1941: Top 3 Allied Bombers

[Shortround6]

Correct in the context of 1941 , but incorrect in a technical sense. To meet specification N.15/44 for Royal Navy use, de Havilland produced a carrier-borne variant. This resulted in 50 Sea Mosquito TR Mk 33s which featured folding wings, a thimble nose radome and fuselage hardpoints for mounting torpedoes. These were followed by 14 Sea Mosquito TR Mk 37s, which differed in having ASV Mk. XIII radar instead of the TR.33's AN/APS-6.
The Royal Navy also operated the Mosquito TT Mk 39 for target towing. A number of B.Mk XVIs bombers were converted into TT.Mk 39 target tug aircraft.

And were any of these Mosquitoes capable of dive bombing?
BTW I don't think ANY of the Mosquitoes were actually posted to the carriers despite the initial order or intent.

 

[Timppa]

One in each category:

SBD-3 Dauntless
Boston III
Short Stirling I

 

[Shortround6]

I'll rephrase that...operational bomb loads
Cheers
Steve

B-17 was basically a story in reverse. great things were expected of it from its inception in 1934, for which it could not deliver. Dogged persistence eventually got it across the line, in a vastly different form and for a completely different role for which it was originally intended. To me, there is no contest in comparing a thorouighbred like to the mossie to a near broken down hack like the B-17

Gee, a little bit of bias here or what?

The Mosquito could have ben ready for service more or less in the guise it was introduced in 1942, at least 2 years before it did

Heavy on the less side than the more, A spring 1940 Mosquito would have had Merlin X engines instead of Merlin XX series engines (Merlin 21s in the early versions) and would have been lucky to get constant speed props and not two position props. A bit of a hit to the performance as not only were the peak power ratings lower on the Merlin X but so were the max cruise and climb ratings.

Merlin X engine was good for 1075hp for take-off and 1130hp at 5,250ft and 10010hp at 17,750ft. on 87 octane fuel. Limits on climb were 2600rpm and 5 3/4lb boost and max cruise was 2600rpm and 4lb boost. 100 octane improved things(1280hp for take-off at 10lb boost) but let's remember than Blenheims were being filled with 87 octane on the inner tanks and 100 octane on the outer tanks. The 100 octane being used for take-off/climb out and emergency while the 87 octane was used for cruise ( with attendant tank switching and possiable mistakes/errors). Supply of 100 octane did get better fast during 1940.

Merlin 21 was good for the same 1280hp for take off (at 12lbs boost) and had the higher limits of 2850rpm and 9lbs for climb and 2650rpm and 7lb boost for max cruise.
Merlin 23s were cleared for 14lbs boost for take-off (1390hp) and 14lbs boost in low gear and 16lb boost in high gear (as were the Merlin 21s after a period of time).
Merlin 25s and Packard built Merlin 225s kept the same climb and cruise ratings but were cleared for 18lbs of boost for 1610/1635hp for take-off and combat ratings.
Which engines were the planes carrying 4000lb cookies using?

The Mosquito may have been a thoroughbred but it needed to fed on grain and not grass in order to get the performance it was noted for.

AS for "operational bomb loads" both the B-17 and Mosquito had rather restricted bomb bays. The often quoted figure of B-17s carrying only 4000lb to Berlin was because it was an average number. The restricted Bomb bay meant that it couldn't carry a large load of incendiaries as the incendiary bombs were rather bulky for their weight. Planes carrying incendiaries (usually the 2nd or 3rd bomb group to cross the target) often carried about 3000lbs while the planes carring HE bombs on the same raid carried 5000lbs of HE bombs. The Mosquito could carry what weight of normal incendiary bombs? (not target markers).
Yeah, lets compare best possible bomb load for the Mosquito (weigh wise) to that averaged payload of the B-17.

see: 303rd BGA Combat Missions and Reports

On Mission 60 to Schweinfurt the 303rd BG was carrying 16 250lb incendiaries in each plane.
Mission 74 each plane carried 12 1000lb bombs plus incendiaries. to Frankfurt, Germany
Mission 85 Solingen, Germany: 8x500 lb G.P. 20 M47A1 65 lb Incendiaries
Mission 113 Ausburg Germany Group A - 12 x 500 lb bombs
Mission 131 Stedorf, Germany 10 x 100 lb G.P. bombs plus 42 x M47A1 Incendiaries
Mission 155 Berlin Germany Group A - 10 x 500 lb G.P.; Group B - 42 x 65 lb
M47A1 Incendiary bombs

Please note in the last mission that the group B was only carrying 2730lbs of "bombs", but not due to weight problems.

The B-17 had nowhere near the flexibility of bomb load the Lancaster or some of the other British heavy bombers but the Mosquito, as good as it was, was not a miracle airplane that could actually carry many of the loads normally carried by B-17s, in fact it could often only carry 1/2 to 1/3 of the loads internally even if the racks would allow it.

 

[stona]

If you take every fifth mission and average the bomb loads you will find that the average bomb load is between 5,000lbs and 6,000lbs.

This is what I meant by operational bomb load.

A slightly modified Lancaster could carry a 22,000lb Grand Slam bomb, but I'd hardly call that the operational load of the type.

I'm not suggesting that the two engine Mosquito could carry as much as the B-17, which was anyway hamstrung by the weight of its defensive armour and armament, but it could and did carry 4,000lbs operationally and regularly (not in 1941) and that is not so far behind a typical operational load for the B-17.

Cheers

Steve

 

[Shortround6]

It did by carrying a special single 4,000lb bomb. It's flexibility was even more limited than the B-17s. If the Mission requirement was for large quantities of incendiaries it might take 4 Mosquitoes to carry the same load as a single B-17.
Without the 4,000lb cookie the Mosquito drops to 2,000lbs pretty quickly (or 3,000lbs with under-wing bombs).
Want to try to put 8 250lb incendiaries in a Mosquito? 1/2 the load the B-17 carried. How about 4 500lb bombs (easy) plus 10 65lb incendiaries? oops, two Mosquitos could carry the eight 500lb bombs but you need a third with appropriate bomb racks to carry the 20 incendiary bombs.

On the other hand if you need a 4000lb blast bomb the B-17 is no good, the only way it can carry one is outside. Not bad if the target is in coastal France but otherwise it pretty much a no-go.

The B-17 had trouble carrying the quantities and types of incendiaries wanted for some targets. The B-17 is often over rated by claiming it carry 12,800lbs inside, it could but the load was pretty useless, eight 1600lb AP bombs that each carried only bit less explosive than a 500lb GP bomb. Something like under 300 of these bombs were dropped in Europe during the war but many US aircraft have their max bomb load calculated by using them (P-61 could carry 4).

Plan fact is the Mosquito could not replace the B-17 on a one for one basis and could not do it on a 2 for one basis either using many common bomb loads due to the volume the bombs took up, not the weight.

Going by weight alone disregards the limits the bomb bays put on various aircraft in regards to flexibility. British sort of had the same problem with some of their bombers in reverse. Lots of little bomb bays/bomb/cells out in the wings that could hold 250lb bombs but once they decided they wanted heavier bombs the bays/cells became so much wasted space. Too small to put the equivalent weight of 500lb bombs in and because the bomb doors were often held shut by rubber bungee cords lighter bombs or small bomb carriers could not be used in those positions.

See: Aerial Bombs

for bombs used (which changed with time) and recommendations as to which type to use on which targets (without after the war studies.)

 

[stona]

I wouldn't want to replace my B-17s with Mosquitos. They served entirely different purposes.

The B-17 loads seem to have reduced as they carried more incendiaries, which is hardly surprising. Incendiaries are essential for area raids on cities (whatever euphemisms the USAAF and RAF might have used to describe them) and would eventually comprise 15% of the total weight of ordnance dropped by the 8th AF's bombers during the war. The figure is 21% for Bomber Command, but you can get a lot more of the relatively light and bulky incendiaries, packed in their SBC's, into the cavernous bomb bay of a Lancaster.

Cheers

Steve

 

[wuzak]

It did by carrying a special single 4,000lb bomb. It's flexibility was even more limited than the B-17s. If the Mission requirement was for large quantities of incendiaries it might take 4 Mosquitoes to carry the same load as a single B-17.
Without the 4,000lb cookie the Mosquito drops to 2,000lbs pretty quickly (or 3,000lbs with under-wing bombs).
Want to try to put 8 250lb incendiaries in a Mosquito? 1/2 the load the B-17 carried. How about 4 500lb bombs (easy) plus 10 65lb incendiaries? oops, two Mosquitos could carry the eight 500lb bombs but you need a third with appropriate bomb racks to carry the 20 incendiary bombs.

On the other hand if you need a 4000lb blast bomb the B-17 is no good, the only way it can carry one is outside. Not bad if the target is in coastal France but otherwise it pretty much a no-go.

The B-17 had trouble carrying the quantities and types of incendiaries wanted for some targets. The B-17 is often over rated by claiming it carry 12,800lbs inside, it could but the load was pretty useless, eight 1600lb AP bombs that each carried only bit less explosive than a 500lb GP bomb. Something like under 300 of these bombs were dropped in Europe during the war but many US aircraft have their max bomb load calculated by using them (P-61 could carry 4).

Plan fact is the Mosquito could not replace the B-17 on a one for one basis and could not do it on a 2 for one basis either using many common bomb loads due to the volume the bombs took up, not the weight.

Going by weight alone disregards the limits the bomb bays put on various aircraft in regards to flexibility. British sort of had the same problem with some of their bombers in reverse. Lots of little bomb bays/bomb/cells out in the wings that could hold 250lb bombs but once they decided they wanted heavier bombs the bays/cells became so much wasted space. Too small to put the equivalent weight of 500lb bombs in and because the bomb doors were often held shut by rubber bungee cords lighter bombs or small bomb carriers could not be used in those positions.

See: Aerial Bombs

for bombs used (which changed with time) and recommendations as to which type to use on which targets (without after the war studies.)

The maximum bomb load for a Mosquito B.XVI was 5000lb - 1 x 4000lb + 2 x 500lb.

After the bulged bomb bay came into effect the Air Ministry wanted to find other was to use the space. One solution was a modified Wellington rack. This could carry 8 x 500lb MC bombs in the Mosquito bomb bay, but for CoG reasons de Havillands recommended against it. The AM's response was to ask if 4 x 500lb and 4 x 250lb but I have no record of a response.

There is alos the "Avro 6 store carrier" of which there are many references but little evidence. This would have enabled 6 x 500lb bombs internally plus the two externally.

The Mosquito could certainly carry the 400lb and 500lb incendiary bombs, which were similar in size to the 500lb MC bomb. They coudl also carry a pair of 160lb/250lb Small Bomb Containers which had the smaller incendiaries. Not sure on the mid sized IBs.

 

[Shortround6]

The maximum bomb load for a Mosquito B.XVI was 5000lb - 1 x 4000lb + 2 x 500lb.

And the prototype Mosquito B.XVI first flew in Jan of 1944. about 6-7 months after the last major change to the B-17 started production.

There is alos the "Avro 6 store carrier" of which there are many references but little evidence. This would have enabled 6 x 500lb bombs internally plus the two externally.

The Mosquito could certainly carry the 400lb and 500lb incendiary bombs, which were similar in size to the 500lb MC bomb. They coudl also carry a pair of 160lb/250lb Small Bomb Containers which had the smaller incendiaries. Not sure on the mid sized IBs.

I never doubted the ability of the Mosquito to carry 500lb incendiary bombs, trouble is without the near mythical "Avro 6 store carrier" (pictures in another thread?) the Mosquito is limited to 4 such "stores" inside the plane. Perhaps two more could be carried underwing with without two much penalty. B-17s made at least one run to Berlin carrying five 500lb M17 incendiaries +three 1000lb GP bombs per plane. Mission no 146 of which the 303rd was a small part. "A total of 610 B-17s and 12 Combat Wings were dispatched against Berlin. 514 attacked the primary, dropping 800 tons of 1,000-lb. M-44 General Purpose and 443.5 tons of M-17 Incendiary clusters by PFF methods with unobserved results."

Now to equal the bomb tonnage dropped by the B-17s on this raid you would need 800 Mosquitoes carrying two 1000lb apiece inside and a pair of 500lb M-17 Incendiary clusters under wing with an additional 162 Mosquitoes carrying six 500lb M-17 Incendiary clusters each.

This is a 500lb M-17 incendiary cluster so your speed, mileage and bomb stowage may vary from "normal" 500lb bombs.

 

[wuzak]

Now to equal the bomb tonnage dropped by the B-17s on this raid you would need 800 Mosquitoes carrying two 1000lb apiece inside and a pair of 500lb M-17 Incendiary clusters under wing with an additional 162 Mosquitoes carrying six 500lb M-17 Incendiary clusters each.

This is the crux of the matter.

The goal is not to carry as many bombs to target as the B-17s did. The goal is to drop as many bombs on the target. Depending on tactics, that may require fewer Mosquitoes.

Then again, raids with large incendiary mixes tended to be more area raids. Something for which the Mosquito was not suited.

In any case, the Mosquito does not, in my mind, qualify as a 1941 bomber.

 

[bobbysocks]

from what little i have read about it the boston/havoc was a decent bomber. maybe not a world beater but sufficient for the time....and until something better could come along.

 

[parsifal]

B-17s were what they were.....a heavy bomber operating at high altitude plastering bombs on a city in order to flatten that city. RAF used them to a limited extent for spoofing and LR ASW work. Point is, arguing that the B-17 was more flexible than a mosquito because it had the greater choice of bombs has to be one of the most misplaced arguments Ive ever seen in this place.

Mosquito was a far more flexible aircraft than the B-17 could ever hope to be. Lets list some of its capabilities

Low level strike...tick
High level strike...tick
Medium level strike...tick
Rocket and cannon armed ground attack...tick
Close support...tick
Anti shipping...tick
High speed recon...tick
Anti submarine...tick
ship borne strike...potential
transport...tick
target tug...tick
fighter...tick
night fighter...tick
night intruder...tick
precision (well as good as the technology of the time would allow) bomber......tick


It did all of these with reasonable proficiency

B17s were designed as an anti-shipping weapon, but failed pretty miserably. They failed at ground support, failed at anything involving bombing other than flattening cities at a high altitude, as others have pointed out, were restricted in payload compared to other kindred aircraft.

Using the same list as above, what were the B-17s capabilities?

Low level strike...very poor
High level strike...tick (more than that really...it was outstanding in this role)
Medium level strike...passable
Rocket and cannon armed ground attack...nope
Close support...fail
Anti shipping...fail
High speed recon...nope
Anti submarine...tick
ship borne strike...no potential
transport...tick
target tug...tick
fighter...nope
night fighter...nope
night intruder...nope
precision (well as good as the technology of the time would allow) bomber......arguable, but I would say no

In case its not speaking clearly enough, I totally reject the contention that the B-17 was a more flexible, or even a more useful aircraft than the Mosquito. you have got to be kidding

 

[Vincenzo]

I did some search for a list
allied 1941 bombers 2 engines or more, only operational (corrections and add welcomed)
Whitley
Manchester
Fortress
Beaufort
Blenheim
Boston
Halifax
Hampden
Hudson
Maryland
Stirling
Wellington
Ju 86
Potez 633
Do 17
S.M. 79
Yak-2
Yak-4
SB
Ar-2
Pe-2
DB-3
Il-4
Yer-2
TB-3
Pe-8
A-20
B-17
B-18
B-23
(B-25 not sure)
(B-26 not sure)
Martin 139

 

[nuuumannn]

De Havilland were saying for two years before they did that they could build a war winner, but were constantly denied permission. They eventually received some support from a few very courageous officers in the RAF, and from there were able to force the issue by the sheer brilliance of the design.

Parsifal, whilst a likely story that the myth of the Mossie has hinged on for many years, it's not strictly true. The concept of the unarmed high speed bomber had been discussed in the Air Ministry before de Havilland first proposed their idea and it was agreed on favourably by Ludlow-Hewitt and Liptrot after Volkert of HP had released his 1937 paper on unarmed bombers - Liptrot even producing his own views that were designed to rock the establishment a little. de Havilland toyed around with ideas based on P.13/36 and agreed to the unarmed bomber idea of two crew and wooden construction after they themselves were not happy with any of their own ideas about an Albatross derivative. The Air Ministry was less than enthusiastic about this as well. The problem for GdeH was that the power operated gun turret dominated defence arguments for bombers and B.12/36 and P.13/36 and subsequent aircraft were to be fitted with them. Britain led the world in turret development at this stage and turrets were seen as the best defence for bombers. Boulton Paul played a big part in this with their A Mk.I turret for the Defiant; developed by de Boysson with SAMMS in France, it was more advanced that current British ideas - bearing in mind BP were the first to put a power operated turret into a bomber. Ludlow Hewitt stated as much that the RAF needed a 'Speed Bomber', not an unarmed bomber.

When GdeH proposed their high speed bomber no one believed his figures; this is where the reluctance to accept it came from, not the fact that it was made of wood or even unarmed. VCAS Sholto Douglas went so far as to propose that it be fitted with a turret, which was actually going to be the production variant and the high speed unarmed aircraft was to be a technology demonstrator and Freeman urged that this unarmed one go ahead as well. Nevertheless, Ludlow-Hewitt was opposed to the Mosquito because of the unarmed aspect of it, but Tedder actually showed his support after early misgivings. Thankfully, owning largely to Freeman, the turret Mosquito as dropped and never built, specifically when Bishop and Walker produced figures that stated performance would drop considerably. The turret idea was re-examined for a night fighter spec re-written in December 1940 calling for a twin engined night fighter with a turret, but GdeH stated it was a dumb idea fitting a turret to the Mosquito. A mock up was fitted to W4050.

The Mossie came to life when Liptrot offered a night fighter requirement to de Haviiland for the design and a reconnaissance version and it was a production order for a fighter variant in July 1940 that kept the project alive. it's also worth remembering that simultaneous to the Mosquito development there was Blackburn's B.28, which was designed as a high speed bomber, initially unarmed, but with the intention of fitting a turret if need be, but from the start, the B.28's multi role aspects were emphasised - a heavy fighter and reconnaissance aircraft as well as a bomber. Bristol had also proposed a fast bomber version of the Beaufighter, which was attracting interest, but was not continued with as Bristol concentrated on the likes of the Beaumont and Buckingham development. Ironically, the Mossie did what the Buckingham was designed to do, but better.

Even by the end of December 1940, the Mosquito prototype had demonstrated its high speed to higher ups in the air staff and they were suitably impressed, but that production was to concentrate on recon and fighter variants first, then bombers. This explains the delay in getting bomber Mosquitoes into service, not a reluctance to accept it. The bomber prototype was initially one of the first batch of recon aircraft built. You also have to remember the Mosquito prototype was hand built and getting it into production took much working out. Trials at high speed revealed issues like excessive vibration when the bomb doors were opened and other snags that needed solving before the bombers could go into production.

 

[nuuumannn]

Another thing worth remembering about the Air Staff's attitude toward de Havilland is that by 1938 when the firm was first offering the idea, the company had never built a front line combat aircraft that had entered RAF service (The Airco DH.2,4,9 and 9A and 10 etc were not built by de Havilland, the firm did not exist until 1921/22, these aircraft were designed by GdeH whilst working for Airco), only derivatives of wooden airliners converted into bombers, lots of training aircraft and civilian light machines of wooden construction. You can hardly blame the Air Ministry for not accepting their ideas since the firm's engineers had no experience in such things, particularly not all-metal aircraft, of which the Flamingo was the only sizeable metal machine they had built. This is partialy what makes the achievement of the Mosquito so remarkable.

 

[Shortround6]

B-17s were what they were.....a heavy bomber operating at high altitude plastering bombs on a city in order to flatten that city. RAF used them to a limited extent for spoofing and LR ASW work. Point is, arguing that the B-17 was more flexible than a mosquito because it had the greater choice of bombs has to be one of the most misplaced arguments Ive ever seen in this place.

Mosquito was a far more flexible aircraft than the B-17 could ever hope to be. Lets list some of its capabilities


In case its not speaking clearly enough, I totally reject the contention that the B-17 was a more flexible, or even a more useful aircraft than the Mosquito. you have got to be kidding

Boy, somebody go their knickers in a twist.

Please show me the post where I claimed the B-17 was a more flexible aircraft overall?

What started this was Wusaks post #11
in part " The Mosquito was, arguably, without peer in its category/class of bomber - light to medium bomber."

and Stona's post #14 "What does that make the B-17 then, in terms of bomb load?"

My Post # 17 in part "It would be quite some time before the Mosquito, extraordinary aircraft that it was, would come close to challenging the B-17 for bomb load carried"

Stona's post #19 "I'll rephrase that...operational bomb loads'

and so on with a discussion about the bombloads carried by the two aircraft.

Nobody but you brought up the other roles, although I replied. SO to you go the honors of bringing up "one of most misplaced arguments Ive ever seen in this place."

I will freely admit/agree that the Mosquito was a much more versatile aircraft overall because I never said it wasn't.

But the Idea/myth that the Mosquito could carry the same bomb load to targets in Europe needs a good going over.

 

[nuuumannn]

"one of most misplaced arguments Ive ever seen in this place."

Here's another, said with tongue firmly planted in cheek - in my experience, that's a pretty big call, SR!

Three of the best, Wellington, Whitley and B-17 in no particular order, although honourable mention goes to the Maryland and Manchester. I can hear y'all say Wha?! And I guess with hindsight its easy to make the case by mentioning the Lancaster, but all the ingredients were already there in the Manchester to make the Lanc work before the Merlins were put in place and Chadwick was already working on a four engined Manchester when the first prototype was being built. The Manchester was a very advanced aeroplane with modern electrical systems, which proved troublesome (British electrics!). There were stability issues with the small fins and the awkward top turret, which caused vibration when rotated, but that was replaced and changes to the Manchester Mk.III (named Lancaster) in the size of fin led to the Manchester Mk.IA, the definitive variant before the Mk.III took precedent in production. Obviously, the engine issues were dogged and were seriously restricting and I don't wish to gloss over the troubles it suffered, the Manchester did have good performance/load carrying capability for a bomber of its day, although the early Forts trump just about everything else (with the exception of the Ju 88 in speed) for speed/range/height at the time.

 

[wuzak]

Interesting thought: Part of teh Manchester's problem was that the Vultures had to be de-rated in service, which reduced the ceiling at which they could operate. Would they have worked better with turbos - possibly a pair of B-series turbos or a single C-series would have been needed. Thus the engines would given ~1,800hp to over 20,000ft - a substantial gain over the OTL Vultures. Obviosuly it would have increased empty weight, requiring a reduction in bomb and/or fuel load.

The other issue was that at the time the turbos weren't exactly plentiful, certainly not for foreign powers.

 

[nuuumannn]

I think the problems with the short casing bolts was the most serious issue though, also the mating faces between the casing halves didn't line up and because of the short bolts fracturing under load, the casings ripped apart and the flailing interiors tore the entire engine to bits. Once these issues had been solved, the Vulture proved a good engine under test and the Vulture V in the Tornado didn't have the same issues, but Rolls ended production because there was little need for the engine, whereas concentrating on the Merlin and Griffon was more productive since more aircraft operated them. Still, fitting four Merlins was a better option than continuing with the Vulture, regardless of how much better it became after modification. It would be interesting to hypothesise what might have been had Chadwick opted to drop the Vulture engined Avro 679 and go stratight for a Merlin engined Manchester from the start as Handley Page did with the HP.56 powered by two Vultures that was not built, and went for the HP.57 Halifax. Volkert chose this route in 1937 because he had heard that there might be shortages of Vultures further down the line.

 

[stona]

The Manchester should be on the list. It flew its last mission on 25th/26th June 1942. By this date the Lancaster was already being delivered in numbers, and crews being converted. It had proven a more than capable, if unintentional, 'stop gap'.

Francis Mason has written:

"It was not on account of any failure of the Manchester, or of its Vulture engines, that the Lancaster came into being. If an error of judgement occurred it lay in not pursuing the four engine bomber from the outset."

I couldn't put it better myself. The British, unlike their German counterparts, made a relatively easy recovery from this 'error of judgement' because the Manchester was essentially a very good aeroplane to start with, unlike its German counterpart (the He 177).

Cheers

Steve

 

[tomo pauk]

Main issue both for Manchester and He-177 was the engine choice. Claiming that one was essentially a very good aeroplane, while the other is not is way off the reality.
The British, ie. Avro, have had, on the other hand, a common sense to admit to themselves that the powerplant chosen is really a self-inflicted wound, and that emerging 4 engined bombers both from UK and USA are better suited for strategic job. Going for 4 Merlins meant an increase of power available, along with better odds with engine-out situation.
The second Mason's sentence is also true for the He-177:

....If an error of judgement occurred it lay in not pursuing the four engine bomber from the outset