then the execution consisted of slow dribble air raids for hours and hours, which suppressed French artillery that did not want to give away its positions "while" an air raid was in progress. The German plan just made that "while" stretch out 10-12 hours with only short breaks. In the meantime, German leg units snuck across the river at whatever loop they could find, under that air distraction.

Not exactly telling the Stuka to put its bomb down over there on the third stone house from the left, is it?

[Erwin]

Interesting bg info, Jason.

"...the size of the map has absolutely nothing to do with accuracy of any type of support."

Yes, I know that Pak. The point is that CM maps are small and LOS is rarely more than 200-300 hundred meters. So, it's hard to target or be further than that from any type of CAS.

Therefore, CAS in CM2 seems rather dangerous to friendlies, and probably shouldn't be used unless the map is very large and the spotter can spot targets 400+ meters away. (As I mentioned, I have repeatedly had friendlies bombed when they were about 300 meters from the attack radius edge.)

[sburke]

From another thread

In Guderian's XIX Panzer Corps and the Battle of France there is a section describing German CAS procedures and the grid they used. It seems Major Fritz Bayerlein (later to command Pz Lehr)was tasked to come up with the procedure as major issues were identified as problems in early march war games. Specifically the maps used by the army and Luftwaffe were of different types.

In an example they cite " a normal request went through Division to the corps CAS officer (Nahkampffuhrer II) of IInd Air Corps (Fliegerkorps II was the direct air support for XIX Pz Corps)

in this specific example apparently the 1st Pz Div operations officer requested permission for the Panzer crews to talk directly to the Stuka pilots to guide them to targets and identify the line of friendly troops. The first part was refused on the grounds that their technically inferior equipment would not allow for this. For the second, red or purple smoke grenades or swastikas were to be used as identification markers.

As to the actual Sedan crossing, XIX corps had a lot of issues. Traffic snarls were raising concerns the artillery would not be fully ready. The actual bridgehed size and location was altered from what had been designated by Pz Grp V Kleist. French artillery made any daytime movement to recon the crossing sites hazardous. 2nd Pz was slow moving up and was still 5 km short of it's crossing site at 8:15.

The Luftwaffe attack went in 2 hours late -10:00 instead of 08:00. (No explanation given in this book). One Stuka squadron struck the assault positions of the 1st Motorcycle Recon Battalion. Apparently the corps Military Police company commander was killed during one of the Sedan bombing raids further disrupting traffic flow. After 1400 hours the Luftwaffe commitment began to increase culminating in a massed raid of approx 1,000 aircraft around 1500. This is when the Germans began the assault crossing. It wasn't to sneak in under a distraction but a concerted fire plan no different than any other assualt crossing where the suppression aspect is steadily increased until just before the assault forces go in. In fact 10th Pz was particularly hard hit by French artillery that the air and artillery plan had missed.

To give fair credit to XIX corps and the Luftwaffe, it did not take 2 days to develop the air attack plan. It was developed through the night of May 12-13th as part of the overall assault plan between Guderian, his Chief of staff, artillery commander and Luftwaffe liason officer.

[JasonC]

sburke - that is fair. It isn't modern CAS or anything like what we see in CMx2. Much more like, buy air support and it may show up and may hit something it picks. Or not. But thanks for the corrections on the Sedan details.

[sburke]

sburke - that is fair. It isn't modern CAS or anything like what we see in CMx2. Much more like, buy air support and it may show up and may hit something it picks. Or not. But thanks for the corrections on the Sedan details.

Yeah definitely not. I found no reference to any type of forward observer. The Luftwaffe seemed to be used as just additional artillery firing on pre determined zones with the effort shifting on a schedule.

[JonS]

FWIW, AFAICT*, the basic air plan used at Sedan (described by Jason and sburke above) was produced and settled between Guderian and the LW on 30 April 1940 ... that is two weeks before it was implemented. There were last minute alterations on the 12th (mainly the identification and selection of some specific targets), but nothing that materially altered the April plan.

* Frieser, Blitzkreig legend, p.154-155, and especially footnote 37.

[Michael Emrys]

Frieser, Blitzkreig legend, p.154-155, and especially footnote 37.

As I recall he also wrote that almost the entire Luftwaffe in the west was dedicated to supporting the attack on Sedan that day. Which means that they couldn't have been doing much in other sectors at the time.

Michael