In Part 1 I looked at how changes to second edition of Wing Leader: Victories affected air combat. In this second part I break down how the tweaks to bombing affect the results of air-to-ground attacks.

If air combat has barely changed since the first edition, the bombing system has evolved significantly. The rules haven’t changed radically, and mostly comprise minor fixes. However, the ratings and modifiers, the underlying numbers, have changed a lot.

Bombing

The evolution of the bombing system has been driven by experience and by the realisation that bombing represented a far greater part of the game than anticipated. When I devised Wing Leader I imagined that the game’s focus would be on the duel between interceptors and escort. I reckoned bombing would represent no more than a third of all scenarios. It turns out that bombing features in the majority of scenarios and is one of the largest parts of the game. This has prompted me to devote a lot of attention to getting it right.

The main problem with the first edition I had to address was the relationship between bombing hits and target damage ratings. The biggest problem of the first edition was that the late war aircraft dealt out far too much damage, because their bomb values were so huge.

Surface Targets

Surface targets underwent a significant overhaul between the publication of Wing Leader: Victories and Supremacy. The second edition now adopts the Supremacy target counters as standard. One of the changes was to reduce the number of flak channels available to certain units, so as to de-power flak.

The other change was to tweak the various defence values. Defence modifiers were rationalised, in particular reducing the modifiers for ships, which had a potent effect on bomb hit averages. One of the themes that informs the second edition revisions is my greater understanding of how powerful a +1 or -1 modifier is in a 2d6-based combat system, something that became clear as my spreadsheet tools for analysing combat became more sophisticated. The tools proved that the -3 for DDs and -2 for other ships was simply too great and had to be shaved back to -2/-1.

Damage values were also reviewed. In truth, not a lot changed. Certain targets like trucks had to remain vulnerable to strafing, and so their values stayed the same. Similarly, the tougher targets didn’t change much, though we added the ‘hard target’ qualifier in the Supremacy rules to prevent certain targets like Bridges and Bunkers being rocketed to death. Most of the tweaks rationalised the values of naval targets, which had been expanded in Supremacy to include a wider range of cruisers, as well as small vessels such as gunboats.

Target Analysis

As part of the second edition revisions I went back to sources to try and get a greater understanding of how bombing affected targets and what was needed to render targets ineffective. This would allow me to crunch the numbers and ‘fit’ them to the expected outcomes. Numerous sources were consulted, and I took my views on naval targets from various accounts of Pacific War battles, and Coastal Command fights. However, for tactical land targets I was able to look at ORS data from Northwest Europe in 1944-45. I found Ian Gooderson’s Air Power at the Battlefront to be a priceless summary of the ORS findings.

To try and summarise my thoughts on targets would require an article of its own, but here are some quick notes:

• An number of tactical targets, such as Troops and even Tanks operated in varied postures (moving, dug-in, camouflaged, etc.), some more vulnerable than others, and this was something the first edition did not address.
• Soft transport such as Trucks and Trains were some of the most easy-to-find, lucrative, and vulnerable targets on the battlefield. The vast lines of wrecked transport in key battles attests to how easily even strafing attacks could dispatch these targets.
• Troops and Tanks were less vulnerable to hard kills than to soft kills. Troops were particularly affected by the suppressive effects of bombing, which lasted something like four times longer than artillery barrages. Very few tanks were destroyed by air attack (the histories are full of overclaiming on this matter); however, many were abandoned when they came under attack, and this seems to have been a function of crew experience, with veterans far less likely to bail out.
• Bridges were a precision targets that required direct hits to damage. With some exceptions, near-hits wouldn’t cut it.
• Airfields are complex systems. Damage to these comes in various forms, from cratering runways to the destruction of flight lines (something that can be mitigated by dispersal and revetments). Most important are hits on key centres and systems. An examination of the Battle of Britain reveals that airfields were affected less by cratered runways and more by hits on control rooms and buried telephone lines. Some of the true heroes of the battle were the Post Office engineers who repaired crucial telephone circuits, sometimes with unexploded bombs nearby.
• Factories could be bombed and temporarily put out of operation, but were hard to destroy utterly. Even if buildings were demolished, machine tools proved resilient to attack and could be put back into use within days, at the same or a different location.
• Ships were hard to hit, but particularly vulnerable to small numbers of bomb hits. Damage to critical systems or locations could mean the difference between operation and non-operation, or a survivable or catastrophic hit. Only the biggest vessels, such as the Yamato, were armoured sufficiently that it required lots of attacking sorties to peck them to death.

This does not cover everything but gives a hint of the direction I was thinking as I delved into the numbers.

Bomb Values

As described in my extended mea culpa on the second edition of the game, the big shift in the bombing system has been in the calculation of bomb values. I dug deep into the relationship between bomb hits and damage values, and how VPs ramp up when hits are multiples of the damage value. As I explored the problem, I discovered that some scenarios were highly volatile, since generating multiples of target VPs could easily move the needle on the victory dial from defeat to victory, with no ability for the defender to recover. So one of the goals of the second edition redesign has been to ‘flatten’ bomb values using a square root curve, and then rebalance scenarios. Put more simply: I aim to balance scenarios around achieving Heavy Damage levels on targets, rather than higher levels of damage. (That said, we still expect some of the ‘softer’, low VP targets, such as Trucks and Troops, to take a heavy beating.)

In the next sections we will look at how the new bomb values output into the game, breaking it down by the type of attacking aircraft.

Dive Bombers

Dive bombing was the primary precision-bombing tactic used in the early war, and though abandoned in the latter part of the war because dive bombers proved so vulnerable, it was employed up to the end in the Pacific. The typical bomb load for dive bombers like the Ju 87B or SBD-3 was 1,000 lb, or a bombs value of 9, though some late war aircraft like the SB2C could haul an impressive 2,000 lb (bombs value 13). One interesting exception was the Val dive-bomber, which carried a light 550 lb payload, but was regarded as a major threat. In the first edition of Wing Leader, the Val was assessed as having a meagre bombs value of 5, but the ‘flattening’ effect of the new square root curve increases this to 7.

The base bombing modifier for dive bombing is +3, though this can be reduced by flak and defence modifiers. Table 7 shows us the mean and median bomb hit outputs for different bombing modifiers (the base +3 is shaded in green). Now, I reference mean values extensively in scenario design, since bombing scenarios usually feature multiple bomber squadrons and damage is assessed in the aggregate. Of course there are other variables in play, including bombing altitude, flak effects and disruption, all of which can depress the outputs further. There are few positive bombing modifiers, though the most likely one applicable here would be the use of Veteran aircrew.

The table in the boxout compares these outputs to a number of targets. It assumes the +3 base bombing modifier is in effect, modified only by the defence modifier. No other mods such as for flak hits or altitude are being applied, so these represent the best case numbers. The boxout expresses the mean percentage of damage inflicted by a full squadron attack, and from this we can derive a figure for the number of squadrons required to achieve a given level of damage.

Example 1: From the table we can see that a Stuka squadron attack (BV 9) will deliver 94% of the damage needed for heavy damage level against a Tanks target, and a useful 60% of the damage value against a Bridge. Clearly, one squadron is sufficient for the tanks, while you’ll want to allocate at least two Ju 87 squadrons (strictly speaking, 1.7 squadrons) to be sure of that bridge.

Example 2: Squadrons of Vals (BV 7) attacking cruiser CA 1 will on average do 50% of the damage value on each attack. A minimum of two squadrons are needed to take on a cruiser while 2.4 squadrons are needed against carrier CA 2. Battleship BB2, benefitting from its armour modifier, is going to require 5.6 squadrons, or hope the raiders roll some lucky hits.

Remember that the boxout table describes optimal conditions. Effects such as disruption and flak hits will reduce the mean values and make the raider more reliant on lucky rolls to hit. There will be a more in-depth discussion of flak below.

Fighter-Bombers

The fighter-bomber came to replace the dive bomber in the late war. It was a less accurate platform, but far more survivable, thanks to its speed. In the early war the fighter-bomber was limited to small bomb loads, of around 500 lb (bombs value 6). However, in the late war, the Western Allies operated more powerful aircraft, capable of hauling either 1,000 lb (BV 9) or 2,000 lb payloads (BV 13).

In Wing Leader the optimal form of fighter-bomber attack is the steep dive profile, which benefits from a +2 bombing modifier. However, it is limited to attacks from altitude 1 or above, so the best net bombing modifier it can achieve is +1. Table 8 shows us the bombing outputs, here compared to a number of tactical targets:

As with the dive bombing analysis, the boxout represents an optimal squadron attack without penalties for flak hits, etc. What’s striking is how rising defence modifiers have a major effect on damage. The reduction in mean damage for a –1 modifier is in the region of a quarter to a third. This is important because in the late war in Northwest Europe, fighter-bombers tended to operate in flights rather than squadrons. This touches on another second edition rules change, where attacks by flights are handled by a –1 bombing modifier instead of halving the bombs value, which still allows the possibility of a 100% hit, while pushing the average way down.

In the boxout, some of the target types, such as Troops, Tanks and Artillery look very vulnerable. When I began crunch the numbers for the second edition, I started to consider whether we should vary the defence modifiers for them. Troops were known to be particularly vulnerable when caught in the open but far harder to kill when entrenched. The printed defence modifier on the target counter did not capture all the possible battlefield variables and so we might want to vary these through the use of scenario special rules. The second edition includes rules for variable defence modifiers and even new markers to mark these targets.

Imagine that a –1 modifier applied to troops, artillery or tanks represents dug-in or camouflaged positions. A –2 could be applied to complex entrenchments and emplacements. This means that the printed +0 value represents units operating in an exposed position. Table 9 shows the effect of these modifiers on fighter-bomber attacks.

This table demonstrates the power of the defence modifier. The effects of bombing against entrenched troops are more than halved. Against Artillery and Tanks the number of squadrons required to achieve heavy damage increase from around 2 to 3. The ability to alter the defence modifier becomes a powerful tool in the palette of the scenario designer.

Medium Bombers

The ‘by-the-book’ definition of a medium bomber is an aircraft that could carry a medium bomb load to medium range. In practice many mediums didn’t fit this definition. A medium payload was defined as something like 3,000 to 4,000 lb of bombs, but the Ju 88A-4 could max out at 5,500 lb, while the Ju 88A-15 could lift 6,500 lb at a pinch. Those kind of loads would stress the aircraft and radically reduce its range, so they would usually carry far less than that. In the second edition we peg the Ju 88A-4 as carrying a ‘typical’ load of roughly 3,000 lb. However, it raises the question of what to do about those missions where bombers attacked with a full load. One of the new features of the second edition rules is the Max Load ability, assigned to medium and heavy bombers, that give scenario designers hints on how to recreate a fully-loaded raid.

In Wing Leader the square root rule means that medium bomb values have been greatly reduced from the first edition. They range from bombs values of 14 for the G4M ‘Betty’ to 19 for the Heinkel 111H-1. In the game, the average bombs value for a medium bomber is 16. As for the attack profile, though mediums can employ glide bombing, this analysis is going to focus on level bombing as the most typical form of attack.

One of the big variables for medium bombers is attack altitude. On the whole, mediums would attack from altitudes above the reach of light flak, where heavy flak effectiveness began to decline. Typical bombing heights for the Luftwaffe in the Battle of Britain were around altitudes 7 to 9, and this was typical for other air forces. However, the USAAF practiced low level raiding in the Pacific. The other variable was the bombsight, which was crucial when bombing from higher altitudes. Table 10 gives us a peek at the results gleaned from bombing at low and medium altitudes.

Of particular interest is the differences between the percentage of damage value for low and medium attacks.

• Low altitude attacks are doing roughly 50% more damage than medium attacks.
• Comparing attacks on the Bridge at BV 16, the low level attack requires around 2.9 squadrons to achieve heavy damage while the medium altitude attack needs 4.5.

Another thing that’s clear from this is that the mediums are doing far less damage to targets than the dive bombers and fighter-bombers, despite the greater bombload. They lack precision. However, a crucial difference is the exposure to ground fire. Dive bombers have to attack at low altitude to achieve their accuracy; they must fly into the teeth of the flak defences. The mediums have the option of attacking from above the light flak envelope.

It’s worth examining the problem of flak in the context of comparing low and medium altitude attacks. Historically, dive-bombers suffered greatly at the hands of flak gunners. Fighter-bombers benefitted from their speed, and a new feature of the second edition is to give them a defensive modifier against flak. (It’s also worth noting that the focus of the fighter-bomber was the tactical target in a relatively flak-free, permissive environment, while the dive bomber was a utility player, sometimes sent in against well-defended precision targets, such as ships and bridges.)

Medium bombers were intended to go up against significant flak defences, and so attacks from above the light flak envelope greatly reduced losses. There were exceptions, such as the USAAF B-25 raids on Rabaul, but the danger of low level raids is that the player will be trading off VP for bomber losses, at 2 VP a pop, with damage on ground targets.

The Flak Attacks table shows the mean aircraft losses depending on the number of direct-firing flak units engaged.

Lets’s apply these numbers to some examples:

Example 1. A dive bomber attacking a target defended by a light and heavy flak unit will lose 0.66 aircraft. A medium bomber attacking the same target will lose 0.56 aircraft, while a fighter-bomber benefits from its speed modifier to only lose 0.46 aircraft.

Example 2. A medium bomber attacks the same target, but from above the light flak envelope, and above the threshold for the +1 direct fire altitude modifier. The result is a loss of 0.25, or less than half the low-level attack losses.

The lesson from this is that mediums attacking from higher altitude inflict less of a pasting, but they are doing so with far fewer losses. To measure the benefit of higher altiude we can compare the loss rates for medium bombers (with BV 16) against the gains from damage, to see which type of attack is more ‘efficient’:

• The low altitude attack will inflict 5.7 bomb hits for every aircraft loss.
• The medium altitude attack will inflict 8.4 bomb hits for every aircraft loss

It’s clear that losses for attacks from medium altitudes will far less costly. The tradeoff, of course, is that far more bomber squadrons will be needed to inflict heavy damage. Scenarios featuring few medium squadrons may need to pivot around achieving minor damage to targets rather than heavy damage.

Of course, flak doesn’t just inflict losses. It also affects bombing. Look at Table 10 again and note the profound effect of defence modifiers on these attacks. Even a -1 flak modifier can reduce bomb hits by something like a third to a half. Let’s look at those examples again in terms of the chances of flak modifiers being applied by direct fire:

Example 1. The low altitude dive bomber and medium bomber have a 72% chance of receiving a bombing marker from flak; for the fighter-bomber this figure is 58%.

Example 2. The medium altitude bomber has a 41% chance of being hit with a bombing marker.

In short, higher bombing altitude means far fewer flak effects.

Heavy Bombers

There are few scenarios in which players can bomb with heavy bombers. Most scenarios featuring heavies depict them en route to their targets. However, the forthcoming Wing Leader: Eagles campaign, set at Rabaul, will change all that. The player will get a chance to run B-24 raids, and the choice of attack altitude becomes a vital one. Already testing has revealed the value of attacking from high altitude so as to minimise the effects of Japanese interception.

In the second edition the bombs values of heavies are around 20, though they can be Max Loaded to 30. If these numbers don’t look far off what the mediums could deliver, don’t worry. The heavies are, of course, operating at far greater ranges, and they attacking mob-handed. In the game a USAAF heavy bomber group is represented by no less than six squadrons.

Often, the heavies are also operating at altitudes of 12 or higher, where the effects of flak are greatly reduced. Heavies should experience fewer flak casualties and reduced flak effects on bombing. Table 11 shows how the heavies roll.

In the boxout we show the percentage damage for a single squadron attack, and in the x6 column the cumulative damage for a full heavy bomber group. If anything, these numbers reveal that the game looks more lethal than historically, as these values suggest it would take 4 squadrons of heavies to heavily damage a Factory target, and 12 squadrons, or two bomber groups, to fatally damage it.

At this point it’s time to hold my hands up and agree that this appears to be overcooking the effects of strategic bombing. Factories were difficult to destroy, not least because they were hard to find, they could be defended with flak and smoke screens, and larger raids suffered from the problem of bombing short caused by the dust and smoke from the first waves.

The assumption in Table 11 is that the game is generating optimal results. For example, it does not reflect the effects of flak. A single Hvy Flak A battery using barrage fire would  inflict a bombing modifier on 27% of the attacking squadrons, reducing the bomb group from 150% to roughly 125% effectiveness, and increasing the flak density can greatly reduce that effectiveness. Air action can reduce it even more. If we were to add in the effects of weather and countermeasures, we would knock the numbers down further. For example, applying a -1 defence modifier marker to represent smoke screens immediately drops the x6 effectiveness to from 150% to 78%. Adding defence modifiers for follow-on waves as a scenario special rule to reflect short bombing begins to give us results that look far more historical.

Of course a problem with making high-altitude bombing more realistic is that it can increase the frustration of players playing the game. Too much realism can suck, and in scenario design we need to find a sweet spot where the raiding player is challenged by the problem of bombing while not feeling the game mechanics are conspiring to exasperate them.

Torpedo Bombers

Torpedo bombers are an interesting case, in that they match a fixed bombs value (BV 20) up against hard-to-hit targets, but unlike dive bombers they are unaffected by the armour modifiers of battlecruisers and battleships. A lucky hit will blow all but the biggest ship sky-high, but the mean damage will be far lower. It’s worth noting that Torpedo bombers are vulnerable aircraft that will have to transit a lot of flak. Given that most ships have two flak batteries aboard, there’s at least a 72% chance that a torpedo attacker will be affected by a bombing marker.

The base attack modifier for torpedoes is a +1 (we’ll ignore the early American torpedoes for this analysis) but unless stationary, ships will benefit from a -1 or -2 defence modifier, so the net modifier will be in the region of +0 or -1. The flak might tempt players to accept the long range attack modifier so as to launch from one square away, and depress the chances further. However, anvil attacks offer an opportunity to boost the chance of a hit. Table 12 shows the outputs from torpedo attacks.

As with all these tables, these are optimal numbers assuming no flak effects apply. With torpedo attacks the averages suggest that two or three squadron attacks are required to heavily damage a ship target. The high probability of flak effects may push that to three or four squadrons. For example, a -1 bombing marker would reduce the damage value percentage against a cruiser from 40% to 25%. Heavily-protected battleships may require the attention of a very large number of torpedo squadrons.

Rockets and Strafing

Finally, we take a look at the business of rocketing and strafing targets. As with bombs, the value of air-to-ground rockets has been nerfed downward. The singular characteristics of rockets are:

• Great accuracy (+3 base modifier)
• Lower BV than regular bombs
• Attacks must be pressed to the target’s square (though long-range attacks are possible with a penalty)
• Rocket BV is halved against certain targets
• Strafing can be combined with rockets

This adds up to a tool that is very useful against soft tactical targets, like Trucks and Trains. Table 13 gives us a view on the effects of rockets, without adding in the additional firepower of strafing.

On the face of it, comparing with Table 8 these numbers suggest that rockets are far more powerful than bomb attacks with fighter-bombers and are particularly devastating against soft targets such as Trucks. (The ORS data from Normandy might bear this out.) However, a caveat must be applied, which is that the damage is effectively capped by the lower bombs value. 8x HVAR will never achieve more than 7 hits on a target, and so can never inflict more than heavy damage to tanks in a single attack. Adding the aircraft’s firepower for strafing can raise this value slightly–the P-47 can add 2 for strafing and the Typhoon 3. However, this remains a tradeoff with bombs, which will inflict lower mean damage but higher maximum damage.

Conclusion

Wargame combat systems are rarely perfect and Wing Leader is no exception. The bombing rules try to encompass a wide range of situations and have an answer for them all. These mechanics use an attritional model which, it could be argued, might be less appropriate when applied to some targets, such as ships, which tended to be vulnerable to hits on critical systems rather than the slow chipping away of strength. However, they key thing is not the detail but the overall outputs.

The first edition had a major problem with bombs values, which made it too easy for single squadrons to obliterate targets. The second edition does a better job of giving believable ballpark outputs. Unlike the old numbers, medium bomber squadrons will not obliterate all targets with their low-level attacks. There are tradeoffs associated with different attack profiles. Fighter-bomber flights have become more viable against tactical targets. This article provides a window into the kinds of results you’ll see from the second edition.

You can order your copy of second edition Wing Leader: Victories here.

If you already have a copy, order your update kit here.

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Articles in this Series: Part 1  Part 2