A "what if" discussion, if the allies had primarily used "fast" bombers

[Mr_sukebe]

Here’s a discussion point that I thought might be interesting to open to the wider audience of this forum.

 

The question being, “how might aerial warfare in WW2 have developed if the UK and US had standardised on “fast bombers”, e.g. Mosquito or similar.

Upfront, this is a theoretical only discussion, and I’d like to avoid getting into “this is better than that, purely because we operated it”.  In short, please be polite and respectful to your fellow forum members.

 

My understanding of what actually happened in WW2 is:

• Pre-war, no only knew how “bombing” would play out.  I believe that the prevailing view following the Spanish civil war, was that “the bomber will always get through”.  My assumption being that the expectation was that a combination of determination, numbers and self protection would be enough for bombers to make it through to their targets
• Linked to the above, and following Guernica, I get the impression that the press and a good deal of the public, expected any city/country being repeatedly bombed would almost certainly capitulate
• How this translated into bomber design is probably best illustrated by the types of bombers that were in service at the start of say 1940.  In the heavier bombers, the US had B17s,  the RAF the Hampden and Wellingtons (clearly others, but these are good examples).  ALL of these subscribed to the use of self defence, with a variety of turrets and gun mounts
• How effective the bombers were in reality was rather quickly shown.  The losses of the RAF bombers were such that they mostly stopped daylight bombing and shifted to night time bombing.  Unsurprisingly, that had result of the accuracy of navigation and bombing being pretty damn hopeless until direction finders and similar were developed.  I did read one story of an RAF bomber which had taken off to attack a city in northern Germany and only realised on the day after that they’d actually nearly bombed Liverpool
• With such poor accuracy, the RAF also shifted it’s bomber force from tactical strikes on military targets (capital ships being a good example) to “strategic” bombing of population centres, working on the assumption that the population would demand they surrender and also disrupting the “workforce”.  As shown by productivity in both the UK and Germany over the period of the European war, it achieved neither
• When the US started to undertake daylight raids, they very quickly found out just difficult it really was.  I’ve read of typical loss rates of circa 10%.  Applying that and your average aircraft crew has at 7% chance of surviving 25 missions
• Additionally, whilst the Norden gunsight was supposed to enable real precision bombing, we also know that it simply...didn’t.  Accuracy was nothing like the claims by the manufacturer.  Apparently the Germans had acquired the plans prior to the start of the war and rejected it.  The RAF asked to buy it and when finally allowed to test one, simply didn’t think that it was worth the expense to fit.  As we now know, the US themselves ended up moving towards more strategic style bombing, (e.g. involvement in Dresden) and that from the start of 1945 applied strategic “firebombing” to Japanese cities

 

In short, high level strategic bombing really didn’t achieve much of it’s supposed aims and the cost was phenomenal.  Apparently something like a 1/3^rd of the allied “spend” on military equipment was spent on the bombers forces.

 

 

In parallel to the above, towards the end of the 30’s the RAF were offered the Mosquito as a design  The proposal being that it was very difficult to catch, as it eschewed the use of turrets and similar, which added weight and increased aerodynamic drag.

The RAF initially showed little interest and it was mainly good fortune that the manufacturer continued to develop it regardless

The stats of the Mosquito are an interesting comparison:

• Losses were less than 1%
• It could very nearly carry the same bomb load as a B17
• Only needed 2 crew
• Had the range to hit Germany
• I’ve not found the cost per aircraft, but my assumption is that they were substantially cheaper than say a B17 or Lancaster

    

Additionally, and whilst not often mentioned, I can’t help but think that in many ways, it set the example of how most bombers were designed in the future, I.e. Typically relying on speed/altitude for self protection. Great examples being the Canberra and many follow on strike aircraft (e.g. Tornado, Jaguar, F111 etc).  Whilst initially you make not think it, even the B52 was fast at it’s introduction, being able to maintain at high sub-sonic speed over a LONG distance.  In short, most post war strike/bomber aircraft design used same type of core design principles.

 

 

Back to my opening question.  Imagine that the allies had NOT gone down the route of relying on bomber self defence and had instead bought “fast” bombers like the Mosquito.  Whilst the P38 was initially built as a long range fighter, and didn’t have the range of a Mosquito, it could carry a similar bomb load, and with some further design, I refuse to believe that something like an updated P38 couldn’t have been built by the US to extend it’s range and make it almost directly comparable to the Mosquito.  Yes, I know that the US was offered the design of the Mosquito, but we know they wanted to make an aircraft with a metal airframe, and the objective of this discussion is not to start criticising aircraft.

 

So picture the scene in 1942, the RAF are churning out thousands of Mossies (no Lancasters or normal heavies) and the US turn up with their equivalent (let’s call it a P38LRBomber).  How do we think that might play out?

• Would the RAF have been more inclined to carry out more “tactical” bombing of military targets?
• Would the Luftwaffe have placed thousands of flak guns around German cities?  If not, how might they have used them?
• Whilst the above figures are about allied bomber losses, along the way, B17s and similar in daylight raids certainly shot down Luftwaffe aircraft.  Could the allied fast bombers have shot down Luftwaffe interceptor aircraft?  If not, what kind of problem would that have created?
• How would Luftwaffe aircraft design have evolved.  My assumption is that they wouldn’t have felt the need for as many guns or as much armour, probably making the “interceptors” like the 190A8 a good deal faster
• Would allied bomber losses have actually been lower?  The obvious thought is “of course”.  However, we know that the Luftwaffe would have responded in a different way.  Would the fast bombers have simply been intercept by faster 190s and losses been just as bad?
• If the “fast” bombers were cheaper to build, would there have been more in the air?  There’s still a limitation on the number of trained pilots available, as the Luftwaffe also found out?  Having said that, could you have split a B17 pilot/copilot across two fast bombers?
• Would general bombing accuracy have been better?  We know that low level strikes were FAR more accurate than high level from 20,000’, but if there had been 30,000 fast bombers, would they have been used that way?
• How might bomber tactics play out?  Part of the expectation of the use of the B17s was the “combat box”, which when entered by an enemy fighter means that it’s not going to be shot at by a single turret gunner.  It may have 10 different aircraft shooting at it.  Would the “safety in numbers” idea still work when there are no defensive weaponry?  I’m assuming not, but does that mean that instead of 1000 bomber strikes, that there might have been 100 different strikes of 10 aircraft, all at different times, altitudes and angles?

 

Just a few thoughts/questions.  I’m curious about the views of others on the subject.

[Svsmokey]

Two thoughts occur....I think you may have overstated the relative bombloads of the Mosquito vs the B-17 . The former's small bomb bay meant it could only carry 4 (modified) 500 lb bombs . The B-17's average 500 lb bombload was 8 , and it could carry much more .

More to the point of such a thoughtful post , i surmise that a "fast bomber" campaign would have proven a negative for a secondary (but very important) purpose of the bombing campaign-clearing the skies of the Luftwaffe over Europe prior to D-day .

The more dispersed operations , the lack of defensive armaments of the fast bomber (3 german fighters were shot down by gunners for every B-17 lost to air attack) , effects on escort fighters and the difference in political and other pressures resulting from attacks on military targets vs cities would all seem to point to a less-effective campaign to destroy the Luftwaffe .

Edited July 11, 2022 by Svsmokey

[Dragon1-1]

13 hours ago, Svsmokey said:

The more dispersed operations , the lack of defensive armaments of the fast bomber (3 german fighters were shot down by gunners for every B-17 lost to air attack) , effects on escort fighters and the difference in political pressures resulting from attacks on military targets vs cities would all seem to point to a less-effective campaign to destroy the Luftwaffe .

Unless the targets hit would have been airfields. A single Mossie is capable of potentially taking out an entire squadron of German fighters, as long as they're on the ground and not in the air. With their speed, they could disable German radars and then hit their airfields with the planes still parked there. This would be not entirely unlike modern tactics to achieve air superiority - SEAD/DEAD first, runway strike OCA second. Fast bombers could be very precise, hard to kill and still hit hard enough to destroy their targets. Indeed, of the 4 bombs on the Mossie, it would get more on target than a B-17. 

[Mr_sukebe]

15 hours ago, Svsmokey said:

Two thoughts occur....I think you may have overstated the relative bombloads of the Mosquito vs the B-17 . The former's small bomb bay meant it could only carry 4 (modified) 500 lb bombs . The B-17's average 500 lb bombload was 8 , and it could carry much more .

More to the point of such a thoughtful post , i surmise that a "fast bomber" campaign would have proven a negative for a secondary (but very important) purpose of the bombing campaign-clearing the skies of the Luftwaffe over Europe prior to D-day .

The more dispersed operations , the lack of defensive armaments of the fast bomber (3 german fighters were shot down by gunners for every B-17 lost to air attack) , effects on escort fighters and the difference in political pressures resulting from attacks on military targets vs cities would all seem to point to a less-effective campaign to destroy the Luftwaffe .

 

Some interesting thoughts.

Couple of points:

• Whilst I've not found what I'd consider a truly "credible" source, from doing a search since first reading your point, I got the impression that a general consensus was pointing towards 2 Luftwaffe fighters being downed for every 3 B17s.  If that is true, then it really isn't a great trade, particular since even the lucky members of the shot down B17 who successfully bail out are likely to end up in a POW camp, whereas if the Luftwaffe successfully bails out, then he's likely to have a new plane waiting for him.  I got the impression that the Luftwaffe towards the end of the war had more aircraft than pilots and fuel to use them.  If you've got a better source, then please do add
• Whilst the DCS Mossie can currently only carry 4 bombs, the real "bomber" Mossie (can't remember which revision) could carry a 4000lb "cookie", which is far more comparable to the B17 bomb load, particularly so if delivered with a high level of accuracy at low level, as against carpet dropped from 20,000 feet.

All the same, you make a good point that B17s probably shot down several thousand Luftwaffe aircraft, and it would seem highly unlikely that "fast bombers" could have done the same.  Whether it might have been cheaper/possible to send additional escorts is an interesting question.

Edited July 10, 2022 by Mr_sukebe

[Svsmokey]

2 hours ago, Dragon1-1 said:

Unless the targets hit would have been airfields. A single Mossie is capable of potentially taking out an entire squadron of German fighters, as long as they're on the ground and not in the air. With their speed, they could disable German radars and then hit their airfields with the planes still parked there. This would be not entirely unlike modern tactics to achieve air superiority - SEAD/DEAD first, runway strike OCA second. Fast bombers could be very precise, hard to kill and still hit hard enough to destroy their targets. Indeed, of the 4 bombs on the Mossie, it would get more on target than a B-17. 

Low-level WW2 airfield attacks were famously costly , being very heavily defended . Further , the simple tactic of using dispersal airfields would render such attacks less effective . 

[Svsmokey]

I read of b-17 kills vs losses quite some time ago . I'll try to find the reference . While interception of a heavy bomber stream was easy , and the resulting opportunity for escorts to engage high , imagine how difficult it would be to intercept small units moving very low and fast , thus providing little chance for escorts to engage . I take your point regarding the 4000 lb bomb , but that bomb would be of limited use generally . And , again , the comparison is the max bombload of the Mossie vs the average bombload for a B-17 . The 500 pound bomb had much more general use-at least among the Allies .

1 hour ago, Mr_sukebe said:

Some interesting thoughts.

Couple of points:

• Whilst I've not found what I'd consider a truly "credible" source, from doing a search since first reading your point, I got the impression that a general consensus was pointing towards 2 Luftwaffe fighters being downed for every 3 B17s.  If that is true, then it really isn't a great trade, particular since even the lucky members of the shot down B17 who successfully bail out are likely to end up in a POW camp, whereas if the Luftwaffe successfully bails out, then he's likely to have a new plane waiting for him.  I got the impression that the Luftwaffe towards the end of the war had more aircraft than pilots and fuel to use them.  If you've got a better source, then please do add
• Whilst the DCS Mossie can currently only carry 4 bombs, the real "bomber" Mossie (can't remember which revision) could carry a 4000lb "cookie", which is far more comparable to the B17 bomb load, particularly so if delivered with a high level of accuracy at low level, as against carpet dropped from 20,000 feet.

All the same, you make a good point that B17s probably shot down several thousand Luftwaffe aircraft, and it would seem highly unlikely that "fast bombers" could have done the same.  Whether it might have been cheaper/possible to send additional escorts is an interesting question.

 

 

[Svsmokey]

https://390th.org/learn-about-390th/wwii-air-war-over-europe/

This site lists 6000+ fighters shot down by 8th Air Force gunners alone .

[Svsmokey]

Took some digging , but according to the USAAF , 2,452 heavy bombers shot down by enemy aircraft in the ETO , 6098 enemy aircraft shot down by heavy bombers in the ETO . I wish they had broken down B-17 vs B-24 , which was easier to shoot down & thus skewed the ratio (2.49) lower .

Source:

https://apps.dtic.mil/sti/citations/ADA542518

Edited July 11, 2022 by Svsmokey

[Bremspropeller]

I think you'll arrive at a much more realistic figure if you divided those +6000 by ten.

 

[Mr_sukebe]

14 hours ago, Svsmokey said:

Took some digging , but according to the USAAF , 2,452 heavy bombers shot down by enemy aircraft in the ETO , 6098 enemy aircraft shot down by heavy bombers in the ETO . I wish they had broken down B-17 vs B-24 , which was easier to shoot down & thus skewed the ratio (2.49) lower .

Source:

https://apps.dtic.mil/sti/citations/ADA542518

 

Great link, my thanks for that.

Some interesting stats within that I thought that I'd pull out:

• Claimed enemy aircraft killed by Heavy bombers in ETO (pg263):   6098
• Claimed enemy aircraft killed by fighters in ETO (pg263): 14218
• Heavy bomber losses in ETO to fighters (pg 255):   2452
• Heavy bomber losses in ETO to AA (pg 255):  2439
• Fighter losses in ETO to fighters (pg 255): 1691
• Price of B17 (pg134):  $301k to $187k (I assume due to improving productivity)
• Price of P38:  $134k to $97k
• Price of P47: $113k to $83k
• Price of P51: $83k to $51k 

Some thoughts on the above:

• Yes, the claims are that each heavy bomber downed also resulted in the loss of roughly 2.5 enemy fighters.  Having said that, those as "claims" and I'd be surprised if the enemy downed figure was accurate.  I'll also re-iterate the point that an aircraft downed doesn't necessarily mean a loss of the pilot if he can get out in time.  The best case scenario is 10 B17 crew either killed or POW, vs 2.5 Luftwaffe fighter pilots, roughly a ratio of 4:1.  Being fair on the claims, you can rather understand it.  Just how do you decide who achieved the "killing shot" when you're in a combat box formation and maybe there's 100 M60s trying to shoot the same 190.
• The claimed kill loss ratio of US fighters is roughly 9:1.  Again, a rather "ambitious" figure.  All the same, it's interesting that the fighters claim to have killed over twice as many.  That would rather infer that it was massively more cost effective in man-power to use allied fighters to knock out enemy fighters.
• The outright cost for a P51 (nearly a 1/4 of the cost of a B17) along with the above ratio on kills by fighters does make me wonder why using bombers to kill fighters was considered as a suitable tactic

 

Keep it coming guys, this is interesting stuff.  My thanks again to SVSM for the link.  A LOT of data, but some really interesting bits within it.

 

Edited July 11, 2022 by Mr_sukebe

[jurinko]

I wondered about that as well. What if you send swarms of P-38 jabos to attack Ploiesti, try to hit certain installations (damaged atmospheric distillation column stops the whole refinery) and you can run away or fight enemy fighters on even terms. Instead of losing sixty cumbersome B-24s and hundreds of trained personnel trying to do the same at half speed and 10 times the cost. 

Concerning the less bomb load for Mosquito, you can get 2-3 mosquitos for cost of one B-17. There are scenarios where big bombers were effective, like breaking the Saint Lo defense line, but more widespread use of fighter bombers hitting precisely for a fraction of cost could increase overall air power efficiency. 

 

[Svsmokey]

On 7/11/2022 at 10:19 AM, Mr_sukebe said:

The outright cost for a P51 (nearly a 1/4 of the cost of a B17) along with the above ratio on kills by fighters does make me wonder why using bombers to kill fighters was considered as a suitable tactic

The thing is , the bombing campaign should be credited with the kills by escort fighters as well , as these could not happen without the Luftwaffe rising to intercept the bombers . 

The Luftwaffe tried a similar gambit during the Battle of Britain , but was foiled by British small-unit tactics , among other things .

I'm leaving this discussion now to provide air for other ideas as to how the effects of a fast-bomber campaign may have changed history . Great OP . 

Edited July 13, 2022 by Svsmokey

[Bozon]

Replacing the heavy bombers with fast bombers is the wrong way to look at it - you have to completely reimagine the airwar. Forget bomber streams, forget escort fighters as we know them, forget carpet bombing to destroy 1 building. So lets try.

Fast light bombers "Mosquito style" that relay on avoiding interception do not fly in large formations - heavy bombers do because they rely on mutual gunners protection and it is easier for the escort fighters to protect the sheep when they are clustered together. Fast bombers that want to avoid interception come either very high, or very low. Lets start with high.

High penetration: Mosquitoes could fly at 30k and were about as fast as the fighters. This limits interception to front sector and forces the defenders to climb to altitude well in advance of the bombers - they have to climb higher (30k vs. ~20k of heavy bombers) and have half the time to do it. This means that any change of flight path by the bombers will render interception very difficult to impossible. The defenders have to compensate by launching from multiple airfields at different regions to vector in to this one formation. The interception requires close control by the GCI. Therefore multiple penetration routes will put a huge strain both on the number of interceptors required and the ability of GCI to handle multiple interceptions simultaneously.

The interceptors will have difficulty to attack from above with energy advantage because everyone are flying close to their ceiling - so interceptions are largely flat. If interceptors fall behind they will not be able to catch up with the bombers, or do so very slowly and be vulnerable to escort fighters. Relatively minor course corrections can foil a head on attack and individual planes are more free to manauver out of the way of front sector attackers since a tight formation is not required. In case of attcks from the rear sector, the escort fighters only need to make the interceptors break once to make them fall out of the race. Escorts will enjoy a much larger effective range since they can fly faster close to their optimal speed and do not need to zig zag in order to stay with the bombers - with the mosquitoes, their cruise speeds were higher than the escorts (with drop tanks) so they needed to slow down for their escorts not to waste to much fuel. The speed also means much less time in crossing flak zones.

The final attack would be done from much lower altitude in order to ensure accuracy. This means that starting from quite a large distance from target the bombers can enter a shallow dive and perform the last legs at a VERY high speed rendering interception at this stage almost impossible.

Low penetration: Intecepting a NOE small formation was increadibly difficult during WWII, unless by chance. Radar is of little help and information from ground spotters was too slow to reach the interceptors. Interception involved a lot of guess work to anticipate the future position of the targets to intecept and required a relatively large number of interceptors to covers a large area of search. Again this puts a huge straign on interceptors force and the GCIs relative to the number of bombers, especially if multiple interception attampts are happening at the same time over a large area. Multiple formation penetrating at different paths confuse the GCI since it is difficult to build a coherent picture from the multiple spotters reports that spot different formations. Mosquitoes proved to be difficult to shoot down in a maneuvering combat, thus if intercepted escort fighters have the ability and time to engage and clear bombers that are in combat with enemy fighters, at least enough to allow them to run away from the interceptors - even if it means that the mission is foiled, only few bombers will be lost. THESE bombers might not get through, but it means that others will, and these will return another day (or even on the same day given half the mission time of heavy bombers).

General strategy:

As I explain above, fast bombers require a large interception effort per bomber formation - much more than heavy bombers that are detected at a large distance, are completely predictable, and there is a large number of them at the same location. Therefore instead of streams, fast bombers would have been used with small escorted formations penetrating at different paths and split between high and low penetrations to put maximum strain on the interceptors. Since light bombers are cheaper and reuire less crew, you can have many more of them than heavy bombers and strain the defenders even more.

Instead of one big attack per day, the attacks can be staggered so intetrceptors that launched to the first bombers will be returning to base to refuel while new formations are penetrating - this means that the defenders have to maintain a still even larger interceptors force to keep up the rotation. Interceptors have to be spread all over the territories in many airfields in order to have some in the interception cone of a bomber formation - this is a nightmare to manage.

Deception tactics - bombers that fly as fast and as high as fighters and in small formations look the same on radar. When the GCI vectors interceptors he cannot tell if he is intercepting bombers or fighters, so formations of fighters that perform sweeps also act as bait, that draw away interceptors and engage them in combat. This both wastes interceptors resources and makes them engage dangerous fighters that are free from escort duties and are eager to engage.

Attacking targets from low altitudes allow precision bombing. To destory a factory you do not need 50 heavy bombers to lay waste to everything within 5 miles radius, and more often than not still miss the target - you only need 1 or 2 small bombers to reach and lob their bombs through the front door. Many such targets that require a little less precision can even be attacked at night when the moon is full, or using illuminations flares. Mosquitoes demonstrated both day and night low altitude precision attacks were possible. Night attacks are even more difficult to intercept than day attacks and the same bomber force would be able to do both, while night and day interceptors are normally NOT the  same force - thus defense requires to produce also a sizeable night fighters force. Did we mention straign on the defenders resources?

My conclusion is that a large force of small fast bombers would have been singincantly more effective than the heavy bombers force. These would not be only moquitoes as other types would have been developed has this been the strategy. The interceptors force would also be different and optimized to hunt smaller pray, though I doubt the difference in types would have been as dramatic. The claim that the purpose of the heavy bomber force was to draw out the lufwaffe to get shot down does not hold water. Small bombers would have drawn out the interceptors as well and the escorts/sweepers could have engaged in an even more favoarable conditions. The losses that the heavy bomber force sustaned were HUGE both in manpower and in material, and did not justify the losses inflicted upon the lufwaffe. The bombing effectivness on strategic ground targets would have increased significantly when using small bombers, minus the war crimes of the heavy bombers in bombing cities into firestorms.

I don't blame the decision makers of the time. They were not stupid. It was just completely radical change from everything that came before it and at the start of the war just as unproven as the heavy bombers raids. They went with what they knew and prepare for before the war.

Edited July 16, 2022 by Bozon

[Mr_sukebe]

Bozon,

Thanks for your thoughts.

As you say, there's some interesting options that the fast bomber groups could use to "spoof" and/or make it much more difficult to intercept.

Having said that, we know that the Luftwaffe also had some very bright sparks, and they'd certainly try to respond to that.  It's interesting to try to imagine how that escalation might have played out.

[Svsmokey]

Alternative history is interesting because its discussion can inform actual history .

So i am bumping a worthy topic .

[Mogster]

You could write a book on this topic easily…

Just a couple of points.

Assuming your “fast” bomber force is extensive enough to destroy/disable large important targets you first have to identify what’s important to the enemy war effort.  Industrial intelligence in WW2 was very limited, neither side really understood the others war economy in any detail and what was needed to really damage their military efforts. When Germany started to to build the V1 and V2 launch sites the USAAF and RAF was tasked with attacking them just because it had been noticed that the enemy was putting a lot of effort into building them. For a long time the allies were unsure what they were actually for. When operation Chastise attacked the Ruhr hydro electric dams the actual detail behind the raid and its objectives were highly sketchy. Just a vague “this is the power and if we turn it off then we can reduce the enemy’s industrial capacity”. No detail around how much of the Ruhr industries power was provided by the dams, which dams were the most important, what were the individual factories making? How long would repairs take etc etc etc.

The results of precision attacks on specific targets tend to have been used for propaganda purposes and so are well known, but in reality these attacks were rare. The attacks were rare no so much because of a lack of capability but a lack of intelligence and the ability to identify suitable targets.

If your real time knowledge of your enemies industrial strategy is poor to non existent then you are left with gross assumptions. “If I destroy this city where X is probably produced then the enemy industrial capacity will be reduced” you’re left with an area bombing strategy as was followed mostly. No “fast” bomber could carry the range of loadouts a heavy bomber could. Even if the “fast” bomber could carry a similar overall load the option to carry many small bomblets or incendiaries made area bombing much more effective. Also in WW2 no “fast” bomber could carry the heavy specialised ordinance to destroy hardened targets either. 
 

https://www.lancaster-archive.com/lanc_bomb_loads.htm