Target Schweinfurt

[wuzak]

...With de Havilland Mosquitos.

The ball bearing industry was identified as one of the main targets for bombing by the USAAF target selection committee. It was thought to be a choke point for German industry, which it may have proved if the plants could have been bombed repeatedly in a short period of time.

The first full scale attempt was on August 17th, 1943, by the 8th AF. The original planne called for this to be followed up by RAF Bomber Command that night, but BC ended up striking the weapons development and testing facility at Peenamunde instead.

But what if we use Mosquitos for the task - as a complement to the 8th AF effort, or as an alternative?

On the August raid, the B-17s carried 3 x 1000lb GP bombs plus 5 x 100lb incendiaries. Reconnaissance afterwards showed that there were some 80 direct hits on the plant with HE bombs - ie the 1000lb GP bombs.

The bomber Mosquito available in quantity at that time was the B.IV. The bomb load is usually specified as 4 x 500lb bombs, but they could carry 2 x 1000lb GP or 2 x 1000lb MC bombs. 627 squadron carried these loads in their B.IVs and B.XXs (Canadian built B.IV) on a raid on Gestapo Headquarters in Oslo in 1944.

The British 1000lb GP bomb was more prevalent at the time, the MC having entered production in the early part of 1943. The British 1000lb GP bomb had a charge to weight ratio of 33%. The 1000lb MC bomb had a charge to weigh ratio of 47% - equivalent to the US 1000lb GP bomb.The 500lb MC bombs had a charge to weight ratio, so two of them may be better than a single 1000lb GP bomb.

The British 400lb and 500lb IB incendiary bombs are similar in size to the 500lb MC bomb, but a little longer. No sure if they would fit in with a load of MCs, and I'm not sure it would be desirable on an industrial target.

Let's say we have 100 B.IVs at our disposal. What damage can we do to the target?

Can we get 80 direct hits on the factory buildings with 1000lb bombs?

From what altitude would the attack be made?

 

[wuzak]

My personal preference would be for a low level strike.

The advantages of this are
1) Radar is less likely to provide early warning to the Germans - at 15,000ft Radar could pick up the aircraft as much as 60 miles away, maybe more, but at sea level the radar's effectiveness is reduced.
2) Mosquito B.IV sea level performance is roughly on par with that of the Fw 190A and Bf 109F (and G?). That is, the defenders do not have a large performance advantage.
3) Low level bombing missions during daylight had a high degree of accuracy. Bombing may be more effective.
On the other hand low level bombing may not allow the bombs to break through roofs as well as from altitude, though falling roofs may have helped to protect equipment from blasts (per Donald Miller, Masters of the Air).
4) Low level raids eliminate one of the Mosquito's blind spots - behind and below.
5) Fast moving low level aircraft would be more difficult for anti aircraft defences to aim at and track.

The downside is that the target (Schweinfurt) would be at the edge of the operational radius of the B.IV Mosquito at sea level.

I would send them in 4 or 5 different groups, rather than as one large formation. These would take, as much as possible given range considerations, alternative routes.

I would not attempt to escort the bombers. Mustang Is, Spitfires V, XII and IX, and Typhoons could provide some cover, but only in teh genaral area, and not as close escort.

If the Mosquitos were to be used in conjunction with the 8th AF Double Strike on Regensberg and Schweinfurt I think the raid could be timed to use those forces as a distraction.

Mosquitos could be sent at the same time as the Regensberg force. My understanding is that RAF pilots had experience with instrument take-offs, so would have been able to cope with the fog that delayed the 8th AF. The Regensberg formation would spend some time joining up over the UK, during which time Mosquitos would be on their way to target. The Regensberg formation would probably still receive all the Luftwaffe's attention.

By the time the Schweinfurt force is ready to go - a couple of hours later, the Mosquitos may be back in England. If enough survive without damage they could be refuelled and rearmed, and sent again, after the Schweinfurt force is sent.

 

[Glider]

I would go in with one large group. The problem with different groups is that there would be a delay between them arriving over the target. The following groups would find the defences waiting and alert and quite possibly fighters overhead.

Also if some low level escort could make the trip, why not. If nothing else they could straff as a diversion, take on the gunners or intercept any fighters that might get in the way. That said I don't think any RAF fighters had the range.

 

[davebender]

How many Mosquito light bombers (i.e. not pathfinder, night fighter or recon aircraft) were available during 1943?

 

[Vincenzo]

105th, 109th, 139th Squadrons had Mosquito a january, ad december also 141st, 169th, 239th, 627th (i've just situation at january, july '43 and january 44 (i suppose that in december '43 was the same of january '44, the situation in july was the same of january)
Pathfinder squadrons were 105th, 109th, 139th, 627th (this from wiki)

 

[davebender]

Which squadrons were tasked with recon and night fighter missions?

 

[Vincenzo]

the list sure not include fighter unit, probably also not recon unit

 

[tomo pauk]

Maybe it would be the best to take off in early morning hours (say, 3:00 AM), so the light flak belt located at France and low countries is rendered useless?

 

[wuzak]

Which squadrons were tasked with recon and night fighter missions?

None of those.

Recon squadrons had PR Mosquitos.

 

[Balljoint]

The better strategy that could well have struck a significant blow was the original plan under which the RAF heavies were to bomb the night of the 17th. But Peenemunde was a flashier target.

1000 pound bombs are marginal for machine tool targets. This is particularly so with sensitive fuses that detonate upon roof impact. Unless the cast iron machine base is broken, the German machine operator, who were often master and journeyman machinists, could rebuild and repair the damage. The 4000 or 8000 pound bombs used by the RAF would have been more effective in a following raid with the machines buried under protective debris.
The RAF instead fixated on German cities and didn't get around to Schweinfurt until February. Opportunity lost.

 

[wuzak]

The better strategy that could well have struck a significant blow was the original plan under which the RAF heavies were to bomb the night of the 17th. But Peenemunde was a flashier target.

And it could be argued that the Peenemunde raid put back the development and production of the V1 and V2, delaying their operational use until after D-Day. V1s could have made a mess of the invasion beaches on or after D-Day (if Hitler was so inclined to use them in that way).

There was nothing stopping the RAF BC from hitting Schweinfurt on the 18th (maybe not possible?), 19th or 20th.

1000 pound bombs are marginal for machine tool targets. This is particularly so with sensitive fuses that detonate upon roof impact. Unless the cast iron machine base is broken, the German machine operator, who were often master and journeyman machinists, could rebuild and repair the damage. The 4000 or 8000 pound bombs used by the RAF would have been more effective in a following raid with the machines buried under protective debris.
The RAF instead fixated on German cities and didn't get around to Schweinfurt until February. Opportunity lost.

As you say, Harris was fixated on city busting. As that was the case he would have been very reluctant to spare the heavies on a "panacea" target. He may have released Mosquitoes, not involved in pathfinding, for such missions. To get the required number of Mosquitoes they would also have to be drawn from other commands.

As such you would be restricted to the 500lb and 1000lb GP and MC bombs, as the Mosquito was not yet cleared to use the 4000lb bomb. The GP bombs would be less suitable for damaging machine tools than the MC bombs or the US GP bombs. But at low level would it be possible for Mosquitoes to drop bombs through the walls, rather than the roofs, and therefore minimise the protection of machinery afforded by debris?

Also, it must be noted that the USAAF could have used 2 x 2000lb GP bombs, rather than 3 x 1000lb GP, bombs per aircraft, but chose not to. A case of needing more bombs to get a decent number of hits?

 

[davebender]

Maybe it would be the best to take off in early morning hours (say, 3:00 AM), so the light flak belt located at France and low countries is rendered useless?

Darkness has little effect on radar directed flak.

By attacking at night you will be intercepted by German night fighter aircraft rather then day fighter aircraft. Not sure that would be an advantage as German night fighters were pretty good by mid 1943.

Attacking at night means navigating and bombing in the dark. Schweinfurt is out of RAF radio navigation range so bombing accuracy will almost certainly be worse. There is a significant chance they won't even find Schweinfurt.

 

[iron man]

The unfortunate thing in this is the simple fact that German industry had amassed a huge surplus of finished product by this point. Even if complete destruction of German production is acheived, the Swedish production can be called on to "fill in the blanks" while the Germans restore production elsewhere.

As was pointed out upthread, utterly destroying machine tools was problematic unless direct hits on individual machines can be realized. This was proven out during post-war analysis of the Allied bombing effort.

The power grid would have been a far better target to go after...if such an effort were mounted; specifically the load control switching and transformer sites. This equipment was utterly fragile and more importantly? Productive capacity to provide for wholesale replacement of these items was virtually non existant; they built for expansion and maintenance. There was no way to suddenly have capacity to produce countless thousands of electro-mechanical switches. These are sophisticated devices; they were built by a few highly trained people...you can't throw a couple of thousand "Ostarbeiter" at a problem like this and expect a suitable resolution.

This was an opportunity missed. Bearings were a "panacea"

Hindsight is always 20/20.

 

[wuzak]

Darkness has little effect on radar directed flak.

And how much of the light flak defences in France in August 1943 was radar directed?

And when you say radar directed, do you mean that the radar tells them where the aircraft is or actually controls the gun? I would have though that in 1943 it was the former.

Flak wasn't exactly a raging success against Mosquitoes. And radar directed flak tended to be the bigger units, not the small ones that would need to engage Mosquitoes.

By attacking at night you will be intercepted by German night fighter aircraft rather then day fighter aircraft. Not sure that would be an advantage as German night fighters were pretty good by mid 1943.

Day fighters had marginal performance advantages over Mosquitoes during 1943, especially at certain altitudes - like sea level. As excellent as German nightfighters were in 1943 they would find it difficult to track down and shoot down bomber Mosquitoes.

Attacking at night means navigating and bombing in the dark. Schweinfurt is out of RAF radio navigation range so bombing accuracy will almost certainly be worse. There is a significant chance they won't even find Schweinfurt.

I am unsure as to the radio navigation range, whether Schweinfurt is within that range. But an attack at low level would make those systems unusable also.

Three months earlier 617 Squadron flew at low level in Lancasters at night and found their 3 targets - the Mohne, Eder and Sorpe Dams. Why couldn't Mosquitoes find Schweinfurt? It should be noted that the Luftwaffe scrambled nightfighters to intercept the dams raid, but they failed to make contact as they flew too high and their radars could not find teh Lancs near the ground.

3am departure would have them arriving in the Schweinfurt area at around 4:30-5:00am, which should give, even allowing for double daylight savings time (in effect during the summer months of the war in the UK), sufficient light to find and prosecute the target.

 

[wuzak]

The unfortunate thing in this is the simple fact that German industry had amassed a huge surplus of finished product by this point. Even if complete destruction of German production is acheived, the Swedish production can be called on to "fill in the blanks" while the Germans restore production elsewhere.

As was pointed out upthread, utterly destroying machine tools was problematic unless direct hits on individual machines can be realized. This was proven out during post-war analysis of the Allied bombing effort.

The power grid would have been a far better target to go after...if such an effort were mounted; specifically the load control switching and transformer sites. This equipment was utterly fragile and more importantly? Productive capacity to provide for wholesale replacement of these items was virtually non existant; they built for expansion and maintenance. There was no way to suddenly have capacity to produce countless thousands of electro-mechanical switches. These are sophisticated devices; they were built by a few highly trained people...you can't throw a couple of thousand "Ostarbeiter" at a problem like this and expect a suitable resolution.

This was an opportunity missed. Bearings were a "panacea"

Hindsight is always 20/20.

Be that as it may, the ball bearing industry was identified as one of the prime targets for bombing by the "experts" advising the USAAF.

Harris would probably have thought the electricity industry was also a "panacea" target.

 

[tomo pauk]

Darkness has little effect on radar directed flak.

By attacking at night you will be intercepted by German night fighter aircraft rather then day fighter aircraft. Not sure that would be an advantage as German night fighters were pretty good by mid 1943.

Attacking at night means navigating and bombing in the dark. Schweinfurt is out of RAF radio navigation range so bombing accuracy will almost certainly be worse. There is a significant chance they won't even find Schweinfurt.

Wuzak covere this already, so just some things:
I was talking about 'light flak belt'. Light flak was being radar directed (= hands off) some time in 1960s, IIRC Bofors leading the way with Girrafe + 40L70 combination? Flying at 500-1000 ft, the heavy flak, even the one receiving target information from the fire control radars (but still operated 'hands on') was ineffective. More so with a fast cruising target - Mosquito.
The German night fighters would be hard pressed to find the Mosquitoes with ground clutter cutting in, and even with Mossie found on the radar screen there is only a slim (non existing?) chance to catch one, because of target's high speed.
The early morning take off can insure that a good part of the sortie the LW day fighters would not present the threat. Once the dawn sets in, the Mossies are in Germany proper already, and in short time their bombs are off, and the cruise speed can be further upped.

 

[Balljoint]

And it could be argued that the Peenemunde raid put back the development and production of the V1 and V2, delaying their operational use until after D-Day. V1s could have made a mess of the invasion beaches on or after D-Day (if Hitler was so inclined to use them in that way).

There was nothing stopping the RAF BC from hitting Schweinfurt on the 18th (maybe not possible?), 19th or 20th.

As you point out, Hitler viewed the V1 and V2 as terror weapons rather than tactical. As he said, "terror can only be broken with terror".

Peenemunde could have been hit over a large window of time. Schweinfurt offered only a small window of opportunity. The only thing stopping a RAF raid on the 18th or 19th was the same thing that stopped the 17th raid –Harris. Harris viewed the ball bearing strategy as "completely mad".

There was one serendipitous consequence to the raid. A key project working on the Me-262 was destroyed substantially delaying production. But Hitler already had delay pretty well covered.

 

[tomo pauk]

Harris viewed the ball bearing strategy as "completely mad".

Was he wrong about that?

A key project working on the Me-262 was destroyed substantially delaying production.

Care to elaborate about the 'key project working on the Me-262'?

 

[davebender]

WWII era flak wasn't terribly accurate vs aircraft that spent most sorties at high altitude. On the other hand bombing accuracy was almost always bad from high altitude.

When aircraft attack from low altitude to achieve decent bombing accuracy then a large number of aircraft can expect to get chewed up. It makes little difference whether the bombers are Lancasters or Mosquitos.

 

[wuzak]

WWII era flak wasn't terribly accurate vs aircraft that spent most sorties at high altitude. On the other hand bombing accuracy was almost always bad from high altitude.

When aircraft attack from low altitude to achieve decent bombing accuracy then a large number of aircraft can expect to get chewed up. It makes little difference whether the bombers are Lancasters or Mosquitos.

What is your evidence for this Dave?

Did Mosquitoes get chewed up from low level?

Do you think a target flying at least half as fast again may be a more difficult target to hit?

Is flak more accurate at low level?