What if America built De Havilland Mosquitoes instead of the B-17 Flying Fortress?

[JDCAVE]

As an aside, there were plans for a twin carrier for the 2,000lb armour piercing bombs for the Mosquito.

The obvious target for such a load would be ships, but would they be useful against reinforced bunkers?

Dad dropped 12 X 1,000 lb A.P. A.N.M. bombs on the U-boat pens at Bergen Norway. I understand they bounced off. The Tallboys dropped by 617 and 9 Squadrons on a later date penetrated the roof and put the pens out of commission.

jim

 

[wuzak]

AP bombs were typically used against shipping. I fail to see what use a bomb with a 9% charge to weight ratio would be against oil targets. Better to use HC bombs against such targets. 2, 4, 8, or 12,000 lb HC munitions were routinely dropped on oil targets. The charge to weight ratio was 71% for the 2,000lb bomb. Lots of these were dropped by Halifaxes during the war.

Jim

drgondog opined that dropping a mixture of HE and AP bombs of 2,000lb and up against oil and industrial targets would have been better than using HE bombs in the range of 250lb to 1,000lb as was done historically by the 8th AF.

Part of the discussion involves the idea of using Mosquitoes to attack strategic targets. That inevitably involves discussing what bombs the Mosquito could use - and the 2,000lb AP was the largest AP bomb that the Mosquito could carry, with an adapter to carry two such bombs was in the works, albeit very late in the war.

And as you said, the 2,000lb AP bomb would not be that useful due to its low charge weight.

Neither the Mosquito or B-17 could carry the 8,000lb or 12,000lb HC bombs. The 2,000lb HC bomb was too long to fit in the Mosquito or B-17, but could be carried externally on the B-17.

From what I've read, as the oil campaign dragged on the 8th AF actually moved to using larger numbers of smaller bombs, essentially carpet bombing the area in order that they may get some hits on vital equipment.

 

[wuzak]

Dad dropped 12 X 1,000 lb A.P. A.N.M. bombs on the U-boat pens at Bergen Norway. I understand they bounced off. The Tallboys dropped by 617 and 9 Squadrons on a later date penetrated the roof and put the pens out of commission.

jim

I would suggest that most oil and industrial targets did not have the same level of protection as the U-boat pens.

I think that drgondog 's thinking is that the AP bombs will penetrate areas were regular HE bombs would not.

In December 1944 the Pölitz synthetic oil refinery was bombed by 200+ RAF bombers, including 617 Squadron using Tallboy bombs.

 

[wuzak]

IMO - a mix of 2000# AP with 2000#HE would have been a far superior load out for B-17/B-24 against targets like Schweinfurt and Petroleum/synthetic plants.

When I went to the Brookland Museum there was a test bomb used in the development of Tallboy and Grand Slam, specifically for ballistic testing. IIRC the nominal weight was 4,000lb.

If that was made into a production bomb with a similar charge-to-weight ratio as the Tallboy (~40%) that may have been the weapon you were looking for.

The only problem is the length - I'm not sure how long exactly, but likely too long for B-17 or Mosquito. B-17 would also need bomb bay mods, or carry them externally.

 

[Thumpalumpacus]

If I'm bombing a refinery I don't want AP. Fuse likely won't initiate until it buries into the ground, where the effects of its smaller charge will suffer more absorption from the ground, mitigating its damaging effects.

I'd hit a refinery with a mix of heavy HE and cluster-bomb submunitions, relying upon the former to tear shit up, and the latter to put odd leaks in the piping everywhere (with instant fuses) so as to complicate the repair process, as well as making the repair parties very nervous if I use delayed fuses on some of 'em.

AP will slice through most things it will hit in a refinery before exploding because while a refinery is big, the metal ain't that armory. AP shells in the Pacific were known to pass entirely through destroyers without detonating. Give me some big booms and a lot of small, randomly-fused small booms if I'm attacking something like this:

 

[JDCAVE]

drgondog opined that dropping a mixture of HE and AP bombs of 2,000lb and up against oil and industrial targets would have been better than using HE bombs in the range of 250lb to 1,000lb as was done historically by the 8th AF.

Part of the discussion involves the idea of using Mosquitoes to attack strategic targets. That inevitably involves discussing what bombs the Mosquito could use - and the 2,000lb AP was the largest AP bomb that the Mosquito could carry, with an adapter to carry two such bombs was in the works, albeit very late in the war.

And as you said, the 2,000lb AP bomb would not be that useful due to its low charge weight.

Neither the Mosquito or B-17 could carry the 8,000lb or 12,000lb HC bombs. The 2,000lb HC bomb was too long to fit in the Mosquito or B-17, but could be carried externally on the B-17.

From what I've read, as the oil campaign dragged on the 8th AF actually moved to using larger numbers of smaller bombs, essentially carpet bombing the area in order that they may get some hits on vital equipment.

But the Mosquito could carry the 4,000 lb HC. i see no reason to carry AP munitions to an oil target.

 

[WARSPITER]

The tallboy type bomb is useful if you want to 'sink' infrastructure. The idea of these bombs was to hit in or close to structures. The bomb
was designed to penetrate below ground before detonation. Torpex was 1.5 times more powerful than tnt so a lot of heat is generated
when detonation takes place. This makes a camoflette which means it literally vaporises the earth around the explosion, creating a large
underground hole. For buildings this is bad news as the foundation on one side can suddenly disappear and the building tips into the hole.

Good example is one of the concrete V2 launch buildings. Literally useless after one such attack as the whole structure was 'tipped', even
though it had a concrete and steel hide that couldn't be penetrated.

Any large buildings / structures at oil facilities would suffer the same fate. Very hard to jack a building up to level. Chalk up another one
to Barnes Wallis.

 

[drgondog]

AP bombs were typically used against shipping. I fail to see what use a bomb with a 9% charge to weight ratio would be against oil targets. Better to use HC bombs against such targets. 2, 4, 8, or 12,000 lb HC munitions were routinely dropped on oil targets. The charge to weight ratio was 71% for the 2,000lb bomb. Lots of these were dropped by Halifaxes during the war.

Jim

The primary reason to insert AP into a mix of HE and Incindiary is to plow up hardened concrete substructure with subsurface explosions. That said, I don't know how effective they could have been.

 

[FLYBOYJ]

But the Mosquito could carry the 4,000 lb HC. i see no reason to carry AP munitions to an oil target.

But can it drop it accurately? I've read other comments where the reason why the Mossies were brought into the mix with 4000 lb HE was to "mix up the situation and piss off people," LOL!

 

[Thumpalumpacus]

The tallboy type bomb is useful if you want to 'sink' infrastructure. The idea of these bombs was to hit in or close to structures. The bomb
was designed to penetrate below ground before detonation. Torpex was 1.5 times more powerful than tnt so a lot of heat is generated
when detonation takes place. This makes a camoflette which means it literally vaporises the earth around the explosion, creating a large
underground hole. For buildings this is bad news as the foundation on one side can suddenly disappear and the building tips into the hole.

Good example is one of the concrete V2 launch buildings. Literally useless after one such attack as the whole structure was 'tipped', even
though it had a concrete and steel hide that couldn't be penetrated.

Any large buildings / structures at oil facilities would suffer the same fate. Very hard to jack a building up to level. Chalk up another one
to Barnes Wallis.

Now, getting one on a Mosquito ...

 

[wuzak]

But can it drop it accurately?

Can any aircraft drop the 4,000lb HC accurately?

An alternative would be the 4,000lb MC bomb, which was more accurate and also could be dropped at low level, if that was so desired.

I've read other comments where the reason why the Mossies were brought into the mix with 4000 lb HE was to "mix up the situation and piss off people," LOL!

Are you talking about the nuisance raids by the LNSF?

They, of course, were an attempt to lure night fighters away from the main raids by the heavies. And to do that they needed to provide some sort of threat, so the 4,000lb HC bomb helped with making Mosquito raids threatening for the Germans.

I have also read that Mosquitoes could disrupt the German war effort by flying over an area and triggering air raid warnings.

 

[wuzak]

Now, getting one on a Mosquito ...

The tallboy was roughly half the length of the Mosquito and only a couple of thousand pounds lighter than the empty weight of a Mosquito B.XVI.

A Mosquito carrying a Tallboy would be some sight!

 

[FLYBOYJ]

Can any aircraft drop the 4,000lb HC accurately?

Probably not - but then again we can start the debate about which bomber of WW2 was the best high altitude bombing platform for larger bomb delivery

An alternative would be the 4,000lb MC bomb, which was more accurate and also could be dropped at low level, if that was so desired.

Agree

Are you talking about the nuisance raids by the LNSF?

Yes, that was it

They, of course, were an attempt to lure night fighters away from the main raids by the heavies. And to do that they needed to provide some sort of threat, so the 4,000lb HC bomb helped with making Mosquito raids threatening for the Germans.

OK

I have also read that Mosquitoes could disrupt the German war effort by flying over an area and triggering air raid warnings.

Agree

 

[JDCAVE]

Probably not - but then again we can start the debate about which bomber of WW2 was the best high altitude bombing platform for larger bomb delivery…

Perhaps more productive is to discuss which specialized unit actually and most consistently delivered such ordnance to target with precision…

 

[MikeMeech]

It is not too small to matter it is to big to be taken seriously by anyone working in advanced science at the time. Your quoted date of 1893 is three years after Lord Rayleigh had done his experiment, which I did at school and I am sure many forum members did, dropping a droplet of camphor oil onto water covered in lycopodium powder, this typically estimates the size of a Camphor molecule as 1.7nanometers. As I remember my physics teacher telling me, the accuracy doesnt matter, at the time no one had any idea how big or small an atom or molecule was, if it is wrong by a factor of ten it was far too small for anyone to consider measuring with the methods they had in 1890. Johnson Matthey in London produced 30 bars of 90% platinum and 10% iridium and in 1889 bar number 6 was accepted as the closest to the prototype meter standard selected in 1799

The standard metre copy you describe when the USA took the metre standard was numbered copy bar no No 27, it deviated from the standard metre by 1.6 microns.

To summarise this part, while Angstrom was developing his Angstrom unit in the mid 1800s discussing measurements of 10 to the power minus 10 metres (10 to the power minus 7 mm) the world standards based on bars of metal couldn't produce reliable metal samples of a metre to better than 0.01mm, or 10 microns. In aerodynamics in the 1930s and 1940s companies like de Havilland and North American were discussing surface finish of 2 microns for polished aluminium and 5 microns for a good paint finish. Testing a paint surface for thickness and smoothness could induce irregularities or 1 to two microns. All of these measurements are below or in the ball park of the difference between the USA standard metre and the official standard held by in Paris by the Mètre des Archives).
As an inspector of 30 years working in metrology and other things I ca see the fundamental and unavoidable mistake made by the people concerned in the period 1799 and 1893, recognised by any person with a scientific background, can you?



Your point was made with respect to de Havilland ordering or supervising production of their Mosquito design in the USA. The Mosquito can stand beside the P-51 as being at the top of aircraft design. For choice of aerofoil, cooling drag regime and surface cleanliness and overall low drag design they are on par by their own route and path, they have almost nothing in common other than with the same engine both were approx. 30 MPH faster than a Spitfire with the same engine.
As a company de Havilland could build you an engine pre and post war, build you a metal or wooden aeroplane, they designed their own suspension for the Mosquito based on compressed rubber good enough to cope with massive overload on recon versions and also carrier landings. They manufactured propellers under license from Hamilton in USA, produced their own hydraulic and electrically actuated propellers even developed phenol-formaldehyde resins which were half the weight of aluminium for propeller blades. The notion that de Havilland could not cope with any metrology issues between USA and UK is just funny, in a very funny way. I really don't know where you get your ideas from.

Hi
The part work from the 1930s 'Aero Engineering' Volume III, has a chapter on the de Havilland Variable Pitch Airscrew which includes a schedule of fits, clearances and repair tolerances, amongst other info, this was the licence produced Hamilton type, there does not seem to be much of a problem in transferring US 'standards' to 'British' standards:

The tolerances relating to Fig. 16 are below:

Mike

 

[MikeMeech]

This is not necessarily Australian and American inches versus UK inches. Engineering drawing dimensioning and tolerancing has come a long way since WWII. Many lessons were learned. I have posted the following figure on my website in an article of Geometric Dimensioning and Tolerancing.

View attachment 648494

Try to make sense of this drawing! Assume it was prepared in England and that somebody in the USA is trying to make sense of it. Here in Canada, we had expatriate Brits running around and we could ask, but we still had problems.

Hi
According to Molson & Taylor in 'Canadian Aircraft since 1909', page 376, the Canadian built H P Hampden aircraft were identical to the British built ones. On the Lancaster it states, page 66, that:
"Interchangeability of Canadian and British components was stressed and gauges supplied; where an aircraft drawing, tool drawing and gauge were all in disagreement, the gauge was considered the master authority. Also, a new system of optical jig alignment was introduced for the first time in North America. This system, which had been developed in Britain by Taylor, Taylor & Hobson Ltd. was a great improvement on previous methods and aroused much interest, and was later used and developed still further in the United States."

The British Aviation Industry used laid down standards for tolerances as indicated in the 1943 book 'Airframe Construction and Repair' by John T Henshaw:

The 'Newall system' mentioned was still in use when I trained to be an airframe fitter in the early 70s (this was called a Bilateral system) also in use at that time was the 'British Standard System' (this was called Unilateral and Bilateral system, it had four grades of Bilateral hole K,X,Y & Z, and four grades of Unilateral hole B, U, V & W), all this is from my workshop notes.

It should be remembered that standards and interchangeability came into the British aviation industry during WW1 when aircraft started to become mass produced rather than built for an individual customer. This meant main structure and components were built on jigs, AGS parts were in use, there were standards sizes for cables for both controls and flying/landing wires and other items. Aircraft would be repaired on squadrons overnight, replacing items like wings, tailplanes, fuel tanks engines etc that were issued from the RFC 'logistics system', that could not be done if items were not inter-changeable. The 'Newall system' was also in use at that time.

Mike

 

[JDCAVE]

But can it drop it accurately? I've read other comments where the reason why the Mossies were brought into the mix with 4000 lb HE was to "mix up the situation and piss off people," LOL!

Yes. However Oboe guided Mosquito could, in theory, have done so with accuracy. However, such aircraft typically dropped target indicators, rather than bombs. The "cookie" was not particularly aerodynamic, and accurate delivery suffered as a result.

Thread creep! Wow! 43 pages on why didn't the US build Mosquitoes instead of B-17's. The correct answer is "Because they didn't." It's irrelevant. The US chose the tools they wanted to fight the battles over Europe and it didn't include the Mosquito. Basil Dickens, the head of Operational Research, Bomber Command, notes the topic had come up many times during the war. Why not Mosquitoes instead of 4-engine heavy bombers? His answer, not mine, is attached. "It was bombs on the target per casualty that really mattered, and
there is little evidence of the bombing accuracy of the Mosquitoes."

The full document is available here and is a fascinating read, even if your lips get tired.

Operational Research and Strategic Bombing

Series Description This series consists of documents covering the role of operational research and its impact on strategic bombing operations in the Second World War. One of the most most significa…

lmharchive.ca

Jim

 

[pbehn]

Hi
According to Molson & Taylor in 'Canadian Aircraft since 1909', page 376, the Canadian built H P Hampden aircraft were identical to the British built ones. On the Lancaster it states, page 66, that:
"Interchangeability of Canadian and British components was stressed and gauges supplied; where an aircraft drawing, tool drawing and gauge were all in disagreement, the gauge was considered the master authority. Also, a new system of optical jig alignment was introduced for the first time in North America. This system, which had been developed in Britain by Taylor, Taylor & Hobson Ltd. was a great improvement on previous methods and aroused much interest, and was later used and developed still further in the United States."

The British Aviation Industry used laid down standards for tolerances as indicated in the 1943 book 'Airframe Construction and Repair' by John T Henshaw:
View attachment 648857
View attachment 648858
The 'Newall system' mentioned was still in use when I trained to be an airframe fitter in the early 70s (this was called a Bilateral system) also in use at that time was the 'British Standard System' (this was called Unilateral and Bilateral system, it had four grades of Bilateral hole K,X,Y & Z, and four grades of Unilateral hole B, U, V & W), all this is from my workshop notes.

It should be remembered that standards and interchangeability came into the British aviation industry during WW1 when aircraft started to become mass produced rather than built for an individual customer. This meant main structure and components were built on jigs, AGS parts were in use, there were standards sizes for cables for both controls and flying/landing wires and other items. Aircraft would be repaired on squadrons overnight, replacing items like wings, tailplanes, fuel tanks engines etc that were issued from the RFC 'logistics system', that could not be done if items were not inter-changeable. The 'Newall system' was also in use at that time.

Mike

Firstly regarding your previous post, it doesn't surprise me at all, when you look at all the science and units that de Havilland were involved in, if they couldn't handle a simple conversion they wouldn't get past first base.

Regarding this post, I worked for years on pipes, part of that is measuring the pipe ends. In one company, in addition to other measurements they used a go-no go gauge. After many years and discussions that must have totalled days we concluded that the go- no go gauge was a fantastically fine taper gauge that could tell you which was the biggest and smallest go no-go when all other means of measurement said they were the same. Similarly it could indicate the temperature and rate of cooling of a pipe and the relative temperature differences between welding areas, inspection areas and the stockyard.

Finally I don't think there was any difference between the US survey foot and the imperial foot. The different conversion factors probably represent the difference between the national standard metre given to the USA, the national standard metre given to the UK and the actual standard metre held in Paris. The USA metre was 1.6 microns short. I presume the UK metre was also bigger or smaller than that in Paris because non of the 28 national standards distributed were exactly 1m, only the one in Paris was, this maintains the claim that the Paris standard sits above all others. The USA and UK are sovereign states, they must control things like their own weights and measures. If their standard system depended on access to a metal bar in Paris then in 1914 to 18 they could have been screwed and in 1940-45 they would have been screwed. Symbolically and wisely they stuck to what they could control in house, if Adolf had won, making a new standard system would have really tickled his ego. As previously, in the real world of science they were discussing Angstrom units from the late 1800s and before WW2 started there were the first lasers and scanning electron microscopes which made the whole thing a sort of exercise in nostalgia.

 

[wuzak]

When I went to the Brookland Museum there was a test bomb used in the development of Tallboy and Grand Slam, specifically for ballistic testing. IIRC the nominal weight was 4,000lb.

If that was made into a production bomb with a similar charge-to-weight ratio as the Tallboy (~40%) that may have been the weapon you were looking for.

The only problem is the length - I'm not sure how long exactly, but likely too long for B-17 or Mosquito. B-17 would also need bomb bay mods, or carry them externally.

The test bomb next to a Tallboy

 

[wuzak]

The primary reason to insert AP into a mix of HE and Incindiary is to plow up hardened concrete substructure with subsurface explosions. That said, I don't know how effective they could have been.

Thinking of the B-17, you could load up one side of the bay with 2 or 3 1,600lb AP and the other withe 1 x 2,000lb HE + 1 x 1,000lb HE or incendiaries.